MATERIALS SELECTION

MECHANICAL DESIGN SECOND EDITION

MICHAEL F. ASHBY Department of Engineering, Cambridge University, England

E I N E M A N N n OXFORD AMSTERDAM BOSTON LONDON NEW YORK PARIS SAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYO

Contents

PREFACE ACKNOWLEDGEMENTS

1 Introduction 1.1 Introduction and synopsis 1.2 Materials in design 1.3 The evolution of engineering materials 1.4 The evolution of materials in vacuum cleaners 1.5 Summary and conclusions 1.6 Further reading

2 The design process 2.1 Introduction and synopsis 2.2 The design process 2.3 Types of design 2.4 Design tools and materials data 2.5 Function, material, shape and process 2.6 Devices to open corked bottles 2.7 Summary and conclusions 2.8 Further reading

3 Engineering materials and their properties 3.1 Introduction and synopsis 3.2 The classes of engineering material 3.3 The definitions of material properties 3.4 Summary and conclusions 3.5 Further reading

4 Materials selection charts 4.1 Introduction and synopsis 4.2 Displaying material properties 4.3 The material property charts 4.4 Summary and conclusions 4.5 Further reading

xi xiii

vi Contents

5 Materials selection - the basics 5.1 Introduction and synopsis 5.2 The selection strategy 5.3 Deriving property limits and material indices 5.4 The selection procedure 5.5 The structural index 5.6 Summary and conclusions 5.7 Further reading

6 Materials selection - case studies 6.1 Introduction and synopsis 6.2 Materials for oars 6.3 Mirrors for large telescopes 6.4 Materials for table legs 6.5 Cost - structural materials for buildings 6.6 Materials for flywheels 6.7 Materials for high-flow fans 6.8 Golf-ball print heads 6.9 Materials for springs 6.10 Elastic hinges 6.1 1 Materials for seals 6.12 Diaphragms for pressure actuators 6.13 Knife edges and pivots 6.14 Deflection-limited design with brittle polymers 6.15 Safe pressure vessels 6.16 Stiff, high damping materials for shaker tables 6.17 Insulation for short-term isothermal containers 6.18 Energy-efficient kiln walls 6.19 Materials for passive solar heating 6.20 Materials to minimize thermal distortion in precision devices 6.21 Ceramic valves for taps 6.22 Nylon bearings for ships' rudders 6.23 Summary and conclusions 6.24 Further reading

7 Selection of material and shape 7.1 Introduction and synopsis 7.2 Shape factors 7.3 The efficiency of standard sections 7.4 Material limits for shape factors 7.5 Material indices which include shape 7.6 The microscopic or micro-structural shape factor 7.7 CO-selecting material and shape 7.8 Summary and conclusions 7.9 Further reading

Appendix: geometric constraints and associated shape factors

Contents vii

8 Shape - case studies 8. 1 Introduction and synopsis 8.2 Spars for man-powered planes 8.3 Forks for a racing bicycle 8.4 Floor joists: wood or steel? 8.5 Increasing the stiffness of steel sheet 8.6 Ultra-efficient springs 8.7 Summary and conclusions

9 Multiple constraints and compound objectives 9.1 Introduction and synopsis 9.2 Selection by successive application of property limits and indices 9.3 The method of weight-factors 9.4 Methods employing fuzzy logic 9.5 Systematic methods for multiple constraints 9.6 Compound objectives, exchange constants and value-functions 9.7 Summary and conclusions 9.8 Further reading

10 Case studies: multiple constraints and compound objectives 10.1 Introduction and synopsis 10.2 Multiple constraints - con-rods for high-performance engines 10.3 Multiple constraints - windings for high field magnets 10.4 Compound objectives - materials for insulation 10.5 Compound objectives - disposable coffee cups 10.6 Summary and conclusions

11 Materials processing and design 1 1.1 Introduction and synopsis 11.2 Processes and their influence on design 1 1.3 Process attributes 1 1.4 Systematic process selection 1 1.5 Screening: process selection diagrams 1 1.6 Ranking: process cost 1 1.7 Supporting information 1 1.8 Summary and conclusions 1 1.9 Further reading

12 Case studies: process selection 12.1 Introduction and synopsis 12.2 Forming a fan 12.3 Fabricating a pressure vessel 12.4 Forming a silicon nitride micro-beam 12.5 Forming ceramic tap valves 12.6 Economical casting 12.7 Computer-based selection - a manifold jacket

viii Contents

12.8 Computer-based selection - a spark plug insulator 12.9 Summary and conclusions 12.10 Further reading

13 Data sources 13.1 Introduction and synopsis 13.2 Data needs for design 13.3 Screening: data structure and sources 13.4 Further information: data structure and sources 13.5 Ways of checking and estimating data 13.6 Summary and conclusions 13.7 Further reading

Appendix: data sources for material and process attributes

14 Case studies: use of data sources 14.1 Introduction and synopsis 14.2 Data for a ferrous alloy - type 302 stainless steel 14.3 Data for a non-ferrous alloy - AI-Si die-casting alloys 14.4 Data for a polymer - polyethylene 14.5 Data for a ceramic - zirconia 14.6 Data for a glass-filled polymer - nylon 30% glass 14.7 Data for a metal-matrix composite (MMC) - AilSiC, 14.8 Data for a polymer-matrix composite - CFRP 14.9 Data for a natural material - balsa wood 14.10 Summary and conclusions 14.1 1 Further reading

15 Materials, aesthetics and industrial design 15.1 Introduction and synopsis 15.2 Aesthetics and industrial design 15.3 Why tolerate ugliness? The bar code 15.4 The evolution of the telephone 15.5 The design of hair dryers 15.6 The design of forks 15.7 Summary and conclusions 15.8 Further reading

16 Forces for change 16.1 Introduction and synopsis 16.2 The market pull: economy versus performance 16.3 The science-push: curiosity-driven research 16.4 Materials and the environment: green design 16.5 The pressure to recycle and reuse 16.6 Summary and conclusions 16.7 Further reading

Contents ix

APPENDIX A: Useful solutions to standard problems A.l Constitutive equations for mechanical response A.2 Moments of sections A.3 Elastic bending of beams A.4 Failure of beams and panels A.5 Buckling of columns and plates A.6 Torsion of shafts A.7 Static and spinning discs A.8 Contact stresses A.9 Estimates for stress concentrations A. 10 Sharp cracks A. 1 1 Pressure vessels A.12 Vibrating beams, tubes and discs A. 13 Creep and creep fracture A.14 Flow of heat and matter A. 15 Solutions for diffusion equations A. 16 Further reading

APPENDIX B: Material indices

APPENDIX C: Material and process selection charts C. 1 Introduction C.2 The materials selection charts

Chart 1: Young's modulus, E against density, p Chart 2: Strength, o f , against density, p Chart 3: Fracture toughness, KIc, against density, p Chart 4: Young's modulus, E, against strength, a f Chart 5: Specific modulus, Elp , against specific strength, a f / p Chart 6: Fracture toughness, KIc, against Young's modulus, E Chart 7: Fracture toughness, KIc, against strength, a f Chart 8: Loss coefficient, v , against Young's modulus, E Chart 9: Thermal conductivity, h, against thermal diffusivity, a Chart 10: T-Expansion coefficient, a, against T-conductivity, h Chart 11: Linear thermal expansion, a, against Young's modulus, E Chart 12: Normalized strength, a,/E, against linear expansion coeff., a Chart 13: Strength-at-temperature, a(T) , against temperature, T Chart 14: Young's modulus, E, against relative cost, CRp Chart 15: Strength, o f , against relative cost, CRp Chart 16: Dry wear rate against maximum bearing pressure, P,,, Chart 17: Young's modulus, E, against energy content, qp Chart 18: Strength, a f , against energy content, qp

C.3 The process-selection charts Chart PI: The material-process matrix Chart P2: Hardness, H, against melting temperature, T , Chart P3: Volume, V, against slenderness, S Chart P4: The shape classification scheme

X Contents

Chart PS: The shape-process matrix Chart P6: Complexity against volume, V Chart P7: Tolerance range, T, against RMS surface roughness, R

APPENDIX D: Problems D1 Introduction to the problems D2 Use of materials selection charts D3 Deriving and using material indices D4 Selection with multiple constraints D5 Selecting material and shape D6 Selecting processes D7 Use of data sources D8 Material optimization and scale

Index

Adaptive design 11 Aesthetics 2, 351 et seq. Alloys, see Metals Approximate solutions for standard problems 375

et seq. Atomic bonding 43, 46 Attributes:

materials 66, 67 processes 261

Bar codes 354 Batch rate 276

size 275 Beams 73,75

static solutions 73, 75, 167 et seq., 380, 382 vibrating 398

Bearings for ships rudders 157 Bells 46 Bending of beams 167 et seq., 380, 382 Bicycle forks 198 Buckling:

local 176 of columns 384 shape factor for 171

Case studies, see particularly Chapters 6, 8, 10 and 12 bar codes 354 bearings for ships rudders 157 bicycle forks 198 ceramic valves for taps 154, 290 connecting rods 228, 278 cork screws 14 data for a ceramic 340 data for a ferrous alloy 334 data for a glass-filled polymer 342 data for a metal-matrix composite 344 data for a natural material 347 data for a non-ferrous alloy 335 data for a polymer 338 data for a polymer-matrix composite 345 deflection-limited design with brittle polymers

192 diaphragms for pressure actuators 122

disposable coffee cups 241 economical casting 292 elastic hinges 116 energy-efficient kilns 143 fabricating a pressure vessel 284 fans 105, 281 floor joists 200 flywheels 100, 388 forks 359 forming a fan 28 1 forming a silicon nitride micro-beam 289 forming ceramic tap valves 290 golf-ball print heads 108 hairdryers 357 heat-storing walls 147 knife-edges and pivots 125 magnet windings 232 man-powered planes 194 manifold jacket 293 micro-beams 289 oars 85 precision devices 15 1 pressure vessels 133, 284, 396 seals 119 shaker tables 137 short-term isothermal containers 140 spark plug insulator 298 springs 11 1, 206, 219, 334 stiffened steel sheet 204 structural materials for buildings 97, 200 table legs 93 taps 290 telephones 355 telescope reflectors 89, 344 vacuum cleaners 4 wing spars 194

Catalogue of data sources 313 et seq. Centrefugal forces and stresses 100, 388 Ceramic valves for taps 154, 290 Ceramics, see also Charts, and Material properties

20, 35, 88, 96, 104, 114, 125, 323 alumina 35, 127, 156, 160 brick 100, 149 cement 149, 324 common rocks 149, 325

496 Index

Ceramics (continued) concrete 92, 100, 140, 149, 324 diamond 35, 127, 154 ice 53, 149 magnesia 160 mullite 156 porous ceramics 147 sapphire 127 selection of 32 et seq. sialons 35, 156 silicon 127, 154 silicon carbide 35, 127, 154, 156 silicon nitride 35, 127, 156 stone 100, 325 tungsten carbide 127 zirconia 35, 142, 340 et seq.

Charts, see Material Selection Charts and Process Selection Charts

Classes: materials 20, 21, 35, 414 processes 246, 248, 416

Cold working 250 Columns 76, 384 Complexity 266 et seq. Composites, see also Charts, and Material properties

21, 35, 324 carbon fibre reinforced polymer, CFRP 88, 92,

96, 104, 108, 114, 135, 196, 199, 345 ceramic matrix 367 glass fibre reinforced polymer, GFRP 88, 92, 96,

104, 108, 114, 135, 140, 147 glass filled nylon 342 intermetallic matrix 367 Kevlar fibre reinforced polymer, KFRP 140 metal matrix composites, MMC 230, 236-7,

344, 367 Compound objectives 211 et seq., 228 et seq. Conceptual stage of design 8, 9, 15 Connecting rods 228, 278 Constitutive equations 376 Constraints 66, 69 et seq.

multiple 210 et seq., 215, 228 et seq. Contact stresses 391 Cork 36, 122, 147 Cork screws 14 Correlations between material properties see also

Charts 310 Corrosion 59, 60 CO-selection of material and shape 186 Cost 276 et seq.

capital 277 case studies 278, 292 dependence on finish 271 estimation 276 modelling 276 of casting 278, 292 of labour 277

of material 22, 56, 276-7 of process 274 of product 24 1 -2 technical modelling of 278

Coupling lines and equations 218 Cracks 133 et seq., 394 Creep solutions 398

Damage-tolerant design 44, 133 indices 411

Damping, see Loss coefficient Data:

catalog of sources 3 13 et seq. checking methods 309 correlations 3 10 estimation 309, 3 13 examples 334 et seq. for a ceramic 340 for a ferrous alloy 334 for a glass-filled polymer 342 for a metal-matrix composite 344 for a natural material 347 for a non-ferrous alloy 335 for a polymer 338 for a polymer-matrix composite 345 for further information 307 for material properties, see Material properties for screening 305 handbooks 313 et seq., 334 et seq. information services 330 et seq. Internet access 308 levels, of breadth and precision 303 needs 303 sheets 334 et seq. sources and their use 303 et seq., 334 et seq. structure 305 types 305 world-side web sources 330 et seq.

Data sources 334 et seq. for cement and concrete 324 for ceramic-matrix composites 324 for ceramics and glasses 323 for foams 324 for manufacturing processes 327 for metal-matrix composites 324 for metals 314 et seq. for natural fibres 326 for polymer-matrix composites 324 for polymers and elastomers 322 for stone, rocks and minerals 325 for woods and wood-based composites 326 world-wide web sites 327 et seq.

Decoration 353 Density:

charts 37, 39, 41 data 37

Index 497

definition 22 origins 36

Deflection-limited design 73, 167, 192, 380, 389 Deflection-limited design with brittle polymers 192 Design:

adaptive 11 conceptual 8 detailed 8 embodiment 8 flow chart 9 industrial 351 et seq. mechanical 1 museums 353 original 10 process 8 et seq. tools 11 types 10 variant 11

Design-led selection 8, 17 Detailed stage of design 8 Diaphragms for pressure actuators 122 Diffusion 404 Disks:

elastic deflection 388 spinning 388

Disposable coffee cups 241

Economics of casting 292 Economic criteria for selection 275 Elastic bending 73, 167 et seq., 380

buckling 171, 176, 384 contacts 390 energy 111,206,219,330 hinges 116 stress concentrations 392 twisting 386

Elastomers, see also Charts, and Material properties 21, 36, 114, 119, 125, 147 butyl rubber, BR 36, 143 chlorosulphinated polyethylene, CSM 143 natural rubber 36 polychloroprene, CR 143 polyurethanes 36 silicones 36

Electro-mechanical design 232, 412 Embodiment stage of design 8 Energy content of materials 368 et seq. Energy-efficient kilns 143 Energy storing devices:

flywheels 100 et seq., 388 pressure vessels 133 et seq., 284, 396 springs 111,206,219,334

Engineering alloys, see Metals Engineering ceramics, see Ceramics Engineering polymers, see Polymers Environmental attack 59, 60

Environmental impact of materials 367, 373 indices 368

Estimation methods for material data 309 Evolution:

of engineering materials 3 of hairdryers 357 of telephones 355 of vacuum cleaners 4

Exchange constants 218, 220 Expert systems 308

Fabricating a pressure vessel 284 Failure diagrams 178 Failure in bending 75, 170, 382 Failure in torsion 170, 386 Fans 105, 281 Finite element analysis 8 Floor joists 200 Flywheels 100, 388 Foams, see also Charts, and Material properties 36,

122, 143, 324 cork 36, 122, 147 phenolic foam 239, 241 polycarbonate foam 243 polyester foam 36 polyethersulphone foam 239 polyethylene foam 243, 245 polymethacrylimide foam 239 polypropylene foam 241, 245 polystyrene foam 36, 92, 239, 241, 243, 245 polyurethane foam 241

Forces for change 363 et seq. Forks 359 Forming a fan 281 Forming a silicon nitride micro-beam 289 Forming ceramic tap valves 290 Forming, see Processes Fracture toughness:

case studies 133, 192 charts 43 et seq. data 43 et seq. definition 26 lower limiting value 45 origins 43 et seq.

Function 8, 13, 69 Function structure 8, 17 Functional requirements 17 Functionally graded materials 367 Fuzzy logic 214

Glasses, see also Charts, and Material properties 20, 35, 92, 125 borosilicate glass 35 quartz 127

498 Index

Glasses (continued) silica glass 35, 160 soda glass 35

Glass temperature: definition 28 influence on damping 46

Golf-ball print heads 108 Green engineering 367 Guide lines for materials selection 80 et seq. Hairdryers 357 Handbooks 313 et seq., 334 et seq. Heat capacity, see Specific heat Heat flow 402 Heat-storing walls 147 History of material usage 3 Hot working 250 Hysteresis, see Loss coefficient

I-Beams 163 et seq., 172 et seq. Indices, see Material indices Industrial design 2, 334 et seq. Information content 266 et seq. Insulation:

for kiln walls 143 for thermal storage 147 latent heat 'sinks' 142 short term 140

Intelligent materials 367 Introduction 1 Internet data sources 308

J-integral 40 Joists 200

Kilns 143 Knife-edges and pivots 125

Lattice resistance 39 Leak-before-break criterion 133 Lightweight design 71 et seq., 408-9 Local buckling 176 Local issues in selection 68 Log decrement, definition 27 Loss coefficient:

chart 48 data 48 definition 27 origins 46

Magnet windings 232 Man-powered planes 194 Manifold jacket 293 Market need 8-9, 12

Market pull 363 Material classes 21, 35 Material indices 69 et seq., 78, 408 et seq.

catalog 407 et seq. damage-tolerant design 41 1 definition 70 derivation of 71, 78 efficient thermal design 41 1 elastic design 408 electro-mechanical design 232, 412 examples of derivations 71 et seq., minimum cost design 76 minimum energy-content design 368 et seq.,

408,409 minimum weight design 71, 73, 75 stiffness-limited design 408 strength-limited design 409 tables of 78, 408 et seq. thermo-mechanical design 41 1 vibration-limited design 410 with shape included 180 et seq.

Material properties 20 et seq., 32 et seq. coefficient of friction 59-60 corrosion 62 cost 22, 56, 58, 364 creep constants 28 definitions of 22 density 22, 37, 39, 41 eco-indicators 369 endurance limit 22 energy content 369 environmental 367 failure strain 40 fatigue ratio 27 fracture toughness 26, 41, 45, 47 glass temperature 28 hardness 25, 266 high temperature strength 55 J-integral, critical 40 log decrement 27 loss coefficient 26 maximum service temperature 28 melting point 28 moduli 22, 37, 42, 45, 48, 52, 57, 266, 309 modulus of rupture 24 parabolic rate constant 30 process zone size 46-7 Q-factor 27 relative cost 57-8 resilience 25 softening temperature 28 specific damping capacity 27 specific heat 28, 48 strength 23, 39, 42, 47, 58 surface energy 43 tensile strength 38 thermal conductivity 27, 3 1, 49

Index 499

thermal diffusivity 28, 49 thermal expansion coefficient 28, 52, 312 thermal shock resistance 28 toughness 26, 45 ultimate strength 25 wave velocity 37-8 wear constant 29, 60

Material Selection Charts 32 et seq., 413 et seq. modulusldensity 37, 418 strengthldensity 39,420 fracture toughnessldensity 4 1, 422 moduluslstrength 42, 424 specific moduluslspecific strength 44, 426 fracture toughnesslmodulus 45, 428 fracture toughnesslstrength 47, 430 loss coefficient/modulus 48, 432 thermal conductivitylthermal diffusivity 49, 434 thermal expansionlthermal conductivity 51, 436 thermal expansion/modulus 52, 438 strengthtthermal expansion 54, 440 strengthltemperature 56, 442 moduluslrelative cost 57, 444 strengthlrelative cost 58, 446 coefficient of friction 59 wear ratehardness 60, 448 resistance to environmental attack 62 moduluslenergy content 370, 450 strengthlenergy content 37 1,452 use of 77 et seq.

Materials, see Metals, Ceramics, Polymers, Glasses, Elastomers, Composites, Wood, Foams , Porous ceramics or individual material names

Materials in design 1 Materials selection, 65 et seq.

case studies, see Case studies software 375 et seq.

Mechanical design 1 Merit indices, see Material indices Metals, see also Charts, and Material properties

20, 35, 314 et seq. aluminium alloys 92, 104, 111, 135, 154, 196,

199, 230, 337 beryllium alloys 92, 104, 119, 213, 231 cast irons 100, 104, 108, 140, 230 copper alloys 135, 154, 236 gold 154 invar 43, 122, 154 lead alloys 104 magnesium alloys 92, 104, 11 1, 140, 199, 231 manganese-copper alloys 140 molybdenum alloys 154 nickel alloys 293 silver 154, 237 speculum metal 89, 92 steels, carbon 92, 100, 114, 119, 125, 127, 135, 196, 199, 201, 204, 230, 236 steels, stainless 334 et seq.

tin alloys 111, 135, 199 titanium alloys 104, 125, 213, 230 tungsten alloys 154 type metal 11 1

Micro-beams 289 Microscopic ('microstructural') shape factors 182 Minimum cost design 76 et seq., 408-9 Minimum energy-content design 368 et seq.,

408 - 9 Minimum weight design 71 et seq., 408-9 Modelling: 69 et seq., 86 et seq.

aids 376 et seq. examples 86 et seq.

Moduli: charts 37,42, 44-5,48, 52, 57, 370 data 37 definitions 23 origins 36

Moments of sections 164, 378 Multiple constraints 210 et seq., 228 et seq. Multiple design objectives 210 et seq., 228 et seq. Museums 253

Normalized strength: charts 44 data 44 definition 43

Oars 85 Objectives 66, 69, 218 et seq. Optimization 67 et seq. Optimum design 65 et seq. Original design 10

Peierls stress, see Lattice resistance Performance 65 et seq., 79 Performance-maximising criteria, see Material

indices Pivots 125 Poisson's ratio, see Moduli Polymer forming 180, 183 Polymers, see also Charts, Foams and Material

properties 21, 35, 129, 143, 147, 332 epoxies, EP 11 1 nylons, glass-filled 342 nylons, PA 108, 111, 114, 119, 122, 125, 129 polycarbonates, PC 129 polyethylene, high density, HDPE 108, 119,

122, 143, 149, 160 polyethylene, low density, LDPE 119, 122, 338 polypropylene, PP 119, 122, 125, 143 polystyrene, PS 129 polytetrafluorethylene, PTFE 1 19, 122, 125, 160 polyurethanes, PU 122

500 Index

Polymers (continued) polyvinylchloride, PVC 108 silicones 122

Porous ceramics, see also Charts and Material Properties 147 brick 100, 149 cement 149, 324 common rocks 149, 325 concrete 92, 100, 140, 149, 324 ice 53, 149

Precision 270 et seq., 282, 286, 290-1, 295 Precision devices 15 1 Pressure vessels 133, 284, 396 Primary forming methods 246 Problems Appendix C Process:

attributes 261 catalog of methods 246 classes 246, 248 costs 274 et seq., 292

Process selection 246 et seq., 281 et seq. case studies 281 et seq. ranking 274 screening 264 strategy 273 supporting information 279

Process selection charts 264 et seq., 454 et seq. complexity /size 270, 284, 464 hardnesslmelting temperature 266, 285, 456 materiallprocess matrix 454 shape classification 268, 460 shapelprocess matrix 462 surface area/section/slendernesslvolume 269,

283,458 tolerancelsurface roughness 265, 270, 286, 466

Process zone: chart 47 definition 46

Processes 246 et seq., 327 adhesive bonding 256, 258 ballistic-particle manufacture 259 blow moulding 249, 251 casting 247-8, 288, 292 cold working 250 composite forming 254 CVD 248,291 deformation 248, 250 die casting 282, 287, 292 die pressing 253 drawing 253 electroforming 287, 291, 297 electron-beam casting 29 1 extrusion 252 fabrication 256, 288 fastening 256-7 filament winding 254 finishing 248, 257

forging 252 friction welding 258 grinding 256 heat treatment 248, 256 HIPing 253 hot working 250, 288 injection moulding 250, 282 investment casting 247, 282, 297 joining 248, 256 laminated object manufacture 260 machining 48, 255, 288 micro-fabrication 289 moulding 249 polymer forming 248-9 powder methods 248, 252, 291 primary forming 246 rapid prototyping 258 resin-transfer moulding 250, 287 rolling 251 sand casting 247-8, 292 secondary forming 247 sheet forming ,253 sintering 248, 252, 291, 299 solid-ground curing 259 special forming methods 248, 254 spray forming 255 squeeze casting 287 stereo-lithography 260 tertiary forming 247 transfer moulding 250 turning 255 warm working 250 welding 256-7

Processing 246 et seq. Production rate 276 Properties, see Material properties Property limits 68, 70 Property profiles 20, 66

Ranking of materials 65, 67 Ranking of processes 274 Recycling of materials 373 Reuse of materials 373 Roughness 265, 270- 1 Rubber, see Eiastomers

Science push 366 Screening of materials 65, 67 Screening of processes 264 Seals 119 Secondary forming processes 247 Section shape, see Shape Shaker tables 137

Index 501

Shape, see also Shape factors 13, 162 et sq . , 194 et s q . case studies 194 et seq. classification 268 efficiency of 172 macroscopic 162 microscopic 13, 182 et seq. moments of area 164 selection of 186

Shape factors 162 et seq., 190 CO-selection with material 186 definition of 162 examples of use 186, 194 et seq. for elastic bending 167, 180 for elastic buckling 171 for elastic twisting 170, 180 for failure in bending 170, 181 for failure in twisting 170, 182 geometric constrains for 190 et seq. in material indices 180, 195 limits imposed by material 175 et seq. microscopic or "microstructural" 182 et seq. values for 165, 166

Shear modulus, see Moduli Short-term isothermal containers 140 Software for materials selection 375 et seq. Spark plug insulator 298 Specific heat:

chart 49 data 49 definition 28 origins 49

Specific stiffness: chart 44 data 44 definition 43

Specific strength: chart 44 data 44 definition 43

Springs 11 1, 206, 219, 334 Standard solutions of mechanics and heat flow 375

et seq. Stiffened steel sheet 204 Stiffness-limited design 408 Strength-limited design 409 Strength:

charts 39,42,44, 54 data 39 definition 23, 38 origins 38

Strength at elevated temperature: chart 56 data 56 definition 55

Stress concentrations 392 Stress intensity factors 394 Structural index 71, 82 et seq. Structural load coefficient, see Structural index Structural materials for buildings 97, 200 Structure-sensitive properties 34 Supporting information for materials 67-8 Supporting information for processes 279 Surface finish 271

Table legs 93 Taps 290 Technical systems 8-9 Telephones 355 Telescope reflectors 89, 344 Tertiary forming processes 247 Texture 253 Thermal conductivity :

charts 33,49, 51 data 49 definition 27 origins 47 et seq.

Thermal diffusivity: chart 33 data 49 definition 27 origins 47 et seq.

Thermal distortion: case study 151 chart 54 definition 28 origins 54

Thermal expansion coefficient: charts 51 -2, 54 data 51 definition 28 origins 50

Thermal shock resistance: chart 52 data 52 definition 28 origins 53

Thermal stress: chart 52 data 52 definition 53 origins 53

Tolerance 265, 270- 1 Torsion of shafts 386

shape-factors for 170- 1 Toughness:

chart 43 data 43 definition 26 origins 43

502 Index

Tubes 175 et seq. failure mechanisms 177

Types of design 10

Useful solutions to standard problems 375

Vacuum cleaners 4 Value functions 218, 220 Van der Wads bonding 40 Variant design 1 1 Vibration 398

natural 151 damping of 137, 151 supressing 15 1, 204

Warm working 250 Wave velocity:

chart 37 data 37 definition 38

Wear constant: chart 60 data 60 definition 61

Weight factors 212 Wing spars 194 Woods, see also Charts, and Material properties

84,92,96, 100, 115, 147, 182, 200, 326 ash 347 balsa 196, 347 bamboo 199-200 hickory 347 pine 201 spruce 196, 199, 347 wood products (ply, etc.) yew 347

World-wide web 308, 330 et seq., 340

Yield-before-break criterion 250 Youngs modulus, see Moduli