基于微凸体接触压力分布的粗糙表面法向接触建模

An elasto-plastic contact modeling approach is proposed to characterize the total contact load and real contact area of rough surface. The finite element method (FEM) is firstly used to analyze the elasto-plastic contact behaviors of asperity against the rigid flat. The effects of four different plastic yielding equations on the load and real area of asperity contact are analyzed. The relations between the dimensionless contact load and the dimensionless deformation calculated with four different plastic yielding equations are the same, and the solutions vary between the Hertz solution and the AF model. Based on the contact stress distributions of different contact loads, the asperity contact regime is divided into the elastic regime, the mixed elasto-plastic regime and the fully plastic regime. The increasing change of contact stress distribution is considered when obtaining the relation between the contact load and the contact deformation. Statistical analysis of the GW (Greenwood J A and Williamson J B P) model is then applied to integrate the formulations of contact load over the rough surface. The model is compared with the purely elastic model, the CEB model, the ZMC model, the KE model and the JG model, and the effect of plasticity index on the relation between the contact load and the mean contact separation of rough surface is also investigated. The results show that the proposed model can better describe the relation between contact load and deformation. The total contact load of rough surface predicted by the proposed method agrees well with the KE model and the ZMC model. With the increase of mean contact separation, the total contact load becomes smaller. The plasticity index has a great effect on the contact load predicted by different models. The difference between the total contact load of rough surface calculated by 6 elasto-plastic models is small at a lower plasticity index, while the difference is greater at a higher plasticity index, especially for the CEB model; and the CEB model predicts the largest contact load of rough surface.