Modeling adhesive contact behavior with interfacial displacement discontinuities

Abstract

Coatings or layers are beneficial for modifying adhesive contact behaviors. However, imperfect bonding at the layer–substrate interface due to various factors can potentially affect adhesive contact responses. This study incorporates interfacial displacement discontinuity, accounting for dislocation-like and spring-like bonding imperfections, into an adhesive contact model. Adhesive interactions are modeled by Lennard-Jones(LJ) surface force law, with the effects of imperfections captured through layer surface deformation computed via fast Fourier transform (FFT). Therefore, a model for adhesive contact on an imperfect layer–substrate system is developed, and the effects of imperfection coefficients are then examined. The results indicate that normal imperfection coefficients have more pronounced effects than tangential ones, with smaller values exerting a greater impact. Dislocation-like imperfections dominate in contact systems with higher Tabor parameters, while spring-like imperfections are more prominent in systems with lower values. These imperfection coefficients, along with material parameters such as imperfection depth (layer thickness), the layer’s work of adhesion, and elastic modulus ratios, influence the adhesive force. The imperfection coefficients alter the adhesive force magnitude but do not affect the governing relationship between material parameters and adhesive force. Dislocation-like imperfections reduce adhesive force, while spring-like imperfections can either increase or decrease it, depending on the imperfection depth. Interfacial imperfections can raise the maximum subsurface von Mises stress, compromising system reliability. These findings emphasize the effects of discontinuous displacement-type imperfections on adhesive contact and provide valuable insights for engineering applications.