Adhesive contact analysis for anisotropic materials considering surface stress and surface elasticity

In this study, an adhesive contact problem for anisotropic materials is analyzed by considering surface stress and surface elasticity. The displacement field on the surface is obtained from the surface Green’s function considering the surface stress and surface elasticity. The displacement due to the adhesive force, i.e., the van der Waals force, calculated from the Lennard–Jones potential is used in the analysis. The adhesive force is calculated from the distance between two surfaces. First, an adhesive contact problem of a rigid spherical indenter and an isotropic substrate with various material properties is analyzed under a condition in which no surface mechanical property is considered, and the results are compared with the Johnson–Kendall–Roberts theory in order to validate the calculation algorithm of the analysis. Next, a substrate with orthotropic properties is subjected to adhesive contact analysis. When the elastic modulus in the normal direction to the substrate surface increases, the maximum adhesion force increases, similar to the case of the isotropic substrate. However, when the elastic modulus in the tangential direction of the substrate surface is varied, the maximum adhesion force does not vary much. Finally, an anisotropic half-substrate is subjected to adhesive contact analysis considering the surface mechanical property. This analysis reveals that when the values of the surface mechanical property are varied, the maximum adhesion force changes, similar to the case of varying the elastic modulus in the tangential direction of the surface.