Numerical Simulation of Surface Crack Propagation in Thermal Barrier Coatings Under Thermal Mismatch Stress

The effect of thermal mismatch stress on the surface crack propagation in thermal barrier coatings was investigated by extended finite element method (XFEM). The results show that the location, slope angle and length of the crack have a significant effect on the crack propagation length, energy release rate and stress level of crack tip under the thermal mismatch stress. Among the cracks with the same initial length, the one at the valley has the longest extension length and the highest energy release rate. The larger the slope angle, the shorter the length of crack expansion but the larger the strain energy. The larger the initial crack length, the longer the crack propagation length and the faster the expansion rate, and the greater the energy release rate. The crack propagation affects each other under the condition of multiple cracks.