Crack Tip Plasticity in Dynamic Fracture Mechanics.
NORTHWESTERN UNIV EVANSTON ILL STRUCTURAL MECHANICS LAB
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The objective of this work is to develop a procedure by which crack tip plasticity can be taken directly into account in rapid crack propagation. To set the stage, a background description of linear elastic dynamic fracture mechanics is first given. Existing solutions for dynamic crack propagation and for quasistatic crack growth accompanied by crack tip plasticity are reviewed. It is found that existing dynamic plastic fracture solutions are essentially confined to strip yield Dugdale model plastic zones that are collinear with the crack. The ultimate goal of the research reported in this paper is to provide the basis of a computational procedure for plastic dynamic crack propagation in structures of engineering interest. The prerequisite for such a development is knowledge of the nature of the crack tip singularity, which can be obtained via an asymptotic analysis in which attention is focused on the very near crack tip region. Here we have considered the specific case of crack propagation in antiplane strain Mode III. The results suggest some interesting general conclusions, and the analysis has pointed the way to the solution of the Mode I problem.
- Numerical Mathematics