M A/ .F S E I G O L O N H C E K.Worden, .W .A Bullough & .J Haywood University of ,dleiffehS UK ~~ dlroW cifitneicS NewJersey • London • Singapore • Hong Kong Published by Word Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore 596224 USA office: Suite 202, 1060 Main Street, River Edge, NJ 07661 UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. SMART TECHNOLOGIES Copyright © 2003 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN 981-02-4776-1 Printed ni Singapore by World Scientific Printers )S( etP dtL Preface The editors have been involved in a number of conferences covering the field of smart technologies. Two of them played particularly significant roles in the creation of this book. The first was a one-day meeting within the Insti- tute of Physics Congress in Brighton during March 1998. This was formed from several keynote speeches by experts in different aspects of the field. Since then we, along with the other members of the Dynamics Research Group at the University of Sheffield, were proud to be able to host the In- ternational Conference on Smart Technology Demonstrators and Devices, which was held in Edinburgh during December 2001. This conference aimed to aid the transfer of smart technologies from the laboratory to the market- place by focussing on working demonstrators and devices. In many ways it was a natural progression from the IOP meeting on theoretical basics to the Edinburgh meeting on fully-formed technology demonstrators. Using the relationships built during these and other similar meetings, the editors have been able to invite some of the leading specialists in the various disciplines involved to help them put together a book that provides an up-to-date introduction to the rapidly developing world of smart tech- nologies. Each author has been given a chapter in which to describe their particular enabling technology and it's relevance to the field. Because the authorship is taken from several different disciplines, the book hopefully reflects the multicultural nature of the field and will allow the reader to ap- preciate the different points of view that must be considered when designing smart technologies. Particular emphasis has been placed on the use of examples of actual structures, materials, devices, systems and machines that have been de- iv ecaferP veloped with the concept of smart technology in mind. This hopefully highlights the broad range of applications that can benefit from the con- cept. Anyone who needs to be briefed on the current status of these interdis- ciplinary technologies, or is interested in future developments in these fields will hopefully find this book helpful. It is presented in understandable and non-mathematical terms, making it accessible to engineers and scientists from an undergraduate level upwards. Keith Worden, Bill Bullough and Jonathan Haywood October 2002 Contents Preface v Chapter 1 The Smart Approach ~ An Introduction to Smart Technologies 1 1.1 What Constitutes a Smart Technology? ............. 1 1.2 Application of Smart Technologies . . . . . . . . . . . . . . . . 2 1.2.1 An Interdisciplinary Field . . . . . . . . . . . . . . . . . 2 Chapter 2 Sensing Systems for Smart Structures 7 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Sensor Requirements in Smart Systems ............. 8 2.3 Sensor Technologies for Smart Systems . . . . . . . . . . . . . . 11 2.3.1 The Options . . . . . . . . . . . . . . . . . . . . . . . . 11 2.3.2 Using Conventional Sensors . . . . . . . . . . . . . . . . 13 2.3.3 New Technologies Fibre Optic Sensors ........ 15 2.3.4 MEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2.3.5 Piezoceramics and Piezoelectric Polymers ........ 30 2.3.6 Film Technologies: Coatings and Threads ........ 31 2.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Chapter 3 Vibration Control Using Smart Structures 37 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.1.1 The Dynamics of Structures . . . . . . . . . . . . . . . . 39 3.1.2 Modal Analysis of Structures . . . . . . . . . . . . . . . 40 3.2 Sensors and Actuators . . . . . . . . . . . . . . . . . . . . . . . 42 vii viii Contents 3.3 Active Control of Structures . . . . . . . . . . . . . . . . . . . . 45 3.3.1 Modal Control . . . . . . . . . . . . . . . . . . . . . . . 46 3.3.2 Adding Damping Derivative Feedback ........ 48 3.3.3 Positive Position Feedback . . . . . . . . . . . . . . . . 48 3.3.4 Other Controllers . . . . . . . . . . . . . . . . . . . . . . 50 3.4 Examples of Vibration Control . . . . . . . . . . . . . . . . . . 50 3.4.1 A Cantilever Beam . . . . . . . . . . . . . . . . . . . . . 52 3.4.2 A Slewing Beam . . . . . . . . . . . . . . . . . . . . . . 55 3.4.3 A Slewing Frame . . . . . . . . . . . . . . . . . . . . . . 57 3.4.4 Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.4.5 Plate Example . . . . . . . . . . . . . . . . . . . . . . . 64 3.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Bibliography 69 Chapter 4 Data Fusion The Role of Signal Processing for Smart Structures and Systems 71 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4.2 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.3 Sensor Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.4 The JDL Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 4.5 The Boyd Model . . . . . . . . . . . . . . . . . . . . . . . . . . 82 4.6 The Waterfall Model . . . . . . . . . . . . . . . . . . . . . . . . 84 4.7 The Omnibus Model . . . . . . . . . . . . . . . . . . . . . . . . 85 4.8 The Relevance of Data Fusion for Smart Structures ....... 86 4.9 Case Study: Fault Detection Based on Lamb Wave Scattering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 4.9.1 Lamb Waves . . . . . . . . . . . . . . . . . . . . . . . . 88 4.9.2 Novelty Detection . . . . . . . . . . . . . . . . . . . . . 90 4.9.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 4.10 Sensor Optimisation, Validation and Failure-Safety ....... 94 4.10.1 Optimal Sensor Distributions . . . . . . . . . . . . . . . 94 4.10.2 Failure-Safe Distributions . . . . . . . . . . . . . . . . . 98 4.11 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 Appendix A The Multi-Layer Perceptron 101 Bibliography 105 Contents ix Chapter 5 Shape Memory Alloys A Smart Technology? 109 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 5.2 Structural Origins of Shape Memory ............... 111 5.3 One-Way Shape Memory ..................... 111 5.4 Two-Way Memory Effect ..................... 113 5.5 Pseudoelasticity or the Superelastic Effect ............ 114 5.6 A Brief History of Memory Alloys and their Application .... 115 5.7 Why Not Use Bimetals? ...................... 118 5.8 Types of Shape Memory Alloy .................. 118 5.9 Nickel Titanium Shape Memory Alloys .............. 119 5.9.1 Background ......................... 119 5.9.2 Mechanical Behaviour ................... 119 5.9.3 Corrosion Characteristics ................. 121 5.9.4 Ternary Additions ..................... 121 5.9.5 Summary of Mechanical and Physical Properties .... 122 5.10 NiTi Shape Memory Alloys in Smart Applications ....... 122 5.11 Shape Memory Alloys as Smart Actuators ............ 125 5.11.1 Political Factors ...................... 126 5.11.2 Economic Forces ...................... 126 5.11.3 Social Forces ........................ 127 5.11.4 Technological Forces .................... 128 5.12 Shape Memory Alloys and their Fit to Smart Technologies... 128 5.12.1 Shape Memory Alloys A Smart Material? ...... 128 5.12.2 Shape Memory Alloys in Smart Structures ....... 129 5.12.2.1 Passive Composite Structures ......... 130 5.12.2.2 Structural Shape Control ............ 131 5.12.2.3 Vibration Control ................ 132 5.12.2.4 Buckling Control ................ 133 5.12.2.5 Acoustic Radiation ............... 133 5.12.2.6 Active Damage Control ............. 134 5.13 Final Thoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Bibliography 137 Chapter 6 Piezoelectric Materials 141 6.1 Introduction to Piezoelectricity .................. 141 6.1.1 Crystallography of Piezoelectricity ............ 142 Contents 6.1.2 The Interaction Between Mechanical and Electrical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 6.1.3 Some Piezoelectric Materials . . . . . . . . . . . . . . . 145 6.2 Applications of the Direct Piezoelectric Effect .......... 147 6.3 Acoustic Transducers . . . . . . . . . . . . . . . . . . . . . . . . 149 6.4 Piezoelectric Actuators . . . . . . . . . . . . . . . . . . . . . . . 149 6.4.1 Bimorphs and Other Bending Piezo-Actuators ..... 150 6.4.2 Monolithic Actuators . . . . . . . . . . . . . . . . . . . 152 6.4.2.1 Moonies and Cymbals ............. 153 6.4.3 Stack and Multi-Layer Actuators ............. 156 6.4.3.1 Multi-Layer Characteristics .......... 157 6.4.3.2 Dynamic Characteristics of Multi-Layers . . . 158 6.5 The Problem of Amplification . . . . . . . . . . . . . . . . . . . 161 6.5.1 Mechanical Amplification . . . . . . . . . . . . . . . . . 162 6.5.2 The Summation of Multiple Small Steps ......... 163 6.5.3 The Impact Technique . . . . . . . . . . . . . . . . . . . 166 6.6 Further Application Examples . . . . . . . . . . . . . . . . . . 167 Bibliography 169 Chapter 7 Magnetostriction 171 7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 7.1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . 172 7.2 Rare Earth Intermetallics . . . . . . . . . . . . . . . . . . . . . 175 7.3 Actuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 7.3.1 Generic Actuators . . . . . . . . . . . . . . . . . . . . . 182 7.3.2 Magnetostrictive Motors . . . . . . . . . . . . . . . . . . 184 7.3.3 Sonic and Ultrasonic Emission .............. 186 7.3.4 Vibration Control and Absorbers ............. 187 7.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 Bibliography 191 Chapter 8 Smart Fluid Machines 193 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193 8.2 Concepts and Philosophy . . . . . . . . . . . . . . . . . . . . . 193 8.3 More Philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . 201 8.4 The Strictor Driven-Hydraulic Valve . . . . . . . . . . . . . . . 203 8.5 Electrostructured Fluids . . . . . . . . . . . . . . . . . . . . . . 203 Contents xi 8.6 Performance Prediction . . . . . . . . . . . . . . . . . . . . . . 206 8.7 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 Bibliography 219 Chapter 9 Smart Biomaterials "Out-Smarting" the Body's Defense Systems and Other Advances in Materials for Medicine 221 9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 9.2 Dumb Biomaterials The First Generation .......... 226 9.3 Planning and Refinement Second Generation Biomaterials . 229 9.3.1 Calcium Phosphate Ceramics . . . . . . . . . . . . . . . 231 9.3.2 Bioactive Glasses . . . . . . . . . . . . . . . . . . . . . . 233 9.4 Smart Surfaces Tailored for Specific Applications Third Generation Biomaterials . . . . . . . . . . . . . . . . . . . . . . 235 9.4.1 Materials-Tissue Interface . . . . . . . . . . . . . . . . . 235 9.4.2 Functionalised Surfaces . . . . . . . . . . . . . . . . . . 237 9.4.3 Biologically Modified Surfaces . . . . . . . . . . . . . . . 239 9.4.3.1 Bacterial Adhesion . . . . . . . . . . . . . . . 240 9.4.3.2 Bone Bonding . . . . . . . . . . . . . . . . . . 241 9.4.3.3 Blood Compatible Surfaces ........... 241 9.5 Really Smart Biomaterials The Next Generation ...... 242 9.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Bibliography 247 Chapter 10 Natural Engineering The Smart Synergy 249 10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 10.2 Intelligent Biomimetics . . . . . . . . . . . . . . . . . . . . . . . 250 10.2.1 Sensory Mechanisms . . . . . . . . . . . . . . . . . . . . 250 10.2.1.1 Arthropod Mechano-Receptors ......... 250 10.2.1.2 Vertebrate Sensors . . . . . . . . . . . . . . . 259 10.2.2 Integration and Coding . . . . . . . . . . . . . . . . . . 261 10.2.3 Actuation . . . . . . . . . . . . . . . . . . . . . . . . . . 261 10.2.3.1 Skin . . . . . . . . . . . . . . . . . . . . . . . 261 10.2.3.2 Deployable Structures . . . . . . . . . . . . . . 263 10.2.4 Implementation . . . . . . . . . . . . . . . . . . . . . . . 264 10.2.4.1 Liquid Crystals . . . . . . . . . . . . . . . . . 264 10.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268 Bibliography 269 Chapter 1 The Smart Approach An Introduction to Smart Technologies Keith Worden, William A. Bullough and Jonathan Haywood Dynamics Research Group, Department of Mechanical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK. 1.1 What Constitutes a Smart Technology? The words intelligent and smart are often used as tools to market new products but sometimes this is done with little thought as to what this should mean. Some of these products may incorporate the highest of high technology but do they really possess an awareness of their situation? And are they then capable of reacting to it? These are the key attributes that a technology must exhibit for it to be considered a truly smart technology. By situation we could mean the technology's environment, it's condition, or it's motion for example. The subsequent reaction could be to protect itself in some manner, instigate a repair to itself, or to adapt it's function so that it is tailored specifically to the situation. Technologies with the ability to sense changes in their circumstances and execute measures to enhance their functionality under the new circum- stances offer enormous benefits in performance, efficiency, operating costs and endurance.