Dynamic Failure of Materials and Structures (eBook)

Dynamic Failure of Materials and Structures 1
1 Dynamic Characterization of Soft Materials 14
1.1 Introduction 14
1.2 Conventional Kolsky Bar 15
1.3 Modified Kolsky Bar for Characterizing Soft Materials 19
1.3.1 Weak Transmitted Signal Measurement 19
1.3.2 Inertia Effects 21
1.3.2.1 Axial Inertia (Dynamic Stress Equilibrium) 22
1.3.2.2 Radial Inertia Effects 25
1.3.3 Pulse-Shaping Technique for Kolsky-Bar Experiments on Soft Specimens 26
1.3.3.1 Introduction to Pulse Shaping Technique 26
1.3.3.2 Pulse-Shaping Design for Testing Soft Materials 27
1.4 Upper Limit in Strain Rates 32
1.5 Single-Loading Feature 33
1.6 Experiments at Intermediate Strain Rates 36
1.7 Summary 37
References 38
2 Dynamic Shear Failure of Materials 42
2.1 Introduction 42
2.2 Dynamic Shear Testing 43
2.2.1 Experimental Considerations 43
2.2.2 Selected Dynamic Shear Studies Using the SCS 46
2.3 Dynamic Shear Failure 50
2.3.1 Some Facts on Adiabatic Shear Failure 50
2.3.1.1 On the Role of Thermal Softening and the Critical Strain Criterion 51
2.3.1.2 On Geometrical Imperfections and ASB Formation 56
2.3.1.3 On the Effect of Hydrostatic Pressure on ASB Formation 61
2.3.1.4 On Thermal Effects and Identification of a Fully Formed ASB by Thermal Means 68
2.4 Conclusions 71
References 72
3 Dynamic Response of Glass-Fiber Reinforced Polymer Composites Under Shock Wave Loading 75
3.1 Introduction 76
3.2 Analytical Analysis 78
3.2.1 Wave Propagation in Elastic--Viscoelastic Bilaminates 78
3.2.2 Solution at Wave Front: Elastic Precursor Decay 80
3.2.3 Late-Time Asymptotic Solution 81
3.3 Plate Impact Experiments on GRP Composites 87
3.3.1 Material: GRP Composites 87
3.3.2 Plate Impact Shock Compression Experiments: Experimental Configuration 88
3.3.3 Plate Impact Spall Experiments: Experimental Configuration 89
3.3.3.1 t--x Diagram (Time vs Distance) and S--V Diagram (Stress vs Velocity) for Plate Impact Spall Experiments 89
3.3.4 Shock--Reshock and Shock Release Experiments: Experimental Configuration 91
3.3.4.1 t--x Diagram for Shock--Reshock and Shock Release Experiments 92
3.4 Target Assembly 93
3.5 Experimental Results and Discussion 93
3.5.1 Plate Impact Shock Compression Experiments 93
3.5.1.1 Structure of Shock Waves in the GRP 94
3.5.1.2 EOS for the S2-Glass GRP 97
3.5.1.3 Hugoniot Stress Versus Hugoniot Strain (Hugoniot) 98
3.5.1.4 Hugoniot Stress Versus Particle Velocity 99
3.5.2 Plate Impact Spall Experiments 101
3.5.2.1 Spall Strength Following Normal Shock Compression 102
3.5.2.2 Spall Strength of GRP Following Combined Shock Compression and Shear Loading 103
3.5.3 Shock--Reshock and Shock Release Experiments on S2-Glass GRP 105
3.5.3.1 Self-Consistent Dynamic Shear Yield Strength Determination Method 107
3.5.3.2 Calculation of Off-Hugoniot States for Reshock/Release Loading 110
3.5.3.3 Determination of the Critical Shear Strength in the Shocked State for S2-Glass GRP 112
3.6 Summary 114
References 116
4 Dynamic Compressive Strengths of Polymeric Composites: Testing and Modeling 119
4.1 Introduction 119
4.2 Models for Predicting Compressive Failure 121
4.2.1 The Kink Band Model 121
4.2.2 Microbuckling Model 123
4.3 Dynamic Microbuckling Model 124
4.3.1 Derivation of Rate-Dependent Tangent Shear Modulus 124
4.3.2 Dynamic Microbuckling Model for Off-Axis Specimens 126
4.3.3 Comparison of Microbuckling Model and Kink Band Model 127
4.3.4 Effect of Shear Stress on Compressive Strength 128
4.4 Compressive Failure Tests 129
4.4.1 Compressive Test on 0 Composite Specimen 129
4.4.2 Compressive Test on Off-Axis Specimens 130
4.4.2.1 Compressive Testing of S2/8552 Composite 130
4.4.2.2 Testing Carbon/epoxy Off-Axis Specimen 133
4.4.3 Experimental Results of Off-Axis Specimens 135
4.5 Longitudinal Compressive Strength 137
4.6 Conclusion 139
References 139
5 Transverse Response of Unidirectional Composites Under a Wide Range of Confinements and Strain Rates 142
5.1 Introduction 142
5.2 Experimental 146
5.2.1 Materials 146
5.2.2 Low Strain Rate Testing 148
5.2.3 High Strain Rate Testing 148
5.2.4 Confinement 149
5.2.5 Confinement Method for Low Strain Rate Loading 150
5.2.6 Varying Confinement with Polycarbonate Pads Inserts 152
5.2.7 High Strain Rate Confinement Method 154
5.3 Low Strain Rate Results 156
5.4 High Strain Rate Results 160
5.5 Summary 161
References 161
6 Shock Loading and Failure of Fluid-filled Tubular Structures 164
6.1 Introduction 164
6.2 Korteweg Model of Wave Propagation 165
6.3 Limiting Cases of FSI 171
6.3.1 Thick, Stiff Tube 1 171
6.3.2 Coupled Fluid Motion and Tube Deformation, = O(1) 174
6.3.2.1 Simplified FSI Models 176
6.3.3 Thin, Flexible Tube 1 177
6.4 Experimental Results 178
6.4.1 Small Coupling 179
6.4.2 Elastic Motions 180
6.4.3 Plastic Motions 180
6.4.4 High Explosives 182
6.5 Moderate Coupling 182
6.5.1 Elastic Waves 183
6.5.2 Plastic Deformation 184
6.5.3 Composite and Polymer Tubes 187
6.6 Summary 191
Appendix 192
References 198
7 Impact Response and Damage Tolerance of Composite Sandwich Structures 202
7.1 Introduction 203
7.2 Sandwich Materials Investigated 204
7.2.1 Facesheet Materials 204
7.2.2 Core Materials 207
7.3 Sandwich Beams under Low Velocity Impact 212
7.3.1 Sandwich Beam Testing 212
7.3.2 Load Histories 213
7.3.3 Strain Histories 215
7.3.4 Modeling 218
7.3.5 Damage Mechanisms 220
7.4 Sandwich Panels under Low Velocity Impact 225
7.4.1 Introduction 225
7.4.2 Experimental Procedures 225
7.4.3 Quasi-Static Behavior 228
7.4.4 Behavior under Low Velocity Impact 229
7.4.5 Damage Evaluation 233
7.5 Post-Impact Behavior of Composite Sandwich Panels 235
7.5.1 Introduction 235
7.5.2 Experimental Procedure 236
7.5.3 Results and Discussion 236
7.6 Conclusions 240
References 242
8 Failure of Polymer-Based Sandwich Composites Under Shock Loading 245
8.1 Introduction 245
8.2 Material Systems 251
8.2.1 E-glass Vinyl Ester Composite 252
8.2.2 Carbon Fiber Vinyl Ester Composite 252
8.2.3 Polyurea Layered Materials 253
8.2.4 Polyurea Sandwich Composites 254
8.2.5 Sandwich Composites with 3D Woven Skin 254
8.2.6 Core Reinforced Sandwich Composites 255
8.3 Experimental Setup 256
8.3.1 Shock Tube 257
8.3.2 Loading and Boundary Conditions 259
8.3.3 High-Speed Imaging 259
8.4 Results and Discussion 260
8.4.1 Blast Resistance of Laminated Composites 260
8.5 Blast Resistance of Layered Composites 265
8.5.1 PU/EVE Layered Material 266
8.5.2 EVE/PU Layered Material 266
8.6 Blast Resistance of Sandwich Composites 267
8.6.1 Polyurea-based Sandwich Composites 267
8.6.2 Sandwich Composites with 3D Skin and Polymer Foam Core 270
8.7 Summary 276
References 277
9 Fiber--Metal Laminate Panels Subjected to Blast Loading 279
9.1 Introduction 279
9.2 Blast Loading Studies on FMLs: Defining the Structural Materials 281
9.2.1 Materials 281
9.2.2 Important Properties of FMLs 282
9.2.3 Naming Convention 283
9.3 Localized Blast Loading Response 284
9.3.1 Overview of Test Programme 284
9.3.2 Results 284
9.4 Uniformly Distributed Blast Response 289
9.4.1 Overview of Test Programme 289
9.4.2 Results 290
9.5 Combining the Results 291
9.6 Modeling 293
9.6.1 Modeling Challenges 293
9.6.1.1 Defining the Load 293
9.6.1.2 Modeling Debonding Failure 294
9.6.1.3 Strain Rate Effects in the FML Panels 295
9.6.2 Comparison with Experiments 295
9.7 Blast Response of FMLs Based on Other Composites 296
9.7.1 Glass Fiber PolyAmide 6,6 (GFPA) 296
9.7.1.1 Defining the Al/GFPA FMLs 296
9.7.1.2 Localized Blast Testing 297
9.7.1.3 Uniformly Distributed Blast Testing 298
9.7.2 Glass Fiber Epoxy (GLARE©) 299
9.7.2.1 Defining the Tested GLARE© Material 299
9.7.2.2 Blast Test Results 300
9.7.3 Comparing Different Types of FML Panels 301
9.7.3.1 General Comparison 301
9.7.3.2 Nondimensional Analysis 302
9.8 Research Opportunities 303
9.9 Conclusions 304
References 304
10 Sandwich Panels Subjected to Blast Loading 307
10.1 Introduction 307
10.1.1 Sacrificial Cladding 308
10.1.2 Sandwich Panels 309
10.2 Blast Loading Conditions 311
10.2.1 Air Blast Loading 311
10.2.2 Underwater Blast Loading 312
10.2.3 Simulated Blast Load 314
10.3 Sandwich Panels with Cellular Cores 314
10.3.1 Mechanical Properties of Cellular Materials 314
10.3.2 Sandwich Panels with Honeycomb Cores 316
10.3.3 Sandwich Panels with Foam Cores 321
10.4 Sandwich Panels with Micro-Architectured Cores 323
10.4.1 Cores Manufactured Using Tooling 324
10.4.2 Cores Manufactured Using Selective Laser Melting 325
10.5 Sandwich Panels with Macro-Architectured Cores 326
10.6 Future Work 329
10.7 Conclusions 331
References 332
11 Advanced Numerical Simulation of Failure in Solids Under Blast and Ballistic Loading: A Review 336
11.1 Introduction 336
11.2 Background 339
11.2.1 Projectile Penetration 339
11.2.2 Blast Response of Structures 340
11.2.2.1 Blast Modeling 342
11.2.2.2 Blast Effects Modeling 343
11.3 Experimental Validation 344
11.3.1 Diagnostic Penetration Experiment 345
11.4 Modeling Requirements 347
11.5 Conclusions 353
References 354
12 Advances in Cohesive Zone Modeling of Dynamic Fracture 357
12.1 Introduction 357
12.2 Origins of the Cohesive Zone Approach 360
12.3 Finite Element Implementation Using Interface Elements 362
12.4 Intrinsic Approach 367
12.4.1 The Polynomial Potential Law 367
12.4.2 The Exponential Potential Law 370
12.4.3 Intrinsic Laws for Ductile Fracture 371
12.4.4 Application of the Intrinsic Approach to Brittle Fracture 373
12.4.5 Issues with the Intrinsic Approach 377
12.4.5.1 Mesh Dependency of Arbitrary Crack Paths 378
12.4.5.2 Lift-Off 380
12.4.5.3 Artificial Compliance 380
12.5 Extrinsic Approach 384
12.5.1 Linear Irreversible Softening Law 384
12.5.2 Applications of the Extrinsic Approach 387
12.5.3 Issues with the Extrinsic Approach 390
12.5.3.1 Mesh Dependency of Arbitrary Crack Paths 392
12.5.3.2 Mesh Dependency of Dissipated Fracture Energy 394
12.5.3.3 Scalability Issues for Three-Dimensional Problems 396
12.5.3.4 Time Discontinuity 397
12.6 Discontinuous Galerkin Formulation of Cohesive Zone Models 398
12.6.1 Motivation 398
12.6.2 The Discontinuous Galerkin Framework 399
12.6.3 Application: Ceramic Spall Test 402
12.6.3.1 Comparison of DG/hybrid and CG/intrinsic approaches 402
12.6.3.2 Scalability of the DG Method 404
12.7 Conclusions and Recommendations for Future Work 407
12.7.1 Computational Challenges 407
12.7.2 Extrinsic vs. Intrinsic Cohesive Laws and Associated Open Problems 408
References 409
Index 414