BOUNDARY ELEMENT PREDICTION OF THE FAILURE RESISTANCE OF THERMAL BARRIER COATING (TBC) SUBJECTED TO THERMO-MECHANICAL LOADING

The present study describes a sub-regional boundary element procedure for the analysis of cracked thermal barrier coatings under cyclic thermo-mechanical loads. The boundary integral equations of uncoupled quasi-static thermo-elasticity are employed to account for the transient nature of the thermal load. A crack is laid along the interface between a metallic substrate and a ceramic coating. Crack closure occurs on account of the thermal distortion and the pressure load that acts on the coating’s surface. Therefore, the heat flux between the crack faces is affected by the level of crack closure and the accurate determination of temperatures and displacements requires iterative solution of the thermal and mechanical part of the problem. The results reveal that parameters such as the coefficient of friction and thermal contact resistance have a severe impact on the predicted failure capacity of cracked structures and should be taken into consideration for the estimation of fatigue life.