一种考虑侧接触的微凸体弹塑性接触力学模型

Elastic-Plastic Model for Contact of Two Asperities Considering Shoulder-Shoulder Contact

为了准确预测复杂机械系统装配界面的接触特性,构建了一种考虑侧接触的微凸体弹塑性接触力学模型。利用塑性流动下体积守恒的原理,解决了单对微凸体在侧接触形式下接触力学模型难以表征的问题。以微凸体接触力学模型为基础,通过引入微凸体接触点处的等效曲率半径参数,结合装配界面微凸体、装配界面压力的分布规律,将微凸体接触特性扩展到复杂机械系统的整个装配界面。与弹性-塑性接触模型在接触载荷方面的预测结果比较表明,提出的微凸体侧接触弹塑性力学模型与弹性-塑性接触模型在弹性接触载荷预测方面基本相同,但在完全塑性接触载荷预测方面存在较大差异,且两者预测结果的差距随塑性指数和载荷的增加而增加,因此所提出的模型在完全塑性接触载荷预测方面更为接近有限元分析的结果。

To precisely predict the contact performance of assembly interface in complex mechanical system,an elastic-plastic model considering shoulder-shoulder contact of two asperities is presented,which solves the difficulty in shoulder-shoulder contact modeling of asperity under the assumption of volume conservation in the plastic flow regime.Introducing the equivalent radius of curvature at a contact point between two asperities and considering the distributions of surface roughness and contact pressure,the prediction of contact behaviors can be spread from the asperities to the assembly interface in complicated mechanical system according to the proposed model.The numerical results of estimating contact force with the proposed model and the Elastic-Plastic Model show that both predictions for elastic contact force get coincident but obviously different for purely plastic contact force,and the difference increases with plastic degree.The prediction with the proposed model,compared with that with CEB,approaches to finite element analysis more closely.