Splats Formation, Interaction and Residual Stress Evolution in Thermal Spray Coating Using a Hybrid Computational Model

Due to the multilayered pattern of coating deposition, residual stresses are commonly developed in thermal spray coatings (TSCs). The large deformation, complex interaction and material mismatch are the main contributing factors to residual stress formation. The constitutive behavior and lifetime are directly dependent on the nature and extent of the residual stress field. In the present study, a computational approach for effective prediction of residual stress evolution in TSCs has been proposed. The proposed approach is hybrid in the sense that it combines “point cloud” (PC) and finite elements (FE) to model the residual stresses. Sprayed droplets deposition and associated deformations are captured on PC using smooth particle hydrodynamics, a popular meshless approach for modeling of violent fluid flows. The conversion of deformed droplets from PC to FE domains is done using several recent algorithms for point cloud processing. Then, conventional FE schemes are used to model the heat transfer and structural deformation occurring during the process. The proposed approach has been found to be effective in predicting residual stress evolution in thermal barrier coatings (TBCs). It can capture the effects of microstructural defects (such as pores and cracks) and interaction of process parameters on residual stress distribution.