FRACTURE ANALYSIS OF PIEZOELECTRIC MATERIAL USING XFEM

Abstract

The analysis of any physical domain problem by the finite element method or by any other domain type methods can be very complex. The modelling process of complicated domain is difficult using standard finite element method since the mesh should conform to the boundary of domain and discontinuities (conformal mesh) and remeshing is needed at each step during crack growth. Therefore, extended finite element method (XFEM) is useful method that avoids these problems as it can capture the discontinuities present in the domain though enrichment independent of the meshing. In this report, stationary edge crack and center crack modelling has been done using XFEM and level set approach. The effect of various parameters (electric loading, aspect ratio, and crack inclination angle) on stress intensity factor (SIF) and electric displacement intensity factor (EDIF) have been observed and discussed. The effect of electric field direction on the fracture parameters is analysed. The edge crack and center crack propagation modelling have also been performed in presence of randomly distributed multiple holes and cracks in the domain. Maximum principal stress criterion is used for crack growth direction. Equivalent stress intensity factor is used as the fracture criterion. The piezoelectric CT specimen modelling has been done and results are validated. Further, CT specimen crack propagation has been performed for same material. In the last, different types of crack surface boundary conditions have been discussed and effect of permittivity of the medium inside the crack gap on the SIF and EDIF has been observed.