Finite element simulation of residual stresses and failure mechanism of plasma sprayed thermal barrier coatings considering real interface

In order to increase the efficiency of gas turbine engines, which are used for propulsion and electricity generation, the turbine inlet temperature (TIT) has to be as high as possible. Using Thermal Barrier Coatings (TBC) allows the metallic internal components to operate at elevated temperature near to its melting temperature. Thermally growing oxide induces cracks formation in the top coat that may lead to complete failure TBC due to spallation. This research aims at investigating the development of the stresses and critical cites that have possibility of crack nucleation due to thermal mismatch during operating cycle of a typical plasma sprayed TBC. A true finite element model was developed based on a scanning electron microscope image taking the advantage of a commercial finite element package (ABAQUS) and image processing techniques. The model including the effect of creep on all layers and plastic deformation of BC, TGO and substrate. The results show that unlike common unit cell models in literature, a better understanding can be achieved by having a model based in an SEM image that represents the real geometry.