Dielectric Elastomers as Electromechanical Transducers: Fundamentals, Materials, Devices, Models and Applications of an Emerging Electroactive Polymer Technology

✍ Scribed by Federico Carpi, Danilo De Rossi, Roy Kornbluh, Ronald Edward Pelrine, Peter Sommer-Larsen

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Leaves: 334
• Edition: illustrated edition
• Category: Library

✦ Synopsis

This book provides a comprehensive and updated insight into dielectric elastomers; one of the most promising classes of polymer-based smart materials and technologies. This technology can be used in a very broad range of applications, from robotics and automation to the biomedical field.
The need for improved transducer performance has resulted in considerable efforts towards the development of devices relying on materials with intrinsic transduction properties. These materials, often termed as "smart" or "intelligent", include improved piezoelectrics and magnetostrictive or shape-memory materials. Emerging electromechanical transduction technologies, based on so-called ElectroActive Polymers (EAP), have gained considerable attention. EAP offer the potential for performance exceeding other smart materials, while retaining the cost and versatility inherent to polymer materials. Within the EAP family, "dielectric elastomers", are of particular interest as they show good overall performance, simplicity of structure and robustness. Dielectric elastomer transducers are rapidly emerging as high-performance "pseudo-muscular" actuators, useful for different kinds of tasks. Further, in addition to actuation, dielectric elastomers have also been shown to offer unique possibilities for improved generator and sensing devices.
Dielectric elastomer transduction is enabling an enormous range of new applications that were precluded to any other EAP or smart-material technology until recently.
This book provides a comprehensive and updated insight into dielectric elastomer transduction, covering all its fundamental aspects. The book deals with transduction principles, basic materials properties, design of efficient device architectures, material and device modelling, along with applications.
* Concise and comprehensive treatment for practitioners and academics
* Guides the reader through the latest developments in electroactive-polymer-based technology
* Designed for ease of use with sections on fundamentals, materials, devices, models and applications

✦ Table of Contents

cover.jpg......Page 1
Preface......Page 2
Dedication......Page 3
List of Contributors......Page 4
Introduction: History of Dielectric Elastomeractuators......Page 7
Section I: Fundamentals......Page 10
1.2 Fundamentals of DE transduction......Page 12
1.3 The constant volume assumption and resultant Maxwell stress......Page 14
1.4 Analysis of several important DE conditions......Page 16
1.5 Strain response and stability......Page 17
1.7 Stiffness modulation......Page 19
1.8 Summary......Page 21
2.1 Conventional actuators and the need for new approaches......Page 22
2.2 Muscle......Page 23
2.3 Relaxor ferroelectric polymers......Page 25
2.4 Ionic actuators......Page 26
2.6 Discussion and conclusions......Page 28
Section II: Materials......Page 31
3.1 Introduction......Page 33
3.2 The elastic modulus......Page 34
3.3 The vulcanization......Page 36
3.5 Processing......Page 39
4.2 Basic model of operation......Page 41
4.3 Overview of polymer performance......Page 42
4.4 Silicones and acrylics......Page 43
4.5 Dynamic response......Page 45
4.7 Future improvements and discussion......Page 49
5.2 Concepts for IPN dielectric elastomers......Page 51
5.4 VHB-based IPN dielectric elastomers......Page 52
5.5 Conclusions and future developments......Page 58
6.1 Introduction......Page 59
6.2 Methods for increasing the dielectric permittivity: summary......Page 61
6.3 Random composites......Page 63
6.4 Field-structured composites......Page 72
6.5 New synthetic polymers......Page 73
6.6 Conclusions......Page 74
7.2 Conductive fillers in insulating matrix......Page 77
7.3 Metal films for compliant electrodes......Page 79
7.4 Unconventional electrode materials......Page 82
Section III: Devices......Page 85
8.1 Introduction......Page 87
8.3 Dielectric elastomer actuator design issues and unique features......Page 88
8.4 Enhanced actuator configurations......Page 89
8.5 Motor configurations......Page 94
8.7 Beyond actuators: generators, sensors and tunable structures......Page 95
8.8 Summary and discussion......Page 96
Acknowledgements......Page 97
9.1 Introduction......Page 99
9.2 Design......Page 100
9.3 Theoretical design tools......Page 103
9.4 Challenges......Page 107
9.5 Applications......Page 108
Acknowledgement......Page 110
10.2 Actuator configurations......Page 111
10.3 Testing of DESCE......Page 112
10.4 Sensor configurations......Page 114
10.5 Conclusion......Page 115
11.1 Introduction......Page 117
11.2 Technology......Page 118
11.3 Modelling......Page 122
11.4 Characterization......Page 124
11.5 Applications......Page 126
11.6 Conclusion......Page 129
12.1 Introduction......Page 131
12.2 Helical dielectric elastomer actuators......Page 132
12.3 Folded dielectric elastomer actuators......Page 134
12.4 Examples of applications......Page 136
12.5 Conclusions......Page 139
13.1 Introduction......Page 140
13.2 Device concept......Page 141
13.3 Prototype devices......Page 143
13.4 Conclusions......Page 148
14.1 Introduction......Page 149
14.2 General principles of dielectric elastomer variable stiffness......Page 150
14.3 Variable damping......Page 152
14.5 Summary......Page 153
15.2 General principles of the dielectric elastomer generator mode......Page 154
15.3 More detailed analysis of the generator mode......Page 157
15.4 Practical considerations......Page 158
15.5 Applications of dielectric elastomer generators......Page 160
15.6 Summary......Page 163
Section IV: Models......Page 164
16.1 Introduction......Page 166
16.2 Infinitesimal strain model......Page 167
16.3 Finite strain model......Page 168
16.4 Temporal dependency......Page 171
17.1 Introduction......Page 176
17.2 Experimental data......Page 177
17.3 Material modelling......Page 178
17.4 Finite element simulation......Page 179
17.5 Experimental data versus simulation......Page 181
17.6 Conclusion......Page 182
Acknowledgement......Page 183
18.1 Introduction......Page 184
18.2 Electrical effects in continuous dielectric media......Page 185
18.3 Theory of electro-elastic membranes......Page 186
18.4 Dielectric elastomer actuators: a diaphragm configuration......Page 187
18.5 Constitutive equations......Page 189
18.6 Numerical results: a qualitative analysis......Page 190
Section V.I: Biomedical, Haptic and Micro-Scale Applications......Page 196
19.1 Introduction......Page 198
19.2 Competitive and developmental advantages of DEA use......Page 200
19.3 Case studies: possible application of DEA technology to orthotics and prosthetics......Page 202
19.4 Limitations and design considerations of orthotic and prosthetic uses of dielectric elastomer......Page 208
19.5 Conclusion......Page 209
20.1 Introduction......Page 212
20.2 Force feedback system......Page 213
20.3 Miniature rolled DE actuators......Page 215
20.4 Electrical safety issues......Page 219
Acknowledgements......Page 220
21.1 Introduction......Page 222
21.2 Thickness-mode actuator configuration......Page 223
21.3 Design parameters and modelling......Page 225
21.4 Applications of thickness-mode actuators......Page 228
21.5 Summary......Page 230
22.1 Introduction......Page 232
22.2 Representative applications......Page 234
22.3 Challenges......Page 241
Acknowledgements......Page 242
23.1 Introduction......Page 244
23.2 Design of a cell......Page 245
23.3 Braille display devices......Page 247
23.4 Experimental evaluation......Page 251
Acknowledgement......Page 253
Section V.II: Robotic and Biorobotic Applications......Page 254
24.2 Advantages of biomimetics......Page 256
24.4 First generation of EPAM-enabled robots......Page 258
24.5 Future generations of EPAM-enabled robots......Page 260
24.6 Summary and conclusions......Page 263
25.1 Introduction......Page 264
25.2 Locomotion of earthworm......Page 265
25.3 New actuation ideas for dielectric elastomers......Page 266
25.4 Building the proposed actuator......Page 269
25.5 Simulation and experimental results......Page 270
25.6 Building and operating of earthworm robot......Page 271
25.7 Conclusion......Page 273
Acknowledgement......Page 274
26.1 Introduction......Page 275
26.2 Binary actuators......Page 276
26.3 Properties of DEAs......Page 277
26.4 Binary robotic systems with DEAs......Page 278
26.5 Conclusion......Page 280
26.6 Appendix: summary of DEA failure modes study......Page 281
Acknowledgement......Page 282
27.1 Introduction......Page 284
27.2 Rolled DE actuators......Page 285
27.3 Arm wrestling robot......Page 289
27.4 Conclusions......Page 293
Acknowledgements......Page 294
28.1 Introduction......Page 295
28.2 Feldmans muscle model......Page 296
28.3 Dielectric elastomers, artificial motor unit fibres and pseudomuscular ac tuators......Page 299
28.4 Compliance control: introduction to the dynamic case......Page 301
28.5 The compliance operator......Page 302
Acknowledgements......Page 303
Section V.III: Commercial Applications......Page 304
29.2 UMA platform......Page 306
29.3 Improvements in robustness......Page 307
29.5 Improvements in performance......Page 310
29.6 Improvements in manufacturing......Page 312
29.7 Electronics and power supplies......Page 313
29.10 Commercialization conclusion......Page 315
30.2 Design and operation......Page 318
30.3 Performance......Page 320
30.4 Harmonic distortion......Page 321
30.5 Loudspeaker shape effects......Page 323
30.6 Applications......Page 324
Index......Page 326