The Separated Dynamic J Integrals and Response Simulations of Interfacial Cracks Subject to Impact Loading

摘要

The path-independent dynamic J integral originally derived by Nishioka and Atluri is valid for homogeneous materials. Recently, an extended path-independent dynamic J integral has been derived by the present authors, for non-homogeneous materials. They have also derived the dynamic J integrals separated into both material sides for an interfacial crack tip. Is this paper, dynamic finite element analyses are carried out for interfacial cracks in bimaterial plates subject to impact loading. Different cases of material mismatch are considered. The path independence of the dynamic J integral components and the separated dynamic J integrals are verified for impact interfacial crack problems by the numerical results. Several points were elucidated from the numerical simulations. For instance, (i) if the dynamic J integral response curves are normalized properly, the response curves for the same mismatch ratio with different rigidities coincide each other. (ii) The major responses of the dynamic J integral components always manifest themselves when the impact stress wave in the compliant material side impinges to the crack tip. (iii) The separated dynamic J integral or equivalently separated energy release rate from the compliant material dominates the fracture process of an interfacial crack with a large mismatch ratio.