Virtual material based modeling for contact stiffness characteristics of bolted joint interface

Abstract

Avirtual material modeling method of rough contact interface based on the statistical model was proposed in which the bolted joint interface was equivalent to a layer of virtual material and rigidly connected with the contact bodies. Based on the Greenwood-Williamson statistical model of the rough interface, the analytical expressions of elastic modulus, Poisson's ratio, density and thickness of the virtual material were derived. The relationship between the virtual material parameters and the surface properties was established. Effects of surface roughness and material property of contact body on the virtual material parameters as well as the interfacial contact stiffness were investigated. Modal experiment measurements and finite element analysis incorporating virtual material for a bolted joint structure were performed to validate the accuracy of the modeling method. The results show that the material parameters of virtual material are dependent on the normal load, surface roughness and matrix elastic modulus. With the increase of normal load and matrix elastic modulus, the elastic modulus of virtual material increases, and the Poisson's ratio and thickness decrease; with the increase of interface roughness, the elastic modulus and Poisson's ratio decrease, while the thickness increases. The contact stiffness of bolted joint interface increases with the increase of normal load and decreases with the increase of interface roughness.