Fatigue life prediction of composites and composite structures Anastasios P. Edited by Vassilopoulos CRC Press Boca Raton Boston New York Washington, DC WOQDHEAD PUBLISHING LIMITED Oxford Cambridge New Delhi
past Contributor contact details xi Preface xv 1 Introduction to the fatigue life prediction of composite materials and structures: past, present and future prospects 1 A. P. Vassilopoulos, Ecole Polytechnique Federate de Lausanne (EPFL), Switzerland 1.1 Introduction 1 1.2 Experimental characterization of composite materials 4 1.3 Fatigue life prediction of composite materials and structures - and present 11 1.4 Conclusions and future trends 33 1.5 References 38 Part I Fatigue life modelling 2 Phenomenological fatigue analysis and life modelling 47 R. P. L. Nussen, Knowledge Centre Wind Turbine Materials and Constructions, The Netherlands 2.1 Introduction 47 2.2 Fatigue experiments 48 2.3 Measurements and sensors 51 2.4 Test frequency 53 2.5 Specimens 54 2.6 S-N diagrams 58 2.7 S-N formulations 62 2.8 Future trends 75 2.9 References 76
vi 3 Residual strength fatigue theories for composite materials 79 N. L. Post, J. J. Lesko and S. W. Case, Virginia Tech, USA 3.1 Introduction 79 3.2 Major residual strength models from the literature 80 3.3 Fitting of experimental data 87 3.4 Prediction results 96 3.5 Conclusions and future trends 96 3.6 References 99 4 Fatigue damage modelling of composite materials with the phenomenological residual stiffness approach 102 W. Van Paepegem, Ghent University, Belgium 4.1 Introduction 102 4.2 What are phenomenological residual stiffness models? 103 4.3 Literature review of some representative residual stiffness models 106 4.4 Numerical implementation of residual stiffness models 109 4.5 Variable amplitude loading 118 4.6 Degradation of other elastic properties 126 4.7 Future trends and challenges 131 4.8 Sources of further information and advice 133 4.9 References 133 5 Novel computational methods for fatigue life modeling of composite materials 139 A. P. Vassilopoulos, Ecole Polytechnique F6derale de Lausanne (EPFL), Switzerland and E. F. Georgopoulos, Technological Educational Institute of Kalamata, Greece 5.1 Introduction 139 5.2 Theoretical background 143 5.3 Modeling examples 154 5.4 Experimental data description 155 5.5 Application of the methods 158 5.6 Comparison to conventional methods of fatigue life modeling 166 5.7 Conclusions and future trends 169 5.8 References 171
vii Part II Fatigue life prediction 6 Fatigue life prediction of composite materials under constant amplitude loading 177 M. Kawai, University of Tsukuba, Japan 6.1 Introduction 177 6.2 Constant fatigue life (CFL) diagram approach 180 6.3 Linear constant fatigue life (CFL) diagrams 182 6.4 Nonlinear constant fatigue life (CFL) diagrams 187 6.5 Prediction of constant fatigue life (CFL) diagrams and S-N curves 198 6.6 Extended anisomorphic constant fatigue life (CFL) diagram 205 6.7 Conclusions 209 6.8 Future trends 211 6.9 Sources of further information and advice 214 6.10 Acknowledgments 215 6.11 References 215 7 Probabilistic fatigue life prediction of composite materials 220 Y. Liu, Clarkson University, USA and S. Mahadevan, Vanderbilt University, USA 7.1 Introduction 220 7.2 Fatigue damage accumulation 223 7.3 Uncertainty modeling 228 7.4 Methods for probabilistic fatigue life prediction 232 7.5 Demonstration examples 239 7.6 Conclusion 244 7.7 References 246 8 Fatigue life prediction of composite materials based on progressive damage modeling 249 M. M. Shokrieh and F. Taheri-Behrooz, Iran University of Science and Technology, Iran 8.1 Introduction 249 8.2 Progressive damage modeling under static loading 250 8.3 Progressive fatigue damage modeling 251 8.4 Problem statement and solution strategy 253 8.5 Gradual material property degradation 255 8.6 Framework of progressive fatigue damage modeling of cross-ply laminates 265 8.7 Required experiments 266
discussion viii 8.8 Specimen fabrication 266 8.9 Experimental set-up and testing procedures 267 8.10 Longitudinal tensile tests 268 8.11 Transverse tensile tests 271 8.12 In-plane static shear tests 275 8.13 Experimental evaluation of the model 276 8.14 Conclusion 288 8.15 References 289 9 Fatigue life prediction of composite materials under realistic loading conditions (variable amplitude loading) 293 A. P. Vassilopoulos, Ecole Polytechnique Federale de Lausanne, Switzerland and R. P. L. Nussen, Knowledge Centre Wind Turbine Materials and Constructions, The Netherlands 9.1 Introduction 293 9.2 Theoretical background 1: classic fatigue life prediction methodology 295 9.3 Theoretical background 2: strength degradation models 302 9.4 Experimental data 311 9.5 - Life prediction examples 318 9.6 Conclusion and future trends 327 9.7 References 329 10 Fatigue of fiber reinforced composites under multiaxial loading 334 M. Quaresimin, University of Padova, Italy and R, Talreja, Texas A&M University, USA 10.1 Introduction 334 10.2 Fatigue behavior of short fiber composites under multiaxial loading 336 10.3 Fatigue behavior of continuous fiber composites under multiaxial loading 354 10.4 Conclusions 381 10.5 Acknowledgments 382 10.6 References 382 10.7 List of symbols 388 11 A progressive damage mechanics algorithm for life prediction of composite materials under cyclic complex stress 390 T. P. Philippidis and E. N. Eliopoulos, University of Patras, Greece 11.1 Introduction 390 11.2 Constitutive laws 393
ix 11.3 Failure onset conditions 404 11.4 Strength degradation due to cyclic loading 406 11.5 Constant life diagrams and S-N curves 414 11.6 FAtigue DAmage Simulator (FADAS) 416 11.7 Conclusions 433 11.8 Acknowledgements 434 11.9 References 434 Part III Applications 12 Fatigue life prediction of bonded joints in composite structures 439 T. Keller, Ecole Polytechnique Fe^lerale de Lausanne (EPFL), Switzerland 12.1 Introduction 439 12.2 Fatigue behavior of adhesively-bonded double-lap joints 443 12.3 Stiffness-based modeling of fatigue life 449 12.4 Fracture mechanics-based modeling of fatigue life 452 12.5 Structural joints: bridge deck-to-girder connections 456 12.6 Conclusions and future trends 464 12.7 References 465 13 Health monitoring of composite structures based on acoustic emission measurements 466 T. T. Assimakopoulou and T. P. Philippidis, University of Patras, Greece 13.1 Introduction 466 13.2 Acoustic emission (AE) monitoring of composite structures 467 13.3 Materials and specimens 470 13.4 Material characterization 471 13.5 Residual strength degradation 477 13.6 Acoustic emission (AE) schemes 481 13.7 Failure modes: discussion 499 13.8 Conclusions 500 13.9 Acknowledgements 502 13.10 References 502 14 Fatigue life prediction of wind turbine rotor blades manufactured from composites 505 M. M. Shokrieh and R. Rafiee, Iran University of Science and Technology, Iran 14.1 Introduction 505
x 14.2 Framework of the developed modeling technique 508 14.3 Loading 510 14.4 Static analysis 513 14.5 Fatigue damage criterion 517 14.6 Stochastic characterization of the wind flow 524 14.7 Stochastic implementation on fatigue modeling 527 14.8 Summary and conclusion 533 14.9 References 535 Index 538