不同真空度气体对粗糙表面接触摩擦的影响

在大气压作用下,通过对不同真空度下接触物体表面摩擦力的测量,研究气体对粗糙接触物体表面摩擦的影响,该实验采用的摩擦副材料是铝合金/有机玻璃、45钢/有机玻璃。实验结果显示:随着真空度的增大,2种摩擦副的摩擦力近似呈现线性变化,静摩擦因数则先减小而后趋于稳定,再有回增的趋势;45钢/有机玻璃摩擦副静摩擦因数取得最小值所对应的真空度比铝合金/有机玻璃摩擦副的更大。通过分析得出静摩擦因数变化的原因:随着真空度的增大,摩擦副接触间隙间的气体密度减小,当固体刚开始运动时,产生摩擦的气体分子与固体表面的分子减少;随着真空度的增大,正压力增大,材料的变形程度增大。

Effect of Gas at Different Vacuum on Rough Surface Contact Friction

By measuring the tangential load on the surface of different vacuum contact object under the action of external pressure,the effect of gas on the surface friction of rough contact object was studied.The friction pair material used in this experiment is aluminum alloy/plexiglass,45 steel/plexiglass.The experimental results show that the friction force of the two friction pairs shows nonlinear variation with the increase of external pressure,while the static friction coefficient of the two friction pairs is first decreased,then tends to be stable,and then is increased again.The vacuum degree corresponding to the minimum value of static friction coefficient of the 45 steel/plexiglass friction pair is larger than that of the aluminum alloy/plexiglass friction pair.The reasons for the change of static friction coefficient are as follows:with the increase of vacuum degree,the density of gas molecules between the contact clearance of friction pair is decreased,which causes the decrease of the number of gas molecule and solid surface molecule that produce friction when the solid begins to move;with the increase of vacuum degree,the positive pressure is increased,which causes the increase of the deformation degree of the material.