Fracture of materials with strain gradient effects

Fracture in materials with strain gradient effects is studied by analytical and finite element methods, using Fleck and Hutchinson's strain gradient plasticity theory. Analytical solutions are obtained for the near-tip field in an elastic-plastic material with strain gradient effects. The mixed mode near-tip stress field in a power-law hardening solid is the linear superposition of its counterparts in mode I and II. The size of the dominance zone for the near-tip field is approximately I, the intrinsic material length on the order of a few microns. For an interface crack between dissimilar elastic-plastic materials with strain gradient effects, the analytical near-tip field does not agree with numerical results, indicating the existence of nonseparable fields.