颗粒滚动-滑动转换机制及摩擦系数的试验研究

Experimental study of rolling-sliding transition and friction coefficients of particles

颗粒间的滑动、滚动摩擦对其微观、宏观动力特性有很大的影响。在颗粒流体动力学研究中,对颗粒介质的滑动摩擦已有深刻的认识,而对滚动摩擦及其与滑动摩擦间相互关系的研究还需进一步深入。滚动摩擦的影响因素较多,且作用机理复杂,至今没有形成统一的理论。通过颗粒滑动–滚动摩擦试验,分析了颗粒表面粗糙度和形状对颗粒摩擦力的影响,初步研究了颗粒滚动–滑动摩擦的转化机制。试验结果表明:颗粒在不同的粗糙度和不规则形态影响下表现出滑动或滚动的不同运动形式,并呈现出一定的转化特性。该试验还进一步测定了颗粒滑动、滚动摩擦系数,定性地分析了颗粒的表面粗糙度和几何形态对它们的影响。

The rolling-sliding friction is important to the dynamics of granular materials on micro and macro scales.In the granular flow dynamics,the sliding friction has been investigated well,but the mechanism of rolling friction is paid less attention before.The rolling friction is influenced by many factors,and there is no unified theory to describe the rolling friction.The experiment for friction coefficients under the influences of normal loads,roughness of contact surfaces,particle shapes has been carried out;and the transition mechanism of the rolling-sliding friction is studied.It is shown that the particle performs sliding when the particle shape is quite irregular and the contact surface is too smooth;otherwise,the particle performs rolling.Moreover,the sliding friction coefficient and rolling friction coefficient are measured under various particle shapes and surface roughnesses.