FINITE-ELEMENT ANALYSIS OF PLASTICITY-INDUCED CRACK CLOSURE UNDER PLANE-STRAIN CONDITIONS

In this study, fatigue crack growth in an elastic-perfectly plastic solid is modeled using a two-dimensional finite element analysis. Plane deformations are enforced and crack advance is simulated by node release. The analysis suggests that crack closure occurs for a transient period of crack growth, with a residual wedge of material being left on the crack flanks near the initial location of the crack tip. The influence of specimen geometry and load level upon closure response is determined, and explained in terms of the 'T-stress'. This stressis the non-singular constant second term in the series expansion of the normal stress parallel to the crack plane.