Abstract
A finite element analysis code was developed to accurately predict stress and damage fields in thermal barrier coatings (TBCs) systems subjected to thermo-mechanical fatigue loadings (TMF loadings). A modified inelastic constitutive equation for the TBCs and a Chaboche-type viscoplastic constitutive equation for Ni-based super alloy (IN738LC) were installed to simulate high temperature creep and cyclic deformation. In addition, an alternative algorithm for simulating fatigue crack propagation based on a damage parameter was developed. In this report, analyses of the TBC/IN738LC system subjected to in-phase and out-of-phase TMF loadings which has been often used to investigate the damage mechanism of TBC were performed using the developed analysis code. The results confirmed that stress and damage distribution in the TBC/IN738LC system can be appropriately simulated. From the analysis results, it was found that crack initiates at the top coat surface and propagates for the top coat/bond coat interface in the in-phase loading analysis. On the other hand, crack initiates and propagates along the top coat/bond coat in the out-of-phase analysis.
