基于近场动力学理论的热障涂层热冲击开裂行为

To study the failure mechanism of the thermal barrier coating after thermal shock, a thermal shock test of the ceramic-based Thermal Barrier Coating (TBC) was designed and completed. The failure mode of TBCs and the effect of thermal shock temperature were studied. Based on the Peridynamic (PD) theory, thermal-mechanical coupling equations were derived, and programs were coded to simulate the temperature and failure growing of TBC, and the effect of temperature on damage of TBC was analyzed. It is shown that longitudinal cracks propagated from the surface of the ceramic layer to the interface between the ceramic layer and the bond coat layer along the thickness direction. Some of the cracks were branched and turned to be transverse cracks parallel to the interface. As the thermal shock temperature increased, longitudinal cracks in the coating initiated earlier, and the number of the cracks gradually increased and reached a peak at 0.50 s. The PD method can capture the initiation and propagation of cracks, crack position, crack growing and shock temperature effects, and these numerical results agree well with the experimental ones.