An extended multiphase hybrid-stress finite element method for modelling interface crack propagation between two dissimilar materials

Abstract

In this work, an extended multiphase hybrid-stress finite element method (X-MHSFEM) is developed to investigate the stress intensity factor, kinking angle, and propagation path of an interface crack. Further, we have simulated the propagation of the interface crack by using the X-MHSFEM. Several types of element models containing the interface and matrix cracks are introduced in the propagation process of the interface crack. The derivation of the functional of the element containing the two materials, one interface, and all types of cracks, is performed. Stress functions are enriched by the asymptotic singular items that accounts for the oscillatory behavior to describe the stress concentration in the vicinity of the interface crack-tip, and the stress concentration near the matrix crack-tip are also captured by inserting certain singular stress terms of Williams expansion into the physical field of whole model. The stress intensity factors of the tips of the interface and matrix cracks are calculated by the least square method. The maximum and relative maximum circumferential stress criterion are employed as the fracture criteria for predicting the interface crack propagation along the interface or the deflection into layers. Further, the matrix crack propagation angle within the layers is determined by the maximum energy release rate criterion. A remeshing algorithm is employed to implement the propagation of the interface and matrix cracks. The effectiveness and accuracy of the present method are validated by comparing the results, obtained by the new method, with the experimental observation and other numerical results. Therefore, the extended multiphase hybrid-stress finite element method can provide an effective medium to deal with the interface crack fracture problems.