Curving of Normal Tension Crack Path in Brittle Fracture
V. D. Kurguzov, A. G. Demeshkin
Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Keywords: brittle fracture, failure criteria, crack path kink, computer model
Abstract
Fracture toughness of compact samples and polymethyl methacrylate double-cantilever beams in tension is investigated experimentally and theoretically. In loading mode I, the critical loads and propagation paths of cracks in these samples differ noticeably. The theoretical model presented is based on the energy concept. It allows predicting instability of crack propagation paths. The model includes stresses in front of the crack tip and the T- stress. The theoretical model is proved using the fracture test data on a few samples with mode I cracks. The computer modeling of crack propagation is performed in the geometrically and physically nonlinear formulation. The calculation and testing data comparison shows that the crack path instability essentially depends on geometry and can be avoided by changing the sample geometry or the type of loading.
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