Abstract

This paper aims at investigating the potential and benefits of the Discrete Element Method (DEM) to predict failure mechanisms leading to interface delamination and fracture in air plasma sprayed Thermal Barrier Coating (TBC) systems. A hybrid lattice-particle approach is proposed to predict residual stress fields due to Coefficient of Thermal Expansion (CTE) mismatch and combined with a mixed-mode Cohesive Zone Model (CZM) to simulate interface delamination during the cooling-down phase. Numer ical calculations are first performed using a unit cell model with a perfectly sinusoidal interface profile, which comes from other contributions, in order to attest the suitability of the proposed DEM-based approach for that purpose. The case of a real microstruc ture is then discussed via an image processing based model which underlines the effect of porosity and surface roughness on the failure mechanism.