Prediction of residual stress and damage in thermal spray coatings using hybrid computational approach

Due to the multilayered pattern of coating deposition, numerical prediction of residual stress and damage in thermal spray coatings (TSCs) has been challenging. Several numerical approaches previously used failed to capture essential aspects such as deposition stress build-up, presence of heterogeneities, and influence of process parameters. In the present study, a hybrid computational approach which combines “point cloud” (PC) and finite elements (FE) has been used to model the spray process as well as the evolution of residual stress and damage. Smooth particle hydrodynamics (SPH) is used to model multiple droplets deposition and associated deformation on PC. Then, several recent algorithms (for point cloud processing) are used to convert the deformed droplets (in form of PC) into FE domains (i.e. splats). The FE mesh of deposited splats is used for thermo-mechanical finite element analysis where the evolution of temperature, residual stress and damage is predicted on simulated coating microstructure. By comparing our numerical results with that of previous works, the hybrid approach has been found to be a viable tool for quantitative assessment of residual stresses and failure in TSCs.