chock fasting technology book

KAROL GRUDZIŃSKI, WIESŁAW JAROSZEWICZ

SZCZECIN 2004

SEATING OF MACHINES AND DEVICES ON FOUNDATION CHOCKS CAST OF EPY RESIN

COMPOUND

Karol Grudziński, Wiesław JaroszewiczSeating of machines and devices on foundation chocks cast of EPY resin compound

This book presents a modern method for the seating of marine and land-based machines and devices on chocks cast of EPY resin compound specially developed for this purpose.General requirements referring to the seating of machinery on foundations (especially those used in shipbuilding) are listed, together with relevant evaluation criteria. The properties of resin compounds used for foundation chocks, the background of chocking arrangement design and the techniques used for casting the chocks in place are also outlined. Many examples of so installed machines and devices are described, illustrating various possibile applications of EPY compound to the seating of new machinery and the repairs of existing one. The results and descriptions of research aimed at fi nding solutions for many practical problems in this fi eld, constituting a scientifi c basis of the methods developed for the seating of machines on their foundations, are also given.The book is addressed to designers and shipbuilding technology specialists as well as the engineers and technicians dealing with the design, modernisation and execution of various heavy machinery installations on land. It may also be of use for the scientifi c workers and students at higher technical schools in the faculties engaged in the fi elds of shipbuilding and off shore technology, machinery design and maintenance, industrial constructions and the building of roads and bridges.

Translation into English: Przemysław Abramowski, Magdalena Abramowska

Verifi ed by Przemysław Wierzchowski

Linguistic editing: Katarzyna Mitan

Cover design: Arkadiusz Wancerz

Pictures in fi gures: 2.1, 2.2a, 5.12a, 5.25, 5.27 and pages 10 and 54 have been taken by Marek Czasnojć

© Copyright by Marine Service Jaroszewicz, Szczecin 2004

ISBN 83-89260-67-0

Publisher: ZAPOL Spółka Jawna, al. Piastów 42, 71-062 Szczecin, tel./fax (091) 4341021.Edition I. Impression 200+30 copies.Typesetting and print: Printing house “Drukarnia ZAPOL Spółka Jawna”

CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1. Characteristics and types of chocking arrangements used for ship machinery . . . . . . . 11

1.1. Basic tasks and requirements related to chocking of ship machinery . . . . . . . . . 11

1.2. Chocking the machinery on metal chocks . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.3. Chocking the machinery on fl exible chocks . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.4. Chocking the machinery on cast resin compound chocks . . . . . . . . . . . . . . . . 14

1.5. Characteristics of seating arrangements based on metal chocks and cast resin compound chocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2. The resin compounds used for ship machinery foundation chocks . . . . . . . . . . . . . . . 19

2.1. General requirements referring to resin compounds used for foundation chocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.2. Development of Polish chocking compounds and the machinery seating technology used for machinery installations . . . . . . . . . . . . . . . . . . . . . . . . . 22

3. Design of machinery chocking arrangements with EPY compound chocks . . . . . . . . . 33

3.1. Documentation of a seating arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . 33

3.2. General guidelines for the design of seating arrangements . . . . . . . . . . . . . . . 33

3.3. Design calculations of installations with EPY compound chocks . . . . . . . . . . . . 35

3.3.1. Calculations of a minimum required area of chock load-bearing surface . . . 36

3.3.2. Calculations of an axial force in the tensioned holding down bolt . . . . . . 36

3.3.3. Calculations of a tightening torque on nuts of holding down bolts . . . . . 37

3.3.4. Calculations of a pressure in the hydraulic bolt stretcher device . . . . . . . 37

3.3.5. Calculations of a bolt elongation caused by pre-tension setting . . . . . . . 37

3.3.6. Calculations of reduced stress or equivalent tensile stress related to the minimum cross-section area of holding down bolt, accounting for pre-tension setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3.3.7. Calculations of tensile stress related to the holding bolt thread root cross-section area, accounting for pre-tension . . . . . . . . . . . . . . . . . . . 38

3.4. Exemplary design calculations of chocking arrangements . . . . . . . . . . . . . . . 38

4. The technology of machinery seating on EPY compound chocks . . . . . . . . . . . . . . . 45

5. Applications of EPY compound chocks for the seating of machinery — practical examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.1. General remarks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

5.2. Statistical data on the use of Polish resin compounds in practice . . . . . . . . . . . 55

5.3. Examples of the seating of shipboard machinery . . . . . . . . . . . . . . . . . . . . . . 57

5.3.1. Main propulsion engines and gears . . . . . . . . . . . . . . . . . . . . . . . . . . 57

5.3.2. Stern tubes, liners of shaft line bearings and rudder arrangment liners . . . . 61

5.3.3. Deck machinery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

4 Contents

5.4. Examples of the seating of land-based machinery . . . . . . . . . . . . . . . . . . . . . 68

5.4.1. Application of EPY chocking compound for the seating of GMVH-12 engine-powered compressors and the repair of their foundations . . . . . 68

5.4.2. Application of EPY compound for the seating of mining machinery . . . . . . 71

5.4.3. Application of EPY compound for the seating of large-size roller bearings in excavators and dumping conveyors . . . . . . . . . . . . . . . . . . . . . . . . 74

5.4.4. Application of EPY compound for the seating of power industry machinery, rails and bridge span bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

6. Research on resin compounds used for foundation chocks . . . . . . . . . . . . . . . . . . . . 83

6.1. General requirements regarding resin compounds used for machinery foundation chocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

6.2. General remarks about research on chocking compounds . . . . . . . . . . . . . . . . 84

6.3. Research on infl uence of various substances and temperature on EPY compound compression strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

6.4. Research on EPY compound fatigue strength under compression loads . . . . . . . 88

6.5. Research on creep process and heat defl ection temperature of EPY compound . . . 89

6.6. Research on the dynamic properties of EPY compound . . . . . . . . . . . . . . . . . . 92

6.6.1. Determination of logarithmic vibration damping decrement and dynamic shear modulus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

6.6.2. Determination of the energy loss factor and dynamic elasticity modulus under compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

6.6.3. Determination of acoustic impedance . . . . . . . . . . . . . . . . . . . . . . . . 100

6.7. Comparative research on static and dynamic properties of three various resin compounds used for foundation chocks of machines and devices . . . . . . . . . . . 102

6.8. Research on fl at butt joints of direct contact and with a thin layer of EPY compound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

6.8.1. Butt joints under normal force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

6.8.2. Butt joints under constant normal force and variable tangential force . . . . 112

6.9. Research on models of holding down bolts fi t in the compound . . . . . . . . . . . . . 112

6.10. Research on optimum application of EPY compound for the seating of deck machinery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

6.10.1. Theoretical analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

6.10.2. Tests on a windlass foundation chock model . . . . . . . . . . . . . . . . . . . . 120

6.10.3. Research fi ndings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

6.11. Research on infl uence of paint coatings on the settling of shipboard machinery seated on cast resin compound chocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

6.11.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

6.11.2. Tested specimens and test bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

6.11.3. Research program, its execution and example results . . . . . . . . . . . . . . 122

6.11.4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

6.12. Analysis of construction and model tests of stern tubes installed with the use of chocking compound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

5Contents

6.12.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6.12.2. Aims of resarch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6.12.3. Analysis of thermal insulation properties of a construction containing an EPY compound layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

6.12.4. Analysis of thermal deformations . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6.12.5. Model tests of the assembling of a propeller shaft stern tube . . . . . . . . . 131

6.12.6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

6.12.7. Epilogue . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

6.13. Research on possible use of the microwaves for additional curing of EPY compound and foundation chocks cast of this compound . . . . . . . . . . . . . . . . 137

6.13.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

6.13.2. Tests on EPY compound specimens . . . . . . . . . . . . . . . . . . . . . . . . . . 138

6.13.3. Tests on models of foundation chocks . . . . . . . . . . . . . . . . . . . . . . . . 140

6.13.4. Some more important conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 143

6.14. Strength tests on holding down bolts anchored in concrete with the use of EPY compound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

6.15. Research on the infl uence of constant humid heat on dielectric properties of EPY compound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

6.16. Research on the infl uence of liquid nitrogen cooling on EPY compound compression and impact strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

6.17. Determination of the states of stress and strain in bolt joints with chocks made of EPY compound and steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

6.17.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

6.17.2. Model of a foundation bolt joint . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

6.17.3. Determination of the assembling — induced states of stress and strain . . . . 153

6.17.4. Determination of the holding — down bolt service states of stress and strain and its service load characteristics . . . . . . . . . . . . . . . . . . . . . . 155

6.17.5. IInfl uence of temperature changes on the assembling — induced state of stress and strain in a bolt joint with resin compound chock . . . . . . . . . 160

6.17.6. Summary and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

The chronological list of research reports concerning Polish resin compounds used for foundation chocks, and their practical application for the seating of machinery . . . . . . . . 171

INTRODUCTION

This book outlines a modern method for the seating of various shipboard and land-based machinery, with the use of chemically curing chocking resin compounds specially developed for this purpose. It also presents the history of such compounds’ development in Poland, and the modern machinery seating technology based on these compounds. The results of thirty — year research and development work in this fi eld are included as well.

Polish chocking resin compounds and the machinery seating technology based on these compounds are a result of scientific research which have been conducted systematically since the early 1970s.

The research was carried out fi rst by the Technical Mechanics Section, and then, since 1982, by the Chair of Mechanics and Machine Elements of the Technical University of Szczecin, in close co-operation with the domestic shipbuilding industry and industrial research centres in Gdańsk — CTO (Centrum Techniki Okrętowej, Ship Design And Research Centre) and CTW PROMOR (Centrum Techniki Wytwarzania, Manufacturing Research Centre), and also with service teams of various companies, specialised in machinery seating. Licence agreements concluded with the Technical University of Szczecin were the basis for this co-operation.

In 1990 the Machinery Installation Service Team, earlier (since 1982) operating as a part of Foreign Enterprise KITI in Warsaw, was transformed into an independent company Marine Service Jaroszewicz (MSJ, sited in Szczecin), which produces the resin compounds and conducts the seating of machinery, based on their use. The company maintains and further develops its co-operation with the Chair of Mechanics and Machine Elements of the Technical University of Szczecin, actively participating in the research process.

The resin compound named EPY (shortly called: “EPY compound”) and produced by MSJ company is an improved version developed from preceding compounds, which is able to match any competing product in the world in any respect. It has obtained the certifi cates of all worldwide classifi cation societies supervising the building and repairs of seagoing vessels, and the certifi cates of the manufacturers of main engines as well as auxiliary machinery installed onboard ships.

MSJ company is also granted the ISO 9002 Quality Certifi cate (issued by Germanischer Lloyd in 1994), confi rming a high level of quality in technical and organisational solutions used by the company. It is also certainly worth mentioning that only three such products in the world possess all the certifi cates required for the seating of main engines and gears onboard ships: Chockfast Orange (USA), Epocast 36 (Germany), and the compound EPY made in Poland.

Introduction8

Thanks to many technical and economic benefi ts brought by this new machine seating technology to shipbuilding industry and stretching across all service life of the machines, this technology is also used more and more often for the seating of various crutial, heavy machinery installed on land. The EPY compound and the technology of its use for the seating of machinery have also won approval certifi cates from the following Polish institutions: Building Research Institute (Instytut Techniki Budowlanej), Road and Bridge Research Institute (Instytut Badawczy Dróg i Mostów) and the President of the State Mining Authority (Wyższy Urząd Górniczy).

This book results from many years of close co-operation between the Chair of Mechanics and Machine Elements and the Marine Service Jaroszewicz company. The need to write it stemmed from the authors’ feeling that it is their duty to bring together in a structured form the results of their thirty-year research work and its eff ects — both scientifi c and practical.

The detailed list of scientifi c research projects realised by the Technical University of Szczecin (published and not published), which were focused on the resin compound and its use for machinery seating, is included at the end of the book.

Since the fi rst installation of machinery with the use of Polish chocking compounds took place in 1974 aboard a seagoing vessel, the total number of installations reached 7199 by the end of 2001, which included 1500 ship main engines and 1083 various land-based machines, such as turbines, engine-powered compressors, hoisting machines used in mining, fans, large bearings of brown coal excavators, bridge span bearings and other types of machinery.

Thanks to the results of professional research in this fi eld many original, innovative, fi rst-in-the-world solutions have been introduced and successfully tested in practice, winning broad recognition and yielding signifi cant technical and economic benefi ts which extend throughout the service life of machines.

The ever-increasing needs of designers, engineers and technology specialists in shipbuilding and off shore engineering were another important motivation for the writing of this book, as the cast-compound chocking technology became a standard for main propulsion engines as well as various auxiliary equipment.

This motivation was also supported by the fact that the new machinery chocking technology began to draw a proliferating interest from engineers of other industry branches, who want to learn about the possibilities for its practical use in various particular cases and situations.

Therefore, the book is addressed not only to designers and engineers of the shipbuilding industry, but also to a broad group of other prospective readers dealing with design, installation and operation of various machines.

This is due to the fact that the technique used for any installation has a signifi cant impact on the time and cost of this operation, achieved fi nal quality and the durability

9Introduction

of installed machines (including the machines mechanically coupled with them), as well as the parameters of vibration isolation and damping, which are all important issues in many branches of engineering.

Taking into account the broad range of readers (including scientific workers and students of technical universities), the layout of the book has been arranged in a way facilitating easy fi nding of a searched topic, or a solution for a particular seating problem.

The book also outlines the general requirements for effective machinery seating and the relevant evaluation criteria. Kinds and characteristics of traditional seating methods using steel chocks are given as well, and a comparative analysis is carried out, confronting the traditional technology and the modern one based on chocks made of resin compounds cast in place.

The properties of resin compounds used for machinery seating are discussed as well, together with the background of chocking system design, and the methods for chock casting in place. Numerous examples included in the book illustrate various possible applications of chocking compounds to the seating of new machinery as well as the repairs and modernisations of existing one.

The descriptions and results of numerical calculations and experimental research (aimed at solving many practical issues) provide a deeper insight into various problems involved in the seating of machinery and the application of resin compounds as a possible solution to these problems in many fi elds of engineering.

They also constitute an important scientifi c basis and a source of data, which can be used for new applications and further research on the improvement of the properties of resin compounds, as well as the methods of their use for the seatring of machinery.

The authors of this book would like to thank all the employees of the Chair of Mechanics and Machine Elements and the Marine Service Jaroszewicz company who actively participated in the research work and the implementation of the new technology, as well as the authors of other materials used for the writing of the book.

Deep thanks are also given to many workers of Polish shipyards and other industries and research&development centres and installation teams, associated with them, who contributed immensely by their inspiration and help in the process of implementation of the new technology, providing many invaluable hints during long, fruitful discussions stimulating a successful development of cast resin compounds and their use for the machinery seating in Poland.

The authors of the book are aware that it is imperfect and that various glitches may be found in it. They will certainly be gracious to the readers who convey their remarks concerning its content and layout. They are also ready to discuss, advise and help in any matters related to the subject of the book.

1. CHARACTERISTICS AND TYPES OF CHOCKING ARRANGEMENTS USED FOR SHIP MACHINERY

1.1. Basic tasks and requirements related to chocking of ship machinery

The seating of a machine consists in obtaining its precise alignment in a specifi ed position, and then fi xing it securely to foundation in such a way that it is able to fulfi l its functions within the assumed service period. This operation must be carried out in accordance with the rules of classifi cation institutions [1] and the requirements of machine manufacturers.

Ship machinery is not installed directly on the supporting surfaces of foundations, but on appropriate intermediate elements, i.e. foundation chocks (Fig. 1.1). This is due to the fact that large supporting surfaces of foundations and machine bodies are diffi cult to match in contact exactly, but also to the often arising need to have the connected machines aligned with high precision.

Introduction of foundation chocks leads to a replacement of a continuous support surface with a “discrete” support at a fi nite number of support points. In case the number of points is larger than three, the whole arrangement becomes statically indeterminate. It becomes diffi cult then to determine the forces acting between the machine and its foundation in the support points. For shipboard machinery the minimum number of foundation chocks is usually four, but it often may be over a dozen, with main engines having as many as a few dozens of support points.

Comprehensive evaluation of a seating technology for ship machinery requires that both technical and economic factors are taken into account. The fundamental task is to correctly place the machines in space in relation to co-operating objects, while providing reliable fi xing which should guarantee their safe operation. It is assumed that the unreliability of the seating cannot lead to additional overhauls of any machine throughout its service life onboard.

The evaluation of technical and economic aspects of a seating arrangement should include:

— Diffi culty of the installation and uninstallation procedure,— Labour costs and costs of materials,— Time of operation and the quality of chock fi tting,— Stress state present after the installation.

The following factors are important in service:— reliability and durability of a seating arrangement,— number and type of required maintenance operations — good isolation of mechanical vibration and structural sound.

1. Characteristics and types of chocking arrangements used for ship machinery12

Fig. 1.1. The layout of a main engine seating arrangement

1.2. Chocking the machinery on metal chocks

Metal chocks made of steel or cast iron, with their characteristic high rigidity, have been traditionally used in shipbuilding (Fig. 1.2a), and the seating arrangements using them are called rigid. The load should be evenly distributed among all chocks (Fig. 1.1), which is obtained by their appropriate placing and fi tting.

Resulting from high rigidity of metal chocks, little inaccuracies in their fi tting may lead to a highly uneven loading of foundations, holding down bolts and the bodies of machines. As this phenomenon in highly detrimental, demanding requirements have been introduced with regard to the precise fi tting of the chocks during the installation of ship machinery [2].

It is especially true in case of main propulsion engines, gears and shaftline bearings. Fitting the chocks in a way fulfi lling the requirements is a diffi cult, labour-consuming and expensive task which includes the need for machining the supporting surfaces of the foundation on board, machining the chocks themselves, and laborious, individual hand-fi tting them during installation. Moreover, metal chocks are conducive to transmission of vibration and structural sound.

Special designs of compensation chocks/shims [3] (Fig. 1.2b, c, d) have been developed for foundation installations as a result of a search for new, more eff ective solutions which would simplify the procedure and improve the seating precision.

13

a) b) c) d)

Fig. 1.2. Examples of ship machinery rigid mounting: a) with a uniform metal chock; b — d) with adjustable metal chocks

1.2. Chocking the machinery on metal chocks

Using them shortens the time of machinery installation on board, but only at the cost of a longer manufacturing time lost on chocks/shims of a complicated form.

Some of them (Fig. 1.2, b, d) provide an easy adjustment of height for the installed machinery, other (Fig. 1.2, c, d) ensure a uniform distribution of pressure on the supporting surfaces of chocks, thanks to a feature of self-alignment in the direction of the load.

All the adjustable metal chocks yield a rigid mounting of a machine and do not introduce any signifi cant changes into the statics and dynamics of a machine-chock-foundation system in comparison to traditional, uniform metal chocks. Another disadvantage is also an increase of the number of contact surfaces, which is going to be discussed in more detail in p. 1.4 below.

1.3. Chocking the machinery on fl exible chocks

The problem of noise and vibration has been steadily growing in importance since the beginning of mechanical propulsion of ships, and in the 1930s [4] a new fi eld of machinery foundation engineering was born when it was discovered that a way of joining the machines and their foundations plays an important role in the propagation of vibration and noise through the ship [5 — 6]. The so called fl exible seating of machinery have been introduced as a consequence, made of rubber chocks instead of traditional steel, or employing special design solutions (Fig. 1.3) [7]. The fl exible seating of ship machinery yields:

— more uniform distribution of load between chocks,— high degree of isolation for mechanical vibration and structural sound generated

by the machines (up to abt. 90%) [5,8], — high degree of machine isolation from kinematic excitations and foundation deforma-

tions,— freedom of thermal deformations of the machinery housing, — possibility to apply lighter foundations.


Fig. 1.3. Examples of fl exible mountings of shipboard machinery

a) b) c) d)

The fl exible seating of ship machinery is a complex issue - theoretically, technologically, and from the operational point of view [9 — 15].

Solutions are found through a process of selection of such chocks and installation designs which would fulfi ll assumed vibration/noise isolation characteristics, and ensure that the machinery is reliably and durably mounted.

The problems posed by fl exible installation concept have not been fully solved up so far. Practical implementation of fl exible chocks requires relying on both computational and experimental methods which generally cannot guarantee that an optimum solution is arrived at [16 — 18].

The development of fl exible seating arrangements for machinery strives for better calculation methods, manufacturing of materials with precisely defined elastic and damping properties and designing such chocks and their arrangements which would optimally fulfi l the task of isolating and damping mechanical vibration and structural sound [19 — 24].

Usage of special flexible chocks with complicated designs raises the cost of an installation considerably. There is an obvious tendency to keep the costs as low as possible in the process of maximising the quality indices of machinery operation and the comfort of the crew and passengers. Due to serious technical diffi culties and high costs, applications of fl exible chocks for heavy shipboard machinery are still far from widespread.

1.4. Chocking the machinery on cast resin compound chocks

The progress of chemistry and materials engineering, which took place in the last 40 years, provided many opportunities for developing special construction materials and technologies which are able to provide technical, economic, and practical benefits - all at the same time. One example of such materials are special chemically curing

151.4. Chocking the machinery on cast resin compound chocks

Fig. 1.4. Casting of compound foundation chocks: 1 — machine bedplate, 2 — foundation, 3 — front plate, 4 — holding down bolt, 5 — chock, 6 — mould barrier (foam)

compositions based on epoxy resins, which were developed for foundation chocks of ship machinery but may also be used for various land machinery requiring precise alignment and reliable mounting.

Chemically curing compounds with precisely defi ned properties continually improved in time proved to be an almost ideal material for machinery foundation chocks. Their introduction to industrial use was decided by the following advantages:

— easy on-site casting of ready-made chocks with any dimensions and shapes, — good strength characteristics and easy maintenance of the hardened compound,— signifi cant reduction of machinery installation time and cost. Compound foundation chocks are cast directly under correctly positioned and aligned

machine (Fig. 1.4), fi lling the entire space delimited for them between the foundation top and the machine bedplate, and ensuring excellent fi t with both contact surfaces.

Signifi cant technical and economical benefi ts obtained by using new technology of chock installation with its modern materials have been proved in practice and established as a new standard for the seating of ship machinery [25 - 30]. Its use is now worldwide, including Polish shipbuilding and ship repair yards. Thanks to its numerous advantages this technology is also gaining in popularity for the seating of many crucial land-based objects.


1.5. Characteristics of seating arrangements based on metal chocks and cast resin compound chocks

In order to shed some light on the problems involved in the seating process, and the progress in this fi eld as far as used materials and methods are concerned, basic characteristics of a traditional seating technique (using metal chocks) will be outlined below in comparison to the modern technology based on cast resin compounds.

The traditional way of seating heavy machinery on its foundations with the use of metal chocks has a few important disadvantages, including:

— the necessity for precise machining of machine foundation load-bearing surfaces,— necessity to pre-machine metal chocks and the diffi cult, laborious, individual fi tting

of chocks to the surfaces of foundation and machine bedplate,— high rigidity of metal chocks,— small effective contact area between the chocks and foundation / machine

bedplate,— poor isolation of mechanical and acoustic vibration.As a result of high rigidity (high value of the modulus of elasticity E) any small inaccuracies

in fi tting of metal chocks may result in appearance of high stresses and deformations in the bodies of machines as well as in foundations — already in the installation phase. Such stresses and deformations have a detrimental eff ect on the durability of machines and the quality of their operation.

Apart from the diffi culty to obtain adequate fi tting and high rigidity, another substantial disadvantage of metal chocks is also their very low eff ective contact area between the faces of machine bedplate and the foundation. Even with accurate fi tting of foundation chocks according to relevant criteria used in this case [2], any unevenness of surface remaining after machining (roughness, undulation, shape errors) is bound to cause a rather spotty, random contact area (Fig. 1.5a), and the total eff ective contact area is only a small percent of that nominal [31].

As a result of appearance of dynamic loads when the machine is running, micro-spots on eff ective contact surface suff er serious resin deformations, which result in so-called settling of connected elements [32], loosening of bolts, and “hammering” of the all the load-bearing surfaces of the foundation, chocks, and the machine bedplate. Final consequences may be cracks in the foundation and the machine body, ruptures of holding down bolts, unstable running of the machine, and failures [29].

Use of chemically curing compound chocks cast in moulds which are prepared between the foundation and the machine positioned in its service position (Fig. 1.4) eliminates many operations, simplifi es the seating process and shortens it considerably.

Apart from a rough mechanical cleaning and degreasing of foundation surface, no other special preparation is required for it. Existence of roughness, corrosion pits and non-parallelity of surfaces, which make the usage of traditional metal chocks much

171.5. Characteristics of seating arrangements based on metal chocks and cast resin compound chocks

Fig. 1.5. Drawings of a foundation bolt joint: a) with a metal chock; b) with a cast plastic compound chock

a) b)

more diffi cult or prevent it at all, is of no importance if cast resin compound chocks are used.

Chocks cast under the machine according to a correct technology adhere tightly to the load-bearing surfaces of the machine and its foundation [25, 26, 33]. They fi ll all the micro-cavities on the contact surfaces (Fig. 1.5b). It is a specifi c case of a joint where eff ective contact area is larger than that nominal.

This ensures a favourable distribution of normal eff ective pressure over the contact area, and a high eff ective friction coeffi cient (close to one or even higher), which have a benefi cial eff ect on the transfer of forces tangential to the supporting surface (see pos. 6.8.2).

Resin compound chocks dampen vibration better and are a substantial barrier for the transmission of structural sound [34 — 37]. Neither any fretting (friction-induced corrosion) occurs on the chock contact surfaces (both with the machine bedplate and the foundation), nor the eff ects of “hammering” or other forms of wear.

2. THE RESIN COMPOUNDS USED FOR SHIP MACHINERY FOUNDATION CHOCKS

2.1. General requirements referring to resin compounds used for foundation chocks

Attempts to rationalise the installation work, to improve the quality and shorten the time of ship machinery seating operations by using various self-adjusting or fl exible chocks (described in Chap. 1) did not enter the shipyard practice on a larger scale, especially with regard to main engines.

The traditional method of seating based on metal (steel or cast iron) chocks began to fade away only when special chemically curing compounds were developed in the early 1960s, together with the cast-in-place technology, which allowed foundation chocks to be made directly under already aligned machines.

The fi rst compound, named “Chockfast”, was developed by the Philadelphia Resins Corp. (USA), and its name directly implies a “fast foundation chock”. The fi rst main propulsion engine was seated on “Chockfast” foundation chocks in USA in 1963, as a part of a repair job.

This new method of seating the machinery with the use of cast resin compound chocks quickly obtained recognition due to its numerous advantages, and began entering shipyard practice not only in ship repair, but also on new ships. Chockfast compound is now manufactured in a number of kinds, and the one which became especially popular for the seating of ship machinery is Chockfast Orange.

The requirements for the resin compounds used for foundation chocks are numerous, varied and diffi cult to meet, especially in case of main engines, gears, shaftline bearings and other machinery requiring accurate alignment. The fact that currently only three such compounds have widespread recognition of worldwide classifi cation societies and engine manufacturers is the best illustration of the above.

Apart from the American compound “Chockfast Orange” and the German compound Epocast 36, The recognition of ship classifi cation societies (supervising the construction and repairs of ships) and ship engine manufacturers has been granted to the Polish compound named EPY and produced by Marine Service Jaroszewicz company by using only domestic raw materials.

Development of a resin compound to be used for foundation chocks required fi nding solutions to many complex problems concerning the composition of a compound, the design of the chocks and the method for casting them, as well as the issues related to machine installation and service.

2. The resin compounds used for ship machinery foundation chocks20

Furthermore, many psychological and formal barriers put up by classifi cation societies, engine manufacturers, shipowners, ship designers and shipyards had to be overcome, as it was a common view that the material with greater strength is a better construction material. Such a reasoning may be correct, but not always, and there are cases when it is downright mistaken.

In case of foundation chocks, epoxy compounds proved to be a much better construc-tion material than steel or iron, despite their much lower compression strength. Basic requirements concerning the compounds used for foundation chocks are laid down in the relevant rules of classifi cation societies [38 — 40].

The compounds should have no air content and good running quality in liquid state, together with little shrinkage during curing. When cured, they should have low creep and high static and fatigue strength in compression.

A characteristic feature of chock compounds (very important for practical issues) is their reactivity [39], infl uencing the shape of chock curing temperature curve and its maximum. However, the curve also depends on the temperature of compound when cast into the mould, ambient temperature, mass and shape of the chock and local heat dissipation conditions.

High curing temperature yields better cross-linking in compound and the resulting chocks have better mechanical properties: higher strength, hardness and better resistance to creep. Compounds with higher reactivity can have lower minimum temperature during casting. Compounds with low reactivity cannot ensure good cross-linking in chocks, especially in circumstances of high heat capacity and good thermal conductivity displayed by the machine and its foundation. On the other hand, too high reactivity may result in appearance of high casting stresses in the chock and high shrinkage in the process of curing.

Total shrinkage is an eff ect of volume changes stemming from the chemical curing reaction, and a heat shrink induced by a drop of the temperature of compound from the maximum value on the exothermal curve to the ambient temperature.

Knowledge of the exothermal properties of a given compound is thus necessary for the determination of important parameters of seating technique, such as minimum and maximum temperatures during casting, desired temperature of compound when cast into the mould, minimum and maximum thickness of chocks, and the relation between curing time and ambient temperature.

Foundation chocks stay in constant contact with humid air, greases, fuel and water, so they must be resistant to ageing in the presence of these media, also at heightened temperature.

How the foundation chock behaves during service is fi rst and foremost dependent on the operational temperature and the pressure exerted on it.

Temperature of the chocks under ship main engines may in some circumstances reach 80°C, so the chock must have adequate resistance to creeping in this temperature, which is in turn a limiting factor on maximum admissible pressure.

212.1. General requirements referring to resin compounds used for foundation chocks

The unavoidable process of compound creeping should be limited to a possibly low drop in chock height, which should almost stop after a relatively short time. These are the reasons why admissible pressures acting on foundation chocks are set at only 5 MPa, while their immediate compression strength may be up to 150 MPa.

Use of compounds for ship machinery foundation chocks requires acceptance from the side of shipowner, machinery manufacturer, and the classifi cation societies supervising the construction of the ship.

Obtaining the classification societies’ approval certificates is based on the results of appropriate laboratory and service tests. It is further required due to specifi c features of such tests that they are carried out in a recognised laboratory under the supervision of classifi cation surveyors, or in the own laboratory of a given classifi cation society.

The requirements of various classifi cation societies diff er with regard to the types of tests and the way they should be carried out. Also the criteria for successful completion of tests are numerous and varied [38 — 40]. For example, Germanischer Lloyd [40] requires that the following parameters of a compound under investigation must be determined:

a) longitudinal modulus of elasticity (in compression) according to ASTM D695 and ISO R 604,

b) surface hardness in Barcol degrees (°B) acc.to ASTM 2583 and DIN EN 59,c) tensile strength acc.to ASTM D638 and ISO R 527,d) compression strength acc.to ASTM D695 and ISO R 604,e) shear strength acc.to ASTM D732,f) bending strength acc.to ASTM D790 (method I, procedure A) and ISO R 178,g) impact strength (Izod method) acc.to ASTM D256 (method A) and ISO R 180,h) shrinkage acc.to ASTM D2566,i) fl ame propagation velocity acc.to ASTM D635 and ISO R 1210,j) settling under load acc.to ASTM D521, while accounting for: — time, h: 24, — test temperature, °C: –30/+23/+50/+70/+100, — sample loading, N/mm2: 3,5/7/14/28,k) the coeffi cient of thermal expansion [1/K] acc.to ASTM D696 and DIN 52 328, in

temperatures from –50 to +150 °C,l) friction coeffi cient against steel for a cast and machined sample, with the use

a release agent and without it,m) curing time in a range of temperatures,n) resistance to oils, petrol, and cold cleaning agents,o) thermal resistance acc. to ASTM D696 and ISO R 75.Moreover, classifi cation societies often require many additional tests to be carried out,

and such tests are outlined in Chapter 5 below.


2.2. Development of Polish chocking compounds and the machinery seating technology

Polish shipbuilding industry, striving for freeing itself from the costly import of compounds and seating services from Western countries, approached the Technical University of Szczecin in 1969 with the initiative to commence research on development of own (domestically made) chemically curing compounds for foundation chocks, and the technology for installation of ship machinery based on such compounds.

As a result of this, the resin compounds: EP-551, EP-571 oraz EP-578 were developed and tested by the Technical Mechanics Section of Technical Univeristy of Szczecin. Soon after that they obtained the approval of the Polish Register of Shipping (PRS), and were introduced as a practical seating method in Polish shipbuilding industry.

The authors of these developments were: J. Lorkiewicz (DEng), K. Grudziński (DEng), and W. Jaroszewicz (MScEng). The fi rst shipboard seating operations were carried out by the Technical University of Szczecin in 1974, and the object was the training/cargo motor ship “Kapitan Ledóchowski” (Fig. 2.1). The scope of the work comprised mounting an electric generating set and three pumps in engine room on chocks of EP-551 compound.

The new compound and its seating technology passed the real-life exam with fl ying colours, and began to be introduced to installation practice in Polish shipbuilding and ship repair yards.

The fi rst operation of seating of a main propulsion engine (HCP-Sulzer 6AL25/30) on foundation chocks made of EP-551 compound took place in Szczecin Shipyard aboard “Karsibor I” ferry (Fig. 2.2a) in November 1976. The engine was mounted in a common frame together with the generator powered by it, and the whole assembly was then installed on its foundation by using cast compound chocks (Fig. 2.2b, c)

More detailed information about carried out research, properties of developed compounds and the machinery seating technology based on these compounds, as well as the number and types of machines installed until 1984, can be found in publications [25 — 26].

Starting from 1978, seating operations have been carried out by specialised teams authorised by the Technical University of Szczecin, which operated within:

— Morska Stocznia Remontowa (Repair Yard for Seagoing Ships) in Świnoujście (the director of the yard was Mr P. Soyka (MScEng) and the head of an installation team was Mr S. Kownacki (MScEng),

— Przedsiębiorstwo Robót Malarskich i Izolacyjnych (Painting and Insulation Works Company) “Malmor” in Gdańsk (the director of the company was Mr W. Symoni (Eng), and the head of an installation team was Mr A. Adamkiewicz (MScEng)),

— Przedsiębiorstwo Zagraniczne (Foreign Company) “KITI” in Poland, sited in Warsaw (the director of the company was Mr A. Łuba (MScEng), and the head of an installation team was Mr W. Jaroszewicz (DEng).

23

Fig.2.1. Training/cargo motor ship “Kapitan Ledóchowski” — the fi rst auxiliary machinery installation on the resin compound foundation chocks developed by the Technical University of Szczecin

2.2. Development of Polish chocking compounds and the machinery seating technology

Research and development projects on the improvement of the properties of compounds were carried out by the Technical University of Szczecin in parallel with the industrial implementation work, including also the research on the seating technology as well as the design, modelling and calculation of holding down bolt joints.

These undertakings were carried out within the framework of the so-called “crucial problems”, in close co-operation with Szczecin Shipyard, CTO (Centrum Techniki Okrętowej — Ship Research Centre) and CTW PROMOR (Centrum Techniki Wytwarzania — Manufacturing Research Centre) in Gdańsk, as well as the Institute of Fundamental Problems of Technology of Polish Academy of Sciences (Instytut Podstawowych Problemów Techniki Polskiej Akademii Nauk, IPPT PAN) and the above mentioned companies conducting seating operations.

An especially important role in the initiation and execution of many research projects was played by a Machinery Installation Service Team (Serwis Posadawiania Maszyn), operating within PZ KITI. The team was directed by Mr W. Jaroszewicz (DEng), a former scientifi c worker of the Technical University of Szczecin (starting from 1972), who was involved in this fi eld since the beginning of his career in science.

His work was awarded in 1980 with a Doctor in Engineering degree, after a defense of the thesis titled “Foundation chocks made of chemically curing compounds for the seating of ship main engines and auxiliary machinery”. The promotor of this work was Mr K. Grudziński (DEng), and the reviewers were Mr E. Skrzymowski (DEng) (Technical University of Szczecin) and Prof. T. Gerlach (Gdańsk University of Technology).

Having been in charge of the Machinery Installation Service Team within PZ KITI since 1982, Mr W. Jaroszewicz has not only conducted a broad range of services for the shipbuilding industry, but also participated actively in the scientifi c research projects carried out by the Chair of Mechanics and Machine Elements of the Technical University of Szczecin.


Fig. 2.2. The fi rst main propulsion engine installed on foundation chocks made of Polish compound aboard “Karsibór I” ferry: a) picture of the ferry; b) layout of the installed machine; c) picture of cast compound chocks

a)

b)

c)

252.2. Development of Polish chocking compounds and the technology used for machinery installations

The research projects in this area have been carried out by a team including Mr J. Lorkiewicz (DEng), Mr W. Jaroszewicz (DEng), Mr L. Łabuć (DEng), Mr R. Kawiak (DEng) and Mr L. Tuczyński (Eng), under the supervision of Mr K. Grudziński (DEng).

The doctorate thesis of Mr R. Kawiak (concerning problems of modelling and calculation of foundation bolt joints), the patents [42 — 44] and a new, improved type of Polish chocking compound called EPAX were among the results of these projects.

This new compound and the technology of ship machinery installation based on its use have again been granted approvals from classification societies and marine engine manufacturers.

Seating operations by using this compound have been carried out on many ships, built or repaired in Polish yards for many overseas shipowners under the supervision of various classifi cation societies, including Polish Register of Shipping (PRS), Lloyd’s Register (LR), Germanischer Lloyd (GL), Bureau Veritas (BV), Det Norske Veritas (DNV) and Maritime Register of Shipping (MRS).

In July 1986 in Gdynia Shipyard four 16ZV40/48 Zgoda-Sulzer engines each rated at 10 000 KM, were installed aboard the motor ferry “Stena Germanica” (Fig. 2.3) by using foundation chocks of EPAX chocking compound.

As far as Gdańsk Shipyard is concerned, the fi rst main propulsion engine (6L40/48 Zgoda-Sulzer engine of 4500 KM rated power) was installed on EPAX compound chocks in October 1986 (m/t “Dalmor”). Szczecin Shipyard installed its fi rst large main engine on EPAX chocks in June 1990 (6L50MCE HCP-MAN/B&W engine of 5181 KM rated power), aboard m/s “Kopalnia Halemba”.

Fig. 2.3. Passenger/car ferry “Stena Germanica” with main engines installed on EPAX compound chocks


In 1990 Mr W. Jaroszewicz took over the Machinery Installation Service Team from PZ KITI and started his own commercial company “Marine Service Jaroszewicz”, rendering seating services from its site in Szczecin

A new chocking compound version named EPY was then introduced to installation work. Its chemical content ensures fast and effective curing at a very low shrinkage, without emission of any byproducts.

The properties of this compound stand equal in any respect to the properties of other modern resin compounds, off ered by the specialised companies from Western countries. This applies in particular to an American compound Chockfast Orange and a German compound Epocast 36.

On the basis of contracts entered with H. A. Springer marine + industrie service GmbH (August 1995), and ITW Philadelphia Resins (July 2001), MSJ company is now an exclusive distributor of Epocast and Chockfast compounds, and an authorised executor of machinery seating operations carried out with the use of these chocking compounds in Poland, Lithuania, Latvia, Estonia, and Russian Baltic yards “Vyborg” and “Jantar”.

Table 2.1 lists some more important properties of the Polish compound EPY against the comparative values for the above mentioned foreign compounds. The values listed for EPY compound have been confi rmed by testing carried out by the Lloyd’s Register of Shipping laboratory in London [45].

27

Table 2.1. Basic properties of compounds used for machinery foundation chocks


The EPY compound has the same approvals of worldwide ship engine manufacturers and classifi cation societies as the Chockfast Orange and Epocast 36 compounds off ered by Western companies, which are currently incorporated in Illinois Tools Works (ITW), an American concern.

It also has the approval certifi cates of relevant domestic institutions, which allow for its use in the construction of roads and bridges, as well as for the seating of machinery used in mining. The list of institutions and engine manufacturers who issued their certifi cates for EPY compound is given in table 2.2.

The production of EPY compound and the machinery seating services are compliant with the procedures of DIN EN ISO 9002 quality management system, which is confi rmed by the certificate no.QS-244 HH issued by Germanischer Lloyd Certification GmbH (obtained by MSJ in 1994), and the certifi cate of a Russian Maritime Register of Shipping No 00.017.258 obtained in 2000.

In order to keep on the cutting edge of state-of-the-art, Marine Service Jaroszewicz company co-operates closely with the Chair of Mechanics and Machine Elements of the Technical University of Szczecin over the further improvement of its compound and the machinery seating technology. This also includes the projects on fi nding solutions for numerous problems associated with broadening of the above mentioned technology scope of application for the seating of various land-based machinery, such as heavy


Table 2.2. List of institutions and ship engine manufacturers, who issued their approval certifi cates for EPY compound


machine tools, presses, compressors, bridge spans, mining machinery etc., used by other technology branches and industries.

The following persons are included in the research on new compounds, carried out by the Technical University of Szczecin: Mr K. Konowalski (DEng), Mr D. Ratajczak (MScEng), Mr J. Ratajczak (MScEng), Mr P. Grudziński (DEng) and Mr M. Urbaniak (MScEng), and the following persons participate in the industrial implementation carried out by MSJ company: Mr Z. Kempkiewicz (MScEng), Mr A. Skierkowski (MScEng) and Mr S. Kłoczko (Eng).

Since the mid 1990s, intensive research projects have been carried out on the following issues: vibration isolation and damping provided by the compounds used for foundation chocks [34 - 37], fatigue strength of the compound, and a fully original method of compound curing based on usage of microwave energy [46 — 48]. The conducted tests of vibration isolation and damping have showed [49 — 50] that the Polish EPY compound rates equal to foreign compounds in this fi eld.

3. DESIGN OF MACHINERY CHOCKING ARRANGEMENTS WITH EPY COMPOUND CHOCKS

3.1. Documentation of an installation

Seating arrangements of ship machinery on foundations must be approved by the classifi cation society supervising the construction or repair of the ship. According to the rules of Germanischer Lloyd [51, 52], the documentation required for an approval of installation design must contain:

1. General information about the ship, installed machine, classification society supervising the construction / repair, and the shipyard conducting the work.

2. The drawing of a seating arrangement (Fig. 3.1a), containing the following information:— arrangement, number and dimensions of all the chocks,— arrangement, number and dimensions of all the damming (front and side),— arrangement, number and dimensions of all the holding down bolts (regular and

fi tted) and tubes (if present),— name of the compound used for chocks, and the materials of holding down bolts,

nuts, dams and tubes.3. Sectional drawings of foundation bolt joints (Fig. 3.1b).4. Information concerning:— chock load-bearing surface,— pressures on the chocks exerted by machine weight and holding down bolts

pre-tension settings, and the total pressure value,— axial force and stress in the holding down bolts and their elongation during

pre-tensioning,— nut tightening torque for holding down bolts, or the pressure in a hydraulic

bolt stretcher,

3.2. General guidelines for the design of seating arrangements

1. Foundation chock heights:— minimum 10 mm,— recommended 20 — 35 mm,— maximum 50 mm (in one layer).In case there is a need to have the chocks cast with height values exceeding the above

stated limits, MSJ company should be contacted in advance.

3. Design of machinery chocking arrangements with EPY compound chocks34

Fig. 3.1. EPY compound chocks arrangement plan (a), and the cross-sections of foundation bolt joints in main shaft bearing, main gear and main engine (b)

a)

b)

2. Casting moulds are made of foamed resins (polypropylene, polyurethane, micro porous rubber, styrofoam) and steel plate of 1 — 2 mm thickness.

3. The width of a mould pouring space used to cast the foundation chocks should be 15 — 30 mm, and the height of a frontal dam wall should allow for the overpour height of 15 — 30 mm.

4. Amount of compound needed to make all the chocks is calculated by using the formula:

mt = α ρ

tA

eH (3.1)

where:m

t — mass of compound, kg

α — coeffi cient accounting for pour-in, overpour and wastage volume, equal to 1,05 — 1,20,

ρt — EPY compound density, equal 1,59 × 10-6 kg/mm3,

Ae — eff ective (total) load-bearing surface area of chocks, mm2,

H — nominal height of chocks, mm.

353.3. Design calculations of seating arrangements with EPY compound chocks

Table 3.1.


The following symbols, units and naming listed in Table 3.1 have been adopted for installation design calculations (acc. to GL design guidelines [52]):


3.3.1. Calculations of a minimum required load-bearing surface area of chocks

(3.2)

where:W — machine weight, N,p

w — Pressure exerted on chocks by machine weight, N/mm2.

Constraints:— p

w ≤ 0,7 N/mm2,

— Am

≤ Ae,

where:A

e — total eff ective load-bearing surface area of the chocks.

3.3.2. Calculations of an axial force in the tensioned holding down bolt

(3.3)

where:p

t — summary pressure on the chocks, exerted by machine weight and the axial

force in tensioned holding down bolts, N/mm2,n — number of holding down bolts.

Constraints:— p

t ≤ p

a,

— Fp > F

o

where:F

o — Axial force inside a bolt exerted by external load, N,

pa — Admissible pressure for used compound, N/mm2,

pa = 5 N/mm2 (MPa) at T ≤ 80°C — for the seating of main engines, gears etc. (acc. to

PRS, ABS, GL, LRS, MRS, BV, DNV),p

a = 15 N/mm2 (MPa) — for the seating of machines where axial alignment is not

required (acc. to PRS),p

a = 30 N/mm2 (MPa) — for the seating of anchor windlasses and mooring winches,

accounting for pull forces, pa ≤ 60 N/mm2 at momentary loads (acc. to PRS).


3.3.3. Calculations of a tightening torque on nuts of holding down bolts

(3.4)

where:T — Holding down bolt nut tightening torque, Nm,D

o — External diameter of a holding down bolt thread, mm,

Fp — Axial force in tensioned bolt, N.

Constraint: calculations are valid for steel holding down bolts with a regular thread, when regular oils are used for lubrication of nut friction surfaces (without special additives such as MoS

2).

3.3.4. Calculations of pressure in the hydraulic bolt stretcher device

(3.5)

where:F

p — Axial force in tensioned bolt, N,

Ap — Eff ective surface of hydraulic bolt stretcher piston, mm2,

k — Hydraulic coeffi cient accounting for settling (in bolt joint).

Constraints:— k = 0,85,In case other value of coeffi cient k is assumed, the classifi cation society (GL) must

be advised about measurement results of an actual axial force in the tensioned holding down bolt.

3.3.5. Calculations of bolt elongation caused by pre-tension setting

(3.6)

where:Fp — Axial force in the tensioned bolt, N,L

1 — L

i — Lengths of successive holding down bolt shank parts, complying with diameters D

s1 — D

si, mm,

Ds1

— Dsi — Successive diameters of a holding down bolt shank, complying with

lengths L1 — L

i, mm.

Constraints:— ∆L ≥ ∆L

m, mm,

— ∆Lm

= 0,12 for pt < 3,5 N/mm2.


3.3.6. Calculations of reduced stress or equivalent tensile stress related to the minimum cross-section area of holding down bolt, accounting for pre-tension setting

1. Spanner-tightened bolts:a) bolts with a shank having a fi xed diameter (Dm = Dr)

(3.7)

where:F

p — Axial force in tensioned bolt, N,

Dm

— Minimum diameter of a holding down bolt shank, mm,D

r — Minor diameter of a holding down bolt thread, mm.

b) bolts with a shank having a variable diameter (0,8 ∆r ≤ D

m < 1,0D

r):

(3.8)

where:P — Holding down bolt thread pitch, mm.

Constraint: σe ≤ 0,9 R

eH (where R

eH — Minimum yield point of bolt material, N/mm2).

2. Hydraulically tensioned bolts:

(3.9)Constraint: σ

e ≤ 0,8 R

eH for k = 0,85.

3.3.7. Calculations of tensile stress related to the holding bolt thread root cross-section area, accounting for pre-tension

(3.10)

In order to protect the nut against self-loosening, the condition σt < 150 N/mm2

must be met (where: σt — tensile stress in a holding down bolt). For low-speed engines

σt < 100 N/mm2 applies instead.

3.4. Exemplary design calculations of chocking arrangements

The input data and design calculation results of 6MU453C MaK engine and G1VY Flender gear can be found below (both were installed on EPY compound chocks). The design specifi cations, the results of calculations and the drawings are presented in the same form as the actual applications submitted for approval to the classifi cation society.


Table 3.2. An example of a design documentation of a main engine seating arrangement with foundation chocks made of EPY compound (Fig. 3.2)

MARINE SERVICE JAROSZEWICZ Szczecin, 14.04.2001ul. Bielańska 23, 70-703 Szczecintel. 48 91 4606624, fax 48 91 4313075


Table 3.2 (cont.)


Fig. 3.2. EPY compound chocks arrangement plan (a) and the cross-sections of foundation bolt joints in 6MU453 MaK main engine (b)

b)

a)


MARINE SERVICE JAROSZEWICZ Szczecin, 14.04.2001ul. Bielańska 23, 70-703 Szczecintel. 48 91 4606624, fax 48 91 4313075

Table 3.3. An example of a design documentation of a main gear seating arrangement with foundation chocks made of EPY compound (Fig. 3.3)


Table 3.3 (cont.)


a)

Fig. 3.3. EPY compound chocks arrangement plan (a) and the cross-sections of foundation bolt joints in main gear Flender type G1VY (b)

b)

4. THE TECHNOLOGY OF THE MACHINERY SEATING ON EPY COMPOUND CHOCKS

Machinery seating technology by using cast EPY compound chocks will be outlined for a case of a main ship propulsion engine. The requirements regarding main engines are especially strict, and the technology of their seating is laid down in the appropriate detail procedures used by the yard building the ship (e.g. Szczecin Shipyard S.A. [53]), and also the procedures of MSJ company, the executor of seating operations [54].

The basis for commencement of seating operations is the documentation of a main engine seating arrangement, accepted by its manufacturer, ship owner and the shipyard, and approved by the classifi cation society supervising the construction of the ship. Seating operations based on the use of of EPY compound may be carried out only by MSJ company employees, or other workers properly trained and authorised by MSJ company.

The execution of seating process of a main engine starts from positioning it on the foundation, then obtaining its adequate alignment by means of adjusting screws or wedges, according to the rules and procedures used by the yard. The engine should be positioned higher than its normal service position by 0,001 — 0,002 part of the chock’s height, to compensate for chock shrinkage in curing, and the deformations caused by the weight of the engine and pre-tensioning of holding down bolts.

After the main engine is positioned on the foundation, holes for holding down bolts are drilled in the foundation plate; in case fi tted bolts are used, the holes have to be expanded. All these operations are carried out by yard employees following the adopted procedure.

Load-bearing surfaces of the engine bedplate and foundation need not be specially machined; it is enough to have them cleaned of dirt and grease. Some classifi cation societies allow for a thin, good quality paint coat to be present on load-bearing surfaces.

In places where chocks are foreseen, moulds are built by providing dams of polyurethane or polypropylene foam, whose thickness may range from 20 to 30 mm (Fig. 4.1). Internal dimensions of the mould (L and B — Fig. 4.1b) are the intended chock dimensions listed in the documentation of an installation. Frontal dam is made of steel plate 1 — 2 mm thick (Fig. 4.1a, b), which is fi xed to the foundation by spot welding. The gap between the frontal dam plate and the foundation is sealed with putty.

Casting moulds must reach out some 15 — 30 mm over the actual chock area, in order to provide a pouring space used for fi lling them with liquid resin mixture (Fig. 4.1). Pouring space must be arranged in such a way that the air cannot be trapped inside the mould, which would prevent fi lling it full. Moreover, mould dams over the pouring space must

4. The technology of the machinery seating on epy compound chocks46

Fig. 4.1. The preparation of the casting mould for the foundation chock: a — b) with holes sealed by tubes of soft rubber or foam; c) with the pre-inserted holding down bolt ; d) mould fi lled with compound

be higher by 20 — 30 mm (Fig. 4.1c), in order to ensure some extra volume of compound, called an overpour. The overpour is necessary due to shrinkage and in order to ensure proper fi lling of the mould. In practice the pouring space of 15 — 30 mm width is usually made over the entire length L of the chock (Fig. 4.1b)

To facilitate dismounting, the surfaces contacting the compound should be covered with a release agent — silicone oil in spray (e.g. Silikone Spray Lubricant, Release Agent PR-225 or WD-40), before the mould is closed with a frontal dam.

Soft rubber or foam tubes are pushed into the holes made for holding down bolts (Fig. 4.1a, b), fi tting tightly and extending across the chock. Alternatively holding down bolts may be inserted (Fig. 4.1c), with lightly tightened nuts. The surfaces on the bolts which will come into contact with compound should be covered with the release agent (solid grease). After the moulds for all the chocks are installed and sealed, main engine’s alignment is checked again (acc. to the installation procedure [53]).

EPY compound has two components. It is supplied in containers (buckets) of varying sizes, which may contain 1, 3, 6 or 12 kg of resin already pre-mixed with fi ller. Needed quantities of hardener are supplied in separate containers.

Everything must be properly prepared in advance before careful mixing of these two components, because after mixing the composition will take only 10 — 20 minutes to start gelation.

Mixing takes 4 — 6 minutes and is performed manually (by using a driller fi tted with a special mixing blade supplied by MSJ company), at a speed of 600 — 800 rpm (Fig. 4.2a),

4. The technology of the machinery seating on epy compound chocks 47

Fig. 4.2. Composition mixing: a) manual, by using a driller; b) in a mechanized way

a) b)

or in a mechanized way (Fig. 4.2b). The temperature of mixed components should be 15 — 25°C, and the minimum ambient temperature in the area of the chocks is 10°C.

During long storage of liquid resin mixture fi llers show a tendency for settling, especially in heightened temperatures, so it is recommended that the liquid containing resin with fi ller is pre-mixed before adding the hardener. After the hardener is added and properly mixed with resin, it is recommended that liquid composition is left undisturbed for 5 — 10 minutes (depending on the ambient temperature), so that any remaining air may escape from it.

Moulds should be fi lled slowly, with a continuous fl ow (Fig. 4.3), avoiding any uncontrolled fl ow interruptions, so that any remaining air may be removed from the composition while preventing introduction of new air. Filling should be carried out in a continuous way until mould is fi lled up together with its overpour (to at least 15 mm above the highest point of the chock — Fig. 4.3a).

Fig. 4.3. Mould fi lling with liquid composition: a) drawing; b) on board

a) b)


Fig. 4.4. Examples of foundation chocks: a) with a regular holding down bolt; b) with a prefabricated EPY compound insert; c) with a perforated element; d) with a bolt fitted to metal and compound elements; e) with a bolt fi tted to EPY compound; 1 — foundation plate, 2 — machine bedplate, 3 — mould foam dam, 4 — EPY chock, 5 — holding down bolt, 6 — fl at bar, 7 — EPY compound tubing, 8 — perforated element,

9 — prefabricated EPY compound element

The overpour (15 — 30 mm) creates the necessary pressure and provides a reserve of compound for a whole chock; it also guarantees good contact between the chock and the bedplate load-bearing surface. It is assumed that the overpour should have at least 1% of the volume of a whole casting. In cases where overpour does not stretch across the whole length of cast chock (e.g. in stern bearings), higher overpours should be used to ensure that the 1% volume margin is maintained, otherwise casting process has to be divided into layers.

Figure 4.4 shows various types of foundation chocks cast from EPY compound. Figure 4.4a shows a standard main engine (ME) holding down bolt joint with the EPY compound foundation chock; its characteristic features are a loosely inserted bolt (no fitting to bedplate, foundation plate or chock) and the fact that the entire chock with its overpour is cast in the mould.

One of the ways to avoid serious technical diffi culties in casting of high chocks (H > 50 mm) and shortening the time of the onboard casting operation is casting the chocks with prefabricated elements (part 9 in Fig. 4.4b; Patent description P-274878) [44]. The prefabricated elements are cast from EPY compound, curing in optimum workshop conditions and then inserted into the moulds in such a way that they are fully enclosed in liquid compound after it is poured into the mould. The compound cast on-site should constitute 30 — 40% of the entire chock.


Fig. 4.5. Removal of an overpour together with a front plate and a perforated element

For many foundation bolt joints (especially for MEs with side stoppers) there is a need to remove the overpours which only have a subserving role in the casting process and do not bear any load in service. Remova of overpours is arduous, but it may be simplifi ed a lot if perforated elements (element no. 8) are inserted into the moulds as shown in Fig. 4.4c (Patent no. 158551 [55]). The elements can be removed together with their overpours after the gelation of cast chocks (Fig. 4.5).

Some number of fi tted bolts are usually used in ME foundation joints (Fig. 4.4d, e) in order to fi x it in an exact position against the foundation. Fitting the bolts the traditional way (Fig. 4.4d) which consists in bolt shank grinding and hole expanding, is laborious, costly and diffi cult to do onboard.

The same task can be fulfi lled by bolts fi tted in EPY compound (Fig. 4.4e; Patent description P-141627 [43]). Fitting of the bolts in compound is achieved by inserting them with some clearance into the holes in ME bedplate and foundation plate, and fi lling the mould with EPY compound up to the level of the bedplate upper surface.

The time of chock curing depends on ambient temperature, equalling:— 72 hrs at 10°C,— 48 hrs at 15°C,— 24 hrs at 20°C.The rules applying to ME alignment procedure should also be obeyed during chock

curing period: no ballasting operations are allowed, no work in engine room, no heavy weight handling on the ship etc.

The chemical processes taking place in the composition curing are very complex, and their course depends on temperature. Cross-linking of the composition requires some time, and the achieved proportions of links depend on the composition’s temperature


Fig. 4.6. An example of a temperature — time curve for foundation chock curing

in curing. As the curing reaction is exothermal, the temperature rises until it reaches a maximum, and then falls. Recording of the composition’s temperature values in time results in plotting a curve, which is called an exothermal curve (Fig. 4.6).

It has been adopted in practice to treat the maximum temperature value recorded in curing as the exothermal temperature.

With a high amount of compound and high ambient temperatures, the temperature inside the compound may rise too high causing a destruction of the chock. If, on the other hand, the temperature of the compound in curing is too low, it only cures partially and cannot achieve its full required hardness and strength.

It is then required to additionally heat the curing chocks from outside. The process of casting and curing should be carried out in such a way that the maximum temperature of the compo sition falls in the range of 80 — 90°C.

Therefore, it is very important to ensure appropriate curing conditions by taking into account many factors, especially the height of the chocks and the temperature of the foundation. Proper dosing of hardener should be adapted for these conditions, as shown in Fig. 4.7. In case ambient temperature is lower than 10°C, heating the chocks from outside should be provided by means of hot air blowing or heat radiators.

After the chocks are cured, frontal dams should be removed from the moulds (Fig. 4.1 and 4.5), hardness of the cured compound should be measured, sharp edges on chocks should be ground smooth, and the alignment of ME should be rechecked. Hardness of the compound measured by using Barcol hardness tester should be at least 40°B. Fig. 4.8 shows the comparative hardness curves, drawn by using various scales [56].


Fig. 4.7. Amounts of hardener in relation to foundation temperature and chock height

Then the adjusting screws should be unscrewed (or the alignment wedges should be removed), the nuts on foundation bolts should be tightened in accordance with the instruction [53], and after that the alignment of ME should be rechecked. In the end a designation plate is fi tted (Fig. 4.9), and a protocol is written.

Fig. 4.8. Hardness graphs in various scales as a function of °B (Barcol) hardness [56]


Fig. 4.9. Designation plate

Cast and cured chocks, together with correctly tensioned holding down bolts, ensure a precise and durable alignment of the machine throughout many years of its service life.

The most important factor influencing the process of machinery seating on cast compound chocks is temperature, which applies to all stages of this operation. The following temperature parameters are of special importance: temperature of components before mixing, temperature of the exothermal curing process, temperature rise rate to the service conditions, and the temperature of chocks in service.

The range of temperatures from 0 to 80°C may be considered to be the possible ambient temperature range. In this range, the diff erence of 10 degrees may amount to a diff erence between a success and a failure in the use of chocking compound. For example, if the temperature of a composition is too high, it may cure so fast that the mould will not be properly fi lled. Too low temperatures may lead to uncompleted curing of compound.

Health and fi re safety issuesEPY compound is based on epoxy resins which are aggressive to some extent in liquid

state and may cause rash or eczema in allergic persons. Due to this fact utmost care should be given to avoidance of any liquid resin getting into skin and eyes contact, and even more so for the very aggressive hardener. Protective clothing is necessary. Fumes of liquid compound may cause irritation of respiration tracts and eyes, so ventilation should be used in closed spaces.

In case of skin contamination it should be wiped clean with a tampon dipped in acetone, and then washed with mild, soapy water, neutralised with acetic acid, washed with water again and greased with protective cream.

Smoking and eating are prohibited during work with hardener. Hardeners are fl ammable liquids, which may be extinguished using water, fi re extinguishing powders and carbon dioxide. Detailed information on these issues is contained in the relevant hazardous chemical substance characteristics cards [57 — 58].


The exothermal chemical reaction which constitutes the curing process does not produce any volatile byproducts. Cured EPY compound is not harmful to health in any way, which is confi rmed by a “Health status attest” (Atest higieniczny) no. 164/PB/251/348/99 issued by the Institute of Maritime and Tropical Medicine in Gdynia.

5. APPLICATIONS OF EPY COMPOUND CHOCKS FOR THE SEATING OF MACHINERY PRACTICAL EXAMPLES

5.1. General remarks

Practical use of foundation chocks made of chemically curing compounds for the seating of ship machinery dates back to the mid 1960s, when it was initiated in the United States with a compound named Chockfast Orange and based on epoxy resins which was specially developed for this purpose. Polish resin compounds for foundation chocks, developed at the Technical University of Szczecin in the years 1970 — 1973, were fi rst used in 1974 on the training motor ship “Kapitan Ledóchowski” built by Szczecin Shipyard.

Chemically curing compounds with precisely defi ned properties (improved as time progressed) have proved to be an almost ideal material for machinery foundations chocks. Their industrial success was decided fi rst of all by the following factors:

1. The capability to mix the composition and easily cast the foundation chocks of any required dimensions and shapes in place of their installation.

2. Good strength properties of curing compound.3. Relatively low value of elasticity modulus and very good natural fi tting over a wide

area of contact together with high friction coeffi cient; these factors ensure a durable installation without any fretting and wear of contact surfaces.

4. Signifi cant shortening of the time spent on the operation of machinery seating on foundations, and lowering of the operation’s cost.

Compound chocks are convenient for use in the seating of new machinery, but also in the repair operations carried out away from repair workshop. Apart from rough cleaning and degreasing of foundation surface, no special surface pre-treatment is needed. Any roughness, corrosion pits and non-parallelism of surfaces, which make use of traditional metal chocks diffi cult or impossible, are of no special importance in case cast compound chocks are used instead.

Signifi cant technical and economic benefi ts and also operational advantages brought by this modern seating technology and its new materials have proved themselves in practice, and as a result a new standard for ship machinery seating has been established. The technology is also used more and more for the installing of various crucial land-based machinery.

5.2. Statistical data on the use of Polish resin compounds in practice

Resin compounds for foundation chocks have been fi rst developed for the needs of shipbuilding industry, and there they found their fi rst use. They are now widely used for the seating of main propulsion engines and gears, seating of stern tubes, rudder

56 5. Applications of EPY compound chocks for the seating of machinery — practical examples

Fig.5.1. Completed machinery seating operations based on use of Polish resin compounds in years 1974 — 2003

Table 5.1. Types and respective numbers of machines installed on Polish resin compound chocks in years 1974 — 2003

arrangement liners, also various auxiliary engine room machinery, deck machinery, column crane bearings etc. Due to their numerous advantages, they are also used more and more for the seating of various heavy land-based machinery.

In the period of 30 years of the practical use of Polish chocking compounds (from 1974 to the end of 2003), the total number of seating operations completed by Technical University of Szczecin, KITI company and MSJ company reached 7719, which includes 6605 shipboard machines and 1114 land-based machines. Quantitative statistical data for consecutive years is shown in Fig. 5.1, and the types of machines installed in the period 1974 — 2003 are given in table 5.1 together with their respective numbers.

575.3. Examples of the seating of shipboard machinery


5.3.1. Main propulsion engines and gears

Compounds for foundation chocks have been developed fi rstly in order to simplify and shorten the installation of ship main propulsion engines and gears.

The traditional way of mounting these machines (by using metal chocks) had many substantial disadvantages, including: the need to mechanically machine the foundation and metal chocks, the need to fi t the chocks manually, and many other, time-consuming and arduous tasks. The requirements which apply to main engine installation (Fig. 5.2) are very high, so the work on the chocks usually went on for a long period of time (2 — 3 weeks), were arduous, and the labour costs were high.

Fig. 5.2. 6RTA76 HCP-Sulzer engine used for propulsion of the ship (at test stand)

Use of compound chocks, cast in place under the properly aligned engine, simplifi ed installation work, shortened installation time and lowered its cost, while giving many technical and operational benefi ts at the same time.

Main ship propulsion engines are the largest group of machines already installed on compound chocks. The numbers of engines which were installed by using this method are broken down in table. 5.2. into groups by particular engine builders.


Table 5.2. List of main engines installed on Polish resin compound chocks from 1974 to 2003

Fig. 5.3. 8RTA68T-B Sulzer main propulsion engine installed on EPY compound chocks: a) general view; b) arrangement of foundation chocks; c) cross-section of a foundation bolt joint

a)

b)

59

An example of the engine installed on EPY compound chocks is shown in Fig. 5.3a. The engine is mounted on 20 chocks whose arrangement is shown in Fig. 5.3b. Fig. 5.4 shows the main gear of a ship, also installed on EPY compound chocks.

Holding down bolts securing the main engine or the gear may be inserted with some clearance (Fig. 5.5a, b) or fi tted in their holes (Fig. 5.5c, d, e). Fitting may be to metal (Fig. 5.5c) or in compound (Fig. 5.5d, e). In case of loosely inserted bolts, elastic tubes made of rubber or polyurethane foam are pushed into their holes before the chock is cast (Fig. 4.1a).

In case of bolts fi tted in metal (Fig. 5.5c), the holes are drilled and expanded, then the fi tted bolts are pushed in, and the mould is fi lled with compound. Such a procedure is highly time-consuming and arduous, especially with large bores (40 — 60 mm). Bolts fitted in compound chocks (Fig. 5.5d, e) are inserted before casting, and the chocks (including tubes) are cast around them.

Fig. 5.4. Ship propulsion gear ABB–Zamech MAV 100–10 installed on EPY compound chocks



Fig. 5.5. Exemplary cross-sections of ship machinery foundation bolt joints: a — b) with loosely inserted bolt; c) with a traditionally fi tted bolt (to foundation and bedplate); d — e) with the bolt fi tted in cast compound

tubing being a part of a whole chock

61

Fitting of holding down bolts in compound is a original solution protected by Polish patent no. 141 627 [43]. Compound tubing, with wall thickness in the range of 2 — 10 mm, is cast together with a foundation chock, which eliminates the need to fi t the bolts in bedplate and foundation plate holes whose diameters are 20 — 60 mm. Time of the operation is signifi cantly shortened as a result, and the cost of the installation is reduced as well. Bolts fi tted in compound may safely transfer very high static and dynamic loads in directions tangential to the supporting surface.

As EPY compound contains ceramic components, any mechanical machining (drilling and expanding) of the holes should be avoided after the chocks are cast and cured.

5.3.2. Stern tubes, liners of shaft line bearings and rudder arrangement liners

EPY compound may be used not only for casting of foundation chocks for main engines, main gears, diesel — electric generating sets, pumps and other auxiliary equipment, but also for the seating of propeller shaft liners, liners of radial bearings being a part of the shaft line, rudder arrangement liners, fi xed and dismountable journals, which are all loaded with high tangential and axial forces. The examples of such machinery installed by using chocking compounds are shown in Fig. 5.6 — 5.8.

Fig. 5.6. Stern tube installed in liners cast from EPY compound



Fig. 5.7. Various types of packing used in stern tube installation: a) welded packing ring; b) and c) packing rings of elastic epoxy resin; d) screwed-on fl ange with O-ring; 1 — stern frame, 2 — EPY compound, 3 — stern tube, 4 — welded packing ring, 5, 6 — packing rings of elastic epoxy resin, 7 — welded fl ange, 8 — screwed-on

fl ange, 9 — O-ring.

Fig. 5.8. The example of EPY compound use for the seating of shaft line elements in the main propulsion system of a twin-propeller vessel

The assembly of a stern tube (Fig. 5.6) includes aligning it and casting the compound, and is very accurate and fast. This technique eliminates the need for precise centring and expanding of a high-bore hole (up to 1 m in diameter) in the stern frame, precise turning of propeller shaft tube, and pushing it in with huge force (up to 1000 kN), which are all necessary operations in case of traditional assembly technique (based on force fi t). The holes where tubes are installed need not be precisely machined in case cast compound technology is used.

In spite of the fact that cast compound tubes fi t very well to metal surfaces in the stern frame hole and the installed stern tube, due to diff erences in thermal expansion coeffi cients

63

they may not always guarantee an excellent tightness of a joint. Because of that a special system of packing must be foreseen in the design of shaft tube installation. Fig. 5.7 shows various types of packing used in the installation of stern tubes in seagoing ships.

Fig. 5.8 shows the example of EPY compound use for the seating of shaft line elements in the main propulsion system of a twin propeller vessel.

Fig. 5.9 shows the elements of rudder arrangement and shaft line installed in cast compound. Same as with the example of stern tube installation, there is no need here for any accurate machining of surfaces and large size holes.

Fig. 5.9. The elements of rudder arrangement and shaft line installed in EPY compound: 1 — EPY compound, 2 — sealing foam, 3 — fi ll-in holes, 4 — overfl ow holes



Fig. 5.10. Excursion ship “Fantasy” with the 10M4725FW Pusnes mooring winch installed on Polish EPAX compound chocks in 1988

5.3.3. Deck machinery

Foundation chocks cast from chocking compound are used not only for the seating of machinery in closed spaces under the deck, but also for seating of various equipment installed on the deck. EPY compound is fully long-term weather resistant, and is used especially for mounting of various winches: anchoring, towing, mooring, and trawl winches. Fig. 5.10 shows the excursion ship “Fantasy”, which has its 10M4725FW Pusnes mooring winch installed on Polish EPAX compound chocks.

An example of a trawl winch installation is shown in Fig. 5.11. Numbers of chocks used for the installing of winches may vary. They depend on the type of winch and its size, and may range from a few chocks to a few dozens.

Fig. 5.12a shows a seagoing vessel with rotating cranes mounted on columns, while Fig. 5.12b presents a simplifi ed sketch of such a crane. The crane has been mounted on a large-size ball bearing (D = 2500 mm).

Fig. 5.12c shows a traditional seating method for the bearings, which is by an accurate fi t of joined surfaces (ink-checked), and Fig. 5.12d — the seating of the same bearing on a thin layer of EPY compound (1 — 3 mm thick). The method used for mounting of the bearing is shown in Fig. 5.13.

Due to use of liquid compound for the seating (excess liquid is pressed out to the sides), a very good fi t of joined surfaces is obtained after curing, without any need for an arduous, costly and time-consuming machining operations on the crane and column contact surfaces. This way the installation takes less time and is cheaper, while the bearing fi tted in this fashion operates very well and is fully reliable.

65

Fig. 5.11. An example of a trawl winch seated on EPY compound chocks: a) drawing of a winch installed on its foundation, b) arrangement of foundation chocks

5.4. Examples of the seating of land-based machinery

Fig. 5.14 shows the “Odyssey”, the world-fi rst fl oating launch platform “Sea Launch” designed for rocket launching of communication satellites to orbit. It was built within a framework of an international program whose participants were: USA (Boeing), Russia (Energya), Ukraine (Yuzhnoye) and Norway (Kvaerner). The platform, built in Vyborg yard in Russia in 1998, has two cylindrical rocket fuel tanks of 40 m length and 80 t weight. The tanks were installed on chocks made of cast EPY compound.


Fig. 5.12. Use of EPY compound for the installation of rotating cranes on deck-mounted columns: a) B567 series ship built by Szczecin Shipyard S.A.; b) sketch of the crane; c) the traditional way of mounting the slew bearing

(D = 2500 mm); d) installation of the bearing with the use of a thin layer of EPY compound

a)

b)

c) d)


Fig. 5.13. A large-size rolling bearing seated with the use of EPY compound: a) cross-section showing how a leak of compound is prevented; b) cross-section showing bearing position adjustment screws; 1 — EPY compound layer, 2 — bearing contact surface, 3 — adjustment screw, 4 — sealing of the edge, 5 — foamed

compound plugs

a) b)

Fig. 5.14. Floating rocket launch platform “Sea Launch” with rocket fuel tanks installed on EPY compound chocks



Numerous advantages shown by the new machinery seating technology based on use of chocks cast from chocking compounds made it more and more popular also for the seating of various, heavy land-based machinery.

This applies in particular to such machines as: turbines, fans, ball mills, heavy machine tools, engine-powered compressors, mining machinery, bridge span bearings, rails of port cranes and rail vehicles, etc.

The quality certifi cate of ISO 9002 standard obtained by MSJ company for the production of its EPY compound and the execution of installation operations is valid not only for ship machinery, but land machinery as well.

EPY compound has also been granted the technical approvals or certifi cates of the following Polish institutions: the approval of Road and Bridge Research Institute for the insta lling of bridge bearings, the certifi cate of State Mining Authority referring to the seating of mining machinery, and the certifi cate of Building Research Institute for the seating of machinery and anchoring of foundation bolts in buildings.

The types of installed land machinery are listed in table 5.1 together with their respective numbers. A few examples of EPY compound use for foundation repairs and the seating of various land-based machinery are outlined below.

5.4.1. Application of EPY chocking compound for the seating of GMVH-12 engine-powered compressors and the repair of their foundations

GMVH-12 engine-powered compressors made by Creusot-Loire (France) are aggregated units including a gas engine of 2026 kW power and a piston compressor (Fig. 5.15). Weight of the whole unit is abt. 85 000 kg. Five such units have been installed on monolithic reinforced concrete foundation blocks according to the design and guidelines of their manufacturer.

The following problems have been identifi ed (and have worsened in time) with these machines during many years of service in KRIO Gas Denitrifi cation Plant in Odolanów, Poland:

— cracking of the reinforced concrete foundation block in its upper part,— ruptures of holding down bolts anchored in the reinforced concrete block,— rise of mechanical vibration amplitude and noise level,— diffi culties in maintaining specifi ed clearances in the crankshaft/pistons system,— cracks in engine blocks and heads as well as anti-vibration cylinders,— high failure rate of the machines.It was then established beyond doubt that the main reason for these problems were

some defi ciencies in the installation of these compressor units on metal chocks. The repair and modernisation of their foundations included:


Fig. 5.15. GMVH-12 compressor unit installed on a reinforced concrete foundation: a) before modernisation (steel chocks); b) after modernisation based on EPY compound use; c) general view of the compressor unit

after its foundation was modernised

a) b)

c)

— removing the cracked, upper layer of reinforced concrete block (some 440 mm in height)— making of a special steel foundation frame,— drilling 62 holes of φ62 diameter to the depth of 600 mm for M40 bolts used to

secure the metal frame to foundation,— pouring the compound over the holding down bolts,

71

— installing the steel frame on top of foundation block by using cast compound chocks (Fig. 5.15b),

— tightening the nuts on the bolts securing the frame to foundation after the compound had cured,

— positioning the compressor unit by using adjustment screws on the metal frame in its service position,

— casting EPY compound chocks between the compressor unit bedplate and the metal foundation frame,

— tightening the nuts on the bolts securing the compressor unit to metal frame after the compound had cured,

All fi ve GMVH-12 compressor units at KRIO plant have been successively reinstalled with repairs of their foundations as described above, and the details concerning the repairs and their executors are given in publication [29].

No signs of any compressor units foundation degradation have been found after eight years of service. Similar repairs of foundations and modernisations of installations have been carried out in a few other gas plants in Poland. Measurements of vibration and noise level (carried out after the repair of foundations and the reinstallation of compressors) have indicated a signifi cant decline in both of these phenomena [59 — 60].

5.4.2. Applications of EPY compound for the seating of mining machinery

Chocks of EPY chocking compound were fi rst used in this fi eld in the installation of a main air exchange fan in “Wieczorek” hard coal mine in 1995. The layout drawing of this fan’s installation is shown in Fig. 5.16a, and the arrangement of foundation chocks in Fig. 5.16b. Weight of this machine was 40 000 kg. Five other fans have been so installed in various mines in the following years.

In 1996 EPY compound was fi rst used for the seating of a mining hoisting machine (Fig. 5.17a), which was a K-6000 type machine serving the “Pułaski” pit shaft (shaft way) of “Wieczorek” hard coal mine in Katowice. During the long service life of this machine some large shifts of its foundations occurred as a result of mining damages, with resulting misalignment of main shaft bearings and the stators of machine motors (Fig. 5.17b).

The repair had to include a restoration of correct alignment between main shaft of the hoisting machine and the stators of its driving motors. EPY compound foundation chocks have been used for this purpose. The values of corrections in vertical alignment ranged from 0 to 35 mm for particular machine elements.

The seating operation of the machine was carried out in April 1996, and it has been in intensive service since that time. The technology of repair with the use of EPY compound for foundation chocks has again proved to be fully practicable and advantageous. Repair time was greatly shortened, accurate alignment of main shaft bearings and driving motor



Fig. 5.16. EPY compound use for the installation of a main air exchange fan in “Wieczorek” hard coal mine: a) fan installation layout drawing; b) foundation chocks arrangement plan

a)

b)

stators was obtained. The machine has been running stably since the time of repair and no objections have been raised.

Similar eff ects have been obtained in the seating of a 4L-4000/2400 hoisting machine in “Zabrze-Bielszowice” hard coal mine, carried out in October 1996. In February 2001 another hoisting machine was installed on EPY compound chocks in “Rudna” copper mine near Polkowice.

Fig. 5.18 shows an example of EPY compound use for the seating of rope pulley bearings (φ6000) in the structure of a hoist tower (Fig. 5.18a). The work have been carried out in “Wieczorek” hard coal mine in 1999.

The seating of mining machinery on EPY compound chocks have proved the signifi cant technical and economic benefi ts which may be achieved by introduction of this new method into mining industry. It makes the seating operations more effi cient and brings in an improvement of fi nal quality achieved - both in the new machinery installation and the repairs of existing machinery, also raising the safety of its operation.


Fig. 5.17.Use of EPY compound for the seating of a K-6000 hoisting machine in “Wieczorek” hard coal mine: a) the tower and the hoisting machine; b) hoisting machine installation drawing; c) arrangement of foundation chocks

Fig. 5.18. Use of EPY compound for the seating of a f 6000 rope pulley in the structure of a hoist tower of a “Roździeński” shaft in “Wieczorek” hard coal mine: a) view of a rope pulley on the hoist tower; b) layout drawing

of rope pulley bearing installation

a) b)

a) b)


5.4.3. Applications of EPY compound for the seating of large-size roller bearings in excavators and dumping conveyors

One of the basic prerequisites for correct running of large-size rolling bearings is an exact fi t of their lower and upper rings (constituting the bearing race) to the load-bearing surfaces over the entire circumference of the supporting structure and the structure rotated on top of the bearing.

The traditional method used for mounting of these bearings requires very precise machining (also manual) of contact surfaces on elements belonging to the supporting structure and the rotating structure. Introduction of a thin layer of EPY compound eliminates a costly procedure of surface machining, ensures a durable and stable installation of the bearing, and an exact fi t of its load-bearing surfaces to the elements of the supporting structure and the rotating structure.

This way the time taken by the installation of large-size bearings is signifi cantly shortened and the cost of the installation is reduced. Such solutions are used not only in cranes installed on ship columns (Fig. 5.11 — 5.12), but also in excavators, dredgers, radar antennas etc.

Fig. 5.19 shows a SRs-1200 brown coal excavator in “Konin” mine, whose bearing has been installed by using EPY compound. During the overhaul of the excavator a thin layer of EPY compound has been used to install the segmented ball bearing of its turn-table (diameter 8500 mm, Fig. 5.19b). The width of this layer was 200 mm, the thickness 5 — 20 mm, and a static loading of the bearing was 12000 kN.

Due to use of the compound a very laborious and costly procedure of machining the excavator structure elements adjacent to the bearing was avoided, and the need to disassemble the excavator was avoided as well. The compound ensured a highly precise installation of the bearing, and a uniform loading on its balls of 110 mm diameter. The overhaul was shortened and its cost was reduced. Many years of subsequent service have proven that the quality of the completed installation is good.

Another big machine whose large-size bearing will be installed by using EPY compound is ZGOT-15400.120 dumping conveyor shown in Fig. 5.20. The dumping conveyor, designed by Technical Design Offi ce SKW S.C. in Zgorzelec, is currently manufactured by FAMAK S.A. in Kluczbork. It will be assembled and used by brown coal mines in Bełchatów. The weight of rotating parts supported by the rolling bearing is 3400 tons, the diameter of the bearing is 12500 mm, and the diameter of a single ball is 200 mm.

5.4.4. Application of EPY compound for the seating of power industry machinery, rails and bridge span bearings

EPY compound is also used more and more for the seating of various machinery used by power industry, such as turbines, ball mills, fans etc. It finds its use for the machinery installed on top of both concrete and steel foundations. Use of the compound


Fig. 5.19. Use of EPY compound for the seating of a turn-table bearing (φ 8,5 m) of a SRs-1200 excavator in the brown coal mine “Konin”: a) view of the excavator; b) layout drawing of the excavator with the cross-section

of the turn-table bearing.

a)

b)


Fig. 5.20. ZGOT-15400.120 dumping conveyor with a ball bearing of φ12,5 m diameter installed by using EPY compound

for foundation chocks, cast in place under pre-aligned machines, simplifi es the installation work also this case, shortens the time taken by the installation and reduces its cost. On the other hand, better fi nal installation quality can be guaranteed than for the case of metal chocks. Fig. 5.21 shows an exemplary installation of a ball mill gear, executed with the use of EPY compound chocks in the power station “Siekierki”.

Fig. 5.22. shows how the compound can be used for positioning of heavy machinery installed on sliding plates.

EPY compound is also used more and more for the installing of straight and circular rails mounted on top of steel constructions, or concrete foundations / cross-ties. The examples of such applications are shown in Fig. 5.23 — 5.25.

Fig.5.26 includes the sketches of various practical methods which may be used for the applications of EPY compound for the seating of bridge span bearings. EPY compound has the technical approval of Road and Bridge Research Institute (no. AT/2001-04-0018). Figs. 5.27 and 5.28 show the examples of existing bridges where EPY compound was used for installation work.


Fig. 5.21. KAU ball mill gear installation (based on EPY compound chocks) - layout drawing

Fig. 5.22. Use of EPY compound for the seating of a turbine on sliding plates: 1 — machine foundation (steel or concrete), 2 — lower sliding plate, 3 — EPY compound, 4 — upper sliding plate, 5, 6 — elements blocking the

slide of an upper sliding plate, 7 — packing, 8 — machine bedplate


Fig. 5.23. Use of EPY compound for the seating of a track rail and a rotation rail of a port crane in Szczecin

Fig. 5.24. The method used for the seating of a rail on top of a concrete foundation by using the EPY compound


Fig. 5.25. Slewing rail of a KWK-1500s excavator (weight 1200 t) installed on EPY compound in the brown coal mine “Konin”: a) excavator layout drawing, b) slewing rail installation drawing, c) the method used for pressing

the compound into the space below the under-rail overlay

a)

b)

c)


Fig. 5.26. Drawings of the seating of bridge span bearing with the use of EPY compound: 1 — span, 2 — pier, 3 — compound, 4 — bearing, 5 — casting mould

Fig. 5.27. Railway bridge in Wolin, Poland with bearings installed on EPY compound chocks in 1994, acc. to drawings shown in Fig. 5.26b

a)

b) c)

d) e)


Fig. 5.28. “Siekierkowski” bridge in Warsaw during construction: a) view of a span, b) view of the bearing installed by using EPY compound in 2001, acc. to the drawing shown in Fig. 5.26e, c) general view

a) b)

c)

6. RESEARCH ON RESIN COMPOUNDS USED FOR FOUNDATION CHOCKS

6.1. General requirements regarding resin compounds used for machinery foundation chocks

There are many resin compounds whose compression strength is higher than the surface pressure exerted on foundation chocks used for the seating of shipboard machinery. Such conclusion, though very important, is insuffi cient for selection and application of a resin compound for this purpose. Apart from suffi cient compression strength, it must meet many other general requirements concerning resin compounds used on ships [39 — 40] and additional requirements concerning resin compounds used for machinery foundation chocks [38].

According to the general requirements of Polish Register of Shipping [61], resin compounds used on ships should:

— undergo a fl ammability test according to subsection 2.4 of the regulations [38],— emit no explosive gases (even in temperatures higher than usual) and no toxic or

suff ocating gases when burning,— should provide failure free operation of machinery in the following temperature

ranges: from –40°C to 70°C on open deck, and from –10°C to 70°C below deck, unless operating conditions require otherwise,

— not become brittle and their mechanical properties should not deteriorate by more than 30% from their initial values during their service life,

— be decay and mildew resistant and should not negatively interact with other adhering materials.

Apart from the general requirements listed above, resin compounds used for chocks must meet many additional requirements connected with the design and technology of mounting, as well as the reliability of mounted machinery during its long-term operation. The following factors must be taken into account when using chemically cured compounds directly under the machinery mounted on the ship:

— the method of preparing and using the compound,— its casting properties,— curing conditions,— casting shrinkage and settlement of chocks during assembly and in service,— work safety.

6. Research on resin compounds used for foundation chocks 84

Chocking compounds cast directly under properly aligned machinery completely eliminated the operation of fi tting the chocks, which was time and labour consuming. Resin compound, thanks to its casting properties, should fi ll the chock mould completely and in particular adhere well to the load-bearing surfaces of foundations and base plates. Casting shrinkage of the resin compound and the settlement of chocks during installation should be as low as possible. The process of mixing, pouring and curing must be possible in the conditions existing in the shipyard, or obtainable there (for instance the temperature of curing phase).

The above enumerated general and additional requirements were used as a basis for the development of the chocking compound and the technology used for chock casting and mounting shipboard machinery on the chocks.

6.2. General remarks about research on chocking compounds

The requirements regarding chocking compounds used for the seating of shipboard machinery (and so the research on them) may be divided into two categories: standard and special.

Standard research is usually conducted on small specimens of resin compounds. The shape and dimensions of specimens as well as the research method are precisely determined by the standards applying to resin compounds. Results of such tests serve to control the quality of resin compounds and to compare them with other similar or different resin compounds tested in the same way.

Real physical characteristics of resin compounds, though crucial to cast foundation chocks, are not evident in standard tests. The elasticity and viscosity properties of resin compounds cause that small specimens behave diff erently during simple test loads than full-sized structural elements (i.e. chocks) made from resin compounds. They show especially high strength and dilatational strain resistance during three-axial compression. The basic advantages of cast resin chocks which are most important for machinery seating, are an excellent fi t to the load-bearing surfaces of machine bedplate and its foundation, close to perfect value of modulus of elasticity, and high eff ective friction coeffi cient in contact with steel. These factors ensure a uniform distribution and transmission of loads in normal and tangential directions to the foundation surface. Resin compounds have of course other important technological and service-related advantages, for instance: they can be easily poured in place, can form chocks of various dimensions and shapes, and they damp vibration very well. Various advantages of chemically cured compounds contributed to their wider and wider applications, fi rst in shipbuilding and ship repair and then also for the seating of land machinery.

Standard research is conducted in conformity with applicable standards concerning resin compounds. Some more important results of such research conducted on chocking compounds are presented in table 2.1.

856.2. General remarks about research on chocking compounds

Striving for a wide application of resin compounds for the machinery seating required, apart from standard research, also various special research which would take into the consideration the real conditions occurring at machinery installation sites and connected with its construction, method of mounting and operation. Further subsections contain the descriptions and results of some more important special research testing carried out on the properties of EPY compound at the Technical University of Szczecin.

6.3. Research on infl uence of various substances and temperature on EPY compound compression strength

During their service life, foundation chocks of main and auxiliary shipboard machinery often come into contact with water and oils. Therefore, they must be resistant to long-term infl uence of these media. The compound EPY meets this requirement, which was confi rmed by appropriate tests.

Cylindrical specimens used for research had the dimensions φ 20 × 25 mm, were cast in a steel mould and cured for 3 days at temperature of 20°C. Next, they were held for 2 hours at 80°C. All specimens were divided into four groups. The fi rst one underwent compression test directly after the specimens were heated and cooled down to 20°C. The remaining three groups of specimens underwent compression tests after 31 days. During this time the specimens from groups two, three and four were kept respectively in the air, machine oil and tap water. The results of compression tests are presented in table 6.1.

Obtained test results did not show any negative influence of air, machine oil and tap water on the chocking compound. Little increase of compression strength after 31 days of specimen storage may be explained by the infl uence of additional time on the curing process.

Tests on the influence of temperature on EPY compound compression strength Rc,

were conducted on specimens prepared and cured identically as the ones used for the tests regarding the infl uence of oil and water. Specimens were cooled in methyl alcohol for 24 hours at minus 20°C. All the instruments contacting the specimens during the compression tests were also cooled to the same temperature. Tests in positive temperatures were conducted in a heating chamber. Before the compression tests, specimens were held for 2 hours at a given temperature. Test results are presented in table 6.2.

The tests (table 6.2) showed a considerable infl uence of temperature on the compression strength of EPY compound. The lower the temperature the higher the strength, and the higher the temperature the lower the strength, which is typical for all chocking compounds based on epoxy resins.

Apart from the above mentioned short-term tests of air, oil and water infl uence on compression strength of EPY compound (table 6.1), the Technical University of Szczecin has also carried out the tests on the long-term infl uence of various media on the strength


Table 6.1. Results of compression tests on specimens kept in air, oil and water

Table 6.2. Results of specimen compression tests conducted at diff erent temperatures

of epoxy compound, which took many years to complete. The tests started in 1975. Since that time, cylindrical specimens of epoxy compound EP-571 of diameter d = 20 mm, height h = 20 mm and composition close to that of EPY have been kept in glass jars with diff erent substances. After some time, a few specimens were taken out of the jars for compression tests. Test results are presented in table 6.3.

According to the results of the tests, only water (especially tap and distilled water) considerably decreased the compression strength of the compound. In case of tap water, the decrease of strength after 27 years equalled 40%. In the same period of time, sea water from

876.3. Research on infl uence of various substances and temperature on EPY compound compression strength

Table 6.3. Compression strength of EP-571 compound specimens subjected to long-term infl uence of various substances


Fig. 6.1. Scheme of loads exerted on specimens during fatigue tests

the Atlantic Ocean caused a considerably smaller decrease (by about 25%) of the compound strength. On the other hand, the resistance of the compound to long-term contact with water, petrol, paraffi n and oil (Hipol 10) is very high. No signifi cant quantitative or qualitative changes were noticed during the compression tests.

It must be stressed that the conditions of the laboratory tests were much worse than threats posed to the real foundation chocks, which results from the relatively high ratio of the specimens’ surface to their volume. In real foundation chocks only the free end surfaces run a risk of contact with any gas or liquid. Conclusions drawn from the above laboratory tests entirely confi rm the experience gathered in the service life of the chocks.

6.4. Research on EPY compound fatigue strength under compression loads

Apart from constant loads aff ecting foundation chocks of main and auxiliary shipboard machinery, which are caused by the weight of machinery and tensioning of holding down bolts, there are also time variable loads appearing in service. Due to that, it was decided to conduct fatigue strength tests of the compound under compression. The tests were carried out in accordance with instructions contained in DIN 50 100 standard. Cubicoidal EPY compound specimens of dimensions 12,5 mm × 12,5 mm × 25,4 mm were cured for 24 hours at a temperature of 23°C and additionally for 2 hours at 80°C.

The tests were conducted in servo-hydraulic strength-testing machine made by INSTRON company (model 8501 Plus). The adopted upper value of compressive stress was fi xed at σ

g

= –5 N/mm2 while the lower value of compressive stresses was changed within the range from –92 N/mm2 to –60 N/mm2. The specimens of the compound were loaded as shown in diagram 6.1 and the results are in table 6.4.

896.4. Research on EPY compound fatigue strength under compression loads

Table 6.4. Results of tests on EPY compound fatigue strength under compression loads (upper compressive stress σ

g = –5 N/mm2 = const.)

The tests showed that EPY compound has a very high fatigue strength under compression loads. The specimens of a very unfavourable shape in comparison with foundation chocks (very slender) endured safely 100 × 103 and 350 × 103 load cycles under variable compressive stress with a lower value σ

d = –65 N/mm2, and 107 load cycles with the lower value stress σ

d

= –60 N/mm2 without being. Next, the specimens were subjected to a static compression test. The results of compression test and its results differed neither quantitatively nor qualitatively between two groups of the same specimens, one of which was earlier subjected to fatigue loads.

Taking into account the fact that the allowable compression stress for chocking compounds is 5 N/mm2, the fatigue strength of EPY compound meets the safety condition with a very high margin. The results of the tests conducted on small specimens with unfavourable shapes can be projected onto machinery foundation chocks only with a further increase of the margin of safety both for static and fatigue strength.

6.5. Research on creep process and heat defl ection temperature of EPY compound

The compound EPY has not only good static and fatigue strength properties but also high creep resistance in elevated temperatures.

Creep resistance of any compound is a fundamental factor limiting the admissible pressures and the operational temperatures of foundation chocks. The limits for pressure and temperature were determined during long-term creep tests carried out at varying values of pressure and temperature.

Creep tests were conducted in accordance with ASTM-D621 standard in creep testing machines designed and made specially for this purpose at the Technical University of Szczecin (Fig. 6.2).


Fig. 6.2. Creep testing machine for chocking compounds: a) general view; b) simplifi ed diagram: 1 — mount, 2 — specimen counterweight, 3 — dial indicator (0,001 mm) measuring specimen distortions (changes in height ∆H),

4 — heating chamber, 5 — tested specimen

a) b)

The dimensions of tested specimens were 12,7 mm × 12,7 mm × 12,7 mm. The specimens were cast in special moulds and cured in various ways: at a room temperature (23°C) for 24 hours without any additional heating, or with 4 hours of additional heating at temperatures ranging from 50 to 90°C. Additional creep tests were carried out on specimens of the same dimensions, cut out from a foundation chock of 300 mm × 300 mm × 40 mm cast between two steel plates 14 mm thick.

All creep tests conducted at temperatures from 50°C to 90°C were done under compres-sive stress of 5 MPa. Specimens were put into the chamber of a creep testing machine at ambient temperature (about 23°C) and loaded to a compressive stress equalling 5 MPa. Indicators were set to zero and the temperature was increased at a rate of about 8°C/h until the foreseen test temperature was reached. Indication readings were recorded during the heating and when the test temperature stayed at the foreseen level. Creep charts were drawn for the averages of values obtained from three test specimens. The tests took 500 hours to complete. The example creep charts are presented in Fig. 6.3, 6.4 and 6.5. The detail results of all tests are comprised in the creep testing report [62].

As it can be seen in the charts (Fig. 6.3 — 6.5), at the beginning the height of the specimens rises when they are heated in the creep-testing machine. This is caused by the thermal expansion of the compound. The rise is higher than the concurrent creep. Creep process is characteristic for all resin compounds and is evidently present during the fi rst period of load test (a few dozens of hours). The process slows down considerably after 200 hours and almost stops after 500 hours, for the case of tested compound. The rate of creep for EPY compound depends mainly on the temperature at which specimens are cured,

916.5. Research on creep process and heat defl ection temperature of EPY compound

Fig. 6.3. Creep curves of EPY compound at various temperatures for specimens cast in moulds and cured for 24 hours at a temperature of 23°C + 4 additional hours at 80°C

Fig. 6.4. Creep curves of EPY compound at various temperatures for specimens cast in moulds and cured for 24 hours at a temperature of 23°C + 4 additional hours at 90°C

Fig. 6.5. Creep curves of EPY compound at various temperatures for specimens cut out from 300 mm × 300 mm × 40 mm chock cast between steel plates at ambient temperature 23°C, and cured for 30 h


Fig. 6.6. Heat defl ection curve for the specimen of EPY compound

and also on the temperature of the test. Low creep of specimens cut out from the chock (Fig. 6.5) is caused by the high temperature of compound exothermal point (about 90°C), which was reached when the compound was cured.

The heat defl ection temperature of EPY compound under load was determined according to the instructions contained in ASTM-D-648-82 standard. The specimens were cast in place in steel moulds. Their dimensions were: length l = 127 mm, height h = 12,7 mm, breadth b = 5,5 mm. They were cured for 24 hours at 20°C and then for 4 hours at 80°C. The specimens were put on two symmetric supports and bent with a force applied in the middle of the length, causing bending stress of σ

g = 1,8 MPa. Bending test was performed in the chamber

filled with heated air. The temperature was measured with thermometers placed near the specimen. Defl ection temperatures (according to ASTM-D-648-82) for three tested specimens were: 105°C, 102°C and 105°C [62]. The chart showing the example of a specimen defl ection as a function of temperature is presented in Fig. 6.6.

6.6. Research on the dynamic properties of EPY compound

The striving to reduce the vibration and noise on engine-driven ships as much as possible was always present. Following the development of technology, higher and higher requirements in this regard were laid down to producers of shipboard machinery and to shipbuilders. Today the elimination of vibration is one of the most important problems in shipbuilding and the service of ships.


There are many sources of various vibration frequencies on ships. Unbalanced forces and moments of a main propulsion engine cause a dominating vibration of low frequency (up to 60 Hz). Apart from that, they also cause vibration of higher frequencies. There are many other machines causing vibration on ships. Vibration of high frequencies in 1000 Hz range is particularly vexing for the crew and passengers. The vibration is partially emitted into the air and results in noxious and unpleasant noise. The rest of vibration energy, in case of rigid joints, goes to the foundation supporting a given machine or to other machinery connected to it. Next, transferred as a structural sound, it reaches all elements of the construction, including distant ones. Transmission of structural sound may result in a very undesirable side-eff ects such as noxious noise caused by the vibration of walls or various barriers both in the engine room and other rooms, and also forced secondary vibration (often even resonant) of other equipment.

Rubber pads or other special vibration isolators may be used to counteract the spread of vibration. Their application, however, is not always possible for the sake of machinery alignment precision, and also high costs and serious technical diffi culties connected with vibration isolators.

Foundation chocks cast from resin compounds off er not only installation advantages but also efficient damping and isolation of vibration usually noticeable by ship crews. Chocking compounds dampen machine vibration better than steel, traditionally used for this purpose. On the other hand, the contact surface between the compound and steel acts as a signifi cant barrier for structural sound. The aim of the research on dynamic properties of EPY compound was to determine:

— the logarithmic vibration damping decrement and the dynamic shear modulus,— the energy loss factor and the dynamic longitudinal modulus of elasticity,— the acoustic impedance.

6.6.1. Determination of logarithmic vibration damping decrement and dynamic shear modulus

Tests [36] were conducted with a torsional pendulum in accordance with PN-83/C-89042 and EN ISO 6721-2 standards. Identical specimens (fl at bars of L = 60 mm, b = 10 mm and h = 1 mm) made of EPY compound and steel were tested comparatively. The logarithmic vibration damping decrement and the dynamic shear modulus of the tested materials were determined experimentally. Fig. 6.7 presents exemplary time-amplitude transient characteristics of both materials at a temperature of 20°C, and Fig. 6.8 — the graphs of the logarithmic damping decrement and the dynamic shear modulus in function of temperature, for EPY compound and Epocast 36 compound (a German product).

The tests showed (Fig. 6.7) that under the same conditions, free vibration in EPY compound fades much faster than in case of steel. The ratio of logarithmic damping


Fig. 6.7. Time-amplitude characteristics of EPY compound and St3 steel obtained at 20°C and at frequency f = 1,77 Hz

Fig. 6.8. The relation of the logarithmic vibration damping decrement Λt and the dynamic shear modulus G’

t

to temperature, for the compounds EPY and Epocast 36

95

decrement of EPY compound and steel is Λ1 : Λ

s = 0,1326 : 0,0413 = 3,21. It means that the

damping coeffi cient of EPY chocking compound is three times higher than that of steel — a traditional material applied for the mounting of main propulsion engines. Dynamic shear rigidity of EPY compound is much lower than that of steel, with a ratio of respective rigidity values (at 20°C) being G’

t : G’

s = 2511 : 80000 = 0,0314. It is a considerable advantage of

the compound over the steel. High fl exibility of resin chocks and high friction coeffi cient in contact with machinery bedplate and the foundation allow for a considerable thermal and mechanical deformation of an engine without slipping. The surfaces of foundation chocks do not wear off , so the trend for the loosening of holding down bolts is much lower than in case of steel foundations.

6.6.2. Determining the energy loss factor and the dynamic elasticity modulus under compression

In order to gather more comprehensive data on the dynamic characteristics of EPY compound, useful for the applications of this compound in machinery foundation chocks, it was subjected to a compression test (Fig. 6.9) whose purpose was to determine the values of the energy loss factor h and dynamic elasticity modulus E

d under compression.

The energy loss factor h is a basic parameter defi ning the quantitative damping properties of the compound. The factor is derived in the following way:

(6.1)

where:W — the energy dissipated in one vibration period in relation to volume unit,U — the potential energy of elastic deformation, corresponding to a maximum

dynamic deformation, in relation to volume unit,ψ — dissipation coeffi cient for vibration energy (the relative dissipation of vibration

energy); ψ = W/U.Cylindrical specimens of φ 20 mm and 55 mm in length were cast in steel moulds,

cured for 24 hours at a temperature of 23°C and additionally cured for 2 hours at 80°C. The tests were performed in a servo-hydraulic testing machine (model 8501 Plus) made by Instron company.

Energy W was determined by using the method of a dynamic hysteresis loop. The service conditions of foundation chocks required the tests to be carried out under compressive loads as it is shown in Fig. 6.9.

Energy W dissipated in one vibration period in a given volume unit is proportional to the area of the dynamic hysteresis loop determined in coordinates σ – ε (Fig. 6.9c). The amount of energy was calculated by numerical integration as below.



(6.2)

The energy of elastic deformation U was derived according to the formula (Fig. 6.9c):

(6.3)

where:ε

a — deformation amplitude caused by dynamic load (Fig. 6.9c).

For a simple compression test, the dynamic rigidity of the compound in the examined point of static characteristic (Fig. 6.9a) is determined by a longitudinal dynamic elasticity modulus Ed derived from the formula (Fig. 6.9c):

(6.4)

The tests were performed for a wide range of variable parameters σśr, σ

a and frequencies

f = 1 — 20 Hz. The exemplary, experimentally determined hysteresis loop is presented in Fig. 6.10, and some of the test results are in Fig. 6.11 — 6.14. Detail reports and results of tests are presented in works [34 — 37, 49].

Fig. 6.9. Charts of a dynamic compression test carried out on EPY compound specimen

97

By looking globally at the obtained test results (Fig. 6.11 — 6.14), we may say that the values of energy loss factor η and dynamic elasticity modulus Ed depend on parameters σ

śr, σ

a, f and T. The dynamic load frequency f has the greatest infl uence on the energy loss

factor η, and temperature T has stronger impact on the dynamic elasticity modulus. Within the assumed range of parameter variability, the following values were obtained for EPY compound: η = 0,012 — 0,047, E

d = 5000 — 8500 MPa. The values obtained for steel are [63]:

η = 0,0016 — 0,0028, Ed = 2,1 × 105 MPa.

The values of energy loss factor h obtained for EPY compound are comparable to the loss factor values of special vibration isolating materials made from natural rubber (η = 0,02 — 0,16 [63]). In conclusion, the compound may be eff ectively used for vibration damping in mechanical systems. More research is carried out to enable the appropriate use of these properties.

Table 6.5 presents the values of the dynamic elasticity modulus Ed and loss factor η

for a few chosen materials.


Fig. 6.10. The dynamic hysteresis loop determined experimentally for the values: σśr

= 10 MPa, σa = 8 MPa,

f = 12 Hz

Table 6.5. Values of dynamic elasticity modulus Ed and energy loss factor η


Fig. 6.11. Results of example tests on a relation of energy loss factor h and dynamic elasticity modulus Ed to

frequency and temperature, at stresses: σśr = 10 MPa, σ

a = 4 MPa

a)

b)


Fig. 6.13. Results of example tests on the energy loss factor η and dynamic elasticity modulus Ed, at 60°C

temperature and mean stresses equal to 3 and 10 MPa

Fig. 6.12. Results of example tests on the energy loss factor η and the dynamic elasticity modulus Ed, at 23°C

temperature and mean stresses equal to 3 and 4 MPa


Fig. 6.14. The relation between the dynamic elasticity modulus and temperature for EPY compound

6.6.3. Determination of acoustic impedance

The concept of the acoustic impedance is a useful tool for the analysis of structural sound isolation. It is a measure of medium resistance to propagation of structural sound. It is known from physics [64, 65] that sound waves propagate in diff erent media with diff erent speeds. If a sound wave, propagating in a material, hits anoth er material of a diff erent acoustic impedance, then the fl ow of energy becomes very ineff ective.

In case of a plane and spherical sound wave travelling far from its source, the specifi c acoustic impedance R can be derived from the following formula for solid, liquid or gaseous bodies [65]:

R = ρv (6.5)where:

ρ — density of a medium, kg/m3,v — speed of acoustic wave in a medium, m/s.

The speed of sound in the analysed medium depends on the elasticity and density of the medium. The specifi c acoustic impedance for a longitudinal wave propagating in a solid body can be derived from the following formula [66]:

(6.6)

where: E — longitudinal modulus of elasticity.


Sound propagating in a material becomes refl ected when coming into contact with the surface of another medium (the compound here) and only a small part penetrates into the second medium. Then, a part of acoustic energy transmitted through the barrier changes into heat and disperses. The remaining part goes to the other end of a chock where it encounters another barrier and becomes refl ected in a major portion again.

If we accept the following values for steel and EPY compound: E1 = 2 ⋅ 1011 kg/ms2,

ρ1 = 7800 kg/m3, E

2 = 4915 ⋅ 106 kg/ms2, ρ

2 = 1590 kg/m3, then we will obtain the following

values of specifi c acoustic impedance for the analysed materials from the formula (6.6):— for steel R

1 = 39,50 × 106 kg/m2s,

— for EPY compound R2 = 2,85 × 106 kg/m2s.

Acoustic energy moving from body 1 to body 2 through the contact surface may be calculated from the following formula [65]:

(6.7)If it is taken into account that the acoustic energy emitted by a machine and moving

through EPY compound chock to the steel foundation must go through a wide contact surface, then such an energy transmitted from the machine to foundation 3 may be calculated according to the formula [65]:

(6.8)

If we substitute the above calculated values to the formula we will obtain:

(6.9)

The above given estimate shows that only about 6% of the sound energy is transmitted from the machine through the EPY compound chock to the foundation.

The result refers only to the propagation of sound energy through the chock to the foundation. The propagation of noise on a ship depends also on many other factors. Main and auxiliary machines mounted on resin compound chocks are fi xed to the foundation by steel bolts which transmit some part of sound energy without much resistance (loss). The amount of this energy depend on the diameter and the length of the bolt, as well as on the design solution and the rigidity of the connection between the machine and its foundation.

Therefore, the matter of vibration damping and isolation requires further, more complex research and development of appropriate design solutions striving for the optimum application of chocking compound.


6.7. Comparative research on static and dynamic properties of three various machinery chocking compounds

There are only three special chocking compounds currently available in the world market for the foundation chocking of main and auxiliary shipboard machinery, which have the approval certifi cates required for these applications. Apart from an American compound called Chockfast Orange (produced by ITW Philadelphia Resins) and a German compound Epocast 36 (produced by H.A. Springer marine + industrie service GmbH), Polish EPY compound produced by Marine Service Jaroszewicz company in Szczecin obtained the approvals of the classifi cation societies supervising the construction and repair of ships, as well as the certifi cates of the manufacturers of main and auxiliary shipboard machinery.

The principal aim of the research presented in this point was to experimentally determine the basic static and dynamic properties of all three compounds (Chockfast Orange, Epocast 36 and EPY) in identical conditions so that the Polish compound can be evaluated in comparison with the best known world products in its class.

The aim of the static strength tests was to determine the compression characteristics and the following parameters based on them:

— compressive strength Rc,

— proof stress R0,2

,— limit of elasticity R

0,02,

— longitudinal modulus of elasticity (Young’s modulus) E.The testing was conducted at ambient temperature on cylindrical specimens of

a diameter d = 20 mm and height h = 25 mm. The specimens of all three tested compounds were cast, cured and kept in the same conditions. Preparations for casting the specimens were done in accordance with the instructions of the manufacturers. Specimens cast in metal moulds were cured for 24 hours at 23°C and then (after their removal from the moulds) additionally cured for 2 hours at 80°C.

Compression test was carried out in the servo-hydraulic testing machine of Instron company (model 8501 Plus) by using a special computer program for static compression. This way it was ensured that the tests on all the specimens and the determination of values of their parameters were carried out in the same way. The results of compression tests are presented in Fig. 6.15.

The tests proved (Fig. 6.15) that all three compounds undergoing static compression tests behave identically as far as their quality is concerned, and the observed quantitative diff erences are minor and unimportant for the application of the compounds in shipboard machinery foundation chocks.

The aim of research into dynamic properties was to determine the dynamic elasticity modulus E

d and the energy loss factor η for all three compounds.

The fundamental characteristic of dynamic research is the fact that both input parameters (force for instance) and output parameters (distortion for instance) must be treated as time

1036.7. Comparative research on static and dynamic properties of three various machinery…

functions. In order to provide test conditions as close as possible to the real operating conditions of foundation chocks, the dynamic tests were conducted using simplifi ed axially symmetric models of the chocks (of outside diameter D = 60 mm, inside diameter d = 25 mm and height H = 20 mm) cast and cured between two steel disks simulating the foundation and the bedplate of a mounted machine. The models of chocks for the test were cast in special moulds. To prevent adhesion of compound to adjoining surfaces, a thin layer of release agent was put on steel surfaces. Cast models of chocks were cured for 24 hours at 23°C and additionally cured for 4 hours at 80°C.

The models of chocks prepared this way along with the steel disks were compressed in the servo-hydraulic testing machine (Instron, model 8501 Plus) with the use of special instrumentation (Fig. 6.16): an extensometer of Instron company, measuring the distortions (height change ∆H) of tested c hocks. The tests were conducted at the ambient temperature of 23°C and at 80°C. A special computer program (Wavemaker) ensured that the dynamic tests were conducted in exactly the same way for all three tested compounds.

Variable parameters during the tests were: mean stress (σśr = 5 and 10 MPa), amplitude of

dynamic stresses (σa = 2, 4, 6 and 8 MPa), frequency (f = 1, 5, 10, 15 and 20 Hz) and temperature

(T = 23 and 80°C). Detail records of dynamic tests are presented in the work [49]. Example test results are presented graphically in Fig. 6.17 and 6.18. Figure 6.17a presents a time function of compressive stress executed as programmed by the testing machine, and Fig. 6.17b, c, d respectively — the time functions of contact distortions (height change ∆H) in chock models made of the three tested compounds. Figure 6.18 presents the dynamic hysteresis loops of tested chock models made of the three diff erent compounds.

Fig. 6.15. Summary results of static compression tests on three compounds


Fig. 6.16. Test stand with Instron machine: a) general view; b) schematic diagram

a)

b)

105

Fig. 6.17. Time functions of compressive stress (s) and distortions caused by it (height changes ∆H) in chock models made of three diff erent compounds (σ

śr = 10 MPa, σ

a = 2, 4, 6, 8 MPa, f = 10 Hz, T = 80°C)

a)

b)

c)

d)

6.7. Comparative research on static and dynamic properties of three various machinery…


Fig. 6.18. Dynamic hysteresis loops for chock models made of three different compounds (for distortions as shown in Fig. 6.17)

a)

b)

c)

107

Time functions of distortions in the tested chock models demonstrate (Fig. 6.17 and 6.18) that the dynamic properties of the three compounds are identical with regard to quality. Slight quantitative diff erences are insignifi cant in practical applications. In conclusion, we may say that the tested compounds are in the same class as far as their static and dynamic properties are concerned.

6.8. Research on fl at butt joints of direct contact and with a thin layer of EPY compound

6.8.1. Butt joints loaded with normal force

Machined surfaces of machinery elements are not perfectly smooth. Existing irregularities (roughness, undulation and shape errors) cause that two such surfaces can not contact each other over the whole nominal contact surface area but only in its little part (Fig. 6.19a). The actual contact surface area is a small percentage of that nominal and depends on the value of normal pressure exerted on the surfaces [67]. What follows is that the actual contact stress pattern and stress values are much diff erent from the ones obtained on the basis of assumptions or calculations made for butt joint of perfectly smooth surfaces. Contact stress pattern and stress values depend mainly on the type and accuracy of machining operations and the physical properties of surface layers. Discontinuous contact of machined surfaces has a signifi cant infl uence on the mechanical characteristics (Fig. 6.19b) of butt joints of machinery components, and as a consequence, also on static and dynamic properties (stiff ness and vibration damping) of any complex mechanical system.


Fig. 6.19. Contact between two machined surfaces and its characteristics: a) sketch of the butt joint; b) relation of normal contact strain to surface pressure (experimentally determined for the contact of two steel surfaces

of roughness parameter Ra = 5 µm)

a) b)


Fig. 6.20. Relation of normal contact strains to mean surface pressure in the contact joint between two steel cylinders without any compound layer (curves “a”) and with compound layer (curves “b”)

Application of a thin layer of compound in the joints between machinery components required conducting the research on fl at contact joints with the compound and without it. Figure 6.20 presents the experimentally determined characteristics [35] illustrating the relation of normal contact strains to mean pressure in a direct contact between two steel cylinders compressed together axially in a compression testing machine. The face of cylinder 1 was milled (R

a = 5 µm), and the face of cylinder 2 — turned (R

a = 5,5 µm). The

tested specimens were pressed against one another with a mean pressure growing from 0 to 100 MPa. Next, they were unloaded and loaded again.

Curves in Fig. 6.20 illustrate the relation of contact strains to mean normal pressure for the contact joint of specimens 1 and 2 without any compound layer, and curves b — for the contact joint of the same specimens with a thin layer (about 0,5 mm) of cured EPY compound. The compound was introduced in a liquid state and, under some pressure of connected components, it precisely fi lled the uneven gap between metal surfaces. In order to facilitate the disassembly of the connected components, their metal surfaces were covered with a thin layer of a release agent.

The tests (Fig. 6.20) show that the thin layer of the compound signifi cantly changes the characteristics of contact joints between machined surfaces. Strains in the joint

109

of components without any compound layer are non-linear (curves “a”). Considerable resin strains (on the points of contact on rough surface) are present during the first loading. During the second loading (not exceeding original values), strains are elastic and non-linear.

Contact strains in the joint of components with a layer of compound (Fig. 6.20, curves b) are elastic, approximately linear in the relation to the applied load, and much smaller. Compression characteristics of tested joints diff er in capability of vibration damping as well (the areas inside the hysteresis loops are diff erent).

The actual contact strains occurring in the joint without the compound are non-uniform. Locally, where the surfaces actually make contact, strains exceed the yield point, which results in a so-called surface settling, which in turn causes a loosening of the bolts. Under cyclic loads this may lead to “hammering” on the surfaces and result in emergency situations.

The compound provides a full contact of connected components as well as a continuous and more uniform distribution of contact strains not exceeding the yield point. It ensures a good interaction of connected components not only under static loads, but also under long-term dynamic loads.

In case of thin layers of compound cast between two metal surfaces, the ratio of cross-section area A to height (thickness) H of the compound layer is very high. The tests were conducted on steel specimens of 20 mm diameter and 25 mm length composed of two parts with a thin layer (about 0,5 mm) of EPY compound in between (Fig. 6.21a). The specimens were subjected to axial compression in a compression testing machine until considerable resin strains occurred (Fig. 6.21b). During the test, the thin layer of EPY compound underwent resin deformations together with the metal parts, increasing its diameter and decreasing its thickness. Nevertheless, it maintained its full tenacity and could be easily separated from steel surfaces due to use of a release agent.


Fig. 6.21. Diagram of a steel specimen with the layer of compound before and after compression test

a) b)


Fig. 6.22. Stress distribution in the middle cross-section of the compound layer

The maximum value of compression stress during the test was σmax

= 1000 MPa. In spite of high values of compression stress, exceeding the compressive strength R

c of

standard compound specimens (φ 20 mm ⋅ 25 mm) many times, thin layers of the compound compressed between two metal surfaces were not destroyed. The high compression strength of the compound may be explained by the limited freedom of transverse straining and by a complex state of stress in the compound. The eff ective friction coeffi cient between metal and compound (cast and cured between metal surfaces) is usually higher than 1, which rules out any sliding of the contact surfaces.

Figure 6.22 presents stress distribution and stress values in the 2 mm thick layer of compound, constituting the middle cross-section of a φ 20 ⋅ 25 mm specimen compressed with evenly distributed stress σ

o = 170 MPa, which were calculated with the fi nite element

method. Parameters assumed for compound: Et = 5000 MPa, ν = 0,37. Calculations prove

(Fig. 6.22) that compound undergoes three-axial compression which is very advantageous. Reduced stress in compound, calculated in accordance with the Huber’s hypothesis [68], is much lower than the component stresses. It explains why the compressive strength of thin layers of compound can be so high.

After the compression tests on thin layers of the compound, the question arose whether after such high compressive strains (considerably exceeding compound strength Rc which was determined for standard specimens), the compound maintains its original strength

111

Fig. 6.23. Results of compression tests on EPY compound specimens φ 20 mm ⋅ 25 mm: a — specimen freely compressed; b — specimen compressed in a steel plate hole (2); c — overloaded specimen taken out from

steel plate and freely compressed [69]


properties. In order to answer this question, a compression test was carried out on specimens [35]. The results are presented in Fig. 6.23. The curve “a” illustrates the compression process of a specimen made of EPY compound, determined in a standard compression test, and the curve “b” — illustrates the compression process of the same specimen precisely fi tted in the hole in a steel plate limiting the specimen’s freedom of transverse deformation. In such conditions, the specimen could not be destroyed. After the specimen was taken out of the hole, it was subjected to a standard axial compression test, where it showed its original compressive strength which is illustrated by curve “c” in Fig. 6.23.

On the basis of tests and theoretical analysis, we may say that a thin layer of the compound compressed between two metal surfaces may safely endure high compression loads. Twenty years of experience prove that this applies not only to static loads, but also the dynamic loads present during the service of machinery.

Results of these tests were used for the seating of large-size bearings in ship cranes, dredgers, brown coal excavators, dumping conveyors etc.


6.8.2. Contact ( butt) joints under constant normal force and variable tangential force

Contact (butt) joints of machinery components are subjected not only to normal forces but the tangential forces as well (Fig. 6.24a). In such cases, a thin layer of EPY compound considerably infl uences their static and dynamic characteristics, and in consequence the operational quality, reliability and durability of contact joints so commonly present in any machinery.

Figure 6.24 presents a model of a bolt joint and the test results [70] concerning its reaction to a constant axial force and a slowly growing load in direction tangential to connected surfaces. In the joint, the external load (tangential) is transferred by a force of friction which depends on the friction coeffi cient and exerted normal force The tests were conducted for a direct contact of joined elements (S-S) and contact with a thin layer of EPY compound cured between two joined surfaces (S-T-S; Fig. 6.24a). In order to prevent a permanent adhesion, the surfaces were covered with a thin layer of release agent. Detail test records are presented in the works [69, 70].

Static characteristics of the tested joints, demonstrating the relation of tangential displacement to the value of mean tangent stress, are presented in Fig. 6.24b. Just like under standard loads, considerable qualitative and quantitative diff erences occur also in this case. Static characteristic of a bolt joint without the compound (Fig. 6.24b, curve 1) is non-linear under the applied loads and shows elastic -resin character of the tangential displacements δ

τ. Irreversible sliding is noticeable. Besides, there are also elastic displacements which

have very low values. On the other hand, the static characteristic of a contact joint with a thin layer of compound (about 0,7 mm) is linear and elastic even under a tangential load three times higher (Fig. 6.24b, curve 2). Under the load, no sliding of contact surfaces was observed which guarantees a better behaviour of such a joint in service.

Figure 6.25 presents the characteristics of tangential displacements at the contact in a bolt joint under tangential static and dynamic stress. In direct contact (S-S) considerable sliding of joined surfaces was observed already under low mean stress (τ ≅ 1 MPa, Fig. 6.25a) and the dynamic sinusoidal stress with relatively small amplitude. On the other hand, if a thin layer of the compound is present (S-T-S joint), even three times higher values of mean stress and dynamic stress amplitude caused little elastic tangential displacement only, which disappeared completely after the removal of tangential load (Fig. 6.25b). Lack of sliding is very advantageous for the joint, as fretting and abrasive wear do not occur. As a result, we benefi t from high durability of bolt joint and its better operation in service, resulting from much higher eff ective friction coeffi cient in the contact between compound and metal, in comparison with a contact between two metals.

6.9. Research on models of holding down bolts fi t in the compound

Fitted bolts are applied in the seating of main and auxiliary shipboard machinery in order to transfer considerable forces acting in directions tangential to the load-bearing

113

Fig. 6.24. The drawing of a bolt joint (a), and its static characteristics under constant axial force and slowly growing load tangential to joined surfaces (b)

a)

b)



Fig. 6.25. Dynamic characteristics of a bolt joint: a) direct contact (butt); b) with a thin layer of the compound

surface under the mounted machine, which applies in particular to main engines and main gears. Boring and reaming of the holes for fi tted bolts, especially in case of cast compound foundation chocks, is diffi cult and costly. In order to avoid these diffi culties, a concept of fi tting the holding down bolts in the chocking compound has been developed. For that purpose, the holes in foundation and bedplate must be bigger than the bolt diameter by 2 — 10 mm. Next, after the engine is aligned and loosely-fi tting bolts are inserted, liquid compound is poured into chock moulds, also fi lling the gaps around bolts in the holes in foundation and the engine’s bedplate. However, any practical application of this method required appropriate laboratory testing.

The tests were fi rst conducted on the model of a foundation joint presented in Fig. 6.26. The holes in joined elements 1, 2 and 3 had the diameters bigger by 2 mm than the diameter of bolt shank 5. In order to prevent adhesion between the bolt and the compound, the bolt was covered with a release agent (Silform AR1). When the model was positioned in such a way that the axis of the bolt was vertical with its nut on the top, and when the appropriate mould was arranged in place, two chocks of dimensions 100 mm × 100 mm × 40 mm were cast in the model including also the compound sleeves between the bolt and the respective

115

plates. Filling the spaces between the bolt and the walls of the holes in plates took place only by the hydrostatic pressure of liquid compound column.

When the compound cured, a model of a “double” bolted joint was ready. Half of the model simulated the real foundation joint subjected to static force. The model was loaded with force P in the compression testing machine as shown in Fig. 6.26. Under the force P = 190 kN, cracks appeared on the fl anks of the chocks. The test was interrupted when the force P reached 211,2 kN. The force required to extrude the bolt equalled 48 kN. The maximum value of pressure on the compound in the plate holes amounted to 159,4 MPa. When the bolt was removed, it was observed that the compound layer of 1 mm thickness fi lled the space between the bolt and plate walls in holes very well and was not destroyed (no upsets or cracks). In the place where force P was exerted, permanent bolt defl ection equalled 1 mm.

Fig. 6.26. The model of a foundation bolt joint with the bolt fi tted in the compound and a scheme showing how the joint was loaded



Fig. 6.27. The drawing of the bolt shank fi tted in compound ( and its loading scheme): 1 — steel plate, 2 — bolt shank, 3 — compound

The test proved that:— the compound fi lled the gap (about 1 mm wide) between the bolt and the walls

of the hole very well;— the joint with the bolt fi tted in the compound can endure considerable transverse

loads;— it is possible to disassemble the joint even after some permanent bolt defl ection.Another test was performed on holding-down bolt shank fitted in the compound

according to Fig. 6.27. The shank was fitted in the hole of steel plate eccentrically, so that the maximum thickness of the compound sleeve was 1,5 mm and the minimum was 0,5 mm.

Liquid compound was poured vertically into the gap between the bolt shank and the wall of a steel plate. The shank was covered with a thin layer of a release agent. The test was performed on two models. In one, the layer of the compound (0,5 mm) was compressed in the thinnest place, and in the other — the thickest part was chosen (1,5 mm). Compression test on the fi rst model was stopped when the force reached 260 kN, and on the other model — at 200 kN. The test was stopped when a permanent distortion (bending) of the bolt shank was noticeable.

The disk was cut after the test in order to examine the condition of the compound. The compound fi lled the gap very well providing the desired tight fi t for the bolt shank. Compression stress (250 and 192 MPa) arising during the test did not destroy the compound (except for its edges). Cast sleeve of the compound did not lose its tenacity either, and it adhered to the walls of the hole in the plate.

117

Further tests concerned the compression strength of the sleeve’s thin wall cast and cured in the gap between the bolt and a semicircular pit in a steel support. The tests were performed as shown in the diagram in Fig. 6.28.


Fig. 6.28. The drawing of a compression test on a thin sleeve cast of chocking compound

The main aim of the tests was to fi nd out how a thin sleeve made of the compound would behave under high compression stress.

Specimens prepared for the tests differed in the thickness of sleeves made of the compound (Fig. 6.28). The surfaces on supports and bolt shank contacting the compound were covered with a release agent (Siliform AR1). The compound was cast and cured for 10 days at about 18°C. After that, all three models underwent a compression test shown in the diagram in Fig. 6.28. The test was performed in a compression testing machine ZD-100. The specimens were subjected to radial force growing from 0 to 1000 kN and distributed on the shank generating line. Compression stress exerted on the compound ranged from 635 to 694 MPa depending on the diameter of the shank.

For all tested specimens, the compound was neither destroyed nor noticeably damaged. There was no outfl ow of the compound under temporary compression force of 1000 kN either. However, considerable resin deformations occurred in bolt shanks in the places of their linear contact with the pressing plate of a compression testing machine. The tests proved a high strength of a thin layer of the compound under static compression when cast and cured between two metal surfaces. No signifi cant diff erences were noticed between the compounds of 2 mm, 1 mm and 0,1 mm thickness.

Positive results of laboratory tests and practical implementations confi rmed that the compound could be applied for fi tting the holding-down bolts used for mounting the engines on shipboard foundations. It was an innovative solution which was patented [43] and approved by classifi cation societies.


6.10. Research on optimum application of EPY compound for the seating of deck machinery

The permissible compression stress on the compound used in foundation chocks under main marine engines amounts to 5 MPa. Such a low permissible stress was determined by classifi cation societies because of the creep compliance the compound shows at higher temperatures. Because the compression strength of standard specimens made of the compound is 140 — 150 MPa, compression safety factor is 28 — 30. In reality, the strength of the compound in a foundation chock is much higher than in case of standard specimen because the ratio of bearing surface to height is high. As a result, safety factor exceeds 30 by a high margin. For the same reason, the creep of compound foundation chocks is also considerably lesser than the creep determined for standard specimens.

Windlasses and mooring winches as well as other auxiliary shipboard equipment do not require such a precise mounting as main engines. Therefore, there is no need to apply such exaggerated, high values of the safety factor. As a result, foundation chocks may be smaller and compound strength properties may be used more rationally.

The application of EPY chocking compound instead of steel chocks under windlasses and mooring winches while keeping the designs of this machinery required special research accounting for compression pressures much higher than 5 MPa.

The aim of the research was to give answer to the question whether chocking compounds used under windlasses and mooring winches could safely endure 15 MPa pressure during installation, operational pressure of 30 MPa and short-time emergency pressure of 60 MPa in the period t = 30 minutes. To answer the question, some theoretical analysis was performed and the tests were carried out on the models of chocks.

6.10.1. Theoretical analysis

For a specimen with dimensions φ 20 mm × 25 mm subjected to free compression, we may assume a uniaxial state of stress if friction is neglected. In a real chock, because of limited possibilities of transverse strain (except for free edges), there is a complex state of stress. The compound in a chock is subjected to three-axial compression, which translates to favourable operational conditions and high static and fatigue strength. By assuming that a cubicoidal element separated imaginatively from a chock cannot be deformed in transverse directions x and y (Fig. 6.29), we can derive the following relation on the basis of the generalized Hooke’s law [68]:

(6.10)

where: p — surface pressure, ν — Poisson ratio.

1196.10. Research on optimum application of EPY compound for the seating of deck machinery

By assuming (on the basis of our own research) that Poisson ratio of EPY compound ν = 0,376, we obtain:

(6.11)

Reduced stress in a chock is derived according to the Huber’s hypothesis [68] from the formula:

(6.12)

By substituting appropriate stress values expressed by pressure p we obtain:

(6.13)

Fig. 6.29. Stress state in chocking compound

The calculations above presented are a rough approximation only. Reduced stress calculated in this way must be lower than a proof stress of the compound determined under uniaxial stress. The yield point for EPY compound R

0,2 equals 90 ÷ 100 MPa. As a result, the

calculated surface pressure in a chock must fulfi l the following condition: p < R0,2

/0,397 ≈ 2,5 R0,2

which results in an increase of a safety factor determined for a standard compound specimen undergoing a simple static compression test by 2,5 times.


Fig. 6.30. The model of windlass chock tested under surface pressure of 90 MPa

6.10.2. Tests on a windlass foundation chock model

The aim of the tests was to check how a model of an EPY compound foundation chock measuring 100 mm × 100 mm 15 mm (Fig. 6.30) is going to behave within the period of 60 minutes under the force F = 900 kN exerting the pressure p = 90 MPa.

A chock of EPY compound was cast in place between two steel plates and cured for 3 days at ambient temperature (about 24°C). Such model of a joint (two steel plates with a chock cast in between) was subjected to compressive load

P = 900 kN in a compression testing machine. The chock was left under the test load (P = 900 kN) for 60 minutes. After that, the load was removed and the chock was thoroughly inspected. No damage and no changes were found in the tested joint. In conclusion, we may say that surface pressure p = 90 MPa (half as much again than the assumed emergency pressure) operating for 60 minutes does not pose any threat to a compound chock cast and cured between two metal plates.

6.10.3. Research fi ndings

On the basis of theoretical analysis with calculations carried out and the conducted tests on models we may say that adopting installation stress of 15 MPa, operational stress of 30 MPa and emergency case stress of 60 MPa (for 30 minutes) for the seating of windlasses and mooring winches on foundation chocks made of EPY compound is safe, and will not produce any adverse eff ects.

6.11. Research on infl uence of paint coating on the settling of shipboard machinery mounted on cast compound chocks

6.11.1. Introduction

Present-day assembly of ships on a slipway consists mainly of connecting together smaller or bigger but already manufactured hull blocks. In order to prevent corrosion, surfaces of the elements are cleaned and covered with one or many layers of protective paint coating which is from more than 10 µm to about 300 µm thick.

1216.11. Research on infl uence of paint coating on the settling of shipboard machinery mounted…

The traditional installation of machinery on ship foundations with the use of metal chocks requires that the coating must be removed before fi tting the chocks to properly cleaned and machined metal surfaces, which is laborious, time consuming and costly.

Nowadays, chocks of chemically cured compound cast in place directly under the machine replaced the traditional metal chocks in the seating of shipboard machinery. Therefore, the question arose whether and how paint coating would infl uence the quality of the seating. In order to answer the question, it was necessary to plan and conduct some unconventional tests which would show the influence of paint coating on the settling behaviour of interacting contact surfaces in real-life conditions in which main engine and auxiliary machinery are assembled on ships. The tests were ordered by Szczecin Shipyard S.A.

The fundamental aim of the tests was to answer a more specifi c question: whether, before commencing the assembly of main engine and auxiliary equipment on a ship, paint coating should be removed from load-bearing surfaces of foundations or left there, so the foundation chocks made of EPY compound are directly cast on the painted surfaces under the machine.

6.11.2. Tested specimens and test bed

The tests were performed on cylindrical specimens cut out from steel plate and coated with anticorrosive paint on one side. Their diameter equalled 90 mm and the height was 40 mm. The specimens were made and painted in Szczecin Shipyard according to a painting plan for B170/III ship series. There were seven specimens, some of them without any coating and some with a single-layer or multi-layer paint coat with thickness ranging from 11 µm to 289 µm. Details concerning paints, number and thickness of coatings are contained in the works [33, 71]. For every specimen supplied by Szczecin Shipyard, a steel counter specimen was prepared whose diameter was 90 mm and the height 46 mm.

In order to attach the instrumentation measuring contact strain, holes were drilled, turned and tapped in the specimens (Fig. 6.31). Contact surfaces of the specimens were ring-shaped, and had a nominal area A = 55 cm2.

Modern servo-hydraulic compression testing machine Instron (model 8501 Plus) with special instrumentation was used for the tests. Special computer program “Wavemaker” managed the whole process of loading control according to an assumed plan, and recorded the result data. Measured values of force and contact defl ections δ (extensometer indications) were frequently recorded in time domain as ASCII files. The files were transferred to Excel spreadsheet for data processing and graphic presentation of the tests and results.


Fig. 6.31. The drawing showing the method used for measurements of contact deflection and roughness parameters of specimens

6.11.3. Testing program, its execution and example results

The tests were carried out in two rounds: first, all specimens and counter specimens were compressed without the compound (Fig. 6.32a, c) and next, the same was done with specimens having a layer of EPY compound cast in between, cured (for 48 hours in a temperature of 23°C) and about 1 mm thick (Fig. 6.32b, d). In order to prevent adhesion of specimens, their contact surfaces were covered with a thin layer of release agent (Spray FT 36).

All specimens (with and without the compound) underwent linear loading to the increasing values of compressive force F and subsequent unloading. Fig. 6.33 — 6.36 present example charts of test programs and test results.

Figure 6.33 presents the values of assumed and exerted surface pressure p and contact distortions δ

a and δ

b caused by the pressure in specimens without paint coating as a function

of time; δa refers to contact joint without the compound (Fig. 6.32a), and δ

b — to contact

joint with EPY compound (Fig. 6.32b). The shape of curve da (Fig. 6.33) demonstrates that the relation of contact distortions to surface pressure for specimens without the compound (metal — metal) is strongly non-linear. In this case contact defl ections (total, both elastic and resin) are considerable (δ

amax = 34 µm). Lower points of curve δ

a, corresponding to zero

pressure, indicate resin contact distortions caused by the preceding maximum loads.

123

Curve δb (Fig. 6.33) presents a time function of contact distortions in specimens with

EPY compound (metal-compound-metal). Maximum contact distortions are much smaller (δ

bmax = 4 µm), elastic and linear.

The results from Fig. 6.33, processed in a way showing the relation of normal contact distortions to surface pressure, are presented in Fig. 6.34. Considerable qualitative and quantitative diff erences can be observed between contact distortions of specimens without the compound (curves δ

a) and with the compound (curves δ

b). Metal surfaces without any

EPY compound, because of their roughness, waviness and shape errors, make contact in a number of “spots” (Fig. 6.32a). Actual surface pressure is very high and causes considerable resin distortions in the spots of contact. As a result, apart from the specimens being brought together in elastic way, there is also permanent closing (so called settling) of surfaces. EPY compound layer between two surfaces (Fig. 6.32b) fi lling all the micro and macro pits ensures a tight contact of surfaces and a uniform load on the whole nominal contact surface. As a result, linear and elastic contact distortions are very low (Fig. 6.33, 6.34 — curves δ

b).


Fig. 6.32. Diagrams of contact surfaces: a), b) specimens without paint coating; c), d) specimens with paint coating


Fig. 6.33. Surface pressure p and the resulting surface distortions (in time) for specimens without paint coating: δ

a — witho ut the compound, δ

b — with EPY compound

Fig. 6.34. Relation of contact distortions to surface pressure in specimens without paint coating: δa — without

the compound, δb — with EPY compound, under load as in Fig. 6.33


Fig. 6.36. Relation of surface distortion to surface pressure in specimens with four layers of paint coating: δa — without the compound, δ

b — with EPY compound, under load as in Fig. 6.35

Fig. 6.35. Surface pressure p and the resulting contact distortions (in time) in specimens with four layers of paint coating: δ

a — without the compound, δ

b — with EPY compound


Figures 6.35 and 6.36 present the program and results of analogous tests conducted on specimens with four layers of paint coating (289 µm thick in total). Curve δ

a shows the

distortions in contact surfaces: metal + paint coating — metal (Fig. 6.32c). Same as in case of specimens in Fig. 6.32a, the distortions da are large, non-linear, elastic and resin. However, the proportions of elastic and resin distortions are diff erent and moreover some rheological eff ects take place in paint coats (distortion changes in time [33, 71]).

Curves δb in Fig. 6.35 and 6.36, presenting the changes of distortions in contact joints of

type metal + paint coating — EPY compound — metal (Fig. 6.32d) are linear. The distortions are very low, in comparison with distortions in the same specimens without a layer of EPY compound. They are also linear and elastic.

Similar results (qualitatively) were obtained in tests of the remaining specimens with paint coats [71].

The tests proved the benefi cial infl uence of EPY compound on compliance abilities of contact joints, both with and without paint coats. When EPY compound was applied, paint coating from 11 to 289 µm thick did not show any adverse eff ect on compliance abilities of the joint or its settling. Contact joints of the same specimens without any EPY compound and with paint coating showed much higher creep compliance (also vibration-induced) — from 7 to 10 times higher, which results in the settling of contacting surfaces [71].

6.11.4. Conclusions

On the basis of the above presented tests, we may reach the following conclusions answering the questions put up in the introduction.

1. In case of mounting the shipboard machinery on foundation chocks cast in place from EPY compound, presence of protective paint coating on foundation surfaces does not have any infl uence on mechanical properties of contact joints between the foundation, chock and bedplate. Neither the type of paint coating nor the number of layers or their thickness (which ranged from 11 to 289 µm) have any practical infl uence on the tested contact joints. If EPY compound is applied, the characteristics of contact joints for specimens with and without paint coating are almost the same.

In conclusion, there is no justifi ed reason to remove protective paint coats from the foundations before the machines are installed on them. On the contrary: the presence of paint coats may be benefi cial for corrosion protection.

2. Mechanical characteristics of contact joints between two clean metal surfaces and joints between one clean metal surface and a metal surface covered with protective paint coat diff er considerably when there is no EPY compound in between. There are contact distortions and noticeable creep in a contact joint with paint coating. Therefore, in case the machinery is mounted on traditional metal chocks, the removal of paint coating is justifi ed.

1276.12. Analysis and model tests of stern tubes installed with the use of chocking compound



Technical University of Szczecin has started the research on mounting propeller shaft stern tubes with the use of chemically cured compounds as early as in 1976. As a result, a new installation technology was implemented in Polish shipyards. The fi rst stern tube was mounted in 1979 by Ustka Shipyard in a B410/2 vessel. Since that time, 927 stern tubes and rudder arrangement liners altogether have been mounted on various ships till the end of 2001.

The research and industrial introduction work conducted till 1994 concerned stern tubes of relatively small diameters up to 510 µm. Positive experience gathered in service of stern tubes installed by using the compound gave good grounds for attempts to use the same technology in the mounting of stern tubes of bigger diameters and lengths. Nevertheless, it was necessary to do some additional design analysis and check many details of the installation technology during appropriately programmed model tests in conditions as close to the real ones existing on ships as possible. Such tests were carried out in 1994 by Marine Service Jaroszewicz in close cooperation with the Technical University of Szczecin, Szczecin Shipyard and Gdynia Shipyard. The detail description of the tests and their results are presented in the report [72] and a short summary is given below.

6.12.2. Aims of tests

The aims were:— to analyse the thermal insulation properties of compound layer in an assembled

construction in comparison with the traditional technology and to formulate possible requirements concerning cooling;

— to analyse thermal deformations of the construction;— to polish up all the details appearing in the mounting of big stern tubes with the use

of EPY compound, and to test them on an appropriate model.

6.12.3. Analysis of thermal insulation properties of a construction containing a layer of compound

In order to analyse the thermal insulation properties of a tube system with a layer of EPY compound, it was necessary to fi rst determine experimentally the thermal conductivity of the compound. Such — research was conducted by the Chair of Heat Engineering at the Technical University of Szczecin [73]. The value of thermal conductivity for EPY compound determined at a temperature of 20°C is:


λ = 0,48 W/mK

A model of three coaxial tubes (Fig. 6.37) was used for the comparative analysis of thermal conductivity between frame tube, propeller shaft stern tube and EPY compound. Boundary conditions of the fourth kind were assumed for the model, i.e. a perfect contact of two elements and temperature equality of both bodies over the surface of contact.

Fig. 6.37. Model of the system: frame tube, propeller shaft stern tube and EPY compound layer

A linear model of a specifi c thermal resistance for a cylindrical wall in radial direction was adopted for the comparative analysis of thermal conductivity. The resistance was calculated from the formula:

(6.14)

where:d

i(i=1,2,3,4) — diameters as in Fig. 6.37,

λi — thermal conductivity.

Calculations were conducted for three cases:1. Propeller shaft stern tube is mounted in compound (as in Fig. 6.37). The following values

were assumed: d1 = 880 mm, d

2 = 960 mm, d

3 = 1000 mm, d

4 = 1550 mm, λ

1 = 0,48 W/mK —

for EPY compound, λs = 58 W/mK — for steel. Thermal resistance calculated according to

the formula (6.14) was rlλw

= 0,015 mK/W.2. Propeller shaft stern tube is mounted by using the method of interference fi tting

(metal-metal). The following values were assumed: d1 = 880 mm, d

2 = 960 mm, d

3 = 1000 mm,

d4 = 1550 mm, λ

s = 58 W/mK. Specifi c thermal resistance calculated according to the formula

(6.14) was rlλw

= 0,0016 mK/W.3. Propeller shaft stern tube is mounted by using the method of interference fi tting along

the part of its length only; the remaining part was left in the air (20 mm thick layer). The

129

following values were assumed: d1 = 880 mm, d

2 = 960 mm, d

3 = 1000 mm, d

4 = 1550 mm,

λs = 58 W/mK — for steel, λ

p = 0,026 W/mK for air. Specifi c thermal resistance calculated

according to the formula (6.14) was rlλw

= 0,25 mK/W.Conclusions:

1. Thermal resistance in the radial direction through a cylindrical steel-EPY contact surface is about ten times higher than the thermal resistance for analogous steel-steel surface.

2. Thermal resistance of the assembly in air is 16,7 times higher than in case of the compound.

6.12.4. Analysis of thermal deformations

First, a coefficient of linear thermal expansion was determined experimentally for EPY compound at various temperatures. Three specimens were measured in accordance with a PN-82/C-89021 standard “Resins. Evaluating the coeffi cient of linear thermal expansion”. Details are presented in the work [74]. Mean values of the coeffi cient for various temperatures are in table 6.6.


Table 6.6. Values of a linear thermal expansion coeffi cient at for EPY compound

Calculating the thermal elongation of propeller shaft stern tube

According to the literature [75], in case of very long stern tubes one end must be left free to enable their unimpeded elongation or shortening in changing temperatures.

In order to calculate the maximum displacement of propeller shaft stern tube end in relation to the other end in changing temperatures, a simplifi ed model shown in Fig. 6.38 was adopted with input data referring to an unfavourable situation.Stern tube elongation caused by rising temperature was calculated using the formula:

(6.15)

where: α

s — thermal expansion coeffi cient of steel propeller shaft stern tube,

l — propeller shaft stern tube length, ∆t = (t

2 – t

1) — diff erence of temperatures.

The following values were assumed: αs = 12,5 × 10–5 1/°C, l = 7000 mm, t

2 = 55°C, t

1 = –5°C.

The result of calculations according to the formula (6.15) was:


∆l = 5,25 mm

The above calculated value is the elongation of a stern tube deforming freely in extremely unfavourable conditions. In reality, difference of temperatures ∆t is usually smaller so elongation ∆l will also be smaller.

If the ends of a stern tube could not move freely, the following longitudinal compressive stresses would occur:

σc = E

sε = E

s∆l/l = 2 · 105 · 5,25/7000 = 150 MPa

where E

s = 2 · 105 МPа — Young’s modulus for steel.

The change of propeller shaft stern tube outer diameter ∆D, assuming that D = 1000 mm and deformation is free, is

∆D = αsD∆t = 12,5 · 10–6 · 1000 · 60 = 0,75 mm

It must be said that the values of thermal elongation ∆l and ∆D are caused only by the diff erence of temperatures ∆t = t

2 – t

1 = 60°C in stern tube and frame tube and they do not

depend on the fact whether the compound is used for mounting or not. Therefore, if the compound is used, the stern tube must have a freedom of displacement in its one end, while staying in contact with compound.

In case there is no freedom of mutual longitudinal and radial displacement of stern tube and the compound (Fig. 6.39), stresses can be expressed by the formulas:

σt = E

t α

t (t

1 – t

2)

σs = E

s α

s (t

1 – t

2)

where: σ

t — stress in compound,

σs — stress in steel stern tube.

Fig. 6.38. Computational model of propeller shaft stern tube elongation

131

For the adopted extreme values: t1 = –5°C and t

2 = +55°C, the following values were

obtained for longitudinal and circumferential compressive stress:σ

t = –11,9 MPA

σs = –150 MPA

In reality, there is always some (limited) freedom of deformation and displacement as well as relatively smaller diff erences of temperatures (∆t = t

1 – t

2). Therefore, the actual values of

thermal stresses are usually smaller than the above calculated values.

6.12.5. Model testing of a propeller shaft stern tube installation

The aim of the test was to check in practice all the details involved in installing a propeller shaft stern tube of a large diameter (about 1 m) with the use of EPY compound. The test was conducted in Szczecin Shipyard on the model constructed by the Mechanical Department W-2 (Fig. 6.40, 6.41, 6.42).

The model of a stern tube (the bearing) of a propeller shaft (Fig. 6.41) was made of a steel pipe with a welding seam. A fl ange was welded on at one end. The outer surface of the pipe had two longitudinal oil grooves 16 mm wide and 14 mm deep and a groove for an oil temperature detector. There were three 10 mm holes bored in the bottom of oil grooves. Oil grooves were covered with steel slats and sealed with silicone.

The model of a frame tube (outer tube — Fig. 6.42) was made of three steel segments welded together. The pipe had holes for fi lling and venting, nine inspection openings with 1,5” threads for plugs and eight holes with M16 threads for adjusting screws (Fig. 6.40). The outer pipe was put on the stand (Fig. 6.42) with inclination of 3°45’ same as on the slipway.

Fig. 6.39. A simplifi ed model for determination of thermal stresses in case there is no freedom of longitudinal and radial displacement



Fore packing was made of polyurethane foam and a steel band (Fig. 6.43). The internal tube was put into the outer pipe together with fore packing by using a gantry crane.Basic data:

— volume of space to be fi lled: V = 118,7 dcm3,— mass of EPY compound to be poured into the space

M = V×ρ = 118,7 dcm3 × 1,59 kg/dcm3 = 188,7 kg,— ambient temperature: 19°C,— temperature of compound before mixing: 28°C,— temperature of compound before fi lling: 36°C,

Fig. 6.40. Model of a propeller shaft stern tube (1) and frame tube (2) with a layer of EPY compound in between

133

Fig. 6.41. The model of a propeller shaft stern tube (internal pipe)

Fig. 6.42. Frame tube model (outer pipe)



— time of pouring 12,6 kg of compound into a side filling hole (gap g = 20 mm): about 1 minute,

— mass of compound poured in during the fi rst stage of pouring: M

1 = 10 × 12,6 kg = 126 kg,

— cure time of compound poured in the fi rst stage: t = 5 hours,— time of pouring 12,6 kg of compound into the upper fi lling hole (gap g = 5 mm):

about 5 minutes,— mass of compound poured in the second stage: M

2 = 5 × 12,6 kg = 63 kg,

— total mass of compound poured in: M = M1 + M

2 = 126 + 63 = 189 kg.

Stern packing was made of polyurethane foam and a steel band as well. After joining the pipes and installing the stern packing, the indicators (Fig. 6.44) were installed to measure the relative movement of the pipes while pouring EPY compound into the space between the pipes and also during the curing phase. Special funnels were put into fi lling holes and overfl ow holes. The methods used for pouring EPY compound into the model and measuring relative displacement of the pipes are illustrated in the photographs (Fig. 6.45).

Fig. 6.43. Fore packing made of polyurethane foam and steel band (before installation)

135

The test, whose fi nal stage is presented in the photograph (Fig. 6.46), provided a wealth of useful information, and in particular it showed that:

1. The method used for packing the fi lled space fully passed the exam of the test during installation, pouring and curing phases.

2. Closing solution used for oil grooves prevented the compound from leaking into them.

Fig. 6.44. The assembled model of a propeller shaft stern tube in a frame tube, with indicators measuring relative displacements of joined elements

Fig. 6.45. Pouring EPY compound into model (a) and recording the relative movement of joined elements (pipes) (b)

a) b)



3. Stern tube of a propeller shaft must be inserted to the frame tube axially with the use of special equipment ensuring a controlled movement of the stern tube without any damage to fore packing.

4. Stern tube must be aligned with adjusting screws to provide its stable position in radial and axial directions.

5. Filling hole (with a diameter of about 40 mm) should be in the upper part of the frame tube, in the place where compound is the thickest and its corresponding overfl ow hole should be located in the highest place of the fi lled space.

6. Propeller shaft stern tube must be filled in at least two stages at a temperature of 20°C.

7. Tests in control points showed that compound fully fi lled the space including these places where the layer of compound was thinnest, i.e. 4 mm.

6.12.6. Conclusion

Approximate calculations and model testing proved that the propeller shaft stern tubes of large diameters (about 1 m) can be installed with the use of EPY compound in real shipyard conditions, and provided a wealth of valuable information necessary to work out the details of installation process.

Fig. 6.46. Final stage of model testing of the propeller shaft stern tube assembly (in Szczecin Shipyard)

137

6.12.7. Epilogue

Having completed the tests in Szczecin Shipyard, the model consisting of a frame tube and propeller shaft stern tube with a layer of EPY compound in between was taken to Marine Service Jaroszewicz company where it was exposed to weather for a long time. After seven years, the outer pipe was cut lengthways with a torch in a few places, and dismantled (Fig. 6.47).

Fig. 6.47. Stern tube assembly model (frame tube and propeller shaft stern tube with EPY compound in between) during its dismantling: a) cutting the outer pipe with a torch; b) upper part of the outer pipe with

a layer of EPY compound

a) b)

When the model was dismantled, it was observed that the compound fi lled the whole space between the pipes, and was fully coherent and uniform. Metal surface in contact with the compound was not corroded. It proved that the contact of the compound with metal surfaces is very tight. Its adhesion to metal was lower than its tensile strength, which as a result made it possible to separate big chunks of the compound from the surface.

6.13. Research on using the microwaves for additional curing of EPY compound and foundation chocks cast of this compound


Basic problem encountered when mounting any machinery on cast-in-place foundation chocks is their proper curing. At ambient temperatures lower than 10°C curing process consumes too much time. In order to shorten it while obtaining the required strength properties, chocks can be additionally heated by using external sources of heat. The most typical method is blowing hot air onto chocks from appropriate heaters; the whole foundation and machinery frame are heated as well in this way. Therefore, it is an arduous and energy-consuming process.



In order to overcome these drawbacks, a research was undertaken on a new original method of chocks curing, employing the microwaves. The aim of the research was to examine the infl uence that microwaves used for additional curing have on strength properties of EPY compound, as well as the opportunities to apply the microwave method for the seating of machinery on ships. Detailed records and results of the research are contained in the works [46 — 48]. Only a certain part of the results is presented below.

6.13.2. Tests on EPY compound specimens

Tests on additional curing of EPY compound with microwaves of a frequency f = 2,45 GHz were performed on cylindrical specimens (φ 20 mm × 25 mm) and on full-size models of foundation chocks. Tests on specimens were done for comparative purposes. Some specimens were cured traditionally and some with microwaves, and then they were subjected to compression tests and creep tests. All specimens used in the tests were cast from the same liquid compound and were cured for 24 hours at a temperature of 23°C. Next, they were divided into seven groups of 10 specimens each. One group was left without additional heating, four groups were additionally heated for 2 hours in an oven at temperatures of 60°C, 80°C and 120°C. Then, two groups were additionally cured in a microwave oven of 850 W power: one for 2 minutes (non stop) and the other — four times for a minute every 5 minutes.

When the specimens cooled down (in about 2 hours), some of them underwent a compression test and other a creep test. The compression tests were carried out in accordance with ASTM standard in a compression testing machine Instron (model 8501 Plus), the creep tests were conducted in a creep testing machines specially prepared for this purpose (Fig. 6.2). The creep test was performed at a temperature of 80°C and under pressure σ = 10 MPa. Results of the tests are graphically presented in Fig. 6.48 and 6.49.

Having analysed the results of compression tests and creep tests (Fig. 6.48 and 6.49), we may say that:

1. Heating the compound in the oven for 2 hours increases its strength. The higher the temperature of heating, the higher the strength. Heating the compound for more than 2 hours at any given temperature does not have any considerable infl uence on the strength of the compound.

2. Additional curing of the specimens in a microwave oven for 1 — 4 minutes produces the same eff ect as heating them for 2 hours in the oven at an appropriate temperature. What increases the strength of the compound is its maximum temperature. In a microwave oven the temperature of specimens reaches 130 — 140°C after about 3 minutes. Too long exposure to microwaves results in an excessive rise of the temperature in the compound and causes its destruction.

3. There are certain optimum conditions (time and temperature) of additional curing, which depend on many factors.

1396.13. Research on using the microwaves for additional curing of EPY compound and foundation…

Fig. 6.48. Compression strength of EPY compound specimens cured in diff erent ways (traditionally and with microwaves)

Fig. 6.49. Creeping properties of EPY compound specimens cured in diff erent ways (traditionally and with microwaves)


6.13.3. Tests on models of foundation chocks

Positive results of the tests on additional microwave compound curing encouraged their authors to start tests on full-size models of foundation chocks. A special device was made for additional microwave curing. Its diagram is shown in Fig. 6.50.

Fig. 6.51. Microwave emission into the model of EPY compound foundation chock

Fig. 6.50. The device for additional compound curing with microwaves: a) schematic diagram, b) elements of the device

a) b)

Tests were conducted on an axially symmetrical model of chock whose drawing is presented in Fig. 6.51. The chock was put on a steel plate and covered with aluminium foil. A microwave antenna was inserted into the central hole in the chock. The chock was additionally cured 3 times for 5 minutes about every 5 minutes. At the intervals, the temperature on the top of the chock was measured with a contact thermometer. After the compound was cured and cooled down, a compression test was performed on 30 specimens of φ 20 mm × 25 mm dimensions taken from diff erent locations in the chock (Fig. 6.52).

141

The results of temperature measurements and compression tests are presented in Fig. 6.53.


Fig. 6.52. Locations in the model of the chock where specimens were cut out for testing

Fig. 6.53. Maximum temperatures and compression strength of EPY compound cured additionally with microwaves in a model of a foundation chock


Tests were also performed on a simplifi ed, axially symmetrical model of a foundation joint (Fig. 6.54) made of two steel plates 38 mm thick which simulated the foundation and an engine bedplate. Between the plates, a 30 mm thick chock of EPY chocking compound was cast. The tests were performed on two chocks. Three dial indicators, installed circumferentially on the plates, measured the changes of chock height under compression in a compression testing machine, after the additional curing with microwaves was completed. Table 6.7 presents the temperature cycles and test results; temperature T was measured in points 1, 2 and 3 (Fig. 6.54a) after cyclic heating with microwaves; mean height change ∆H of the chock was measured under pressure P while at the same time oil surrounding the chock was heated to a temperature of about 80°C. The pressure exerted on the chock and the increase of ambient temperature correspond to the real conditions in which the engine is started and operated.

Table 6.7. Program and results of tests on a model of a foundation chock

143

6.13.4. Some more important conclusions

1. The role of microwaves is mainly to heat the compound. The process takes place inside the compound in its entire volume and is very fast. A temperature of 100°C and a high compression strength are reached within a few minutes. Too long exposure to microwaves causes overheating and destruction of the compound.

2. Weakly cured compound absorbs more microwave energy than a strongly cured one. It means that stronger cured compound is a better conductor of microwaves and the amount of absorbed energy is lower. This matter requires further quantitative research.

3. Tests carried out on the models of foundation chocks produced positive results. They confi rmed the possibility of using microwaves for the additional curing of full-size foundation compound chocks and the effectiveness of the device designed for this purpose.

4. Practical shipboard applications of the method and the device require further work on technical details, work safety and fi nding the optimum parameters of the microwave additional curing process (power, periods of microwave emissions and intervals).

5. Prospective shipboard application of microwave additional curing of compound chocks will signifi cantly reduce the time and energy used for mounting the machines in comparison with the presently used process of thermal curing.


Fig. 6.54. The axially symmetrical model of a foundation joint with EPY compound chock: a) additional microwave curing diagram with marking points of temperature measurement (1, 2, 3); b) diagram of a compression test and

measurements of height changes in the chock

a) b)


6.14. Strength tests on holding down bolts anchored in concrete with the use of EPY compound

Installation of anchor bolts with the use of polymer composites proves to be particularly advantageous in the repair and modernisation work, when it is necessary to replace destroyed bolts or to install new ones in places imposed by constructional changes (for instance in foundation).

The aim of the tests described in details in works [76, 77] and presented in short below, was to examine the practical possibility of using EPY compound for the anchoring of bolts in concrete blocks.

Testing of the load capacity of bolts anchored in concrete by means of EPY compound was conducted on models presented in Fig. 6.55a with three types of bolts whose shapes and dimensions are given in Fig. 6.55b, c, d.

Fig. 6.55. Bolt anchoring in concrete — schematic drawing (a) and anchor bolts having diff erent anchoring solutions: smooth cylindrical surface (b), helical groove (c), tapered surface (d)

a) b) c) d)

Diameters and depth of bolt holes were as follows: D = 18 mm and L = 130 mm and the length of anchoring was l

z = 125 mm. Bolts were driven out of concrete with a hydraulic

press. Mean values of measured forces Nz (load capacities of anchors), taken at the beginning

of the destruction of anchored bolts shown in Fig. 6.55b,c,d equalled respectively 64, 57 and 59 kN. Having analysed the diff erences between the values, we may say that they result from their natural dispersion and the errors of the measuring method, but not from the infl uence of bolt shape along the anchoring area [76]. However, the shape of a bolt along the anchoring area infl uences considerably its destruction process, which shall be demonstrated below. Load capacity of a bolt anchored directly in concrete, measured in accordance with Hilti catalogue [78], amounted to N

zb = 16 kN.


Bolts anchored in concrete by means of compound were also subjected to rising torsional moment tests until the torsional strength limit was exceeded, which happened at torsional stress of τ

śr = 393 MPa. Anchors were not destroyed. Bolt fractures took place beyond the

length of bolt anchoring.The model used for the test of adhesion between the bolt and the compound (or between

bolt and concrete) is presented in Fig. 6.56. The term “adhesion” means the resistance of an anchored bolt when pulled out [76]. The test was performed in 8501 Plus Instron machine. Example diagrams demonstrating the program of the test and its results are presented in Fig. 6.57. They were obtained for the model dimensioned as follows: D = 16 mm, d = 12 mm, and lz = 144 mm. Curve A (Fig. 6.57) refers to a cylindrical bolt anchored directly in concrete, and

curves B and C — respectively to bolts with cylindrical and tapered anchor lengths sunk in EPY compound. For the three anchored bolts used for comparison purposes, stress τ was calculated as the ratio of tensile force F and the sheared cross-section area A

τ. The maximum values of

contact stresses in case of bolt anchored in compound are similar and about three-time higher than maximum stress values determined in pull-out test on bolt anchored directly in concrete. In case of a cylindrical bolt anchoring, destruction of the joint is sudden (curves A and B in Fig. 6.57). Bolts with tapered anchoring shanks do not lose all their load capacity at once (curve C in Fig. 6.57) which prevents failures with serious consequences.

Fig. 6.56. Anchor bolt model used for a test on bolt adhesion to compound

Fig. 6.57. Pulling the bolts out of concrete (A) and compound (B and C)


Apart from the tests, also the numerical computations were done by using the fi nite elements method. Data taken from the experiments [76, 77] were used for the computation. It was assumed that there was perfect adhesion on the contacts between steel and concrete, steel and compound and also concrete and compound. The results of computations are presented in graphical form in Fig. 6.58 and 6.59.

Contact stress τ in a layer of compound (or concrete when h = 0 mm) touching the anchor surface decreases for transverse bolt cross-sections laying in growing distances from the surface of concrete (Fig. 6.58). Maximum values and the rate at which stresses decrease depend on the thickness of compound layer. Therefore, it is the thickness of the compound that considerably infl uences the load capacity of the anchor.

Fig. 6.58. Contact stress distribution on the surface of compound (concrete) contacting the bolt along anchoring area

Fig. 6.59. Relation of anchoring compliance to dimensionless length of anchoring (curve 1) and thickness of compound (curve 2)

147

Figure 6.59 presents the relation of anchoring compliance to a dimensionless length of the anchoring (l

z/d) and the thickness of the compound layer. For a given thickness of the

compound layer (h = 2 mm), anchoring compliance calculated as a relation of a shift of the anchored bolt cross-section lying on the surface of concrete to the force eff ecting such a shift, does not depend on the length of the anchoring if the length l

z is higher than 6 d (Fig. 6.59, curve

1). While at a given anchoring length (for example lz = 256 mm), anchoring compliance increases

when the thickness of the compound layer increases (Fig. 6.59, curve 2).The tests showed good strength properties of foundation bolts anchored in concrete

with the use of EPY compound. Their load capacity is about three times higher than the load capacity of bolts anchored directly in concrete. We may assume the optimum anchoring length (giving the best load capacity) to be l

z = 8d. The shape of the bolt anchoring shank

(smooth cylindrical surface with a groove or a tapered shank) has little infl uence on maximum acceptable load capacity of the anchoring. Nevertheless, it has some infl uence on the way in which the anchoring undergoes destruction. In case of a smooth cylindrical surface, the destruction is sudden and brittle in character. However, in case of a tapered shank the loss of load capacity takes some time and is of elastic — resin character, which may give some protection against failures.

6.15. Research on the infl uence of constant humid heat on dielectric properties of EPY compound

The research was performed in the Electrical Engineering Institute of the Technical University of Szczecin [79]. Its aim was to determine the long-term infl uence of constant humid heat (φ = 96%, T = 40°C) on the following parameters:

— dielectric loss,— permittivity,— through resistivity, — dielectric strength,— surface resistivity.Tests were performed in accordance with the applicable Polish standards (table 6.6). Disks

of diameter of 100 mm and thickness of 3 mm were used in the tests. There were 5 specimens in each test run. The results (mean values) are presented in table 6.8.

6.16. Research on the infl uence of liquid nitrogen cooling on EPY compound compression and impact strength

The engineering process of bushing requires sometimes that the bush is cooled down in order to decrease its diameter so that the mounting becomes possible without use of any axial force. As a result, a so-called expanding pressed joint is made [80]. In case of rudder



bearing liners, made usually of a special resin compound (called “Thordon”), the compound is cooled down in liquid nitrogen to about –180°C. Such a cooled-down bearing liner is then inserted into a steel liner mounted in frame with the use of EPY compound, and cools the steel liner considerably together with the surrounding EPY compound. Therefore, a question arose whether temporary but considerable cooling of EPY compound might lower its compression and impact strength. In order to answer this question, appropriate tests on compression and impact strength were conducted [81].

Compression strength test was performed at room temperatures according to ASTM-D695-69 and PN-83/C-89031 standards in a compression testing machine of Instron company, model 8501 Plus, by using a program series 9 “Automated Materials Testing System 7.03.00”. Specimens for the test, with diameter d = 20 mm and height h = 25 mm, were cast in steel forms and cured for 24 hours at ambient temperature (23°C). Next, they were heated for 2 hours in 80°C and kept for 6 days at ambient temperature. After that, six specimens were cooled down in liquid nitrogen (to about –195°C) for 10 minutes. After they were taken out from the liquid nitrogen (Fig. 6.60), they were left at room temperatures for 4 hours. Next, the compression test was performed on fi ve specimens which were not cooled down and fi ve cooled down ones. Test results obtained in a compression testing machine are presented in tables 6.9 and 6.10.

Table 6.8. The results of tests on infl uence of constant humid heat on dielectric properties of EPY compound

1496.16. Research on the infl uence of liquid nitrogen cooling on EPY compound compression and…

Fig. 6.60. Specimens of EPY compound taken out from liquid nitrogen

Table 6.9. Results of compression testing on EPY compound specimens which were not cooled down

Table 6.10. Results of compression test on EPY compound specimens cooled down in liquid nitrogen


The impact test was performed at room temperature in accordance with PN-81/C-89023 tandard in an impact testing machine of Kögel-Leipzig Company (made in Eastern Germany), having an energy output of 0,4 kGm ≈ 3,924 Nm. Specimens of 10 mm × 15 mm rectangular cross-section and length l = 120 mm (without any notches) were used in the test. Curing and cooling down the specimens in liquid nitrogen was conducted the same way as in the case of specimens for the compression test. Test results are presented in table 6.11.

Table 6.11. Results of impact tests on EPY compound specimens (cooled down in liquid nitrogen and not cooled down)

By comparing test results contained in tables 6.7, 6.8 and 6.9 for specimens cooled down in liquid nitrogen and not cooled down, one may say that there are no fundamental qualitative differences. By examining the compression test curves and the fractures in specimens undergoing the impact test, one did not fi nd any qualitative diff erences either. In conclusion, cooling down the EPY compound in liquid nitrogen (to about –195°C) for a short time (about 10 minutes) has no infl uence on compression and impact parameters and characteristics of the compound in case of tests carried out at room temperature.

6.17. Determination of the states of stress and strain in bolt joints with chocks made of EPY compound and steel


Determining states of stress and strain in a foundation bolt joint is a very complex task which belongs to the fi eld of contact mechanics of deformable bodies, and which is almost unsolvable with the methods known from the science of material strength, principles of mechanical engineering and the theory of elasticity, unless many simplifying assumptions

1516.17. Determination of the states of stress and strain in bolt joints with chocks made of EPY…

are made. However, adopting such assumptions as recommended in the principles of mechanical engineering [82] leads to obtaining calculation results straying rather far from reality.

New computation possibilities in the fi eld of complex mechanical systems have been opened by the fi nite elements method (FEM) combined with numerical processing on computers. This method was used here in an unconventional way to determine the stresses and strains created during the mounting and appearing during service, for two similar models of a foundation bolt joint of main ship engine. The models diff ered only in chock material — in one model the chock was made of EPY compound, in the other it was made of steel.

The aim of the work was to:1. Examine the influence of elastic properties (E and v) of chocking material (EPY

compound and steel) on the size of contact area, pattern and values of pressures exerted on the chock and the fi eld of displacements of joint elements.

2. Determine the values of stress and strain and the operational characteristics of forces appearing in the bolt under the assumed external load and acting on the examined joint in the directions of stretching and pressing.

3. Examine the infl uence of temperature changes on the values of stress and strain created during the mounting in the analysed bolt joint model with a compound chock.

6.17.2. Model of a foundation bolt joint

For the purposes of analysis and computation a simplified axially symmetric model of a foundation bolt joint was adopted (Fig. 6.61) [49, 83]. Such model is generally adopted for bolt joints because of the local character of loading. The model is suffi cient for comparative analysis and the achievement of aims set for this work.

The elements of analysed structure (Fig. 6.61), including EPY compound chock, were treated as elastic bodies. Their dimensions used for input to numerical computations were chosen as corresponding to mean values occurring in practice.

A discrete model of a joint used for FEM numerical computations is presented in Fig. 6.62. Since the computation and analysis were focused mainly on the contact areas between the bedplate, the foundation and the chock (made of compound or steel), two-nodal joint elements were used to enable the contacting surfaces to open out and slide. Coulomb friction forces on contact surfaces were taken into account. However, the area in bolt joint lying between the head of the bolt and the bedplate was simplifi ed by applying one-nodal joint elements.

Due to structural symmetry, a model of only one part of the joint could be used for computation purposes (Fig. 6.62). Finite elements axially symmetrical to Z-axis were used which signifi cantly simplifi ed the computations.


Fig. 6.61. Model of a foundation bolt joint: 1 — foundation, 2 — bedplate, 3 — foundation chock (made of EPY compound or steel)

Fig. 6.62. Bolt joint model used for computations based on FEM ADINA method

153

6.17.3. Determination of the states of stress and strain created during the mounting

The following values were accepted for numerical computations: dimensions as in Fig. 6.61; material constants E

st = 2,1 × 105 MPa, ν

st = 0,3, E

tw = 6369 MPa, ν

tw = 0,375; friction

coeffi cients µst = 0,3, µ

tw = 0,8; bolt pre-tensioning force P

o = 150 kN causing mean surface

pressure on the chock σn = 5 MPa. The assumed assembly pre-tension of the bolt in the

assumed model (Fig. 6.62) was obtained by an appropriate Z-displacement of the middle cross-section in the bolt (Fig. 6.63).

Fig. 6.64 and 6.65 present respectively the fi elds of Z-displacements and distributions of the contact force in the models of bolt joints: with a compound chock (6.64) and with a steel chock (6.65).

Fig. 6.66 presents Z-displacement of bedplate and chock contact surfaces under pre-tension force P

o = 150 kN. In one case, the chock is made of the compound, in the other of steel. In the

fi gure, radius Ro defi nes contact area between bedplate and foundation chock. The areas for both chock materials diff er signifi cantly. Beyond radius R

o, contact between the bedplate and the

foundation chock breaks up (Fig. 6.66). The diff erences in break-up areas and the surface opening range are distinct, again depending on the material of the chock.


Fig. 6.63. Deformed grid of fi nite elements under bolt pre-tension Po = 150 kN (scale 200:1)


Fig. 6.65. Z-displacement fi eld and distribution of contact force in the model of a bolt joint fi tted with a steel chock

Fig. 6.64. Z-displacement fi eld and distribution of contact force in the model of a bolt joint fi tted with EPY compound chock

155

Figure 6.67 presents the distribution of normal pressures in the contact area between the bedplate and the chock in bolt joints under pre-tensioning force P

o = 150 kN. In one case, the

chock is made of compound, in the other of steel. The maximum value of contact pressure in the case of steel chock is almost three times higher than the maximum contact pressure exerted on the compound chock, which results from the distribution of pre-tensioning load on a larger contact surface. The horizontal line in Fig. 6.67 indicates a mean computational value of normal pressure (σ

n = 5 MPa) on the whole nominal contact surface of the chock and

bedplate. Use of compound chocks provides a much better similarity between the actual distribution of pressures and the nominal pressures (assumed for the design calculations of foundation chocks).

6.17.4. Determination of the states of stress and strain and the characteristics of service loads in holding down bolts

It is now assumed that the initially strained bolt joint is loaded with external force F distributed uniformly on the circumference of the plates representing parts of the bedplate and the foundation (Fig. 6.68). External force may stretch or compress the examined joint. The values of the external force F used as input for numerical computations were taken as ranging from –282,743 kN to +282,743 kN in 400 steps. The “minus” sign is assigned to compressing and the “plus” sign to stretching the joint.


Fig. 6.66. Z-displacement of contact surfaces between the bedplate and chocks made of EPY compound (1) and steel (2) under P = 150 kN


The distributions of forces and displacements of joint elements, determined for the maximum values of external compressing and stretching force, are presented respectively in Fig. 6.69, 6.70 and 6.71. As can be seen in Fig. 6.69 and 6.70, in case of compressing the bolt joint with a compound chock the force is exerted on the whole chock more uniformly than in the case of a steel chock. When the joint is stretched by the maximum external force F, the

Fig. 6.67. Distributions of normal pressure on the contact surface between bedplate and foundation chocks made of EPY compound (1), and of steel (2), under P

o = 150 kN

Fig. 6.68. Model of a bolt joint loaded with the external force


Fig. 6.69. Displacement fi eld and distribution of contact force in a model of a bolt joint with compound chock, loaded with external force F = –282,743 kN

Fig. 6.70. Displacement fi eld and distribution of contact force in a model of bolt joint with a steel chock, loaded with external force F = –282,743 kN


chock becomes completely unloaded and whole tension is transferred by the bolt. In such case, the material used for the chock does not make any diff erence. The displacement fi elds of the bedplate and the bolt are the same in both models of the joint (Fig. 6.71).

Fig. 6.72 presents the relation of eff ective tension force (P) in the bolt to external force (F) applied to the joint in both models. The computation was done for the values of external force changing from –300 kN to +282,743 kN. There are three tension ranges in the model with a compound chock (Fig. 6.72, curve 1). Suffi ciently high compressive force provides full contact between the chock, bedplate and foundation.

For the values of external force F ranging from about –4 kN to about +25 kN, the chock, the bedplate and the foundation get into only partial contact on the nominal contact surface. The higher external stretching force, the smaller actual contact area. When external force F is higher than +25 kN, the bedplate does not touch the chock at all (Fig. 6.72).

In case of a bolt joint fi tted with a steel chock, the bedplate and the foundation chock can never get into contact over the whole nominal contact surface (Fig. 6.72, curve 2).

Only partial contact is possible, or none, which happens under sufficient external stretching force higher than about +17,5 kN. Under compressive force, the gap between the joined elements does not disappear completely. It means that the chock transfers the compressive force only through a part of its surface.

Fig. 6.71. Displacement fi eld in both models of bolted joint (compound chock and steel chock), loaded with external force F = +282,743 kN


Fig. 6.72. Relation of bolt tension force P to external force F exerted on the circumference of joined elements (for P

o = 150 kN)

For comparative purposes, Fig. 6.73 presents the relation of force P in the bolt to the external force F applied along the axis of a bolt joint. This way of applying the external force is the most typical solution that can be found in the literature on the principles of mechanical engineering [82].

By comparing the diagrams in Fig. 6.72 and 6.73, we can see considerable diff erences. The curves in Fig. 6.73 refer to the elements of a joint treated as rigid bodies. In reality, they are elastically deformable. Therefore, the curves in Fig. 6.72 are closer to reality than the curves in Fig. 6.73. They show (Fig. 6.72) that the external stretching forces up to about +10 kN and the compressive forces up to about –30 kN applied to the elements of the joint do not signifi cantly change the value of tension in the bolt, which stays at pre-tension value. In particular, the tension does not decrease under compressive force as it can be seen in Fig. 6.73 (for rigid bodies). Due to non-dilatational strain of the elements of the joint, the external force is transferred to the chock without unloading the bolt, which is advantageous for it especially under dynamic loads.


6.17.5. Infl uence of temperature changes on pre-tension stress and strain states in bolt joints with compound chocks

EPY compound chocks have different thermal expansion coefficients than the steel elements, and together they constitute a bolt joint as in Fig. 6.61. The values of thermal expansion coeffi cient and modulus of elasticity for the compound depend considerably on temperature (within the range from –20 to +80°C). Therefore, if we assume that the assembly of a foundation bolt joint took place at a temperature of +20°C, the change of ambient temperature will aff ect the states of stress and strain in the joint.

The aim of the here discussed research was to determine the resulting change of pre-tension stress and strain states in bolt joints with compound chocks of the type shown in Fig. 6.61, with the use of FEM ADINA system. It was assumed that the external diameter of the joint was 240 mm, the assembly took place at a temperature of +20°C, and pre-tension stress of the bolt was P

o = 222500 N. Then the joint was cooled down by 40 K to –20°C, and

then — heated up from the initial 20°C by 60 K (to +80°C). Pre-tension strain of the bolt

Fig. 6.73. Relation of bolt operational force P to external force F, exerted on the axis of bolted joint (at Po = 150 kN)


was obtained with stress σz = 315 MPa applied to the cross-section of the bolt shank on

a plane Z = 0, causing the relevant displacement of the section (Fig. 6.74a). Next, freedom of Z-displacements was locked and thermal stresses were determined.The following values were adopted for numerical computations:

a) for the compound (on the basis of our own research):— at a temperature of +20°C, E

tw = 6369 MPa, ν

tw = 0,375, α

tw = 30,0 ⋅ 10–6 1/K,

— at a temperature of –20°C, Etw

= 8000 MPa, νtw

= 0,375, αtw

= 24,7 ⋅ 10–6 1/K,— at a temperature of +80°C, E

tw = 5000 MPa, ν

tw = 0,375, α

tw = 40,4 ⋅ 10–6 1/K,

b) for steel (constant values): Est = 2,1 ⋅ 105 MPa, ν

st = 0,28, α

st = 12,5 ⋅ 10–6 1/K.

The results of computations are presented in Fig. 6.74. Figure 6.74a presents the distribution of contact force and the fi eld of reduced stress in a foundation bolt joint after its assembly at a temperature of +20°C. Fig. 6.74b and 6.74c present the same values respectively after cooling the joint down by 40K (to –20°C) and heating it up by 60 K (to +80°C).

The computation results show that the changes of temperature in the joint within the accepted range result in the change of the value of contact forces. The drop of temperature slightly decreases the contact forces, and the raise in temperature increases the forces. The respective pre-tension forces in the bolt are as follows:

— at a temperature of +20°C, Po = 222500 N (initial state),

— at a temperature of - 20°C, Po = 217712 N (decrease by 2,15%),

— at a temperature of +80°C, Po = 267193 N (increase by 20,0%).

The increase of bolt tensile stress and contact pressure applied on the chock, under increasing ambient temperature caused by running the engine or other machinery, is advantageous for foundation bolt joints. In reality such high changes of temperatures as above presented seldom ever appear, in particular cooling down to –20°C. Therefore, the fl uctuations of initial bolt tension take place within narrower limits than those given above.

6.17.6. Summary and conclusions

Foundation bolt joint with a compound chock is a complex non-linear system of non-homogeneous bodies, diffi cult to model and calculate, and the same applies to steel chocks as well. Modelling of joints requires accounting for many complex geometric and material factors as well as complicated contact eff ects. Such systems cannot be solved with the known analytical methods of elasticity theory, but it has been made possible nowadays due to numerical methods and advanced FEM programs (for example FEM ADINA system).

The simplifi ed model of a foundation bolt joint with a chock, adopted for the purposes of this work, made it possible to determine the states of stress and strain in the joint exerted by pre-tension alone as well as appearing in its operation. Moreover, it made it possible


Fig. 6.74. Deformed grids of fi nite elements, reduced stress fi elds and distributed normal forces exerted on foundation chock in pre-tension state (a), after cooling down the joint (b), and heating it up (c)

T = +20°C

T = –20°C

T = +80°C


to carry out the analysis of the impact of the assumed pre-tension conditions, the applied external forces, and the changes of temperature in the structure on the size of contact area, distributions and values of contact forces, displacement fi eldsin joint elements and the actual force in the bolt.

Comparative analysis of the obtained computation results shows that the application of compound instead of steel for the foundation chocks of machinery provides tighter contact between the chock and bedplate, as well as more uniform distribution of surface forces, which is true for both pre-tension state and operation conditions. As a result, foundation bolt joints can be more reliable and durable.

The increase of temperature in the bolt joint with a compound chock, caused by running the machine or other environmental factors, results in a slight (up to 20%) increase of tension in foundation bolt joints, which is benefi cial for the machinery. A slight drop of tension in the bolt takes place in lowered temperatures, which may happen when the machinery is not operated or is stored in the open space, for example on the deck of a ship.

Foundation bolt joints of real-life machinery are usually geometrically and physically more complex than the models examined here. The analysis of their static and dynamic states is possible now, but it can only be achieved through the application of more sophisticated models, more complex programs, and computers with high processing power, and all these measures are connected with signifi cant costs.

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[72] Propeller shaft sterntube assembling based on use of EPY chocking compound — report on design analysis and model tests (“Raport z analizy konstrukcji i badań modelowych montażu pochwy wału śrubowego przy zastosowaniu tworzywa EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1994 (unpublished).

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THE CHRONOLOGICAL LIST OF RESEARCH REPORTS CONCERNING POLISH RESIN COMPOUNDS USED FOR FOUNDATION CHOCKS, AND THEIR PRACTICAL APPLICATIONS FOR THE SEATING OF MACHINERY

1. Gluing technology in shipbuilding (“Klejenie w konstrukcjach okrętowych”), scientifi c research work report, Technical University of Szczecin, Institute of Mechanical Engineering (Instytut Budowy Maszyn), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1971 (unpublished).

2. Gluing technology in shipbuilding (“Klejenie w konstrukcjach okrętowych”), scientifi c research work report. Technical University of Szczecin, Institute of Mechanical Engineering (Instytut Budowy Maszyn), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1972 (unpublished).

3. Jaroszewicz W.: Fundamental problems of flexible machinery mounting in shipbuilding (“Podstawowe problemy elastycznego mocowania maszyn i urządzeń okrętowych”), MSc diploma thesis, Technical University of Szczecin, Faculty of Mechanical Engineering and Shipbuilding (Wydział Budowy Maszyn i Okrętów), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1973 (unpublished).

4. Gluing technology in shipbuilding (“Klejenie w konstrukcjach okrętowych”), scientifi c research work report, Technical University of Szczecin, Institute of Mechanical Engineering (Instytut Budowy Maszyn), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1974 (unpublished).

5. Tests of resin foundation chocks used aboard m/s “Kapitan Ledóchowski” (“Badania podkładek fundamentowych z tworzywa sztucznego na m/s “Kapitan Ledóchowski”), materials, Maritime University of Szczecin, Szczecin 1975 (unpublished).

6. Resin compound foundation chocks used under shipboard machinery (“Podkładki z tworzyw sztucznych pod maszyny i urządzenia okrętowe”), scientifi c research work report, Technical University of Szczecin, Institute of Mechanical Engineering (Instytut Budowy Maszyn), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1976 (unpublished).

7. Research methods and usability evaluation criteria applicable to compounds used for foundation chocks (“Metody badań i kryteria oceny przydatności tworzyw na podkładki”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1977 (unpublished).

8. Characteristics of compounds used for foundation chocks of ship main engines and auxiliiary machinery (“Charakterystyka tworzyw stosowanych na podkładki fundamentowe do posad-awiania silników głównych i okrętowych mechanizmów pomocniczych”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Szczecin 1977 (unpublished).

The chronological list of research reports concerning polish plastic compounds used for foundation…172

9. Installation technology for ship main engines and auxiliary machinery based on use of chemically curing compound chocks (“Technologia wykonania posadowień silników głównych i okrętowych mechanizmów pomocniczych na podkładkach z tworzywa chemoutwardzalnego”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Szczecin 1977 (unpublished).

10. Industrial introduction works carried out in 1977 within the framework of a subject “Foundation chocks of chemically curing compounds used for the seating of ship main engines and auxiliary machinery” (“Prace wdrożeniowe zrealizowane w roku 1977 w ramach tematu: ‘Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych‘ ”), scientific research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Szczecin 1977 (unpublished).

11. Design guidelines for the seating of ship main engines and auxiliary machinery on chemically curing chocks (“Wytyczne projektowe dla konstrukcji posadowienia silników głównych i okrętowych mechanizmów pomocniczych na podkładkach z tworzywa chemoutwardzalnego”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Szczecin 1977 (unpublished).

12. Service manual for the seating of ship main engines and auxiliary machinery on chemically curing chocks (“Instrukcja eksploatacji posadowień silników głównych i okrętowych mechanizmów pomocniczych na podkładkach z tworzywa chemoutwardzalnego”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Szczecin 1977 (unpublished).

13. Noise and vibration testing aboard B-491/I i II ferries in Świnoujście (“Badania drgań i hałasów na promach B-491/I i II w Świnoujściu”), scientifi c research work report, Maritime University of Szczecin, Institute of Basic Technical Sciences (Instytut Nauk Podstawowych Technicznych), Szczecin 1977 (unpublished).

14. Noise and vibration testing aboard m/s “Kapitan Ledóchowski” (“Badania drgań i hałasów na statku m/s “Kapitan Ledóchowski”), scientifi c research work report, Maritime University of Szczecin, Institute of Basic Technical Sciences (Instytut Nauk Podstawowych Technicznych), Szczecin 1977 (unpublished).

15. Industrial introduction works carried out in 1978 within the framework of a subject “Foundation chocks made of chemically curing compounds for the seating of ship main engines and auxiliary machinery” (“Prace wdrożeniowe realizowane w roku 1978 w ramach tematu: ‘Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych‘ “), scientific research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1978 (unpublished).

16. Laboratory tests carried out in 1978 within the framework of a subject “Foundation chocks made of chemically curing compounds for the seating of ship main engines and auxiliary machinery” (“Prace laboratoryjne realizowane w roku 1978 w ramach tematu: ‘Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych‘ ”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1978 (unpublished).

173The chronological list of research reports concerning polish plastic compounds used for foundation…

17. Grudziński K., Jaroszewicz W., Lorkiewicz J.: Testing of foundation bolt joints with chocks made of chemically curing compound (“Badania fundamentowych złączy śrubowych z podkładką z tworzywa chemoutwardzalnego”), in the Materials of 8th Symposium of Experimental Research in Solid State Mechanics, Warsaw 1978, Papers Part 1, p. 176 — 187.

18. Laboratory tests carried out in 1979 within the framework of a subject “Foundation chocks made of chemically curing compounds for the seating of ship main engines and auxiliary machinery” (“Prace laboratoryjne zrealizowane w roku 1979 w temacie: ‘Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych‘ ”), scientifi c research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1979 (unpublished).

19. Industrial introduction projects carried out in 1979 within the framework of a subject “Founda-tion chocks made of chemically curing compounds for the seating of ship main engines and auxiliary machinery” (“Prace wdrożeniowe zrealizowane w roku 1979 w temacie: ‘Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych’ ”), scientific research work report, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1979 (unpublished).

20. Jaroszewicz W.: Foundation chocks made of chemically curing compounds for the seating of main engines and auxiliary machinery in ships (“Podkładki fundamentowe z tworzyw chemoutwardzalnych pod okrętowe silniki główne i urządzenia pomocnicze”), PhD thesis, Technical University of Szczecin 1980 (unpublished).

21. Lorkiewicz J., Grudziński K., Jaroszewicz W.: Manufacturing methods for chemically curing foundation chocks, used particularly in shipbuilding (“Sposób wytwarzania chemoutwardzalnych podkładek fundamentowych, zwłaszcza w okrętownictwie”), patent description no. 134437 of 31.12.1980, Patent Offi ce of People’s Republic Of Poland, Warsaw 1987.

22. Open Sea Fishing and Fishery Services Company ODRA (“Przedsiębiorstwo Połowów Dalekomorskich i Usług Rybackich ODRA”) w Świnoujściu: Letter TT/1452/81 of 12.12.1981 concerning “Combustion engine seating on epoxy chocks” (Posadowienia silników spalinowych na podkładkach z tworzyw sztucznych), Świnoujście 1981 (unpublished).

23. Foundation chocks of chemically curing compounds for the seating of ship main engines and auxiliary machinery (“Podkładki fundamentowe z tworzywa chemoutwardzalnego do posadawiania silników głównych i okrętowych mechanizmów pomocniczych”), report on the research projects carried out in 1981, Technical University of Szczecin, Institute of Materials Engineering (Instytut Inżynierii Materiałowej), Technical Mechanics Section (Zakład Mechaniki Technicznej), Szczecin 1981 (unpublished).

24. Grudziński K., Lorkiewicz J.: Information about “Impact of foundation chocks made of chemically curing compounds on vibration and transmission of structural sound (“Informacja nt. ‘Wpływu fundamentowych podkładek z tworzyw chemoutwardzalnych na drgania i rozprzestrzenianie się dźwięków materiałowych’ ”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1982 (unpublished).

25. Grudziński K., Jaroszewicz W., Lorkiewicz J.: The seating of machinery on resin compound chocks (“Posadawianie maszyn na podkładkach z tworzywa sztucznego”), “Przegląd Mechaniczny” periodical, 1983, no. 21, p. 9 — 15.


26. Jaroszewicz W., Kownacki S., Lorkiewicz J., Łabuć L.: Foundation bolt joint with bolts fi tted to epoxy compound, used particularly for the seating of ship machinery (“Fundamentowe złącze śrubowe ze śrubami pasowanymi w tworzywie sztucznym, szczególnie do posadawiania maszyn i urządzeń okrętowych”), patent description no. 141627 of 02.07.1984, Patent Offi ce of People’s Republic of Poland, Warsaw 1988.

27. Lorkiewicz J.: Report on a controlled shear test of a bolt fi tted in EPAX chocking compound, in a model of a foundation bolt joint (“Sprawozdanie z próby ścinania technologicznego śruby pasowanej w tworzywie EPAX w modelu fundamentowego złącza”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1984 (unpublished).

28. Lorkiewicz J.: Report on compression strength testing of a holding down bolt model fi tted in a thin-walled tube of cast EPAX chocking compound (“Sprawozdanie z prób wytrzymałościowych ściskania modelu śruby fundamentowej umocowanej w odlanej, cienkościennej tulei z tworzywa EPAX”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1984 (unpublished).

29. Grudziński K., Lorkiewicz J.: Results of compression testing of thin-walled EPAX chocking compound tubes (“Wyniki prób ściskania cienkich tulejek z tworzywa EPAX”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1984 (unpublished).

30. Lorkiewicz J. : Results of additional tests on models of holding down bolts fitted to EPAX chocking compound cast around them (“Wyniki dodatkowych badań modeli pasowanych śrub fundamentowych zalewanych tworzywem EPAX”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1985 (unpublished).

31. Grudziński K., Jaroszewicz W., Lorkiewicz J.: Chemically hardened resin chocks in ship machinery foundations, “Budownictwo Okrętowe” periodical, 1986, Issue no. 11, p. 479 — 484.

32. Adamkiewicz A.: Usage of chemically curing compounds for the seating of main engines and auxiliary machinery aboard ships, and of land machinery (“Zastosowanie tworzyw chemoutwardzalnych do posadawiania okrętowych silników głównych i urządzeń pomocniczych oraz posadowień lądowych”), “Budownictwo Okrętowe” periodical, 1988, Issue no. 8, p. 33 — 34.

33. Jaroszewicz W., Łuba A.: Chemically curing foundation chocks — manufacturing methods (“Sposób wytwarzania chemoutwardzalnych podkładek fundamentowych”), patent description no. 158551 z 14.04.1989, Patent Offi ce of Poland, Warsaw 1993.

34. Howson J.C., Tech B., Lane P.H.R.: EPY LR approval of a chocking compound for applications where alignment is critical, Technical Report no. 88/9621, Lloyd’s Register, Materials Department, London 1990 (unpublished).

35. Grudziński K., Lorkiewicz J., Tuczyński L.: Research results no. 46/90 — chemically curing compounds — tensile strength testing (“Wyniki badań nr 46/90 na rozciąganie tworzywa chemoutwardzalnego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1990 (unpublished).

36. Grudziński K., Lorkiewicz J.: Research results no. 47/90 — chemically curing compounds — shear strength testing (“Wyniki badań nr 47/90 na ścinanie tworzywa chemoutwardzalnego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1990 (unpublished).


37. Grudziński K., Lorkiewicz J., Tuczyński L.: Research results no. 48/90 — chemically curing compounds — Young modulus testing (“Wyniki badań nr 48/90 modułu Younga tworzywa chemoutwardzalnego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1990 (unpublished).

38. Grudziński K., Lorkiewicz J., Tuczyński L.: Research results no. 49/90 — chemically curing compounds — creep testing (“Wyniki badań nr 49/90 pełzania tworzywa chemoutwardzalnego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1990 (unpublished).

39. Drewek J.: Chemically curing chocking compound EPY — protocol from thermal conductivity measurements (“Protokół z pomiarów współczynnika przewodności cieplnej tworzywa chemo-utwardzalnego EPY”), Technical University of Szczecin, Chair of Heat Engineering, Szczecin 1990 (unpublished).

40. Grudziński K., Kawiak R., Tuczyński: Water and oil impact on compression strength of EPY chocking compound (“Wpływ wody i oleju na wytrzymałość na ściskanie tworzywa podkładkowego EPY”), research results no. 14/91, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

41. Grudziński K., Kawiak R., Tuczyński: EPY chocking compound creep (“Pełzanie tworzywa podkładkowego EPY”), research results no. 15/1991, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

42. Grudziński K., Kawiak R., Tuczyński: EPY chocking compound creep (“Pełzanie tworzywa podkładkowego EPY”), research results no. 16/1991, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

43. Grudziński K., Kawiak R., Tuczyński: Linear thermal expansion coefficient of EPY chocking compound (“Współczynnik liniowej rozszerzalności cieplnej tworzywa podkładkowego EPY”), research results no. 17/1991, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

44. Grudziński K., Kawiak R., Tuczyński: Compression strength of EPY chocking compound (“Wytrzymałość na ściskanie tworzywa podkładkowego EPY”), research results no. 18/1991, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

45. Grudziński K., Kawiak R., Tuczyński: EPY chocking compound friction coeffi cient against steel (“Współczynnik tarcia tworzywa podkładkowego EPY po stali”), research results no. 19/1991, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

46. Grudziński K., Kawiak R.: Research results no. 20/91 of a foundation bolt joint model (“Wyniki badań nr 20/91 modelu fundamentowego złącza śrubowego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).

47. Grudziński K., Kawiak R.: Research results no. 22/91 of a foundation bolt joint model (“Wyniki badań nr 22/91 modelu fundamentowego złącza śrubowego”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1991 (unpublished).


48. Grudziński P.: Analysis of experimental methods for determination of rigidity and damping properties of resins, in the “Report on experimental projects carried out as a part of statutory activity in years 1991 — 1992” (“Analiza doświadczalnych metod wyznaczania sztywności oraz właściwości tłumiących tworzyw sztucznych, w: Sprawozdanie merytoryczne z prac doświadczalnych wykonanych w działalności statutowej w latach 1991 — 92”), task no. 027-0113/15-02 DzS, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1992 (unpublished).

49. Grudziński K., Kawiak R.: Testing of selected properties of EPY chocking compound (“Badania wybranych własności tworzywa podkładkowego EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1992 (unpublished).

50. Kawiak R.: “Some reasons for decrease in time of bolts pre-tensioning values” Niektóre przyczyny spadku wartości napięcia wstępnego śrub, “Przegląd Mechaniczny” periodical, 1992, Issue no. 5 — 6, p. 12, 21 — 22.

51. Grudziński K.: Development of Polish resin compounds and the technology of ship machinery seating based on these compounds (“Rozwój polskich tworzyw i technologii posadawiania na nich maszyn i urządzeń okrętowych”), “Budownictwo Okrętowe i Gospodarka Morska” periodical, 1993, July — August, p. 11 — 13.

52. Grudziński P.: Research into dynamic properties of resin compounds used for the seating of machinery (“Badania dynamicznych właściwości tworzyw sztucznych stosowanych w posadawianiu maszyn”), report from statutory activity in years 1991 — 1992”, task no. 027-0213/018-05-01, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1993 (unpublished).

53. Grudziński P.: Research into damping properties of resin compounds used for the seating of machinery (“Badanie własności tłumiących tworzyw sztucznych stosowanych w posadawianiu maszyn”), in the Materials of 17th Symposium of Machine Design Fundamentals, Szczyrk 1993, Announcements, p. 63 — 64.

54. Gas Denitrifi cation Plant “KRIO” in Odolanów, Poland: Letter DT/129/93 of 16.12.1993, concerning the evaluation of eff ectiveness of compressor unit GMVH-12 seating according to the method proposed by Techmarin company, with regard to vibration damping properties in a whole frequency range noxious to human operators (1 – 500 Hz), Odolanów 1993 (unpublished).

55. Guido B., Lukowiak L., Parosa R., Reszke E.: The concept of a microwave curing method for chemically curing EPY compound (“Projekt mikrofalowej metody utwardzania tworzywa chemoutwardzalnego EPY”), Research and Development Company (Przedsiębiorstwo Wdrażania Postępu Naukowo-Technicznego), Wrocław 1993 (unpublished).

56. Kawiak R.: Techniques for reduction of creep in foundation chocks cast from chemically curing chocking compound (“Sposoby zmniejszenia pełzania fundamentowych podkładek odlanych z tworzywa chemoutwardzalnego”), in the Materials of the VIth Conference on Non-ferrous Metals in Shipbuilding Industry, Maritime University of Szczecin, Szczecin — Świnoujście 1993, p. 201 — 207.

57. Jaroszewicz W.: The technique for curing the chemically curing compound, and in particular the foundation chocks made of this compound, in low temperatures (“Sposób utwardzania kompozycji chemoutwardzalnej, zwłaszcza podkładek fundamentowych z tej kompozycji, zwłaszcza w niskich temperaturach”), patent description no.169265 of 03.02.1993, Patent Offi ce of Poland, Warsaw 1996.


58. Kawiak R.: Protocol no.27/93 from the attempt to fi t the ring of Thordon resin in EPY chocking compound (“Protokół nr 27/93 z próby mocowania pierścienia z tworzywa Thordon w tworzywie podkładkowym EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1993 (unpublished).

59. Grudziński K., Jaroszewicz W., Grudziński P.: Research into vibration isolation properties of EPY compound (“Badania wibroizolacyjnych właściwości tworzywa EPY”), in the Materials of the XVIth Scientific Session of Shipbuilders, Szczecin — Dziwnówek 1994, Materials, p. 159 — 165.

60. Kawiak R., Grudziński K., Grudziński P., Jaroszewicz W.: Research into strength and vibroinsulation properties of EPY resin, Polish Maritime Research, 1994, Issue no. 1, p. 17 — 21.

61. Grudziński K., Jaroszewicz W., Parosa R., Reszke E.: Microwave curing of ship engine foundation chocks made of chemically curing EPY compound (“Mikrofalowe utwardzanie podkładek fundamentowych silników okrętowych odlewanych z tworzywa chemoutwardzalnego EPY”), in the Materials of the Conference “Progress in Electrical Engineering”, Szklarska Poręba 1994, p. 81 — 87.

62. Kawiak R.: Chemically curing resin compounds in bolt joints (“Tworzywa chemoutwardzalne w połączeniach śrubowych”), in the Materials of the VIIth Seminar on Resins in Machinery Design, Kraków 1994.

63. Grudziński K., Kawiak R., Tuczyński L.: Research into creep and thermal defl ection of testing EPY compound — report (“Raport z badań pełzania oraz ugięcia cieplnego tworzywa EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin, 1994 (unpublished).

64. Malinowski L., Jaroszewicz W.: Determination of temperature field in propeller shaft stern bearing installed by using EPY chocking compound — report (“Raport z wyznaczania pola temperatury w łożysku rufowym wału śrubowego posadowionego przy użyciu tworzywa EPY”), Szczecin 1994 (unpublished).

65. Grudziński K., Skierkowski A., Jaroszewicz W., et al.: Propeller shaft sterntube installation based on use of EPY chocking compound — report on design analysis and model tests (“Raport z analizy konstrukcji i badań modelowych montażu pochwy wału śrubowego przy zastosowaniu tworzywa EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1994 (unpublished).

66. Kawiak R.: Testing protocol no. 23/94 — EPY chocking compound viscosity (“Protokół badań nr 23/94 lepkości tworzywa EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1994 (unpublished).

67. Wypychowski K., Ratajczak D., Jaroszewicz W.: Quality System Books. Quality Management System of ISO 9002 standard (“Księgi jakości. System zarządzania jakością wg normy ISO 9002”), Marine Service Jaroszewicz, Szczecin 1994 — 1997 (unpublished).

68. Grudziński K., Jaroszewicz W.: Microwave curing of chocks cast in EPY compound for use in shipboard machinery settings, in the Marine Technology and Transportation, Southampton UK, Boston, Computational Mechanics Publications 1995, p. 309 — 315.

69. Grudziński K., Jaroszewicz W.: ISO 9002 certifi cate for Polish chocking compound EPY and the seating of ship engines based on use of this compound. (“Certyfi kat ISO 9002 dla polskiego tworzywa EPY i posadawiania na nim silników okrętowych”), “Budownictwo Okrętowe i Gospodarka Morska” periodical, 1995, Issue no. 1, p. 14 — 15.


70. Grudziński K., Jaroszewicz W., Kołodziejski W., Klimczak R.: New repair technique for heavy machinery exemplifi ed by the repair of GMVH-12 compressor/engine units (“Nowy sposób naprawy posadowienia ciężkich maszyn i urządzeń na przykładzie motosprężarek GMVH-12”), “Przegląd Mechaniczny” periodical, 1995, z. 21, p. 21 — 24.

71. Inspection testing of vibration parameters after the reinstallation of compressor unit (“Badania kontrolne parametrów drgań po wykonaniu przebudowy posadowienia zespołu sprężarkowego”), Gas Industry Plant in Rembelszczyna near Warsaw. Executed by the team under direction of Prof. G. Bąk (Eng), Warsaw 1995 (unpublished).

72. Ratajczak J.: Vibration isolation characteristics of EPY compound used for ship machinery foundation chocks (“Wibroizolacyjne właściwości tworzywa EPY stosowanego na podkładki fundamentowe maszyn i urządzeń okrętowych”), MSc diploma thesis, Technical University of Szczecin, Faculty of Maritime Engineering, Szczecin 1995 (unpublished).

73. Ratajczak D.: Microwave curing of EPY compound used for ship machinery foundation chocks (“Mikrofalowe utwardzanie tworzywa EPY stosowanego na podkładki fundamentowe maszyn i urządzeń okrętowych”), MSc diploma thesis, Technical University of Szczecin, Faculty of Maritime Engineering, Szczecin 1995 (unpublished).

74. Grudziński K., Konowalski K.: Fatigue compression strength testing of EPY chocking compound — report (“Raport z badań wytrzymałości zmęczeniowej na ściskanie tworzywa EPY”), Technical Uni-versity of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1995 (unpublished).

75. Grudziński K., Kawiak R., Konowalski K., Tuczyński L.: Theoretical and experimental fundamentals of a rudder assembly liner installation procedure based on use of EPY chocking compound (“Podstawy teoretyczno–doświadczalne montażu tulei zestawu sterowego przy użyciu tworzywa EPY”), document prepared on the order by Szczecin Shipyard S.A, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1995 (unpublished).

76. Grudziński K., Kawiak R., Jaroszewicz W.: Problems of machine elements contact over a thin layer of chemically curing compound (“Zagadnienia kontaktu elementów maszyn przy zastosowaniu cienkiej warstwy tworzywa chemoutwardzalnego”), in the Materials of a Science-Technology Conference “Contemporary Problems in Machinery Design and Service”, Technical University of Szczecin, Faculty of Mechanics Engineering, Szczecin 1996, p. 83 — 92.

77. Grudziński K., Ratajczak J.: Determination of a loss factor and the dynamic rigidity of EPY chocking compound (Wyznaczenie współczynnika strat oraz dynamicznej sztywności tworzywa EPY), in Materials of a Science-Technology Conference “Contemporary Problems in Machinery Design and Service”, Technical University of Szczecin, Faculty of Mechanics Engineering, Szczecin 1996, p. 93 — 102.

78. Grudziński K., Jaroszewicz W., Orzechowski S.: Seating of heavy mining machinery on foundation chocks cast from EPY chocking compound (“Posadawianie ciężkich maszyn i urządzeń górniczych na podkładkach fundamentowych odlewanych z tworzywa EPY”), in the Materials of the International Science-Technology Conference “Mine Shaft Transport” 1996, Gliwice 1996, Vol. 2, p. 151 — 155

79. Grudziński K., Ratajczak J.: Research into damping properties of EPY chocking compound used for heavy machinery chocks (“Badanie tłumiących właściwości tworzywa EPY stosowanego na podkładki fundamentowe ciężkich maszyn”), in the Materials of a 2nd Science-Technology Conference “Polymers and Constructional Composites”, Silesian University of Technology, Katedra Budowy Maszyn, Ustroń 1996, p. 279 — 286.


80. Report on vibration measurements on compressor units in Mackowice pumping station, (“Sprawozdanie z pomiarów drgań motosprężarek w przepompowni Mackowice”), Naval Academy of Poland (Akademia Marynarki Wojennej), Institute of Technical Maintenance of Ships, Gdynia 1996 (unpublished).

81. Witek A., Grudziński P.: Identifi cation of elastic-damping properties of epoxy compound chocks in forced vibration situation (“Identyfi kacja parametrów sprężysto-tłumiących podkładek z tworzyw sztucznych w warunkach drgań wymuszonych”), a paper presented at a meeting of Mechanical Engineering Committee of Polish Academy of Sciences (Polska Akademia Nauk), Szczecin 1996 (unpublished).

82. Grudziński K., Konowalski K., Ratajczak J., Tuczyński L.: Research into use of EPY chocking compound for the seating of anchoring/mooring windlasses (“Badania tworzywa EPY w aspekcie jego zastosowania na podkładki fundamentowe wind kotwicznych i cumowniczych”), report no. 3/96, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1996 (unpublished).

83. Konowalski K., Ratajczak J., Tuczyński L.: Research on liquid nitrogen cooling of EPY compound and its impact on the compression strength and impact strength (“Badania wpływu oziębienia tworzywa EPY w ciekłym azocie na jego wytrzymałość na ściskanie oraz udarność”), report no. 2/96, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin, 1996 (unpublished).

84. Grudziński K.: Mechanical characteristics of direct contact (butt) joints and joints with a thin layer of resin compound (“Charakterystyki mechaniczne połączeń stykowych bezpośrednich oraz z cienką warstwą tworzywa”), in the Materials of the IIIrd Professors’ Workshop, Mechanical Engineering Committee of Polish Academy of Sciences (PAN), Koszalin 1997.

85. Grudziński K., Konowalski K., Kawiak R.: Report no. 1/97 on testing the impact of paint coat presence on settling of main engines (or other machinery) on their foundations (“Raport no. 1/97 z badań wpływu powłok malarskich na osiadanie silnika głównego i innych mechanizmów na fundamentach”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin, 1997 (unpublished).

86. Grudziński K., Jaroszewicz W., Konowalski K.: Research into the impact of paint coat presence on the settling of ship machinery installed on chocks made of EPY compound (“Badania wpływu powłok malarskich na osiadanie maszyn i urządzeń okrętowych posadowianych na podkładkach z tworzywa EPY”), “Budownictwo Okrętowe i Gospodarka Morska” periodical, 1997, Issue no. 10, October, p. 23 — 28.

87. Witek A., Grudziński P.: Identifi cation of elastic — damping properties of resin compound chocks in machine subassembly joints (“Identyfi kacja własności sprężysto-tłumiących podkładek z tworzywa sztucznego w połączeniach podzespołów maszyn”), in the Materials of the XVIIIth Symposium of Fundamentals of Machine Design, Kielce — Ameliówka 1997, Part III, p. 293 — 298.

88. Grudziński K., Jaroszewicz W.: Special chocking compound for foundation chocks of ship machinery (“Specjalne tworzywo na podkładki fundamentowe maszyn i urządzeń okrętowych”), in the Materials of the Science-Technology Conference “New materials and new material technologies in shipbuilding and mechanical industry”. Szczecin — Świnoujście 1998, Vol. I, p. XXII — XXX.


89. Grudziński K., Konowalski K., Jaroszewicz W.: Seating of deck machinery on foundation chocks made of chemically curing compounds (“Posadawianie urządzeń pokładowych na podkładkach odlewanych z tworzywa chemoutwardzalnego”), in the Materials of the IVth Conference “Shipbuilding and Maritime Engineering”, Międzyzdroje 03 — 05.06.1998, published by the Technical University of Szczecin in 1998, p. 123 — 132.

90. Grudziński P., Ratajczak J.: Research into rheologic properties of EPY chocking compound used for machinery foundation chocks (“Badania reologicznych właściwości tworzywa EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of the Science-Technology Conference “New materials and new material technologies in shipbuilding and mechanical industry”. Szczecin — Świnoujście 1998, Vol. II, p. 661 — 666.

91. Ratajczak J., Grudziński K.: Research into elastic-damping properties of EPY chocking compound at low values of compression stress (“Badania sprężystych i tłumiących właściwości tworzywa EPY przy małych wartościach naprężeń ściskających”), in the Materials of the Science-Technology Conference “New materials and new material technologies in shipbuilding and mechanical industry”. Szczecin — Świnoujście 1998, Vol. II, p. 679 — 684.

92. Kawiak R.: Research into load-carrying ability of bolts anchored in concrete by using EPY chocking compound (“Badanie nośności zakotwień śrub w betonie wykonanych przy użyciu tworzywa EPY”), report no. 1/98, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1998 (unpublished).

93. Grudziński K., Konowalski K., Tuczyński L.: Experimental determination of the creep characteristics of chocking resins, report no. 2/98, Technical University of Szczecin 1998 (unpublished).

94. Witek A., Grudziński P.: Experimental examination of elastic–damping properties of resin compounds in forced vibration conditions (Doświadczalne badania wlaściwości sprężysto-tłumiących tworzyw sztucznych w warunkach drgań wymuszonych), in the Proceedings of the Conference on Computational Methods and Experimental Measurements’99, Sorrento, Italy 1999, p. 483 — 491.

95. Witek A., Grudziński P.: Accuracy analysis of an identification method of the parameters of resin compound chocks used in machine foundations (Analiza dokładności metody identyfi kacji parametrów podkładek stosowanych w posadowieniu maszyn), in the Proceedings of the 4th International Conference on Computational Methods in Contact Mechanics, Stuttgart, Germany, September 1999, UK, WIT Press 1999, p. 401 — 410.

96. Kawiak R.: Anchoring of foundation bolts by using polymer composites (“Osadzanie śrub fundamentowych za pomocą kompozytów polimerowych”), in the Materials of XIXth Symposium on Fundamentals of Machine Design, Zielona Góra — Świnoujście, September 1999, materials, Vol. I, p. 481 — 486.

97. Grudziński K., Kawiak R.: Polymer composites in bolt joints (“Kompozyty polimerowe w połączeniach śrubowych”), in the Materials of the XIXth Symposium on Fundamentals of Machine Design, Zielona Góra — Świnoujście, September 1999, materials, Vol. I, p. 55 — 60.

98. Grudziński K., Kawiak R.: Report no. 17/99 on strength testing of rope cone endings cast with EPY compound (“Raport nr 17/99 z badań wytrzymałości zamocowania liny w końcówkach stożkowych zalanych tworzywem EPY”), Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1999 (unpublished).


99. Grudziński K., Witek A. et al.: Research into dynamic properties of chocking compounds used for foundation chocks in machinery seating arrangements (“Badania dynamicznych właściwości tworzyw sztucznych stosowanych na podkładki fundamentowe w posadawianiu maszyn i urządzeń”), report on the execution of a research project no. 7T07C01611, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 1999 (unpublished).

100. Kawiak R.: Polymer composites in anchoring of foundation bolts (“Kompozyty polimerowe w zako-twieniach śrub fundamentowych”), “Technologia i Automatyzacja Montażu” scientifi c/technical quarterly, 1999, Issue no. 3, p. 48 — 50.

101. Kawiak R., Konowalski K.: Experimental research of rigidity and damping in contact joints transferring tangential loads (“Doświadczalne badania sztywności i tłumienia styków obciążonych w kierunku stycznym”), in the Materials of the International Science-Technology Conference “Technology impact on the condition of the upper layer- WW ‘99”, Poznań University of Technology, Mechanical Engineering Committee of Polish Academy of Sciences (PAN), Poznań, Studies and Materials, Vol. XVII, p. 261 — 256.

102. Grudziński K., Urbaniak M.: Research into mechanical characteristics of epoxy composites with glass fi bres under compression loads (“Badania charakterystyk mechanicznych kompozytów epoksydowych z włóknem szklanym przy obciążeniach ściskających”), in the Materials of the Conference “Polymers and Composites in Constructions”, Ustroń 2000, Silesian University of Technology, Scientifi c Works of the Chair of Machine Design, 2000, no. 1, p. 245 — 250.

103. Grudziński P., Ratajczak J.: Rheological model of EPY compound used for machinery foundation chocks (“Reologiczny model tworzywa EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of the Conference “Polymers and Composites in Constructions”, Ustroń 2000, Silesian University of Technology, Scientific Works of the Chair of Machine Design, 2000, no. 1, p. 245 — 250.

104. Grudziński K., Konowalski K., Jaroszewicz W.: Fatigue testing and static testing of EPY chocking compound used for machinery foundation chocks (“Badania zmęczeniowe i statyczne tworzywa EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of the Conference “Polymers and Composites in Constructions”, Ustroń 2000, Silesian University of Technology, Scientifi c Works of the Chair of Machine Design, 2000, no. 1, p. 245 — 250.

105. Grudziński K., Ratajczak J.: Research into the dynamic properties of EPY chocking compound used for machinery foundation chocks (“Badania dynamicznych właściwości tworzywa EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of 19th Scientifi c Session of Shipbuilders “Marine Technology 2000”, Szczecin — Dziwnówek 2000, p. 127 — 136.

106. Grudziński K., Konowalski K., Ratajczak J.: Comparative research into mechanical properties of resin compounds used for machinery foundation chocking (“Badania porównawcze właściwości mechanicznych tworzyw sztucznych stosowanych na podkładki fundamentowe maszyn”), in the Materials of 19th Scientific Session of Shipbuilders “Marine Technology 2000”, Szczecin — Dziwnówek, May 2000, p. 117 — 126.

107. Kawiak R.: Identifi cation of the parameters of a foundation chock model made of polymer composite (“Identyfi kacja parametrów modelu podkładki fundamentowej z kompozytu polimerowego”), in the Proceedings of the International Scientifi c Conference MECHANICS 2000, Rzeszów University of Technology, Rzeszów, June 2000, Scientifi c Bulletins of Rzeszów University of Technology, No. 179, Mechanics 54, p. 153 — 156.


108. Kawiak R.: Comparative deformations of chocks made of polymer composites (“Odkształcenia porównawcze podkładek z kompozytów polimerowych”). Composites, Selection of projects carried out by Western Pomeranian Branch of Polish Composite Materials Society, Materials Science Commission (Komisja Nauki o Materiałach) PAN, Poznań Branch, Maritime University of Szczecin, Szczecin 2000, p. 89 — 94.

109. Urbaniak M., Grudziński K.: Use of pulverized epoxy compound waste for re-use in machinery foundation chocks (“Wykorzystanie rozdrobnionych odpadów tworzywa epoksydowego do ponownego zastosowania na podkładki fundamentowe maszyn”), in the Materials of the 2nd

Science-Technology Conference “Recycling of resins”, Ustroń Zdrój 2001, Silesian University of Technology, Scientifi c Works of the Chair of Metals and Polymers Processing (Prace Naukowe Katedry Przetwórstwa Materiałów Metalowych i Polimerowych), p. 141 — 146.

110. Grudziński K., Urbaniak M.: Modifi cation of a chocking compound used for foundation chocks of heavy machinery, with volatile ashes (“Modyfi kacja popiołami lotnymi tworzywa epoksydowego przeznaczonego na podkładki fundamentowe ciężkich maszyn i urządzeń”), in the Materials of the 15th Scientifi c Conference “Modifi cation of polymers”, Świeradów Zdrój 2001, Wrocław University of Technology, Scientifi c Works of the Institute of the Organic Compounds and Resins Technology (Instytut Technologii Organicznej i Tworzyw Sztucznych), p. 203 — 206.

111. Grudziński K., Ratajczak J., Jaroszewicz W.: Use of chemically curing compounds in the construc-tion and modernisation of mining machinery (“Zastosowanie tworzywa chemoutwardzalnego w budowie i modernizacji maszyn i urządzeń górniczych”), in the Materials of the 2nd International Science-Technology Conference “Eff ective and Safe Transport Systems in Mining Industry” (Efektywne bezpieczne systemy transportowe w zakładach górniczych), Mining Industry Mechanisation Centre (Centrum Mechanizacji Górnictwa) KOMAG, Gliwice 2001, Vol. I, p. 247 — 259.

112. Grudziński K., Jaroszewicz W., Orzechowski S., Ratajczak J.: Seating of hoisting machines in mining on foundation chocks cast from EPY chocking compound (“Posadawianie górniczych maszyn wyciągowych na podkładkach fundamentowych odlewanych z tworzywa EPY”), in the Materials of the 4th International Science-Technology Conference, Kraków 2001, AGH University of Science and Technology, Science-Technology Bulletins (Zeszyty Naukowo-Techniczne), 2001, no. 22, p. 52 — 64.

113. Grudziński P., Witek A.: Identifi cation of dynamic parameters of resin compound chocks — accuracy analysis (“Analiza dokładności identyfikacji parametrów dynamicznych podkładek z tworzyw sztucznych”), in the Materials of the 20th Symposium of Machine Design Fundamen-tals, Polanica-Zdrój 2001, Opole University of Technology, Science Bulletins, Mechanics, 2001, no. 270, z. 68, p. 361 — 368.

114. Kawiak R.: Shape factor impact on deformations of foundation chocks (“Wpływ współczynnika kształtu na odkształcenia podkładek wyrównawczych”), in the Materials of the 20th Symposium of Machine Design Fundamentals (PKM), Polanica-Zdrój 2001, Opole University of Technology, Science Bulletins, Mechanics, 2001, no. 270, z. 68, 361 — 368.

115. Kawiak R.: Experimental research of bolt joints (“Badania doświadczalne połączeń śrubowych”), in the Materials of the 5th Science Conference “Experimental methods in design and operation of machines”, Institute of Machine Design and Operation at Wrocław University of Technology, Wrocław — Szklarska Poręba 2001, Vol. II, p. 31 — 38.


116. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of EPY chocking compound room temperature curing time on its strength properties determined in the static compression test (“Badania wpływu czasu utwardzania tworzywa EPY w temperaturze pokojowej na jego właściwości wytrzymałościowe wyznaczane w statycznej próbie ściskania”), report no. 1/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

117. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of Z-1 hardener amounts on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu ilości utwardzacza Z-1 na właściwości wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 2/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

118. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of glass fi bre amounts on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu ilości włókna szklanego na właściwości wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 3/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

119. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of silica fl our amounts on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu ilości mączki kwarcowej na właściwości wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 4/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

120. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of material resources type on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu rodzaju bazy surowcowej tworzywa epoksydowego EPY na właściwości wytrzymałościowe wyznaczane w statycznej próbie ściskania”), report no. 5/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

121. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of heating rate on the temperature of transition from glassy state to high-elasticity state, for epoxy compounds EPY, Chockfast Orange and Epocast 36 (“Badania wpływu prędkości nagrzewania tworzyw epoksydowych EPY, Chockfast Orange i Epocast 36 na temperaturę przejścia ze stanu szklistego do stanu o dużej elastyczności”), report no. 6/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

122. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of modifi ers on the strength properties of EPY chocking compound with glass fi bres, determined in the static compression test (“Badania wpływu środków modyfikujących na własności wytrzymałościowe tworzywa EPY z włóknem szklanym wyznaczane w statycznej próbie ściskania”), report no. 7/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

123. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of hardener type on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu rodzaju utwardzacza na własności wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 8/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).


124. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of glass balls on the strength properties of EPY chocking compound determined in the static compression test (“Badania ilościowego wpływu kulek szklanych na własności wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 9/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

125. Grudziński K., Kawiak R., Ratajczak J., Tuczyński L.: Tests of hardening exotherm end creep of the EPY compound for the purpose of updating the Lloyd’s Register’s of Shipping Certifi cate for this material, report no. 10/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

126. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of a proportion and granulation of smoke-box dust from “Dolna Odra” power station on the strength properties of EPY chocking compound determined in the static compression test (“Badania wpływu udziału i granulacji pyłów dymnicowych z Elektrowni “Dolna Odra” na własności wytrzymałościowe tworzywa EPY wyznaczane w statycznej próbie ściskania”), report no. 11/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

127. Grudziński K., Urbaniak M., Tuczyński L.: The determination of linear contraction during the curing process of compounds: EPY, Chockfast Orange i Epocast 36 (“Oznaczenia skurczu liniowego podczas utwardzania tworzyw: EPY, Chockfast Orange i Epocast 36”), report no. 12/2000, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

128. Grudziński K., Konowalski K., Urbaniak M., Tuczyński L.: On testing the mechanical properties of resins distinguished by FR1, FR2 and EPY symbols, report no. 1/2001, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2000 (unpublished).

129. Grudziński K., Urbaniak M., Tuczyński L.: Research into the impact of elevated temperature on the strength properties of EPY chocking compound (“Badania wpływu podwyższonej temperatury na właściwości wytrzymałościowe tworzywa EPY”), report no. 2/2001, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2001 (unpublished).

130. Grudziński K., Urbaniak M.: Research into the impact of long-time exposition to various media on the compression strength properties of chocking compound (“Badania długotrwałego wpływu różnych ośrodków na wytrzymałość na ściskanie tworzywa podkładkowego”), report no. 2/2001, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2002 (unpublished).

131. Grudziński K., Ratajczak J., Sobczak Ł., Jaroszewicz W.: Use of a chemically curing compound for the fitting of propeller shaft sterntubes (“Zastosowanie tworzywa chemoutwardzalnego do osadzania pochew wałów śrubowych”), in the Materials of a 20th Scientific Session of Shipbuilders, Polish Shipbuilders Society (Towarzystwo Okrętowców Polskich) “KORAB”, Gdańsk 2002, Conference Materials, p. 215 — 225.

132. Urbaniak M., Fabrycy E., Grudziński K.: Research into the EPY epoxy compound cross-linking process, and its selected mechanical properties, by using a diff erential scanning calorimetric method (DSC) (“Badania procesu sieciowania tworzywa epoksydowego EPY metodą kalorymetrii skaningowej (DSC) i jego wybranych własności mechanicznych)”, in the Materials of the 5th Science-Technology Conference “Polymers and Composites in Constructions”, Ustroń 2002.


133. Urbaniak M., Grudziński K.: Investigations of fi ller sedimentation in the resin compounds (“Badania sedymentacji napełniaczy w kompozycjach żywicznych”), report no. 2/2003, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2003 (unpublished).

134. Urbaniak M., Grudziński K.: Determination of the coeffi cient of linear thermal expansion for the EPY resin (“Wyznaczenie współczynnika liniowej rozszerzalności cieplnej tworzywa EPY”), report no. 3/2003, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2003 (unpublished).

135. Urbaniak M., Grudziński K.: Investigations of the viscoelastic properties of the EPY epoxy compound applied for machinery foundation chocks by the dynamic mechanical thermal analysis (“Badania metodą dynamicznej analizy termomechanicznej lepkosprężystych właściwości tworzywa epoksydowego EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of the 16th Scientifi c Conference “Modifi cation of polymers”, Polanica Zdrój 2003, Wrocław University of Technology, Scientifi c Works of the Institute of the Organic Compounds and Plastics Technology, p. 424 — 427.

136. Urbaniak M., Grudziński K.: Thermal investigations of curing process of the EPY epoxy resin applied for machinery foundation chocks (“Badania termiczne procesu sieciowania tworzywa epoksydowego EPY stosowanego na podkładki fundamentowe maszyn”), in the Materials of the 10th Seminar on Plastics in Machinery Design, Technical University of Kraków, Instytut Mechaniki Stosowanej, Kraków 2003, p. 397 — 401.

137. Grudziński K., Ratajczak J., Jaroszewicz W.: The present-day method of machinery and equpment assembling with use of special chemo-hardened plastic (“Nowoczesna metoda montażu maszyn i urządzeń z użyciem specjalnych tworzyw chemoutwardzalnych”), in the Materials of 21st Symposium of Machine Design Fundamentals, Ustroń 2003, WNT, Warszawa 2003, Vol. 1, p. 70 — 88.

138. Urbaniak M., Grudziński K.: Determination of the coefficient of linear thermal expansion for the EPY resin in the range of temperature from –25 to 60°C (“Wyznaczenie współczynnika liniowej rozszerzalności cieplnej tworzywa EPY w zakresie temperatur od –25 do 60°C”), report no. 1/2004, Technical University of Szczecin, Chair of Mechanics and Machine Elements, Szczecin 2004 (unpublished).

139. Urbaniak M., Grudziński K.: Thermal investigation of curing process of EPY epoxy system, Polymers 2004, 49, no. 2, p. 89 — 93.

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