In view of the problem of crack failure of thermal barrier coatings(TBCs) prepared by means of APS

based on the thermal elastic and elastoplastic constitutive relations of the coating system

and taking into consideration the concave and convex morphology of ceramic coat (TC)/oxide layer(TGO)/bond coat(BC) interface

the crack evolution model was established by fracture mechanics and damage mechanics theory respectively according to the difference of position and nature of surface and interface cracks. In combination with contour integral and cohesive element method

the fracture parameters and cracking state of the surface and interface cracks under the thermal load were analyzed

the interaction between the surface cracks of the thermal barrier coating and the interface cracks of the BC/TGO was studied

and the crack failure mechanism under the coupling of thermal

force and chemical fields was revealed. The results showed that the surface cracks greatly changed the stress distribution state in the interface microregion. When the surface crack was near the interface

the interface crack propagation increased by 20%

and the nonuniformity of the crack in the adjacent convex peak can reach 81%. The fracture parameters of the surface crack were mainly dominated by the thermal mismatch and the defects of the multilayer structure. The effect of interface crack on the surface crack was relatively small. The results of the analysis were in agreement with the test results.