Effect of Surface Asperity on Interfacial Contact Process Controlled by Power Law Creep—Numerical Study of Viscoplastic Adhering Process

Abstract

An interfacial contact process due to power law creep is studied using a finite element technique. The contact process is assumed to be produced by power law creep alone after initial intimate contact by instantaneous plastic deformation, i.e., no diffusional mechanisms for void shrinkage are taken into account. Also, the surface oxide film is not considered. If the bonded material is deformed, then the deformation is influenced by the initial faying surface wauiness with the asperity angle αo , and the contact process is achieved by two modes; surface folding at the bond-interface (type I) and interfacial expansion (type II), where the surface folding is the phenomenon that two faying surfaces are overlapped to each other. The surface folding phenomenon occurs preferentially when αo is less than 30 deg (as the surface wauiness height decreases). On the other hand, the interfacial expansion is dominant at αo > 45 deg. This can be explained in terms of the distribution of equivalent strain (stress) in the vicinity of the bond-interface.