Elastic-Plastic Fracture Mechanics Model for Planar Isotropic Porous Materials with Small Mixed-Mode Cracks

Abstract

A porous panel with a small crack subjected to mixed-mode loads under yielding and plane stress conditions is examined here. The recently proposed modified Gurson’s yield criterion is adopted to account for the non-linear behavior of a porous panel with normal anisotropy but planar isotropy. Trends in the constant J contour, based upon a finite element analysis, are correlated with those of constant fatigue life contours under mixed-mode I and II loading conditions. The effects of both the anisotropy parameter and the porosity upon the J integral are then demonstrated. Simulation results show that the transverse strain dominates constant J contours on the -plane as the anisotropy parameter increases under the mixed-mode loads. However, constant J contours are less sensitive to the transverse strain even if a relatively larger void volume fraction appears in the panel.