58487638 the Shock Absorber Handbook

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The Shock Absorber HandbookSecond EditionJohn C. Dixon, Ph.D, F.I.Mech.E., F.R.Ae.S.Senior Lecturer in Engineering MechanicsThe Open University, Great BritainThis Work is a co-publication between Professional Engineering Publishing Ltdand John Wiley and Sons, Ltd.The Shock Absorber HandbookSecond EditionWiley-Professional Engineering Publishing SeriesThis series of books from John Wiley Ltd and Professional Engineering Publishing Ltd aims topromote scientic and technical texts of exceptional academic quality that have a particular appeal tothe professional engineer.Forthcoming titles:Vehicle Particulate EmissionsPeter EastwoodSuspension Analysis and Computational GeometryJohn C. DixonManaging Reliability Growth in Engineering Design: Decisions, Data and ModellingLesley Walls and John QuigleyThe Shock Absorber HandbookSecond EditionJohn C. Dixon, Ph.D, F.I.Mech.E., F.R.Ae.S.Senior Lecturer in Engineering MechanicsThe Open University, Great BritainThis Work is a co-publication between Professional Engineering Publishing Ltdand John Wiley and Sons, Ltd.This Work is a co-publication between Professional Engineering Publishing Ltd and John Wiley and Sons, Ltd.Previously published as The Shock Absorber Handbook, 1st Edition, by The Society of Automotive Engineers, Inc,1999, ISBN 0-7680-0050-5.By the same author: Tires, Suspension and Handling (SAE).Copyright 2007 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester,West Sussex PO19 8SQ, EnglandTelephone (44) 1243 779777Email (for orders and customer service enquiries): cs-books@wiley.co.ukVisit our Home Page on www.wiley.comAll Rights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted inany form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except underthe terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the CopyrightLicensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of thePublisher. Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd,The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or emailed to permreq@wiley.co.uk,or faxed to (44) 1243 770620.Designations used by companies to distinguish their products are often claimed as trademarks. All brand namesand product names used in this book are trade names, service marks, trademarks or registered trademarks of theirrespective owners. The Publisher is not associated with any product or vendor mentioned in this book.This publication is designed to provide accurate and authoritative information in regard to the subject mattercovered. It is sold on the understanding that the Publisher is not engaged in rendering professional services.If professional advice or other expert assistance is required, the services of a competent professional should be sought.Anniversary Logo Design: Richard J. PacicoBritish Library Cataloguing in Publication DataA catalogue record for this book is available from the British LibraryISBN 978-0-470-51020-9 (HB)Typeset in 10/12 pt Times by Thomson Digital, IndiaPrinted and bound in Great Britain by Antony Rowe Ltd, Chippenham, WiltshireThis book is printed on acid-free paper responsibly manufactured from sustainable forestryin which at least two trees are planted for each one used for paper production.Disclaimer: This book is not intended as a guide for vehicle modication, and anyone whouses it as such does so entirely at their own risk. Testing vehicle performance may bedangerous. The author and publisher are not liable for consequential damage arising fromapplication of any information in this book.ContentsPreface xiiiAcknowledgements xv1 Introduction 11.1 History 11.2 Types of Friction 151.3 Damper Congurations 171.4 Ride-Levelling Dampers 331.5 Position-Dependent Dampers 351.6 General Form of the Telescopic Damper 371.7 Mountings 421.8 Operating Speeds and Strokes 471.9 Manufacture 531.10 Literature Review 542 Vibration Theory 612.1 Introduction 612.2 Free Vibration Undamped (1-dof) 612.3 Free Vibration Damped (1-dof) 632.4 Forced Vibration Undamped (1-dof) 682.5 Forced Vibration Damped (1-dof) 712.6 Coulomb Damping 742.7 Quadratic Damping 772.8 Series Stiffness 792.9 Free Vibration Undamped (2-dof) 852.10 Free Vibration Damped (2-dof) 852.11 The Resonant Absorber 862.12 Damper Models in Ride and Handling 872.13 End Frequencies 882.14 Heave and Pitch Undamped 1-dof 902.15 Heave and Pitch Damped 1-dof 912.16 Roll Vibration Undamped 932.17 Roll Vibration Damped 942.18 Heave-and-Pitch Undamped 2-dof 952.19 Heave-and-Pitch Damped 2-dof Simplied 1002.20 Heave-and-Pitch Damped 2-dof Full Analysis 1023 Ride and Handling 1053.1 Introduction 1053.2 Modelling the Road 1053.3 Ride 1113.4 Time-Domain Ride Analysis 1133.5 Frequency-Domain Ride Analysis 1173.6 Passenger on Seat 1183.7 Wheel Hop 1193.8 Handling 1203.9 Axle Vibrations 1223.10 Steering Vibrations 1243.11 The RideHandling Compromise 1243.12 Damper Optimisation 1293.13 Damper Asymmetry 1314 Installation 1354.1 Introduction 1354.2 Motion Ratio 1354.3 Displacement Method 1374.4 Velocity Diagrams 1384.5 Computer Evaluation 1384.6 Mechanical Displacement 1384.7 Effect of Motion Ratio 1394.8 Evaluation of Motion Ratio 1424.9 The Rocker 1424.10 The Rigid Arm 1484.11 Double Wishbones 1504.12 Struts 1534.13 Pushrods and Pullrods 1554.14 Motorcycle Front Suspensions 1564.15 Motorcycle Rear Suspensions 1604.16 Solid Axles 1654.17 Dry Scissor Dampers 1685 Fluid Mechanics 1695.1 Introduction 1695.2 Properties of Fluids 1705.3 Chemical Properties 1715.4 Density 1715.5 Thermal Expansion 172viii Contents5.6 Compressibility 1725.7 Viscosity 1735.8 Thermal Capacity 1755.9 Thermal Conductivity 1765.10 Vapour Pressure 1765.11 Gas Density 1765.12 Gas Viscosity 1775.13 Gas Compressibility 1775.14 Gas Absorbability 1775.15 Emulsication 1795.16 Continuity 1885.17 Bernoullis Equation 1885.18 Fluid Momentum 1895.19 Pipe Flow 1915.20 Velocity Proles 1965.21 Other Losses 1995.22 The Orice 2035.23 Combined Orices 2075.24 Vortices 2095.25 Bingham Flow 2125.26 LiquidSolid Suspensions 2125.27 ER and MR Fluids 2146 Valve Design 2176.1 Introduction 2176.2 Valve Types 2196.3 Disc Valves 2206.4 Rod Valves 2216.5 Spool Valves 2226.6 Shim Valves 2236.7 Valve Characteristics 2256.8 Basic Valve Models 2276.9 Complete Valve Models 2306.10 Solution of Valve Flow 2356.11 Temperature Compensation 2376.12 Position-Sensitive Valves 2406.13 Acceleration-Sensitive Valves 2406.14 Pressure-Rate Valves 2436.15 Frequency-Sensitive Valves 2456.16 Stroke-Sensitive Valves 2456.17 Piezoelectric Valves 2496.18 Double-Acting Shim Valves 2496.19 Rotary Adjustables 2506.20 Bellows Valves 2526.21 Simple Tube Valves 252Contents ix6.22 Head Valves 2576.23 Multi-Stage Valves 2577 Damper Characteristics 2597.1 Introduction 2597.2 Basic Damper Parameters 2637.3 Mechanical Friction 2657.4 Static Forces 2687.5 Piston Free Body Diagram 2697.6 Valve Flow Rates 2717.7 Pressures and Forces 2727.8 Linear Valve Analysis 2737.9 Cavitation 2747.10 Temperature 2767.11 Compressibility 2767.12 Cyclical Characteristics, F(X) 2787.13 Extreme Cyclic Operation 2827.14 Stresses and Strains 2837.15 Damper Jacking 2867.16 Noise 2878 Adjustables 2898.1 Introduction 2898.2 The Adjustable Valve 2908.3 Parallel Hole 2948.4 Series Hole 2948.5 Maximum Area 2948.6 Opening Pressure 2948.7 Area Coefcient (Stiffness) 2958.8 Automatic Systems 2958.9 Fast Adaptive Systems 2998.10 Motion Ratio 3019 ER and MR Dampers 3039.1 Introduction 3039.2 ERMR History 3039.3 ER Materials 3099.4 ER Dampers 3149.5 ER Controlled Valve 3199.6 MR Materials 3219.7 MR Dampers 32410 Specifying a Damper 33310.1 Introduction 333x Contents10.2 End Fittings 33410.3 Length Range 33410.4 F(V) Curve 33410.5 Conguration 33410.6 Diameter 33510.7 Oil Properties 33510.8 Life 33510.9 Cost 33511 Testing 33711.1 Introduction 33711.2 Transient Testing 33811.3 Electromechanical Testers 34211.4 Hydraulic Testers 34411.5 Instrumentation 34511.6 Data Processing 34611.7 Sinusoidal Test Theory 34811.8 Test Procedure 35211.9 Triangular Test 35411.10 Other Laboratory Tests 35611.11 On-Road Testing 357Appendix A: Nomenclature 361Appendix B: Properties of Air 375Appendix C: Properties of Water 379Appendix D: Test Sheets 381Appendix E: Solution of Algebraic Equations 385Appendix F: Units 393Appendix G: Bingham Flow 397References 401Index 409Contents xiPreface to Second EditionIn view of the tremendous worldwide production of automotive dampers (shock absorbers), the formerabsence of a book devoted to this topic is surprising. During some years of damper design, research andcommercial testing, the author has become aware of a need for a suitable book to present thefundamentals of damper design and use, for the benet of the many designers of vehicles such aspassenger cars, motorcycles, trucks, racing cars and so on, since the necessary body of knowledge is farfrom readily available in the research literature. Damper des