Empirical relationship between interfacial shear stress and contact pressure in micro- and macro-scale friction

This study examines the empirical relationship between frictional shear stress and pressure in macroand micro scale contact and sliding. Two types of friction tests are reported; the macro-scale tests deal with kinetic friction between stainless steel surfaces in a vapor phase lubrication condition, and the micro-scale tests measure kinetic friction at interfaces formed between MoS2 basal planes and surfaces of alumina or stainless steel specimens, using a quartz crystal microbalance microtribometer. A numerical model is used to calculate the contact areas in the macro-scale tests. The results from both friction tests confirmed that the interfacial shear stress in the contact area due to kinetic friction is proportional to the average contact pressure, and the constant of proportionality is close to the coefficient of friction (COF). These observations add to the validation of the Amontons' law.

本研究考察了宏观和微观尺度接触与滑动中摩擦剪应力和压力之间的经验关系。报告了两种类型的摩擦试验；宏观尺度试验涉及气相润滑条件下不锈钢表面之间的动摩擦，微观尺度试验使用石英晶体微天平微摩擦计测量二硫化钼基面与氧化铝或不锈钢试样表面之间形成的界面处的动摩擦。一个数值模型被用于计算宏观尺度试验中的接触面积。两种摩擦试验的结果都证实，由于动摩擦在接触区域产生的界面剪应力与平均接触压力成正比，且比例常数接近摩擦系数。这些观察结果进一步验证了阿蒙顿定律。