Influence of near-interface cracks on the stress around the TGO in the thermal barrier coatings during thermal shock: a numerical simulation study

In this paper, the influence of near-interface cracks on the stress around the TGO in the thermal barrier coatings (TBCs) during thermal shock has been calculated using finite element method. The investigation results indicate that the maximum tensile stress was located at the valley of the TC/TGO interface and the crest of the TGO/BC interface when there are no cracks. The existence of the horizontal crack and vertical crack can release this type of stress concentration, while the stress concentration also existed at the crack tip, and the influence of horizontal crack and vertical crack on the stress around the TGO are different. The influence of the horizontal crack on the stress in the through-thickness direction (S22) around the TGO seem less compared with the vertical cracks. Especially, the failure often occurred above the TGO resulting from the propagation of the horizontal crack along the interface direction.