微凸体切向滑移特性

为了从微观角度探究粗糙表面的切向滑移特性,构建一种具有回转抛物体形状的微凸体切向滑移有限元模型.该模型综合考虑了材料的弹性、弹塑性变形和塑性变形特征,分析整个切向滑移过程中切向、法向合力分别随切向、法向位移等参数的变化规律,并给出接触载荷的无量纲化拟合公式；推导了基于Kogut弹塑性(KE)模型的侧接触力学模型,并用该理论解释切向滑移特性.分析表明：KE模型侧接触模型仅仅适用于小变形范围；切向滑移位移越大,切向的塑性流动越大,KE模型侧接触模型与仿真模型的误差也越大；另外,载荷的最大值、最小值和均值都表现出了明显的变化规律.微凸体切向滑移特性的仿真分析以及侧接触理论研究为粗糙表面接触特性的研究奠定了基础.

Tangential sliding characteristics of asperities

In order to investigate the micro tangential sliding characteristics of rough surfaces, a nite element analysis (FEA) model with the shape of the rotary parabola was proposed to simulate tangential sliding of asperities. The model can deal with the deformation mechanism of elastic, elastic-plastic and plastic. The effects of the tangential and normal distance on the tangential and normal force were discussed in the whole tangential sliding process. Based on the results, the fitting formula of the dimensionless variation of the load was presented. Using the Kogut’s elastic-plastic model named KE model, the shoulder to shoulder contact model was deduced to explain the sliding characteristics. It is shown that the KE shoulder to shoulder contact model is valid for the case of small deformations. However, for the large sliding distance, the plastic flow along the slip direction increases with the increasing sliding distance, and the errors between KE model and the FEA model become larger. In addition, the maximum, the minimum and the mean value of the loads have obvious change trends. The simulating and theoretical research of the sliding characteristics between asperities provides a foundation for the study of the sliding characteristics between rough surfaces.