OPTOMECHATRONIC BASED VIBRATION MONOTORING SYSTEM

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DESIGN AND DEVELOPMENT OF

OPTOMECHATRONIC VIBRATION MONITORING

SYSTEM

DEPARTMENT OFMECHANICAL ENGINEERING AND ELECTRONICS & COMMUNICATION

ENGINEERING

A PROJECT REPORT

Submitted in partial fulfillment of the requirement for the award of the Degree of

BACHELOR OF TECHNOLOGY

By

A. Jithendra Swamy (09131A0302)

B. Pavan Kumar (09131A0305)

P.M. Chaitanya Datta (09131A0337)

V. Krishna Chaitanya (09131A0355)

B.N.S.K. Sameer (09131A0410)

Under the Guidance of

Prof. Dr. Rao Tatavarti

DIRECTOR

(Engineering Research & Consultancy)

Co - Guide Co - Guide

Sri. Sanjay K Darvekar Prof. Dr. N. Bala Subramanyam

ASSOCIATE PROFESSOR HEAD OF DEPARTMENT

Dept. of Mechanical Engineering Dept. of ECE

GAYATRI VIDYA PARISHAD COLLEGE OF ENGINEERING (A)

Affiliated to JNTU, Kakinada

Accredited by NBA & NAAC with A Grade with CGPA of 3.47/4.00

MADHURAWADA, VISAKHAPATNAM530041

(2009 - 2013)


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DESIGN AND DEVELOPMENT OF

OPTOMECHATRONIC VIBRATION MONITORING

SYSTEM

DEPARTMENT OFMECHANICAL ENGINEERING AND ELECTRONICS & COMMUNICATION

ENGINEERING

A PROJECT REPORT

Submitted in partial fulfillment of the requirement for the award of the Degree of

BACHELOR OF TECHNOLOGY

By

A. Jithendra Swamy (09131A0302)

B. Pavan Kumar (09131A0305)

P.M. Chaitanya Datta (09131A0337)

V. Krishna Chaitanya (09131A0355)

B.N.S.K. Sameer (09131A0410)

Under the Guidance of


DIRECTOR

(Engineering Research & Consultancy)

Co - Guide Co - Guide

Sri. Sanjay K Darvekar Prof. Dr. N. Bala Subramanyam

ASSOCIATE PROFESSOR HEAD OF DEPARTMENT

Dept. of Mechanical Engineering Dept. of ECE

GAYATRI VIDYA PARISHAD COLLEGE OF ENGINEERING (A)

Affiliated to JNTU, Kakinada

Accredited by NBA & NAAC with A Grade with CGPA of 3.47/4.00

MADHURAWADA, VISAKHAPATNAM530041

(2009 - 2013)


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GAYATRI VIDYA PARISHAD COLLEGE OF ENGINEERING

(AUTONOMOUS)

(Accredited by NBA & NAAC with A Grade with CGPA of 3.47/4.00)

MADHURAWADA, VISAKHAPATNAM

CERTIFICATE

This is to certify that the Project work titled Design and Development of

Optomechatronic Vibration Monitoring System that is being submitted by

A.Jithendra Swamy(09131A0302)(Mech.), B.Pavan Kumar(09131A0305)(Mech.),

P.M.Chaitanya Datta(09131A0337)(Mech.), V.Krishna Chaitanya(09131A0355)

(Mech.) and B.N.S.K.Sameer (09131A0410)(ECE) in partial fulfillment of the

requirements for the award ofBachelor of Technology in concerned department, is

a record of bonafide work done under my guidance. The contents of this Project work,

in full or in parts, have neither been taken from any other source nor have been

submitted to any other Institute or University for award of any degree or diploma and

the same is certified.

Project guide


DIRECTOR

(Engineering Research and Consultancy)

GVPCOE

Project co-guide

Sri. Sanjay K Darvekar

Associate ProfessorDept. of Mechanical Engg

GVPCOE

Dr. B.Govinda Rao

Prof. & Head of Department

Dept. of Mechanical Engg.

GVPCOE

Dr. N.Bala Subramanyam

Prof. & Head of Department

Dept. of ECEGVPCOE


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We dedicate this project to our beloved family and friends!!!


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ACKNOWLEDGEMENT

First and foremost, we are very thankful to goddess Gayatri Devi for showering her

blessings on us. We are highly indebted to our advisor, project guide Prof. Dr, Rao

Tatavarti, Director, GVP SIRC for his constant advice, support and

encouragement. We owe our deepest sense of gratitude to our beloved Prof. Dr.

A.B.Koteswara Rao, Principal, GVPCOEfor providing necessary facilities to carry

out and finish the project successfully. We are grateful to Prof. Dr. Ing. P.Srinivasa

Rao, Director General, GVPSIRCfor providing us an opportunity to explore into

the real world and realize the interrelation of various disciplines.

We sincerely thank our co-guide Sri. Sanjay K Darvekar, Associate

Professor and project co-ordinators, Dr. D. Srinivasa Rao, Professor, Mechanical

Engineering Dept. & Ms. P.Vidya Sree, Assistant Professor, ECE Dept. for their

support throughout the project. This thesis work would not have been complete

without their help and guidance. We are grateful to our Head of Mechanical

DepartmentProf. Dr. B. Govinda Rao and Head of ECE DepartmentProf. Dr. N.

Bala Subramanyam for their support and encouragement.

We owe our sincere thanks to our Department faculty for their continuous

support. My heart-felt thanks to Mechanical and ECE faculty and special thanks toMr. Sivaprasad, Mrs. Bhanupriya, office assistants, Mr. J.Anil Kumar, Mr.

S.Shanmukha Rao, Project Associates, other SIRC interns and Mr. A.

Vishnuvardhan, office attender for their helping hand. Finally, we thank all our

friends and family members for their support without whom this project work would

have not been a possibility.

A.Jithendra Swamy (09131A0302) (Dept. of Mech.)

B.Pavan Kumar (09131A0305) (Dept. of Mech.)

P.M. Chaitanya Datta (09131A0337) (Dept. of Mech.)

V.Krishna Chaitanya (09131A0355) (Dept. of Mech.)

B.N.S.K.Sameer (09131A0410) (Dept. of ECE)


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ABSTRACT

Photonics is being studied today as a possible alternate technology for the

future. The goal of photonics is to use light to perform functions that traditionally fell

within the domain of electronics, such as telecommunications, information

processing, etc. Photonics is related to quantum optics, optomechantronics, electro

optics, optoelectronics and quantum electronics. This project is intended to design and

fabricate the vibration monitoring system using the principles of optomechatronics.

This system consists of a light transmitter and a receiver. The light is projected on to a

machine member, whose vibrations had to be known. The light is back from the

machine and receiver receives the information and process the information in

reflected light. This information changes with the change in the vibrations of the

machine/member. This information is used to monitor the vibrations in the machine.

The caution alarm is adjusted to the system and it will alert the worker when the

vibration in machine reaches beyond the limits.


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TABLE OF CONTENTS

Abstract

1. INTRODUCTION 1-121.1 Introduction to Vibrations 1

1.2. Definition of Vibrations 2

1.3. Origin of Vibrations 3

1.4. Types of Vibrations 4

1.4.1. Free and Forced Vibrations 4

1.4.2. Undamped and Damped Vibrations 5

1.4.3. Linear and non-linear Vibrations 5

1.5. Adverse Effects of Vibrations 5

1.6. Condition Monitoring Methods 6

1.6.1. Vibrations Analysis 6

1.6.2. Oil Analysis 7

1.7. Benefits of Vibration Monitoring 8

1.8. Laser Vibrometers 8

1.9. Objectives 9

1.10. Applications 10

2. BACKGROUND THEORY 14 - 25

2.1. Michelsons Interferometer 14

2.2. Fresnel Diffraction 17

2.3. Basic Equipment for Operations 18

2.3.1. Theory 18

2.4. Half Vertex angle vs. Range achieved by Instrument 21


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3. DESIGN AND DEVELOPMENT OF THE INSTRUMENT

SUPPORTING LASER AND PHOTODIODE 27 - 56

3.1. Design Considerations 27

3.1.1. Material Selection 27

3.2. CATIA Interface and Why CATIA? 29

3.2.1. Sketcher Interface 31

3.2.2. Operation and Profile Tool Bars 31

3.2.3. Constraint Tool Bar 32

3.2.4. Sketch Based tool Bar 32

3.2.5. Dressup Features 33

3.3. Parts of System 33

3.4. Design Iterations 33

3.5. Drawings 36

3.5.1. Base 36

3.5.2. Rails 37

3.5.3. Horizontal Screws 37

3.5.4. Supporting Block 37

3.5.5. Moving Supporter 38

3.5.6. Moving Block 38

3.5.7. Vertical Screw 39

3.5.8. Supporting Cylinder 39

3.5.9. Moving Cylinder 40

3.5.10. Cranks, Horizontal and Vertical Screws and Bolt s 41

3.5.11. Final Assembly 42

3.5.12. Functional Movements of Instrument 43


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3.5.13. Exploded View of Product 43

3.5.14. Finite Element Analysis of the Product Designed 44

3.6. Product Planning 47

3.6.1. CPM Chart 47

3.6.2. Crash Duration 47

3.6.3. Scheduled Times 47

3.7. Fabrication of Designed Components 49

3.7.1. Need for CNC Machines 50

3.7.2. CNC Machining 50

3.7.3. CNC Drilling and CNC Milling 51

3.8. Fabricated Parts 60

4. SENSORS FOR VIBRATION MONITORING 62 - 67

4.1. Laser 62

4.2. Photodiode 65

4.3. Usage of Instrument 67

5. DATA ACQUISITION AND ELECTRONICS 69 - 75

5.1. Block Diagram 69

5.2. Operational Amplifier 71

5.3. Process of Data Acquisition 72

5.3.1. Physical Input/output Signal 73

5.3.2. DAQ Device by Hardware 74

5.3.3. Driver Software 75

5.3.4. Application Software 75


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6. INTRODUCTION TO USB1608FS 77 - 87

6.1. Introduction to USB1608FS 77

6.2. Why USB1608FS 77

6.3. Functional Block Diagram 78

6.4. Connecting USB1608FS to Computer 79

6.5. Installing the USB1608FS 80

6.6. Functional Details 81

6.7. Parts USB1608FS 83

7. LABVIEW SOFTWARE 89 - 94

7.1. Introduction 89

7.2. Data Flow Diagram 89

7.3. Graphical Programming 90

7.4. Benefits 91

7.5. Sub Modules 91

7.6. Front Panel View 93

7.7. Simultaneous Sampling from 8Channels 94

8. ANALYSIS AND RESULTS 96 - 103

8.1. Experimentation 96

8.2. Analysis 99

8.3. Results 101

8.3.1. Power Spectrum 101

8.3.2. Coherence 102

8.3.3. Time Series Plots 103


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9. CONCLUSIONS AND FUTURE SCOPE 105

9.1. Conclusion 105

9.2. Future Scope 105

REFERNCES 107


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LIST OF TABLES

2.1. Ranges at different values of x with changing angle 23

3.1. Schedule Times 49

4.1. Specifications of Laser 64

4.2. Specifications of Photodiode 66

6.1. LED Behavior 85

6.2. Specifications of USB1608FS 87


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LIST OF FIGURES

1.1. .Linear and Non-Linear Vibrations 5

2.1. .Michelsons Interferometer 15

2.2.. Schematic Diagram Explaining Optical Diffraction Phenomenon

by Straight Edge Obstruction 17

2.3. Basic Equipment 19

2.4. Schematic Illustration of the Setup for the Demonstration of the Efficiency

of New Method being Claimed for use as an Optical Microphone 20

2.5. Schematic of the Position of the Equipment 21

2.6. Position of Laser and Diode 21

2.7. Range vs. (=0 to 0.1) 24

2.8. Range vs. (=0.1 to 1) 24

2.9. Range vs. (=1 to 5) 25

2.10. Range vs. (=5 to 90) 25

3.1.(a, b). CATIA Interface 30

3.2. Sketch Tool Bar 31

3.3(a). Dress Features Tool Bar 31

3.3(b). Profile Tool bar 31

3.4. Constraints Tool Bar 32

3.5. Sketch Based Features 32

3.6. Dress-up Features 33

3.7. Iteration 1 34

3.8. Iteration 2 34


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3.9. Iteration 3 35

3.10. Iteration 4 (Final Product) 35

3.11(a). Isometric View of Base 36

3.11(b). Drafts of the Base 37

3.12. Supporting Block 38

3.13. Moving Supporter 39

3.14. Moving Block 39

3.15. Supporting Cylinder 40

3.16. Moving Cylinder 41

3.17(a). Final Product 42

3.17(b). Final Product Draft 43

3.17(c). Functional Movements 43

3.18. Exploded View 44

3.19. Linear Tetrahedron Element 45

3.20(a). Mesh generated during FEA 46

3.20(b). Deformations due to Forces and Self-Weight 46

3.21. CPM Chart 48

3.22. Human Machine Interface where in G-Codes are Displayed

by post-processor 51

3.23. CNC Drilling 52

3.24. Machine Doors Closed During Operation 52

3.25. Drilling at Required Places 53

3.26. Drilling being Carried out for seating screw 53

3.27. CNC Milling 54

3.28. CNC Milling Machine 54


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3.29. G-Codes being developed by the operations in MasterCAM Software 56

3.30. Base 57

3.31. Supporting Block 57

3.32. Rails 58

3.33. Supporter 58

3.34. Supporting Cylinder 58

3.35. Moving Cylinder 59

3.36. Worm Shaft 59

3.37(a, b). Final Product 60

4.1. Laser (LM-MD 8.0-650) 62

4.2. Photodiode (BPW 21R) 65

4.3. Block Diagram for Setup of Instrument 67

4.4. Arrangement of Setup 69

5.1. Block Diagram for Setup of Experiment 69

5.2. Experimental Setup 70

5.3. Equipment during Experiment 71

5.4. Circuit of 741 OpAmp 71

5.5. Experimental Setup of 741 OpAmp 72

5.6. PC Based Data Acquisition 73

5.7. Types of DAQ Devices 74

6.1. Functional Block Diagrams 78

6.2. USB - 1608FS 83


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6.3. Screw Terminal Pinout 84

7.1. ULX Create Virtual Channel 91

7.2. ULX Timing 92

7.3. ULX Task Start 92

7.4. ULX Read 92

7.5. ULX Clear Task 93

7.6. Front Panel View 93

7.7. Amplitude in V and time in s with an i/p Frequency of 50Hz 94

7.8. Correlation between Channels 94

8.1. Setup of Instrument 98

8.2. Functional Block Diagram for Acquiring Data 100

8.3. Power Spectral Graph 101

8.4. Coherence 102

8.5. Time Series plots for Output and Input 103


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1

CHAPTER - 1

INTRODUCTION

1.1. INTRODUCTION TO VIBRATIONS

Noise and vibration are constantly present in our high-tech society. Noise causes

serious problems both at home and in the workplace, and the task of reducing community

noise is a subject currently focused on by authorities in many countries. Similarly,

manufacturers of mechanical products with vibrations causing acoustic noise, more and

more find themselves forced to compete on the noise levels of their products. Such

competition has so far occurred predominantly in the automotive industry, where the

issues with sound and noise have long attracted attention, but, at least in Europe, e.g.,domestic appliances are increasingly marketed stressing low noise levels. Let us list some

examples of reasons why vibration is of interest.

Vibration can cause injuries and disease in humans, with white fingers due to

long-term exposure to vibration, and back injuries due to severe shocks, as

examples.

Vibration can cause discomfort, such as sickness feelings in high-rise buildings

during storms, or in trains or other vehicles, if vibration control is not successful.

Vibration can cause fatigue, i.e., products break after being submitted to

vibrations for a long (or sometimes not so long) time.

Vibration can cause dysfunction in both humans and things manufacture, such as

bad vision if the eye is subjected to vibration, or radar on a ship performing

poorly due to vibration of the radar antenna.

Vibration can be used for cleaning, etc.

Vibration can cause noise, i.e., unpleasant sound, which causes annoyance as well

as disease and discomfort.

The lists above are examples, meant to show that vibrations and noise are indeed

interesting for a wide variety of reasons, not only to protect ourselves and our products,

but also because vibration can cause good things.


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Besides simply reducing sound levels, much work is currently being carried out

within many application areas concerning the concept ofsound quality. This concept

involves making a psychoacoustic judgment of how a particular sound is experienced by

a human being. Harley Davidson is an often-cited example of a company that considers

the sound from its product so important that it tried to protect that sound by trademark,

although the application was eventually withdrawn.

Besides generating noise, vibrations can cause mechanical fatigue. Now and then

people read in the newspaper that a car manufacturer is forced to recall thousands of cars

in order to exchange a component. In those cases it is sometimes mechanical fatigue that

has occurred, resulting in cracks initiating after the car has being driven a long distance.

When these cracks grow they can cause component breakdown and, as a consequence,

accidents.

1.2. DEFINITION OF VIBRATIONS

Vibrationis a mechanical phenomenon whereby oscillations occur about

an equilibrium point. The oscillations may be periodic such as the motion of a pendulum

or random such as the movement of a tire on a gravel road.

Vibration is occasionally "desirable". For example the motion of a tuning fork,

the reed in a woodwind instrument or harmonica, or mobile phones or the cone of

a loudspeaker is desirable vibration, necessary for the correct functioning of the various

devices.

More often, vibration is undesirable, wasting energy and creating

unwanted soundnoise. For example, the vibrational motions of engines, electric

motors, or any mechanical device in operation are typically unwanted. Such vibrations

can be caused by imbalances in the rotating parts, uneven friction, the meshing

of gear teeth, etc. Careful designs usually minimize unwanted vibrations.

The study of sound and vibration are closely related. Sounds, or

pressurewaves, are generated by vibrating structures (e.g. vocal cords); these pressure

waves can also induce the vibration of structures (e.g. ear drum). Hence, when trying to

reduce noise it is often a problem in trying to reduce vibration.


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1.3.ORIGIN OF VIBRATIONS

CAUSES OF VIBRATION

Identifying of the root cause of any problem helps us to tackle the same with greatease. This applies to vibration also. Most of the machines use in our day to day life like

the Mixer, Washing Machine, Vacuum Cleaner, etc. tends to indicate if something is

wrong in them by means of vibration and noise (a major by-product caused by vibration).

Even a novice is able to judge that the machine has a problem based on the sound

that he or she hears from it.

There are some of the major contributors, which cause the change in vibration level of a

machine. Let us discuss these now in details.

1. Unbalance. This is basically in reference to the rotating bodies. The uneven

distribution of mass in a rotating body contributes to the unbalance. A good example

of unbalance related vibration would be the vibrating alert in our mobile phones.

Here a small amount of unbalanced weight is rotated by a motor causing the vibration

which makes the mobile phone to vibrate. You would have experienced the same sort

of vibration occurring in your front loaded washing machines that tend to vibrate

during the spinning mode.

2. Misalignment. This is another major cause of vibration particularly in machines that

are driven by motors or any other prime movers.

3. Bent Shaft. A rotating shaft that is bent also produces the vibrating effect since it

losses it rotation capability about its center.

4. Gears in the Machine. The gears in the machine always tend to produce vibration,

mainly due to their meshing. Though this may be controlled to some extent, any

problem in the gearbox tends to get enhanced with ease. The major things that tend to

cause excessive vibration in gears are

i. Misalignment of the gear axis

ii. Gear teeth running out of contact


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iii. Wear and breakage of gear tooth.

5. Loose Foundations. This is a simple area where engineers fail to look into in any

machine that vibrates. The improper mounting of the machine without holding it

rigidly to the ground causes the machine to vibrate. The next time your water pump at

home vibrates be sure to check out the foundation bolts of the motor before you

proceed with further analysis.

6. Bearings. Last but not the least, here is a major contributor for vibration. In majority

of the cases every initial problem starts in the bearings and propagates to the rest of

the members of the machine. A bearing devoid of lubrication tends to wear out fast

and fails quickly, but before this is noticed it damages the remaining components in

the machine and an initial look would seem as if something had gone wrong with the

other components leading to the bearing failure. Such is the criticality of the bearings

in any machinery.

1.4. TYPES OF VIBRATIONS

1.4.1. FREE AND FORCED VIBRATIONS

Free vibration occurs when a mechanical system is set off with an initial input

and then allowed to vibrate freely. Examples of this type of vibration are pulling a child

back on a swing and then letting go or hitting a tuning fork and letting it ring. The

mechanical system will then vibrate at one or more of its "natural frequency" and damp

down to zero.

Forced vibration is when an alternating force or motion is applied to a mechanical

system. Examples of this type of vibration include a shaking washing machine due to an

imbalance, transportation vibration (caused by truck engine, springs, road, etc.), or the

vibration of a building during an earthquake. In forced vibration the frequency of the

vibration is the frequency of the force or motion applied, with order of magnitude being

dependent on the actual mechanical system.


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1.4.2. UNDAMPED AND DAMPED VIBRATIONS

If no energy is lost or dissipated in friction or other resistance during oscillation,

the vibration is known as undamped vibration. If any energy is lost in this way, however,

it is called damped vibration. In many physical systems, the amount of damping is sosmall that it can be disregarded for most engineering purposes. However, consideration of

damping becomes extremely important in analyzing vibratory systems near resonance.

1.4.3. LINEAR AND NONLINEAR VIBRATIONS

If the value or magnitude of the excitation force or motion) acting on a vibratory

system is known at any given time, the excitation is called deterministic. The resulting

vibration is known as deterministic vibration. In some cases, the excitation is

nondeterministic or random; the value of the excitation at a given time cannot be

predicted. In these cases, a large collection of records of the excitation may exhibit some

statistical regularity. It is possible to estimate averages such as the mean and mean square

values of the excitation. Examples of random excitations are wind velocity, road

roughness, and ground motion during earthquakes. If the excitation is random, the

resulting vibration is called random vibration. In this case the vibratory response of the

system is also random; it can be described only in terms of statistical quantities.

Fig. 1.1. Linear and non-linear vibrations

1.5. ADVERSE EFFECTS OF VIBRATIONS

The objectionable results of machine vibrations, if left uncontrollable can be several.

High stresses and force levels may be set up as a result of vibrations and in

extreme cases may lead to part failure. Such failure can be sudden or gradual, as

in fatigue.

Increased wear of parts and unsatisfactory equipment performance. This requires

increases maintenance and may also involve downtime of equipment.


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In a machine tool with excessive vibrations, parts may be inaccurately machined

and subsequently rejected.

It also causes an inadequately cushioned machine to walk away on its foundation.

Noise may become excessive and thus working conditions may become

unacceptable.

The machine with fewer vibrations will give a product with good surface finish

and good quality of the machined part. As vibrations increase the quality of the

product depletes due to poor machining. If we seek a machine with less

vibrations, the machine and machining cost increases. Vibrations also lead to

increase in machining time.

1.6. CONDITIONING MONITORING METHODS

Condition monitoring is based on being able to monitor the current condition and

predict the future condition of machines while in operation. Thus it means that

information must be obtained externally about internal effects while the machines are in

operation.

The two main techniques for obtaining information about internal conditions are.

1. Vibration Analysis. A machine in standard condition has a certain vibration signature.

Fault development changes that signature in a way that can be related to the fault. This

has given rise to the term mechanical signature analyses.

2. Lubricant Analysis. The lubricant also carries information from the inside to the

outside of operating machines in the form of wear particles, chemical contaminants, and

so on. Its use is mainly confined to circulating oil lubricating systems, although some

analysis can be carried out on grease lubricants.

1.6.1. VIBRATION ANALYSIS

Even in good condition, machines generate vibrations. Many such vibrations are

directly linked to periodic events in the machines operation, such as rotating shafts,

meshing gear teeth, rotating electric fields, and so on. The frequency with which such


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events repeat often gives a direct indication of the source and thus many powerful

diagnostic techniques are based on frequency analysis. Some vibrations are due to events

that are not completely phase locked to shaft rotations, such as combustion in IC (internal

combustion) engines, but where a fixed number of combustion events occur each engine

cycle, even though not completely repeatable. As will be seen, this can even be an

advantage, as it allows such phenomena to be separated from perfectly periodic ones.

Other vibrations are linked to fluid flow, as in pumps and gas turbines, and these also

have particular, quite often unique, characteristics. The term vibration can be

interpreted in different ways, however, and one of the purposes of this chapter is to

clarify the differences between them and the various transducers used to convert the

vibration into electrical signals that can be recorded and analyzed. One immediate

difference is between the absolute vibration of machine housing and the relative vibration

between a shaft and the housing, in particular where the bearing separating the two is a

fluid film or journal bearing. Both types of vibration measurement are used extensively in

machine condition monitoring, so it is important to understand the different information

they provide.

Another type of vibration which carries diagnostic information is torsional

vibration, that is, angular velocity fluctuations of the shafts and components such as gears

and rotor discs.

1.6.2. OIL ANALYSIS

This can once again be divided into a number of different categories.

1. Chip Detector. Filters and magnetic plugs are designed to retain chips and other debris

in circulating lubricant systems and these are analyzed for quantity, type, shape, size, and

so on. Alternatively, suspended particles can be detected in flow past a window.

2. Spectrographic Oil Analysis Procedures (SOAP). Here, the lubricant is sampled at

regular intervals and subjected to spectrographic chemical analysis. Detection of trace

elements can tell of wear of special materials such as alloying elements in special steels,

white metal or bronze bearings, and so on. Another case applies to oil from engine

crankcases, where the presence of water leaks can be indicated by a growth in NaCl or


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other chemicals coming from the cooling water. Oil analysis also includes analysis of

wear debris, contaminants and additives, and measurement of viscosity and degradation.

Simpler devices measure total iron content.

3. Ferrography. This represents the microscopic investigation and analysis of debris

retained magnetically (hence the name) but which can contain non-magnetic particles

caught up with the magnetic ones. Quantity, shape and size of the wear particles are all

important factors in pointing to the type and location of failure.

Successful use of oil analysis requires that oil sampling, changing and top-up

procedures are all well-defined and documented. It is much more difficult to apply

lubricant analysis to grease lubricated machines, but grease sampling kits are now viable

to make the process more reliable.

1.7. BENEFITS OF VIBRATION MONITORING

Vibration analysis is by far the most prevalent method for machine condition

monitoring because it has a number of advantages compared with the other methods. It

reacts immediately to change and can therefore be used for permanent as well as

intermittent monitoring. With oil analysis for example, several days often elapse between

the collection of samples and their analysis, although some online systems do exist. Also

in comparison with oil analysis, vibration analysis is more likely to point to the actual

faulty component, as many bearings, for example, will contain metals with the same

chemical composition, whereas only the faulty one will exhibit increased vibration.

1.8. LASER VIBROMETERS

In recent years there has been a rapid development of vibration transducers based

on the laser Doppler principle. In this technique, a coherent laser beam is reflected from a

vibrating surface and is frequency shifted according to the absolute velocity of the

surface (in the direction of the beam) by the Doppler effect. The frequency shift is

measured by an interferometer and converted to velocity. Note that because the frequency

shift occurs at the reflection, the result is virtually independent of the motion of the

transmitter/receiver; in other words, it measures absolute rather than relative motion.


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Laser vibrometers have the big advantage that they do not load the measurement object,

and the measurement point can be changed easily and rapidly by deflecting the light

beam. This is useful for making repeatable measurements over a grid in the minimum

time possible. For this reason, they are now used extensively for modal analysis

measurements and perhaps to a lesser extent for operational deflection shape (ODS)

measurements. The latter can be very useful for diagnostic purposes, even though not

discussed explicitly in this book, but because a scanning laser vibrometer system is so

expensive (up to hundreds of thousands of dollars) it would only have a very limited

application in machine monitoring. Even without the scanning system, the vibrometers

are quite bulky and difficult to move around, so they could not at present be used for

intermittent monitoring. It is possible that in the future they will be miniaturized to such

an extent that they could be used for portable field measurements. The author has heard a

presentation where the presenter mused that in the future vibrometers could be built into a

hard hat, and the operator would just have to look in the direction of a machine, utter the

ID of the machine into a microphone, and the laser and imaging system would locate the

machine and take measurements at a prescribed number of monitoring points on it.

Currently, however, they are not really a viable option for regular condition monitoring,

even though they are used for example in production quality control measurements.

1.9. OBJECTIVES

In this project, the main objective is to build a vibration monitoring system

equipped with optomechatronics. Till now there are laser vibrometers which operate on

the principle of Doppler affect. In this project the instrument uses the simultaneous

generation and detection of optical diffraction interference pattern on a photo detector.

This system has reduced electronic components and easy to construct. This also has

advantages of the conventional laser vibrometers.

The main objective of this project is to monitor the vibrations in a machine and its

components using a instrument. This instrument can measure the frequency and

amplitude of the vibrations in a machine without any direct contact. This device can also

be used to monitor remote sound.


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1.10. APPLICATIONS

In Engineering

Vibrometers can be used to measure machine vibrations. They allow for

performance evaluation of the machines. They can also be used to measure amplitude and

frequency of vibrating surface when it is placed on it. But the laser vibrometer is an non-

contact vibrometer.

These can also be used to measure seismic activity, machine vibration with or

without the influence of gravity.

a. Building and Structural Monitoring

Vibrometers are used to measure the motion and vibration of a structure that is

exposed to dynamic loads. Dynamic loads originate from a variety of sources including.

Human activities- walking, running, dancing and skipping

Working machines- inside a building or in the surrounding area

Construction work- drilling and excavating

Moving loads on bridges

Impact loads- fall in debris

Collapse of structural elements

Measuring and recording how a structure responds to these inputs is critical for assessing

the safety and viability of a structure. This type of monitoring is called vibration

monitoring.

b. Medical Applications

Vibrations of blood cells can be detected by projecting laser on to the surface of the

body. Infected cells can be easily found out by using laser vibrometer. The heart beat can

also be monitored using this device.


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c. Image Stabilization

Camcorders use vibrometers for image stabilization. Still cameras use vibrometers for

anti-blur capturing. The camera holds off snapping the CCD shutter when the camera is

moving. When the camera is still (for a milli second, as could be the case for vibration),

the CCD is snapped. An example application which has used such technology is the

Glogger VS2, N96. Some digital cameras contain accelerometers to determine the

orientation of the photo being taken and also for rotating the current picture when

viewing.

d. Orientation Sensing

A number of modern notebook computers feature vibrometers to automatically align

the screen depending on the direction the device is held, i.e. switching between portrait

and landscape modes. This feature is relevant in Tablet PCs and some smartphones and

digital cameras.

The Nokia N95 and Nokia N82 have accelerometers embedded inside them. It was

primarily used as a tilt sensor for tagging the orientation to photos taken with the buit-in

camera; later thanks to a firmware update it became possible to use it in other

applications.

As of January 2012, almost all new mobile phones and digital cameras such as

Canons power Shot and Inux range contain at least a tilt sensor for the purpose of auto

image rotation, motion- sensitive mini-games, and to correct shake when taking

photographs.

e. Navigation

An Inertial Navigation System (INS) is a navigation aid that uses a computer andmotion sensors (vibrometers) to continuously calculate via dead reckoning the position of

a moving object without need for external references. Other terms used to refer to inertial

navigation system or closely related devices include inertial guidance system, inertial

reference platform and many other variations.


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A vibrometer alone is unsuitable to determine changes in altitude over distances

where the vertical decrease of gravity is significant, such as for aircraft and rockets. In

the presence of a gravitational gradient, the calibration and data reduction process is

numerically unstable.

f. Acoustics

The present invention is to provide for a method and apparatus to work as an optical

microphone which is operable over the entire range of acoustical frequencies.


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CHAPTER - 2

BACKGROUND THEORY OF OPTICS

There are several optical methods that can be used for deflection of sound from a

distance; the most commonly used being the technique which employs the concept of

Optical interferometry which is well known in the field of electro optics. The technique

involves a high powered coherent light source, like a laser, good quality optical

accessories, like beam splitters, mirrors, collimating lens etc.; and a photo detector.

Although, the use of a laser to transducer sound from one place to another is well realized

in controlled laboratory conditions, the standard existing interferometer techniques how

many limitations if one were to adapt for a real world practical applications.

Most of the devices which utilize optics as a means for monitoring acoustic

vibrations work on the well- knownprinciple of Michelsons interferometer.

2.1. MICHELSONS INTERFEROMETER

The Michelson interferometer is the most common configuration for

optical interferometry and was invented by Albert Abraham Michelson. An interference

pattern is produced by splitting a beam of light into two paths, bouncing the beams back

and recombining them. The different paths may be of different lengths or be composed of

different materials to create alternating interference fringes on a back detector.

Michelson, along with Edward Morley, used this interferometer in the

famous Michelson-Morley experiment (1887) to show the constancy of the speed of

light across multiple inertial frames, which removed the conceptual need for

aluminiferous ether to provide a rest frame for light.

A Michelson interferometer consists of two highly polished mirrors M1 & M2. A

source S emits monochromatic light that hits a half-silvered mirror, surface M, at point C.

M is partially reflective, so one beam is transmitted through to point B while one is

reflected in the direction of A. Both beams recombine at point C' to produce an

interference pattern (assuming proper alignment) visible to the observer at point E. To the

observer at point E, the effects observed would be the same as those produced by placing


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surfaces A and B' (the image of B on the surface M) on top of each other. Let's look at

this interaction in more detail. Imagine that we have two surfaces M1 and M2 as

diagrammed.

Fig. 2.1. Michelsons Interferometer

There are two paths from the (light) source to the detector. One reflects off the semi-

transparent mirror, goes to the top mirror and then reflects back, goes through the semi-

transparent mirror, to the detector. The other first goes through the semi-transparent

mirror, to the mirror on the right, reflects back to the semi-transparent mirror, then

reflects from the semi-transparent mirror into the detector. The principle is when a

parallel beam of light coming from a monochromatic extended light source is incident on

a half silvered glass plate, it is divided into two beams of equal intensities by partial

reflection and transmission. Both beams are coherent. In this experiment coherent waves

are thus produced by the method of division of amplitude.


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If these two paths differ by a whole number (including 0) of wavelengths, there is

constructive interference and a strong signal at the detector. If they differ by a whole

number and half wavelengths (e.g., 0.5, 1.5, 2.5 ...) there is destructive interference and a

weak signal. This might appear at first sight to violate the principle of conservation of

energy. However energy is conserved, because there is a redistribution of energy at the

central beam-splitter in which the energy at the destructive sites is re-distributed to the

constructive sites. The effect of the interference is to alter the share of the reflected light

which heads for the detector and the remainder which heads back in the direction of the

source.

In the late 1800s, the interference pattern was obtained by using a gas discharge

lamp, a filter, and a thin slot or pinhole. In one version of the Michelson-Morley

experiment, the interferometer used starlight as the source of light. Starlight is temporally

incoherent light, but since it is a point source of light it has spatial coherence and will

produce an interference pattern.

In brief two aligned beams of laser light, of which one beam is slightly delayed in

relation to the other beam of same frequency, will cause the two beams to reinforce3 each

other if they are in same phase or cancel each other if one beam is 180 degrees out of

phase. If one of the two beams is reflected by an object in motion such that the direction

of motion is generally in the same direction as the non-reflected stationary beam, and two

beams are aligned by means of suitable mirrors into a single beam, the resulting

interference pattern will move at a velocity that is twice the velocity of the moving object

along the axis of aligned beam. As the interference pattern moves in the direction of the

aligned beam, a light sensor placed in the path of the beam will sense light intensity

variation that vary as a function of the movements of the reflecting object. The

interference caused by the beams of light has been used by inventors to construct

microphones that are very sensitive and other qualities.

However, any quality difference in terms of aberrations, astigmatism, coma and

distortion etc.; results in substantial increase in the noise in the interference fringes

produced at the detector plane thus effecting the practical realization of the technique for

many applications. Ideally both legs of an interferometer should be of equal length. If the


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two jointly arriving beams are not phase synchronized, the constructive and destructive

interference is degraded, thus limiting the devices sensitivity. Moreover, one of the

practical problems is the technique of the prior art is that the large optical path lengths

involved in real world applications, make it extremely difficult to maintain equal path

lengths for the interferometer.

2.2. FRESNEL DIFFRACTION

Fig 2.2 schematically illustrates the concept of generating an optical diffraction

pattern[5] for monochromatic light, by a prior art optical diffraction method. one means of

producing such pattern is through the use of a plane wave[1] from a laser and an opaque

object[2]. According to the established theory of optics, the sharp edge of the object [2]

casts a shadow having fairly sharp outline of the same shape as the object. However the

edge of this geometric shadow is not absolutely sharp and can examined closely it shows

a system of dark and bright bands in the immediate neighborhood of the edge at a

point[4]. The system of dark and bright bands comprises a diffraction pattern in a small

region around the point[4]. The resulting diffraction pattern[5], on a screen[3] is typically

shown for the purpose of illustration. This pattern is due to the diffraction of light around

the edge of the object[2] and a result of interference between the direct and the diffracted

light rays. The diffraction pattern is well known as the Fresnel diffraction pattern.

Fig. 2.2. Schematic diagram explaining the optical diffraction

phenomena by a straight edge obstruction


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The concept of optical diffraction is not new; however the technique could not

find as many applications as the technique of interferometer did, in the field of vibration

monitoring due to the practical limitations involved in its implementation. Generally,

devices based on optical diffraction require an optically opaque object to bend a part of

the laser beam and need a separate recording setup for recording the diffraction pattern

for analysis. Because of the high sensitivity involved in generating optical diffraction

patterns, even laboratory experiments under controlled conditions failed to yield high

repeatability, if utmost case is not taken to meet the various criteria necessary to yield a

diffraction pattern. And in the real world conditions the efficiency of this technique.

Becomes doubtful where the environmental conditions also keep changing. Therefore,

there exists a need for new devices which employ simpler but effective methods for

generation and detection of optical diffraction pattern that would function with good

repeatability and durability even under changing environmental conditions.

The present invention is a new method for simultaneously generating and

detecting the Fresnel diffraction pattern, as disclosed in the description. The new method

of the invention can be easily adopted in making novel devices to monitor mechanical or

pressure vibrations remotely; using any standard laser source and photo detector, one

such example being the optical microphone for remotely detecting sound.

The present invention provides for methods and apparatus for sensing any

vibrations, including sound waves; and in particular using optical means to detect any

mechanical vibrations through certain corresponding changes in optical properties of air

or through other optically transparent or semitransparent medium through which the

mechanical vibrations including sound waves propagate. The present invention generally

relates to the use of the principle of optical diffraction and interference.

2.3. BASIC EQUIPMENT FOR OPERATION

2.3.1. THEORY

The present invention describes an innovative method and apparatus for the

simultaneous generation and detection of optical diffraction interference pattern on a

photo detector. The dropping device disclosed herein comprises of a continuous wave


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coherent collimated beam of light (or a laser) falling on an optically reflected coating on

the surface of the body with inherent vibrations, or with manifest vibrations induced from

another source through any medium where the said light is reflected, and then received

on the surface of a photo detector in such a way that received light falls partially on the

active sensing area (annular ring surrounding the perimeter of the active sensing area) of

the said photo detector.

The spatial intensity pattern produced on the photo detector due to the

interference between the directly incident light and the optically diffracted light, changes,

if the incident light emanating from the reflecting surface undergoes changes in its path

length as a result of the vibrations felt on the reflecting surface. The photo detector

records the precise time varying optical diffraction interference pattern, corresponding to

the time varying vibrations experienced by the optical reflector.

Fig. 2.3 shows a schematic view of the main components of an apparatus for

employing the novel method for simultaneous generation and detection of optical

diffraction pattern using a standard photo detector. Unprocessed raw point light beam

emitted from a coherent monochromatic light source[1] of any constant intensity (a laser

diode source is chosen in the working example, whose DC electrical supply for powering

the laser diode is not shown here), is illuminated on an optical reflector[6] experiencing

inherent vibrations and, or those induced by a vibrating body. The said reflected raw laser

upon reflection by the optically reflecting surface is received on a standard photo

detector[8]. The schematic configuration is organized in such a way that the reflected light

beam is received at the edge of the photo detectors active sensing area, so that part falls

on the outer perimeter of the opaque region[9], which is generally of the order of a micron

thick, of the photo detector.

Fig. 2.3. Basic equipment (Source. US Patent No. US2010/0321698 A1)


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Fig 2.4 shows a schematic configuration of an apparatus which is used as an

optical micro phone. In this working example, a known audio file having arranged of

audio frequency (600 Hz to 4000Hz) is played on the first loud speaker[7]. It is observed

that the second loud speaker[12] connected to the photo detector[8] through a standard

cable[11] reproduces the same music exactly in live.

The vibration introduced at the mirror[6], which is pasted on to the diaphragm of

the loud speaker[7] introduces continuous change in the optical path lengths of the

reflected beam. This results in varying diffraction pattern on the photo detector. That is,

the intensity of the diffraction pattern generated on the photo detector[8] gets modulated

by the amplitude and change of period of vibration. Photo detector[8] detects these

vibrations as corresponding voltage variations. Hence, the vibration amplitudes and

frequency can be reproduced. This indicates that that, instead of loud speaker[7], if an

external sound produced elsewhere or near, vibrates the mirror[6] then it is possible to

detect the sound or vibration using the same concept described above, and hence the

embodiment under discussion would work as an optical microphone.

Fig. 2.4. Schematic illustration of the set up for demonstration of the efficiency of the new method

being claimed for use as an optical microphone (Source. US Patent No. US2010/0321698 A1)


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The input audio file being played by a personal computer[13] is tapped by a standard test

and measurements[14], comprising of analogue to digital conversion circuitry and piped

on to another personal computer[18], through a standard cable[15]. The output from the

photo detector[8], is similarly tapped by the standard test and measurement

apparatus[16],comprising of an analogue to digital conversion circuitry, the signals from

which are piped through a standard cable[17] to the personal computer[18]. However

instead of two separate apparatus a single test and measuring apparatus comprising of a

multi-channel analogue to digital conversion circuitry may also be used.

2.4. HALF VERTEX ANGLE VS. RANGE ACHIEVED BY

INSTRUMENT

Fig. 2.5. Schematic of the position of equipment

Fig. 2.6. Position of laser and diode

2x


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One of the objectives of the present invention is to provide a simple and portable

apparatus for listening to sound emanating from distant locations. Some calculations are

to be carried out to make a instrument. For this purpose, we have to know the distance

between laser diode and photo diode. Also we have to know the perpendicular distance

between vibrating surface to the line joining photo detector and laser diode. The distance

between laser diode and photo detector is fixed. And using this the perpendicular distance

between vibrating surface to the line joining photo detector and laser diode is find out.

In the above Figure;

2x(cm) is the range of movement between the transmitter and receiver.

y (cm) is the range of laser focus. 2 is the total vertex angle at the reflection surface.

From the trigonometric calculation -

x = y Tan

This relation gives the relation between the half vertex angle and range with

different values of x.

y = x cot

dy = - x cosec2 d

dy = - (x/sin2) d

Where; dy is the change of range, d is the change in angle


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Table. 2.1. Ranges* at different values of x with changing angle ()

*Range is the distance from the instrument to the vibrating object

Half

vertex

angle ()

Range* (cm)

x=12 x=11 x=10 x=9 x=7 x=690 7.35089E-16 6.73832E-16 6.12574E-16 5.51317E-16 4.90059E-16 4.28802E-16

85 1.049863962 0.962375299 0.874886635 0.787397972 0.699909308 0.612420645

80 2.115923769 1.939596788 1.763269807 1.586942826 1.410615846 1.234288865

75 3.215390309 2.947441117 2.679491924 2.411542732 2.143593539 1.875644347

70 4.367642811 4.003672577 3.639702343 3.275732108 2.911761874 2.54779164

65 5.595691898 5.12938424 4.663076582 4.196768923 3.730461265 3.264153607

60 6.92820323 6.350852961 5.773502692 5.196152423 4.618802154 4.041451884

55 8.402490459 7.70228292 7.002075382 6.301867844 5.601660306 4.901452767

50 10.06919557 9.230095943 8.390996312 7.551896681 6.712797049 5.873697418

45 12 11 10 9 8 7

40 14.30104311 13.10928952 11.91753593 10.72578233 9.534028741 8.342275148

35 17.13777608 15.70962807 14.28148007 12.85333206 11.42518405 9.997036047

30 20.78460969 19.05255888 17.32050808 15.58845727 13.85640646 12.12435565

25 25.73408305 23.58957613 21.44506921 19.30056228 17.15605536 15.01154844

20 32.96972903 30.22225161 27.47477419 24.72729678 21.97981936 19.23234194

15 44.78460969 41.05255888 37.32050808 33.58845727 29.85640646 26.12435565

10 68.05538184 62.38410002 56.7128182 51.04153638 45.37025456 39.69897274

5 137.1606276 125.7305753 114.300523 102.8704707 91.44041842 80.01036612

4 171.6079951 157.3073288 143.0066626 128.7059963 114.4053301 100.1046638

3 228.9736403 209.8925036 190.8113669 171.7302302 152.6490935 133.5679568

2 343.6350394 314.9987861 286.3625328 257.7262795 229.0900263 200.453773


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Graphs for Range vs. for different vales of x are as follows:

For = 00

to 0.10

Fig. 2.7. Range vs. ( = 0 to 0.1)

For = 0.10

to 10

Fig. 2.8. Range vs. ( = 0.1 to 1)

Range(cm)

Range(cm)

Half Vertex angle ()



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For = 10

to 50

Fig. 2.9. Range vs. ( = 1 to 5)

For = 50

to 900

Fig. 2.10. Range vs. ( = 5 to 90)


Half Vertex an le

Range(cm)

Range(cm)


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CHAPTER - 3

DESIGN AND DEVELOPMENT OF THE INSTRUMENT

SUPPORTING LASER AND PHOTODIODE

3.1. DESIGN CONSIDERATIONS

One of the objectives of the present invention is to provide a simple and portable

apparatus for measuring the vibrations. The main design considered that has to be taken

account is holding both the transmitter (LASER) and receiver (photodiode), which are to

be provided with the functional movements. The basic mechanism consists of the base,

supporting blocks, moving cylinders, moving blocks, cranks, supporting cylinder,

threads, shafts, rails, screws etc.

The main functional movements has to be achieved by the mechanism are

longitudinal translation, vertical translation, rotation about vertical axis. Longitudinal and

vertical translations are achieved with the help of a screw and nut mechanism with a pitch

of 1mm. Rotation about vertical is performed with the help of worm and worm wheel

mechanism

The drawings of the product are drawn using the CATIA V5 R18, and static

analysis of the product by taking the forces on it.

3.1.1. MATERIAL SELECTION

The material selected is Aluminum. Aluminum is remarkable for the metal's low

density and for its ability to resist corrosion due to the phenomenon of passivation.

Aluminum is a soft, durable, lightweight, ductile and malleable metal with appearance

ranging from silvery to dull gray, depending on the surface roughness. It is easily

machined, cast, drawn and extruded. Aluminum can be used as an alloy with other

metals, to extend the already impressive list of its properties. Its surface retains color well

and is therefore remarkably suited for printing.


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Aluminum also has the advantage of a practically infinite capacity for recycling,

making it a choice solution in terms of environmental protection. The use of secondary

aluminum, employing rejects or aluminum products at the end of their life cycle, requires

only 5% of the power required to produce the primary metal.

Aluminum's many properties and qualities explain the magic surrounding this

metal and the reason why its popularity continues to grow among new product designers

who are constantly adding to its already wide range of applications

PROPERTIES

a) Reflectivity.

Aluminum is an excellent reflector of heat, light and electromagnetic waves.

b) Thermal Conductivity.

Aluminum's thermal conductivity is remarkable and promotes its use in diverse

manufacturing sectors, such as kitchen utensils, solar collectors, refrigeration

components, disks and brakes. Aluminum is also used in the electronic industry, to

desalinate sea water and in all fields employing heat exchange devices.

c)

Workability.

If by workability one understands all the methods by which a material may be

destructively or non-destructively shaped, joined and finished, then aluminum must rate

as the most versatile of all the metal. Aluminum may be cast by all known foundry

methods; it can be rolled to any thickness down to foil thinner than tissue paper, it can be

stamped, drawn, spun, roll-formed, or forged; there is almost no limit to the different

cross-sectional shapes in which aluminum may be extruded. All aluminum alloys can be

machined, usually easily and rapidly, at maximum machine speed.

d) Strength.

The use of aluminum for space vehicles and aircraft structures probably represents the

most exacting application of the highest strength aluminum alloys where weight saving is

the primary requirement. While the list of applications for aluminum broadly based on


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lightness benefits is enormous, it is specifically lightness combined with strength which

accounts for the wide use of aluminum alloys for transportation equipment generally and

for moving and movable parts.

e)

Ductility.

Aluminum is easy to process, no matter what method is used (milling, drilling,

shearing, forging or spinning). It is easy to shape, making it ideal for extruding, strip

rolling, bending or other plastic hot or cold fabrication methods. It can also be soldered

and glued.

f) Resistance.

In its pure state, aluminum is soft and flexible. Its resistance can be increased by

alloys or cold treatment.

g) Corrosion resistant.

A compact layer of oxide forms naturally on the surface of aluminum, protecting it

from atmospheric corrosion and giving aluminum products a very long life. The visual

aspect of the material can be further improved by anodizing or heat treatment.

Maintenance of aluminum products is minimal, even when unprotected.

3.2. CATIA INTERFACE AND WHY CATIA?

CATIA (Computer Aided Three-dimensional Interactive Application) is a multi-

platform CAD/CAM/CAE commercial software suite. CATIA supports multi stages of

product development from conceptualization, design (CAD), manufacturing (CAM) and

engineering (CAE). CATIA can be applied to various variety of industries, from

aerospace and defense, automotive and industrial equipment, to high tech, ship building,

consumer goods, architecture and construction and services.

Installation of all CATIA version 5 products requires 2.0 GB on windows, 2.4 GB

on AIX, 2.7 GB on HP_UX and 2.3 GB on Solaris.


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CATIA enables the creation of 3D parts, from 3D sketches, sheet metal, composites,

molded, forged or tooling parts up to the definition of mechanical assemblies.

Fig. 3.1(a). CATIA interface

Fig. 3.1(b). CATIA interface


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3.2.1. SKETCHER WORK BENCH

Fig. 3.2. Sketch tool bar

3.2.2. OPERATION AND PROFILETOOL BARS

Profiles of different shapes are created using profile tool bar. Once a profile has

been created, it can be modified using commands such as trim, mirror, chamfer and other

commands located in their operation tool bar.

Fig. 3.3(a). Dress features tool bar

Fig. 3.3(b). Profile tool bar


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3.2.3. CONSTRAINT TOOL BAR

From left to right, the tools are Constraints defined in dialog box, Constraint, Fix

together, animate constraint and Edit multi-constraint. We use constraints in CATIA to

relate our geometric entities to one another, and to define the size of our geometry. This

is for the obvious reason that a much higher level of precision is required for sketching

when the results of your drawings are 3D machined parts, etc. Profiles may be

constrained with dimensional (distance, angle etc)or geometrical (tangent, parallel,

perpendicular etc) constraints using the commands located in the constraint tool bar.

Fig. 3.4. Constraints tool bar

3.2.4. SKETCH BASED FEATURES

The sketch-based features toolbar appears below, with many common features

that you use frequently in CATIA. From left to right, they are Pad (this is an extrusion),

Pocket (this is a cut), Shaft, Groove, Hole, Rib, Slot, Solid Combine, Multi-Sections

Solid, Removed Multi-Sections Solids. After you complete a sketch, you use it to

generate one of these features. The sketch based features enable the user to develop

required design and the features are as shown in the Fig.

Fig. 3.5. Sketch based features


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3.2.5. DRESS UP FEATURES

The dress-up features toolbar is how you further customize your features. You can

apply an Edge Fillet, Chamfer, Draft Angle, Shell, Thickness, Thread/Tap, and remove a

face (Remove Face).

The dress up features tool bar is shown below.

Fig. 3.6. Dressup features

By using these commands in CATIA and some additional features, we have a CATIA

model has been designed

3.3. PARTS OF SYSTEM

1. Base

2. Supporter

3. Supporting block

4. Supporting cylinder

5. Moving block

6. Rails

7. Screws

8. Worm mechanism

3.4. DESIGN ITERATIONS

The design has carried out four iterations, which include the modification of the

base, moving cylinder and translations mainly. The iterations are made to achieve the

best functionality of the system. The first two iterations are based on modification of the

moving cylinder that holds the transmitter and the receiver. The final two iterations

stresses on the modification of the base for better sliding. The iterations are also based on


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the product analyzed results. The static and dynamic analysis is performed using the

CATIA, and final product drawings are used for the fabrication the product.

The diagrams of the iterations are as follows.

Fig. 3.7. Iteration 1



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Fig. 3.10. Iteration 4 (final product)


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3.5. DRAWINGS

3.5.1. BASE

The metal base is rigid and fixed part of the body. It has the inner guide ways to

translate along the longitudinal axis (along the length) of the base. The inner ways are

highly polished to ensure the movement of the sliding memberwithout any vibrations and

plays. The total length provided in this design is 420mm, height is 57mm and the width

provided is about 90mm.

Fig. 3.11(a). Isometric view of base

Fig. 3.11(b). Drafts of the base


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3.5.2. RAILS

Rails are the elements of the system which acts as the guides for the longitudinal

movements of the transmitter and receiver. There are such two rails in this component.

These rails have a diameter of 1cm and have length of 420mm.

3.5.3. HORIZONTAL SCREW

Horizontal screw serves the purpose of the longitudinal movement.

3.5.4. SUPPORTING BLOCK

Supporting block will acts as the support for the rails. This also supports the

horizontal screws that are used for the longitudinal translation. These blocks are screwed

to the base at four locations as per design.

Fig. 3.12. Supporting Block


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3.5.5. MOVING SUPPORTER

The moving supporter is the platform which moves longitudinally, with the help

of screw mechanism. It has holes provided at proper locations for the passage of the rails.

Its upper surface has profiles cut in it to provide the space for the worm and worm wheel

mechanism.

Fig. 3.13. Moving supporter

3.5.6. MOVING BLOCK

Moving block comes above the moving supporter. Moving block has hallowed

part below it to provide the space for worm wheel and worm. The moving block and

moving supporter are joined with the help of the screws. In the middle moving block

consists of through which allows the worm wheel shafts to connect to the supporting

cylinder for the rotational movement.


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Fig. 3.14. Moving block

3.5.7. VERTICAL SCREW

Vertical screw serves the purpose of the vertical movement.

3.5.8. SUPPORTING CYLINDER

The supporting shaft supports the moving cylinderthat slides along the extruded

shaft as a guide. The bottom extruded part is tightly fitted into the inner hole of the worm

wheel, which is turned with the help of worm shaft. The upper extrusion of the shaft has

guide way which will guide the moving cylinder without any misplacement. The side of

this cylinder has hole in which bearing for the supporting the vertical screw is fitted.


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Fig. 3.15. Supporting cylinder

3.5.9. MOVING CYLINDER

The moving cylinder will slide along the supporting cylinder on the guide

provided between them, as it has outer guide to move in inner guide of supporting

cylinder. It moves vertically with help of the screw mechanism. It has provisions forfixing the nuts, through which the vertical screws will pass. The top extruded provision

will acts as a holder for transmitter/receiver.


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Fig. 3.16. Moving cylinder

3.5.10. CRANKS, HORIZONTAL SCREWS, VERTICAL SCREWS AND BOLTS

Cranks are the components which are used to rotate the screws used in the system

for the functional movements. The horizontal and vertical screws are the screws used to

attain the translation movements. The M6x1mm screws are used with two horizontal


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screws of length 210mm and vertical screws of length 200mm are used. The bolts of

M6x1mm are used for assembly of individual components.

3.5.11. FINAL ASSEMBLY

Design for assembly is one of the crucial tasks. The main assembly mainly

focuses on some conditions, which makes the functionality of the instrument with ease

and decreased wear of the equipment. The assembly is carried out taking the ease of

assembly and dismantling into the consideration.

Fig. 3.17(a). Final product

The above Fig. shows the assembly of the instrument. The cranks in the above

Fig. are used to rotate the screws in the instrument. The assemblies of the parts are made

with the help of screws connections. the rails, horizontal screws are fitted such that the

there is no play to components that are guided on them. The worm and worm gear are

enclosed in the casing with the help the screw connections. Total numbers of the screws

used for the assembly are 54.

Longitudinal screw

Vertical screw

Worm Shaft


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Fig. 3.17(b). Final product draft

3.5.12. FUNCTIONAL MOVEMENTS ACHIEVED BY INSTRUMENT

Fig. 3.18 (c). Functional movements of instrument

1

2

33

2


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The functional movements achieved by the instrument are the movement along

length[1], vertical translation[2], and rotation about vertical axis[3]. Movement along

length is attained by the longitudinal screw. The vertical translation is achieved by the

vertical screw and the rotation about the vertical axis is achieved by the worm wheel and

worm mechanism.

3.5.13. EXPLODED VIEW OF THE PRODUCT

Fig. 3.18. Exploded view

3.5.14. FINITE ELEMENT ANALYSIS OF THE PRODUCT DESIGNED

FEA is applied in the following manner.

Step 1. Identify the problem, sketch the structure and loads.

Step 2. Create the geometry with the FE package solid modeler or a CAD system.

Step 3. Mesh the model.

Step 4. Apply boundary conditions (constraints and loads) on the model.

Step 5. Solve numerical equations.

Step 6. Evaluate the results.

Steps 1, 2, 3, 4 are known as preprocessing, the solution of equations in step 5 is the

processor and step 6 is considered post processing. Most finite element procedures are

based on the "displacement method". From the law of equilibrium, the sum of the forces


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(internal and external) on a node must equal zero. The unknown variables are the

displacements. The following is the matrix form of the equilibrium equations.

[K] [D] = [F] ----- equation 1

[K] = global stiffness matrix

[D] = displacement vector

[F] = load vector.

The stiffness matrix [K] is symmetrical about the diagonal (symmetric matrix).

There are two main types of solving procedures. direct and iterative. Direct solving

procedure is usually based on Gaussian elimination technique. In Gaussian elimination

technique each element is taken and stiffness is calculated and then all the stiffness

matrices are assembled to form a global stiffness matrix. The displacements caused by

the forces are arranged in a displacement matrix computed by the software taking origin

as the reference. Once the stiffness matrix and displacement matrix are calculated the

stresses are computed using equation 1. The stiffness matrix is calculated by using shape

functions.

Fig. 3.19. Linear Tetrahedron element

The shape function is the function which interpolates the solution between the

discrete values obtained at the mesh nodes. The shape functions are tri-linear, the origin

of the Cartesian coordinate system is placed at one node and computations of the

deflection are first made locally and transferred globally. The shape functions taken are

N1 = 1 - , N2 = , N3 = , N4 = ,


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Each point (x, y, z) of the tetrahedron in the original coordinate system can be mapped to

a corresponding point (,, ) in the transformed coordinate system.

Fig. 3.20(a). Mesh Generated during FEA

Fig. 3.20(b). Deformations due to forces and self-weight

The Fig. 3.20(b) shows the deformation due to the forced ad self-weight. The

deformation on maximum deformation from the analysis is 0.000103mm, which is very

small. So the product will not fail.


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3.6. PRODUCT PLANNING

3.6.1. CPM CHART

The critical path method (CPM) is an algorithm for scheduling a set of project

activities. It is an important tool for effective project management.

The essential technique for using CPM is to construct a model of the project that includes

the following.

1. A list of all activities required to complete the project (typically categorized

within a work breakdown structure),

2. The time (duration) that each activity will take to completion, and

3. The dependencies between the activities.

3.6.2. CRASH DURATION

"Crash duration" is a term referring to the shortest possible time for which an

activity can be scheduled. It is achieved by shifting more resources towards the

completion of that activity, resulting in decreased time spent and often a reduced quality

of work, as the premium is set on speed Crash duration is typically modeled as a linear

relationship between cost and activity duration, however in many cases a convex function

or a step function is more applicable.

3.6.3. FLEXIBILITY

A schedule generated using critical path techniques often is not realized precisely, as

estimations are used to calculate times. if one mistake is made, the results of the analysis

may change. This could cause an upset in the implementation of a project if the estimates

are blindly believed, and if changes are not addressed promptly. However, the structure

of critical path analysis is such that the variance from the original schedule caused by any

change can be measured, and its impact either ameliorated or adjusted for. Indeed, an

important element of project postmortem analysis is the As Built Critical Path (ABCP),

which analyzes the specific causes and impacts of changes between the planned schedule

and eventual schedule as actually implemented.


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Fig. 3.21. CPM chartI. Concept

II. Design & Drafting

III. Analysis

IV. Synthesis

V. Selection of Proper Material

V

1 1 1

1

12

O

4

5

I

G

I

C D

E

FA BI I II V 1

H

2

3L

JK

6

6

M

9

7

8

P Q S11 T V

U

1

R

N10

11a

Event

Activities

Critical path


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1. Acquisition of Materials

2. Cutting of materials to get basic

shapes

3. Milling (End Milling)

4. Grinding

5. Polishing

6. Drilling

7. Boring

8. Reaming

9. Threading

10. Turning

11. Welding

11a. Chipping & polishing

12. Slotting

13. Finishing

14. Fitting of Bearings

15. Final Assembly

3.6.4. SCHEDULED TIMES

The table gives the scheduling times of the various activities involved in the

completion of the project. The optimistic time and pessimistic time for the various

activities are determined to know maximum and minimum times required to complete the

project. Considering a working day consists of 6 working hours, number of days had

calculated.

Process Optimistic time

(hours)

Pessimistic Time

(hours)

Concept 4 6

Design and Drafting 8 9

Analysis 3 5

Selection of proper material 1 3

Cutting of materials to get

basic shapes

12 15

Milling(End Milling) 8 12

Grinding 6 9


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Polishing 9 12

Drilling 8 12

Boring 6 9

Reaming(Finishing) 3 5

Threading 3 5

Turning 6 9

Welding 5 8

Chipping and Polishing 2 2

Slotting 6 8

knurling 3 3

Finishing 14 16

Fitting of Bearings 2 2

Final Assembly 9 14

Total Time 118 = 20 days 161 = 27 days

Table. 3.1. Scheduled Times

3.7. FABRICATION OF DESIGNED COMPONENTS

The design has been done in CATIA and analysis is carried out. The designed

parts of the structure are fabricated using Compute Numerically Controlled (CNC)

machining. CNC drilling, CNC milling machines are used in the fabrication.

3.7.1. NEED FOR CNC MACHINING

Machining in a conventional fashion leads to less surface finish, very large

tolerances. Not only have the above mentioned conditions other conditions, other

constraints like making the plays minimal during assembly also substantiated the need for

CNC machining. The CNC machining is completely automated and can produce a part

close to the original CAD design.


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3.7.2. CNC MACHINING

The early servomechanisms were rapidly augmented with analog and digital

computers, creating the modern computer numerical control (CNC) machine tools that

have revolutionized the machining processes. In modern CNC systems, end-to-end

component design is highly automated using computer-aided design (CAD) and

computer-aided manufacturing (CAM) programs. The programs produce a computer file

that is interpreted to extract the commands needed to operate a particular machine via a

postprocessor, and then loaded into the CNC machines for production. Since any

particular component might require the use of a number of different tools drills, saws,

etc., modern machines often combine multiple tools into a single "cell". In other cases, a

number of different machines are used with an external controller and human or robotic

operators that move the component from machine to machine. In either case, the complex

series of steps needed to produce any part is highly automated and produces a part that

closely matches the original CAD design. In general the code is plotted over the tapes and

read into the machines. The proliferation of CNC led to the need for new CNC standards

that were not encumbered by licensing or particular design concepts, like APT. A number

of different "standards" proliferated for a time, often based around vector graphics

markup languages supported by plotters. One such standard has since become very

common, the "G-code" that was originally used on plotters and then adapted for CNC

use. The file format is in wide use today. In turn, while G-code is the predominant

language used by CNC machines today, there is a push to supplant it with STEP-NC, a

system that was deliberately designed for CNC, rather than grown from an existing

plotter standard.

Fig. 3.22. Human Machine Interface where in G- Codes are displayed by postprocessor


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3.7.3. CNC DRILLING AND CNC MILLING

Computer Numerical Control (CNC) Drilling is commonly implemented for mass

production. The drilling machine, however, is often a multi-function machining center

that also mills and sometimes turns. The largest time sink for CNC drilling is with tool

changes, so for speed, variation of hole diameters should be minimized. The fastest

machines for drilling varying hole sizes have multiple spindles in turrets with drills of

varying diameters already mounted for drilling. The appropriate drill is brought into

position through movement of the turret, so that bits do not need to be removed and

replaced. A door is also provided so as to make sure that the part under operation is not

disturbed. The doors operate automatically and seizures themselves shut during the

operation of the machine. In order to be cost-effective, the appropriate type of CNC

drilling machine needs to be applied to particular part geometry. For low-volume jobs,

manual or semi-automated drilling may suffice. For hole patterns with large differences

in sizes and high volume, a geared head is most appropriate. If holes are close to each

other and high throughput is desired, a gearless head can locate spindles close together so

that the hole pattern can be completed in one pass. The drilling used here is M6 drill with

computer operation.

Fig. 3.23. CNC Drilling Fig. 3.24. Machine door closed during operation


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Fig. 3.25. Drilling at required places Fig. 3.26. Drilling being carried out

for seating screw

Computer Numerical Control (CNC) Milling is the most common form of CNC. CNC

mills can perform the functions of drilling and often turning. CNC Mills are classified

according to the number of axes that they possess. Axes are labeled as x and y for

horizontal movement, and z for vertical movement, as shown in this view of a manual

mill table. A standard manual light-duty mill is typically assumed to have four axes.

1.

Table x.

2. Table y.

3. Table z.

4. Milling Head z.

A five-axis CNC milling machine has an extra axis in the form of a horizontal pivot

for the milling head, as shown below. This allows extra flexibility for machining with the

end mill at an angle with respect to the table. A six-axis CNC milling machine would

have another horizontal pivot for the milling head, this time perpendicular to the fifth

axis. CNC milling machines are traditionally programmed using a set of commands

known as G-codes. G-codes represent specific CNC functions in alphanumeric format.


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Fig. 3.27. CNC Milling Fig. 3.28. CNC milling machine

A specific set of G codes have been generated in MasterCAM software and given

for the fabrication. The fabricator altered the codes to suit to the machine available and

operation has been done. Following is a GCode given to the fabricator.

%

O0000(BLOCK NEW)

(DATE=DD-MM-YY - 12-02-13 TIME=HH.MM - 14.06)

(MCX FILE - C.\USERS\SRAVANTHI\DOCUMENTS\MY

MCAMX5\MCX\BLOCK.MCX-5)

(NC FILE - C.\USERS\SRAVANTHI\DOCUMENTS\MY

MCAMX5\MILL\NC\BLOCK NEW.NC)

(MATERIAL - ALUMINUM MM - 2024)

( T240 | 6. BALL ENDMILL | H240 )

( T7 | 10. SPOT DRILL | H7 )

( T214 | 5. FLAT ENDMILL | H214 )

N100 G21

N102 G0 G17 G40 G49 G80 G90

N104 T240 M6

N106 G0 G90 G54 X10. Y80. A0. S1591 M3

N108 G43 H240 Z30.

N110 G99 G81 Z-7. R30. F127.3

N112 X45.


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N114 X80.

N116 Y45.

N118 Y10.

N120 X45.

N122 X10.

N124 Y45.

N126 G80

N128 M5

N130 G91 G28 Z0.

N132 A0.

N134 M01

N136 T7 M6

N138 G0 G90 G54 X45. Y45. A0. S1145 M3

N140 G43 H7 Z30.

N142 G99 G81 Z-10. R30. F114.5

N144 G80

N146 M5

OPTOMECHATRONIC BASED VIBRATION MONOTORING SYSTEM

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