关键词: 平面应力, 裂端约束, J积分, 裂纹扩展

Abstract: The finite element analyses are performed to model quasi-static crack growth under mode I plane stress in a compact tension specimen and a centre-cracked plate. It is found that the crack-tip constraint and stress field defined by HRR singularity solution for a stationary crack are better met by those presented in the propagating crack tip for two different thin specimens, namely, J-dominance is continuously valid for the tip field of a growing crack. Contrary to plane strain, it is noted that, for plane stress case, the higher J-dominance level occurs under pure tension condition, and the lower J-dominance level occurs under pure bending condition. The J-resistance curves measured experimentally from the two specimens geometries coincide with each other and agree well with those calculated by FEM simulations. Therefore, J-R curves under plane stress mode I codition, as a criterion independent of specimen-geometry, are suitable to characterize the materials resistance against crack steady extension and can be reasonably used to appreciate the safety of the thin-walled cracked components or structures for the given material state.

Key words: plane stress, crack tip constraint, J-integral, crack growth