Some Observations from an Elastic–Plastic Finite Element Study of a Mixed-mode Crack Initiation Problem

Abstract

Direction of initial crack extension in an elastic-plastic situation under mixed-mode loading has been predicted through incremental finite element analysis from the crack-tip stress-strain field using the criteria of maximum tangential stress (MTS), maximum tangential strain (MTSN) and maximum tangential principal stress (MTPS) of the linear elastic fracture mechanics(LEFM). The prediction of direction of crack extension as per these criteria remain unchanged at the various stages of loading. The plastic zone at the crack-tip develops symmetrically about a line whose inclination with the crack is close to the initial crack extension angle.