Fractal Theory Model of the Joint Interface During Loading and Unloading Considering Friction Factors

Abstract

On the basis of the elastic, first elastic-plastic, second elastic-plastic and plastic deformation states of asperity, and considering the influence of friction factors, we established a fractal theoretical model of contact area and contact load of a single asperity during loading and unloading at each deformation stage. Parameters were introduced: distribution density function correction coefficients Ce, Cep1, and Cep2, and contact load correction coefficients De, Dep1 and Dep2, of the joint interface at each deformation stage, and then the actual contact area and contact load fractal theoretical models of the loading and unloading process of the joint interface at each deformation stage under the consideration of friction factors were deduced. According to the models, the actual contact area and contact load of the joint interface in the loading-unloading process are related to the friction correction factor, yield limit, equivalent elastic modulus, contour parameter, fractal dimension, and frequency parameter of rough surface, while those in the unloading process are also related to the maximum deformation and residual deformation after unloading.

Keywords

• joint interface
• fractal theoretical
• unloading
• friction factor