The value of the J-integral at the onset of crack extension from a weld defect: weld material is harder than parent material

The paper addresses the problem of crack extension in a weld in an engineering structure for the situation where the crack is parallel to the plane of the weld. An earlier analysis, for the case where the weld material is softer than the parent material, has demonstrated the extent to which the value of the J-integral at the onset of crack extension depends on the flow properties of the weld and parent materials, the crack size and the weld thickness. The present paper extends these earlier considerations to the case where the weld material is harder than the parent material, and again demonstrates the non-uniqueness of the value of J at the onset of crack extension.