8.7 Computer-based selection: a spark-plug insulator 8.8 Summary and conclusions 237 9 Multiple constraints and objectives 239 and 240 9.2 Selection with multiple constraints 9.3 Conflicting objectives, penalty-functions, and exchange constants 245 9. 4 Summary and conclusions 9.5 Further reading 255 Appendix: Traditional methods of dealing with multiple 256 and objective 10 Case studies -multiple constraints and conflicting objectives 10.1 Introduction and synopsis 262 10.2 Multiple constraints: con-rods for high-performance engines 10.3 Multiple constraints: windings for high-field magnets 266 10.4 Conflicting objectives: casings for a mini-disk player 10.5 Conflicting objectives: materials for a disk-brake caliper 10.6 Summary and conclusions 11 Selection of material and shape 11.1 Introduction and synopsis 284 11.2 Shape factors 11.3 Microscopic or micro-structural shape factors 11.4 Limits to shape efficiency 301 11.5 Exploring and comparing structural sections 305 11.6 Material indices that include shape 307 11.7 Co-selecting material and shape 312 11.8 Summary and conclusions 314 11.9 Further reading 12 Selection of material and shape: case studies 317 12.1 Introduction and synopsis 318 12.2 Spars for man-powered planes 319 12.3 Ultra-efficient springs 3 12.4 Forks for a racing bicycle 326 12.5 Floor joists: wood, bamboo or steel? 328 12.6 Increasing the stiffness of steel sheet 331 12.7 Table legs again: thin or light? 333 12.8 Shapes that flex: leaf and strand structures 335 12.9 Summary and conclusions 337 13 Designing hybrid materials 13.1 Introduction and synopsis 340 13.2 Filling holes in material-property space 342 133 The method:“A+B+ configuration+ scale” 346 13.4 Composites: hybrids of type 1 3488.7 Computer-based selection: a spark-plug insulator 235 8.8 Summary and conclusions 237 9 Multiple constraints and objectives 239 9.1 Introduction and synopsis 240 9.2 Selection with multiple constraints 241 9.3 Conflicting objectives, penalty-functions, and exchange constants 245 9.4 Summary and conclusions 254 9.5 Further reading 255 Appendix: Traditional methods of dealing with multiple constraints 256 and objectives 10 Case studies — multiple constraints and conflicting objectives 261 10.1 Introduction and synopsis 262 10.2 Multiple constraints: con-rods for high-performance engines 262 10.3 Multiple constraints: windings for high-field magnets 266 10.4 Conflicting objectives: casings for a mini-disk player 272 10.5 Conflicting objectives: materials for a disk-brake caliper 276 10.6 Summary and conclusions 281 11 Selection of material and shape 283 11.1 Introduction and synopsis 284 11.2 Shape factors 285 11.3 Microscopic or micro-structural shape factors 296 11.4 Limits to shape efficiency 301 11.5 Exploring and comparing structural sections 305 11.6 Material indices that include shape 307 11.7 Co-selecting material and shape 312 11.8 Summary and conclusions 314 11.9 Further reading 316 12 Selection of material and shape: case studies 317 12.1 Introduction and synopsis 318 12.2 Spars for man-powered planes 319 12.3 Ultra-efficient springs 322 12.4 Forks for a racing bicycle 326 12.5 Floor joists: wood, bamboo or steel? 328 12.6 Increasing the stiffness of steel sheet 331 12.7 Table legs again: thin or light? 333 12.8 Shapes that flex: leaf and strand structures 335 12.9 Summary and conclusions 337 13 Designing hybrid materials 339 13.1 Introduction and synopsis 340 13.2 Filling holes in material-property space 342 13.3 The method: ‘‘A þ B þ configuration þ scale’’ 346 13.4 Composites: hybrids of type 1 348 Contents vii