Stress Intensity Factors of Interfacial Crack with Arbitrary Crack Tractions

Abstract

Interfacial crack is much more complicated than a crack in homogeneous material. The crack is always in mixed-mode even for symmetrical geometry and symmetrical load, and the stress intensity factor has a complex value, which poses great challenges to numerical modelling. In some cases, there is surface traction on the crack faces, which can be crucial to the stability of the crack. In the presented research, a procedure is brought forward for analysis of interfacial crack with arbitrary surface traction based on the Scaled boundary finite element method(SBFEM). The surface traction on the crack is firstly divided into two parts, one in the direction normal to the crack face and the other in the tangential direction. Then each part is further divided into a series of power function of the radial coordinate. The solution for each can be solved semi-analytically by the SBFEM and is then superimposed to get the total solution. With this procedure, the stress and displacement are solved analytically in the radial direction, and the stress singularity at crack tip is obtained with high precision without refined mesh. Both anisotropic and isotropic materials can be considered. For validation of the procedure, a plate containing an interfacial crack and assuming different material propertes and different surface traction is investigated. Sensitivity analysis is also performed concerning the plate geometry and material properties. Finally the model is applied to solving the stress intensity factors of an interfacial crack of a gravity dam filled with water.