Discrete Element Method to simulate the thermo-mechanical behavior of plasma-sprayed thermal barrier coatings during a thermal cycle

Abstract

Thermal Barrier Coatings (TBCs) are multilayer systems used in Ni-based superalloy components for gas turbine blades submitted to high temperatures resulting in the development of high thermal stresses. The intricacy of their microstructure coupled to severe environmental conditions lead to their premature failure according to complex mechanisms involving notably creep and Coefficient of Thermal Expansion (CTE) mismatch effects. This work aims to investigate the development of thermal residual stress within TBCs during a heating step using a numerical model based on Discrete Element Method (DEM). The suitability of such an approach is investigated in terms of stress field distribution in comparison to Finite Element Method (FEM). Results reveal the capability of the proposed DEM approach to simulate creep phenomenon in a TBC system under thermal loading and predict accurately thermal stresses leading to failure.

Full Paper