Statistical Model of Normal Contact Stiffness of Fixed Joint Surface during Unloading after First Loading

Donghua Yin,Yonghui Chen,Xueliang Zhang,Yanhui Wang,Shuhua Wen,Guosheng Lan,Jun Liu

doi:10.1155/2021/6626727

Abstract

Based on Kogut and Etsion’s model (KE model), a statistical method is used to establish a model of normal contact stiffness of fixed joint surface during unloading after first loading. Simulation results show that, for the elastoplastic contact, normal contact stiffness of joint surface is the nonlinear function of mean surface separation during loading and unloading and decreases as the separation increases. For different plasticity indexes, the normal contact stiffness of joint surface varies differently following the change of mean surface separation during loading and unloading.

Highlights

Based on Kogut and Etsion’s model (KE model), a statistical method is used to establish a model of normal contact stiffness of fixed joint surface during unloading after first loading
Simulation results show that, for the elastoplastic contact, normal contact stiffness of joint surface is the nonlinear function of mean surface separation during loading and unloading and decreases as the separation increases
Because deformation mechanism has an important influence on the normal contact stiffness of fixed joint surface in the elasticplastic contact problem, the accuracy degree of the model obtained by fitting the finite element analysis curve of each stage of elastic-plastic contact evolution has a great influence on the normal contact stiffness

Summary

Model of Normal Contact Stiffness of a Single Asperity

Model of Normal Contact Stiffness of a Single Asperity during Loading. Erefore, the critical contact load of a single asperity pc that marks the transition from the elastic to the elasticplastic deformation regime can be expressed as follows: pc. According to equation (2), the normal contact stiffness of a single asperity during loading kel is given by kel dpel dω. The normal contact stiffness of a single asperity during this loading is obtained as follows: kepl. Model of Normal Contact Stiffness of a Single Asperity during Unloading. When ωmax ≤ ωc, the normal contact load peu and the normal contact stiffness keu of the asperity during unloading can be expressed as follows: peu. By substituting equations (12), (13) into equation [11], respectively, and making further differentiation, the unloading stiffness of an elastic-plastic deformable asperity can be deduced as follows: kepu.

Statistical Model of Normal Contact Stiffness of Joint Surface

Simulation and Result Analysis of the Model

Findings

Conclusions