Asymptotic fields for dynamic crack growth in pressure-sensitive elastic–plastic materials

Asymptotic analyses for dynamic propagation of mode I planar cracks in pressure-sensitive elastic±plastic materials have been carried out. The material model adopted is based on the Drucker±Prager yield surface obeying the associate ¯ow rule with linear isotropic hardening. The asymptotic solution is assumed to be of the variable- separable form with a power singularity in the radial coordinate from the crack tip. Attention is focused on the inertia e€ect on some features of the asymptotic solutions. It is found that for plane-strain cases, the range of pressure sensitivity can be expanded by increasing the crack speed due to a delay in the occurrence of a hydrostatic stress state ahead of the crack tip. An increase in crack speed produces a corresponding change in the characteristics of the governing equations because of a tendency to produce strain and stress `jumpsʹ. Material and loading mode- dependent speed limits have also been studied under plane-strain and plane-stress conditions. In addition, numerical results are presented for the strength of singularity, the angular distributions of stresses and velocities, and the crack-tip constraint.