Cohesive Modeling of Dynamic Fracture: Rate Dependence and Intersonic Crack Motion
The second dynamic fracture problem addressed in this thesis is concerned with the issue of intersonic crack propagation, a topic of great interest in the fracture mechanics and geophysics community with the recent first direct observations of shear cracks exceeding the shear wave speed in homogeneous brittle specimen. Special interest is placed in this study on the possibility of steady-state and transient intersonic crack motion under mixed-mode conditions. Results show that exclusive shear damage in the cohesive zone is responsible for intersonic crack propagation even though the external load comprises of both shear and tensile components. The situation is very different in the subsonic regime, where crack motion is a result of combined shear and tensile damage inside the cohesive zone. The study also provides information on the effect of mode mixity on the length of the cohesive failure zone.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign