To study the stability of mode I (opening-mode) fracture, we consider a two-dimensional system in which a crack moves along the center line of a very wide, infinitely long strip. We compute the first-order response of the crack to a spatially periodic, perturbing shear stress. We assume isotropic linear elasticity in the strip and a cohesive-zone model of the crack tip. The behavior of this system is strongly sensitive to the dynamics within the cohesive zone; stability cannot be deduced simply from properties of the far-field stress-intensity factors. When the mode I and mode II (sliding-mode) fracture energies are equal, the crack is marginally stable at zero speed and is unstable against deflection at all nonzero speeds. However, when the cohesive stress has a shear component that strongly resists bending into mode II, there is a nonvanishing critical velocity for the onset of instability.
|Number of pages||17|
|Journal||Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics|
|Publication status||Published - Jan 1 1996|
All Science Journal Classification (ASJC) codes
- Statistical and Nonlinear Physics
- Statistics and Probability
- Condensed Matter Physics