A damage model to evaluate the mechanical properties in the medium-long life stage for coating system subjected to elevated thermal loads with 3D-DIC technique

Various damage models were proposed to quantify the life of TBCs subjected to elevated thermal exposure loads, which are of great engineering significance, but they can not achieve satisfactory life prediction accuracy in the medium-long life stages, and also can not distinguish the additional damage caused by thermal cycle. In this paper, based on the 3D-DIC technique, the spalling strain of the coating system under different thermal treatments was obtained, and it can be used as a parameter to quantify the damage of the coatings. Based on the above work, a damage model was developed, which can not only model the damage evolution of coatings but also describe the additional damage introduced by thermal cyclic behavior. Based on the proposed damage model, this paper discussed the life prediction accuracy of coatings in the medium-long life stages and compared the weight method, thickness method and the method proposed in this paper. The results show that the proposed method based on the spalling strain as the damage parameter is of great significance to improve the life prediction accuracy of coatings in the medium-long life stages.