Dynamic Fracture

Dynamic fracture in solids has attracted much attention for over a century from engineers as well as physicists due both to its technological interest and to inherent scientific curiosity. Rapidly applied loads are encountered in a number of technical applications. In some cases such loads might be applied deliberately, as for example in problems of blasting, mining, and comminution or fragmentation; in other cases, such dynamic loads might arise from accidental conditions. Regardless of the origin of the rapid loading, it is necessary to understand the mechanisms and mechanics of fracture under dynamic loading conditions in order to design suitable procedures for assessing the susceptibility to fracture. Quite apart from its repercussions in the area of structural integrity, fundamental scientific curiosity has continued to play a large role in engendering interest in dynamic fracture problems

Table of Contents:
Contents Preface 1.Introduction 1.1 Pressurized Thermal Shock in Nuclear Containment Vessels 1.2 Boiler and Pipeline Burst Problems 1.3 Dynamic Fracture in Airplane Structures 1.4 Notched Bar Impact Testing of Metallic Materials 2. Linear Elastodynamics 2.1 Fundamental Boundary-Initial Value Problems in Elastodynamics 2.2 Bulk Waves 2.3 Lame´ Solution 2.4 Plane Waves 2.5 Propagation of Discontinuities: Wavefronts and Rays 2.6 Two-Dimensional Problems in Elastodynamics 2.6.1 Anti-Plane Shear 2.6.2 Plane Strain 2.6.3 Plane Stress 2.7 Surface Waves 2.8 Half-Space Green’s Functions 2.9 Lamb’s Problem 3. Dynamic Crack Tip Fields 3.1 Dynamically Loaded Cracks 3.2 Asymptotic Analysis of Crack Tip Fields 3.2.1 Anti-Plane Shear 3.2.2 In-Plane Symmetric Deformation 3.2.3 In-Plane Antisymmetric Deformation 3.3 Asymptotic Analysis for Nonsteady Crack Growth 3.4 Intersonic Crack Growth 4. Determination of Dynamic Stress Intensity Factors 4.1 Analysis of Stationary Cracks Under Dynamic Loading 4.1.1 Semi-Infinite Crack Under Uniform Loading 4.1.2 Semi-Infinite Crack Under a Point Load 4.2 Analysis of Moving Crack Problems 4.2.1 The Yoffe Problem 4.2.2 Dynamic Stress Intensity Factors for Moving Cracks 5. Energy Balance and Fracture Criteria 5.1 Energy Balance Equation 5.2 Dynamic Failure Criterion 5.3 Dynamic Crack Initiation Toughness 5.4 Dynamic Crack Growth Toughness 5.5 Dynamic Crack Arrest Toughness 5.6 Application of Dynamic Failure Criteria 6. Methods of Generating Dynamic Loading 6.1 Static Loading of Cracks 6.2 Drop-Weight Tower and Instrumented Impact Testing 6.3 Projectile Impact 6.4 Hopkinson Bar Impact Test 6.5 Explosives 6.6 Electromagnetic Loading 7. Measurement of Crack Speed 7.1 Wallner Lines 7.2 Stress Wave Fractography 7.3 Electrical Resistance Methods 7.4 High-Speed Photography 8. Crack Tip Stress and Deformation Field Measurement 8.1 Jones Calculus 8.2 Photoelasticity 8.2.1 Evaluation of the Dynamic Stress Intensity Factor using Photoelasticity 8.3 Method of Caustics 8.3.2 Caustic in Reflection 8.3.3 Mixed-mode Caustics 8.3.4 Limitations on the Applicability of the Method of Caustics 8.4 Lateral Shearing Interferometry 8.4.1 Evaluation of the Dynamic Stress Intensity Factor using Shearing Interferometry 8.5 Strain Gages 8.6 Interferometry References 9. Dominance of the Asymptotic Field 9.1 Stationary Cracks 9.2 Propagating Cracks 9.3 Dominance of the Asymptotic Field for Propagating Cracks 10. Dynamic Fracture Criteria 10.1 Criteria for Crack Initiation 10.1.1 Initiation of Cracks Under Short Duration Stress Pulses 10.1.2 Loading Rate and Temperature Dependence of Crack Initiation Toughness 10.2 Dynamic Crack Arrest Criterion 10.2.1 Development of the Crack Arrest Criterion 10.2.2 ASTM Standard Method for Crack Arrest 10.2.3 Application of the Crack Arrest Criterion 10.3 Dynamic Crack Growth Criterion 10.3.1 Crack Growth Toughness in Nominally Brittle Materials 10.3.2 Crack Growth Toughness in Ductile Materials 11. Physical Aspects of Dynamic Fracture 11.1 Limiting Crack Speed 11.2 Fracture Surface Roughness 11.2.1 Real-Time Observations of Multiple Crack Fronts 11.2.2 Fast Fracture Surfaces in Polymethylmethacrylate 11.2.3 Origin of the Microcracks 11.2.4 Geometry of the Conic Markings 11.2.5 Statistics of Microcracks in PMMA 11.2.6 Growth of Microcracks 11.2.7 Solithane 113 11.2.8 Polycarbonate 11.2.9 Homalite-100 11.3 Crack Branching 12. Phenomenological Models of Dynamic Fracture 12.1 Discrete Models—Molecular Dynamics and Lattice Models 12.2 Cohesive Zone Models 12.3 Continuum Damage Models References Further Reading Appendix A. Dynamic Crack Tip Asymptotic Fields A1 Dynamic Crack Tip Stress Field for a Stationary Crack A2 Steady-State Dynamic Crack Tip Stress Field: Singular Term A3 Steady-State Crack Tip Displacement and Stress Field: N Terms A4 Transient Crack Tip Displacement and Stress Field: Six Terms Appendix B. Mechanical and Optical Properties of Selected Materials Index