Prediction of the Thermo-Mechanical Contact Behaviour of a Graded Coating/Substrate System Using Advanced Numerical Techniques

Abstract

Coatings or coating combinations are widely used to increase operating life and running performance of engineering materials. Nevertheless, the development and choice of coatings is a very complex and costly task. This selection and optimization is thus based on a recursive procedure combining experimental tests and modeling. Numerical simulation is used to analyze coating behavior, tune the geometrical configuration and define optimal thermo-mechanical properties in relation with the applied stress. The objective of the current work is to develop a 3D thermo-elastic model for coatings with graded properties. Former models dealt with isotropic layers with constant properties adhering perfectly. These last assumptions result in discontinuities in stress and temperature fields at the interface between successive layers. The increasing use of interface layers between coatings and substrates requires theoretical models to predict the thermomechanical behavior of such graded coatings. The gradation in properties of the material reduces induced thermomechanical stress discontinuities. Multigrid techniques are used to improve solver efficiency, reduce CPU time and thus permit the use of fine grids to accurately describe the variations in elastic properties.