Numerical evaluation of stress intensity factors and T-stress for interfacial cracks and cracks terminating at the interface without asymptotic enrichment

摘要

In this paper, we extend the recently proposed extended scaled boundaryfinite element method (xSBFEM)~\cite{natarajansong2013} to study fractureparameters of interfacial cracks and cracks terminating at the interface. Theapproach is also applied to crack growth along the interface and crackdeflecting into the material within the context of linear elastic fracturemechanics. Apart from the stress intensity factors, the T-stress can becomputed directly from the definitions, without any requirement of pathindependent integrals. The method aims at improving the capability of theextended finite element method in treating crack tip singularities of cracks atinterfaces. An optimum size of the scaled boundary region is presented formultimaterial junctions. The proposed method: (1) does not require specialnumerical integration technique; (2) does not require a priori knowledge of theasymptotic fields and (3) the stiffness of the region containing the crack tipis computed directly. The robustness of the proposed approach is demonstratedwith a few examples in the context of linear elastic fracture mechanics. Adiscussion on the crack growth along the interface and crack deflecting intothe material is also presented.