Finite Element Analysis for the Equivalent Stress on Three-Dimensional Multi-asperity Coating

The finite element method is applied to establish two-dimensional and three-dimensional models of elastic multi-asperity contact between the rigid plane and the coating surface. It is found that the changes of elastic modulus ratio, coating thickness, spacing of asperities and indentation depth of the rigid plane influence the total deformation and stress distribution in coating asperity and coating/substrate interface. The results show that the equivalent stress of 3D contact model is greater than that of 2D model due to the stress superposition of asperities. For 3D contact model, the effects of varied levels of indentation depth, coating thickness, elastic modulus ratio, spacing of asperities on the maximum equivalent stress are measured. And the smaller the elastic modulus ratio, indentation depth, spacing of asperities and the larger the coating thickness, the smaller the maximum equivalent stress in the coating surface. The coating/substrate bonding strength has been up-graded obviously by increasing the number of asperities and the coating thickness, reducing the elastic modulus ratio.