TY - GEN
T1 - A study of dynamic crack instabilities using cohesive continuum methods
AU - Klein, P. A.
AU - Nguyen, T. D.
PY - 2005
Y1 - 2005
N2 - Though classical approaches to fracture, based on small deformation theory, have been applied successfully to a wide range of applications, they may be inapplicable for explaining experimental observations in which nonlinear, hyperelastic material response is an essential feature of the phenomenon. Among these phenomena are the branching instabilities observed during dynamic crack propagation. Simulation approaches that incorporate a cohesive view of material are able to demonstrate the appearance of fracture path instabilities. In this work, we study the hypothesis that instabilities occur as a result of a local limiting speed by investigating dynamic crack propagation along a weak plane in a strip described by a cohesive continuum. The introduction of the weak plane allows the fracture properties and the properties of the strain-softened, near-tip region to be selected independently. In the absence of dissipation, a mode I crack in a strip should accelerate to the Rayleigh wave speed if the far-field driving force exceeds the fracture energy. Under these conditions, the local limiting speed hypothesis predicts that the crack speed will be dictated not by the far-field driving force, but by acoustic wave speeds in the region surrounding the crack tip. It then follows that a crack that is unable to accelerate will become surrounded by a growing region of accumulating strain energy. The goal of this work is to study what effect the strain energy accumulating in the near-tip region has on the onset of branching instabilities. The scale and structure of this region will be investigated by evaluating the energy-momentum flux through various contours around the moving crack tip.
AB - Though classical approaches to fracture, based on small deformation theory, have been applied successfully to a wide range of applications, they may be inapplicable for explaining experimental observations in which nonlinear, hyperelastic material response is an essential feature of the phenomenon. Among these phenomena are the branching instabilities observed during dynamic crack propagation. Simulation approaches that incorporate a cohesive view of material are able to demonstrate the appearance of fracture path instabilities. In this work, we study the hypothesis that instabilities occur as a result of a local limiting speed by investigating dynamic crack propagation along a weak plane in a strip described by a cohesive continuum. The introduction of the weak plane allows the fracture properties and the properties of the strain-softened, near-tip region to be selected independently. In the absence of dissipation, a mode I crack in a strip should accelerate to the Rayleigh wave speed if the far-field driving force exceeds the fracture energy. Under these conditions, the local limiting speed hypothesis predicts that the crack speed will be dictated not by the far-field driving force, but by acoustic wave speeds in the region surrounding the crack tip. It then follows that a crack that is unable to accelerate will become surrounded by a growing region of accumulating strain energy. The goal of this work is to study what effect the strain energy accumulating in the near-tip region has on the onset of branching instabilities. The scale and structure of this region will be investigated by evaluating the energy-momentum flux through various contours around the moving crack tip.
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M3 - Conference contribution
AN - SCOPUS:84869801305
SN - 9781617820632
T3 - 11th International Conference on Fracture 2005, ICF11
SP - 5015
EP - 5020
BT - 11th International Conference on Fracture 2005, ICF11
T2 - 11th International Conference on Fracture 2005, ICF11
Y2 - 20 March 2005 through 25 March 2005
ER -