Three‐dimensional cohesive modeling of dynamic mixed‐mode fracture
A cohesive formulation of fracture is taken as a basis for the simulation of processes of combined tension-shear damage and mixed-mode fracture in specimens subjected to dynamic loading. Our three-dimensional finite-element calculations account explicitly for crack nucleation, microcracking, the development of macroscopic cracks and inertia. In particular, a tension-shear damage coupling arises as a direct consequence of slanted microcrack formation in the process zone. We validate the model against the three-point-bend concrete beam experiments of Guo et al. (International Journal of Solids and Structures 1995; 32(17/18):2951–2607), John (PhD Thesis, Northwestern University, 1988), and John and Shah (Journal of Structural Engineering 1990; 116(3):585–602) in which a pre-crack is shifted from the central cross-section, leading to asymmetric loading conditions and the development of a mixed-mode process zone. The model accurately captures the experimentally observed fracture patterns and displacement fields, as well as crack paths and crack-tip velocities, as a function of pre-crack geometry and loading conditions. In particular, it correctly accounts for the competition between crack-growth and nucleation mechanisms.
© 2001 John Wiley & Sons. he support of Caltech's ASCI/ASAP Center for the Simulation of the Dynamic Properties of Solids is gratefully acknowledged. Gonzalo Ruiz gratefully acknowledges the financial support for his stay at the California Institute of Technology provided by the Dirección General de Enseñanza Superior,Ministerio de Educación y Cultura, Spain. We are indebted to Santiago Lombeyda, Research Scientist at the Center for Advanced Computing Research, Caltech, for rendering the simulation results.