Preface xiii
Part 1 Accelerated Testing Methodology 1
Introduction 1
1 Viscoelasticity 5
1.1 Introduction 5
1.2 Concept of Viscoelastic Behavior 5
1.3 Concept of TTSP 6
1.4 Master Curve of Creep Compliance of Matrix Resin 6
1.5 Generalization of TTSP for Nondestructive Deformation Properties to Static, Creep, and Fatigue Strengths of FRPs 8
1.6 Master Curve of Static Strength of FRP 8
1.7 Master Curve of Creep Strength of FRP 10
1.8 Master Curve of Fatigue Strength of FRP 10
1.9 Conclusion 12
2 Master Curves of Viscoelastic Coefficients of Matrix Resin 15
2.1 Introduction 15
2.2 Master Curve of Creep Compliance Based on Modified TTSP 16
2.2.1 Experimental Procedures 17
2.2.2 Reliable Long-term Creep Compliance of Matrix Resin 18
2.3 Simplified Determination of Long-term Viscoelastic Behavior 22
2.3.1 Relation Between Storage Modulus and Creep Compliance 22
2.3.2 Formulation of Master Curve of Creep Compliance 22
2.3.3 TTSP Automatic Shifting Procedure 24
2.3.4 Experimental Procedures 24
2.3.5 Master Curve of Storage Modulus by DMA 25
2.3.6 Comparison of Master Curves of Creep Compliance 27
2.4 Master Curve of Relaxation Modulus by DMA and Creep Tests 28
2.4.1 Determination Procedure of Relaxation Modulus of Matrix Resin 28
2.4.2 Master Curve of Relaxation Modulus of Epoxy Resin 32
2.5 Conclusion 33
3 Nondestructive Mechanical Properties of Fiber-reinforced Polymers 35
3.1 Introduction 35
3.2 Rule of Mixture 35
3.3 Mechanical and Thermal Properties of Unidirectional CFRPs, Fibers, and Matrix Resins 37
3.4 Master Curves of Creep Compliance of Matrix Resin 37
3.5 Conclusion 39
4 Static and Fatigue Strengths of Fiber-reinforced Polymer 41
4.1 Introduction 41
4.2 Experimental Procedures 41
4.2.1 Preparation of Specimens 41
4.2.2 Test Procedures 42
4.3 Results and Discussion 44
4.3.1 Master Curve of Static Strength 44
4.3.2 Master Curve of Fatigue Strength 46
4.3.3 Characterization of Fatigue Strength for Loading Directions of Three Kinds 51
4.4 Applicability of TTSP 53
4.5 Conclusion 53
5 Application 1 of Accelerated Testing Methodology: Static and Fatigue Flexural Strengths of Various Fiber-reinforced Polymer Laminates Under Water Absorption Condition 57
5.1 Introduction 57
5.2 Specimen Preparation 57
5.3 Experimental Procedures 59
5.4 Creep Compliance 60
5.5 Flexural Static Strength 60
5.6 Flexural Fatigue Strength 68
5.7 Conclusion 77
6 Application 2 of Accelerated Testing Methodology: Life Prediction of Carbon-fiber-reinforced Polymer/Metal Bolted Joint 79
6.1 Introduction 79
6.2 Experimental Procedures 79
6.2.1 Preparation of CFRP/Metal Bolted Joints 79
6.2.2 Tensile Static and Fatigue Tests 81
6.3 Results and Discussion 82
6.3.1 Master Curves of Creep Compliance for Transverse Direction of Unidirectional CFRP Laminates 82
6.3.2 Load-elongation Curves at Tensile Static Tests for CFRP/Metal Bolted Joint 84
6.3.3 Master Curves of Static Failure Load for CFRP/Metal Bolted Joint 85
6.3.4 Master Curves of Fatigue Failure Load for CFRP/Metal Bolted Joint 87
6.3.5 Fracture Appearance of CFRP/Metal Bolted Joints Under Static and Fatigue Loadings 91
6.4 Conclusion 94
Part 2 Advanced Accelerated Testing Methodology 95
Introduction 95
7 Formulation of Static Strength of Fiber-reinforced Polymers 97
7.1 Introduction 97
7.2 Formulation of Static Strength 98
7.3 Application of Formulation 99
7.3.1 Experimental Procedures 99
7.3.2 Preparation of Specimens 99
7.3.3 Test Procedures 100
7.4 Results and Discussion 102
7.4.1 Master Curve of Creep Compliance for Matrix Resin 102
7.4.2 Master Curve of Tensile Static Strength for Matrix Resin 104
7.4.3 Master Curves of Three Kinds of Static Strengths of Unidirectional Cfrp 106
7.5 Conclusion 110
8 Formulation of Fatigue Strength of Fiber-reinforced Polymer 113
8.1 Introduction 113
8.2 Formulation 113
8.3 Application of Formulation 114
8.3.1 Specimens and Test Methods 114
8.3.2 Creep Compliance of Matrix Resin 115
8.3.3 Master Curves of Static and Fatigue Strengths for Unidirectional CFRP Laminates 117
8.4 Conclusion 123
9 Formulation of Creep Strength of Fiber-reinforced Polymer 125
9.1 Introduction 125
9.2 Formulation 125
9.3 Application of Formulation 127
9.3.1 Specimens and Test Methods 128
9.3.2 Creep Compliance of Matrix Resin and Static Strength of CFRP Strand 128
9.3.3 Creep Failure Time of CFRP Strand 130
9.4 Conclusion 131
10 Application 1 of Advanced Accelerated Testing Methodology: Static Strengths in Various Load Directions of Unidirectional Carbon-fiberreinforced Polymer Laminates Under Water Absorption Condition 133
10.1 Introduction 133
10.2 Experimental Procedures 133
10.3 Viscoelastic Behavior of Matrix Resin 134
10.4 Master Curves of Static Strengths for Unidirectional CFRP Laminates 137
10.5 Relation Between Static Strengths and Viscoelasticity of Matrix Resin 142
10.6 Conclusion 144
11 Application 2 of Advanced Accelerated Testing Methodology: Life Prediction of Carbon-fiber-reinforced Polymer Structures 145
11.1 Introduction 145
11.2 Procedure of MMF/ATM 145
11.3 Determination of MMF/ATM Critical Parameters 147
11.3.1 Long-term Static and Fatigue Strengths of Unidirectional CFRP Laminates 147
11.3.2 MMF/ATM Critical Parameters of Unidirectional CFRP Laminates 148
11.4 Life Determination of CFRP Structure Based on MMF/ATM 149
11.5 Experimental Confirmation for OHC Static and Fatigue Strengths of CFRP QILs 152
11.6 Conclusion 154
12 Application 3 of Advanced Accelerated Testing Methodology: Effect of Molding Condition on Statistical Static and Creep Strengths of Carbon-fiber-reinforced Polymer Strand 155
12.1 Introduction 155
12.2 Experiments 155
12.3 Creep Compliance of Matrix Resin and Static Strength of CFRP Strand 158
12.4 Master Curves of Statistical Static and Creep Strengths of CFRP Strands 161
12.5 Conclusion 163
13 Application 4 of Advanced Accelerated Testing Methodology: Effect of Carbon Fiber on Statistical Static and Creep Strengths of Carbon-fiberreinforced Polymer Strand 165
13.1 Introduction 165
13.2 Molding of CFRP Strands and Testing Methods 165
13.3 Results and Discussion 166
13.3.1 Creep Compliance of Matrix Resin and Static Strength of Carbon Fibers 166
13.3.2 Static Tensile Strengths of CFRP Strands at Various Temperatures 167
13.3.3 Static Tensile Strength of CFRP Strand Against Viscoelastic Compliance of Matrix Resin 169
13.3.4 Master Curves of Static Tensile Strength for Various CFRP Strands 171
13.3.5 Experimental and Predicted Statistical Creep Failure Times for Various CFRP Strands 172
13.3.6 Fractographs Obtained After Static and Creep Tests 175
13.4 Conclusion 177
Part 3 Integrated Accelerated Testing Methodology 179
Introduction 179
14 Integrated Accelerated Testing Methodology 181
14.1 Introduction 181
14.2 Formulation 181
14.2.1 Viscoelasticity of Matrix Resin 182
14.2.2 General Formulation of CFRP Strength 185
14.2.3 Formulation of Static and Creep Strengths 185
14.2.4 Formulation of Fatigue Strength 187
14.3 Application of Integrated ATM 189
14.3.1 CFRP Strand and Testing Method 189
14.3.2 Master Curve of Relaxation Modulus of Matrix Resin 190
14.3.3 Static Strength of CFRP Strand 192
14.3.4 Creep Strength of CFRP Strand 194
14.3.5 Fatigue Strength of CFRP Strand 195
14.4 Statistical Long-term Life Prediction of CFRP Strand 198
14.5 Conclusion 199
15 Application 1 of Integrated Accelerated Testing Methodology: Statistical Creep and Fatigue Lives of Unidirectional Carbon-fiberreinforced Polymer Laminates Under Bending Load 201
15.1 Introduction 201
15.2 Experiments 201
15.3 Results and Discussion 203
15.3.1 Relaxation Modulus and Loss Tangent of the Matrix Resin 203
15.3.2 Statistical Flexural Static Strength of Unidirectional CFRP Laminates 206
15.3.3 Relation Between Flexural Static Strength of CFRP Laminates and Viscoelastic Modulus of the Matrix Resin 207
15.3.4 Statistical Flexural Static Strength Versus Failure Time 208
15.3.5 Statistical Flexural Creep Strength Versus Failure Time 209
15.3.6 Statistical Flexural Fatigue Strength Against Number of Cycles to Failure for CFRP Laminates 210
15.3.7 Fractographies After Static, Constant, and Cyclic Bending Loads 212
15.3.8 Long-term Prediction of Flexural Creep and Fatigue Strengths of Unidirectional CFRP Laminates 213
15.4 Conclusion 214
16 Application 2 of Integrated Accelerated Testing Methodology: Carbon Fiber and Matrix Resin Mechanical Properties Controlling Statistical Tensile Fatigue Life of Unidirectional Carbon-fiber-reinforced Polymer 217
16.1 Introduction 217
16.2 Formulations 217
16.2.1 Formulations of Fatigue Strength of Unidirectional CFRP 217
16.2.2 Fatigue Degradation Parameter for Unidirectional CFRP 219
16.3 Experiments 222
16.3.1 Test Materials 222
16.3.2 Testing Method and Test Conditions 222
16.4 Results and Discussion 224
16.4.1 Viscoelastic Coefficients of Epoxy Resin 224
16.4.2 Static Strength of CF/EP Strands Using Three Types of Carbon Fiber 224
16.4.3 Tensile Fatigue Strengths of Three Types of CF/EP Strands 228
16.4.4 Influence of Strain Ratio on Tensile Fatigue Strength of CF/EP Strands 229
16.4.5 Influence of Matrix Resin Viscoelasticity on Tensile Fatigue Strength of CF/EP Strands 229
16.4.6 Influence of Mechanical Properties of Carbon Fibers on CF/EP Strand Fatigue Strengths 232
16.4.7 Long-term Fatigue Life of CF/EP Strands 236
16.5 Conclusion 237
17 Application 3 of Integrated Accelerated Testing Methodology: Influence of Mechanical Properties of Carbon Fiber on Statistical Creep and Fatigue Lives of Carbon-fiber-reinforced Polymer Strands with Thermoplastic Epoxy Resin as Matrix 239
17.1 Introduction 239
17.2 Experimental Procedure 239
17.2.1 Specimen Preparation 239
17.2.2 Static, Creep, and Fatigue Tests of CF/TPEP Strands 239
17.3 Results and Discussion 241
17.3.1 Relaxation Modulus of TPEP Resin 241
17.3.2 Static Strength of CF/TPEP Strands with Two Types of Carbon Fibers 242
17.3.3 Creep Strength of CF/TPEP Strands with Two Types of Carbon Fibers 244
17.3.4 Fatigue Strength of CF/TPEP Strands with Two Types of Carbon Fibers 245
17.3.5 Influence of Mechanical Properties of Carbon Fibers on Creep and Fatigue Strengths of CF/TPEP Strands 247
17.3.6 Creep and Fatigue Lives of CF/EP Strands and Their Comparison with CF/TPEP Strands 249
17.4 Conclusion 253
18 Application 4 of Integrated Accelerated Testing Methodology: Statistical Tensile and Flexural Creep and Fatigue Lives of Unidirectional Carbon-fiber-reinforced Polymer Laminates with Polypropylene as Matrix 255
18.1 Introduction 255
18.2 Experimental Procedure 255
18.2.1 Specimen Preparation 255
18.2.2 Test Methods and Test Conditions for CF/PP Laminates 255
18.3 Results and Discussion 256
18.3.1 Relaxation Modulus of Matrix Resin 256
18.3.2 Statistical Tensile and Flexural Static Strengths of CF/PP Laminates 259
18.3.3 Statistical Tensile and Flexural Creep Strengths of CF/PP Laminates 261
18.3.4 Statistical Tensile and Flexural Fatigue Strengths of CF/PP Laminates 264
18.3.5 Long-term Prediction of Tensile and Flexural, Creep and Fatigue Strengths of CF/PP Laminates 267
18.4 Conclusion 268
19 Application 5 of Integrated Accelerated Testing Methodology: Prediction of Creep Failure Life for Unidirectional Carbon-fiber-reinforced Polymer with Heat-resistant Epoxy Resin as Matrix Exposed to High Temperature Under Tension Load 271
19.1 Introduction 271
19.2 Experiments 272
19.2.1 Specimens 272
19.2.2 Testing Method 272
19.2.3 Heat Degradation Treatments 273
19.3 Results and Discussion 276
19.3.1 Relaxation Moduli of Virgin and Heat-degraded Resins 276
19.3.2 Static Strengths of Virgin and Heat-degraded CFRP Strands at Various Temperatures 278
19.3.3 Statistical Creep Failure Times of Virgin and Heat-degraded CFRP Strands 280
19.3.4 Long-term Prediction of Statistical Creep Strength for Heat-degraded CFRP Strands 282
19.4 Conclusion 282
20 Application 6 of Integrated Accelerated Testing Methodology: Effects of Annealing on Statistical Creep Life for Carbon-fiber-reinforced Polymer Strands with Thermoplastic Epoxy Resin as Matrix 285
20.1 Introduction 285
20.2 Formulations 285
20.2.1 Matrix Resin Viscoelasticity 285
20.2.2 Effect of Annealing on Matrix Resin Viscoelasticity 287
20.2.3 Statistical Static and Creep Strengths of CFRP 287
20.3 Experimental Procedures 289
20.4 Results and Discussion 290
20.4.1 Master Curve of the Relaxation Modulus of TPEP 290
20.4.2 Statistical Static Strength of CF/TPEP Strands 291
20.4.3 Statistical Creep Strength of CF/TPEP Strands 293
20.4.4 Progress of Annealing of TPEP During the Operating Process 294
20.4.5 Statistical Creep Strength of CF/TPEP Strands Attributable to Annealing Progress During the Operating Process 295
20.5 Conclusion 296
Appendix A: Effect of Physical Aging on the Creep Deformation of an Epoxy Resin 297
Appendix B: Reliable Test Method for Tensile Strength in Longitudinal Direction of Unidirectional Carbon-fiber-reinforced Polymers 307
Appendix C: Size Dependence on Tensile Strength for Resin-impregnated Carbon Fiber-reinforced Polymer Strands 317
Index 327
