Effects of interface roughness on residual stresses in thermal barrier coatings

Using a newly developed object-oriented finite-element analysis method, bot h an actual microstructure and model microstructures of a plasma-sprayed th ermal barrier coating system were numerically simulated to analyze the full field residual stresses of this coating system, Residual stresses in the ac tual microstructure were influenced by both the irregular top-coat/bond-coa t interface and cracks in the top coat. By treating the microcracked top co at as a more-compliant solid microstructure, the effects of the irregular i nterface on residual stresses were examined. These results then could be co mpared to results that have been obtained by analyzing a model microstructu re with a sinusoidal interface, which has been considered by some earlier i nvestigators.