Fatigue Propagation Analysis of Crack Failure in High-Power IGBT Solder Based on Multiphysics Coupling Model and XFEM

Insulated gate bipolar transistor (IGBT) is one of the most important power modules in electric traction converter systems. However, the IGBT module may suffer from alternating thermal load and frequent vibration impacts, which will cause crack damage and propagation in the solder layer, resulting in early failure. In this article, the 3-D extended finite element method (XFEM) is used to investigate the fatigue propagation characteristics of crack damage in the solder layer of an IGBT module, where the coupling effects of transient temperature and mechanical fields are considered. The thermal-vibration coupling relationship and periodic fatigue propagation of crack damage are analyzed by using XFEM. The distributions of stress, strain, and crack damage evolution state under different thermal-vibration loads are obtained. Based on the fracture mechanics theory and Paris equation, the dynamic crack propagation and damage fatigue evolution of the IGBT solder layer under periodic coupling stress are revealed. Results show that the thermal-vibration coupling effect causes the crack damage propagation of the IGBT solder layer and the change of crack damage fatigue propagation rate. The results of this research may contribute to the failure mechanism and fatigue life prediction of high-power module IGBT devices.