CRITICAL REVIEW OF ELASTIC CONFORMING ROUGH SURFACE MODEL WITH ADHESION AND ITS APPLICATION TO PREDICT THERMAL AND ELECTRICAL CONTACT RESISTANCE

摘要

Adhesion dominates at low contact pressures and the study of rough surfaces has received considerable attention due to advances in design and fabrication of micro and nano devices. It has been seen by a number of researchers that real area of contact cannot be accurately predicted at low contact pressures. This paper focuses on the asperity contact physics at low loads. As a first step, the single asperity adhesion model is expressed in dimensionless forms with size and depth of indentation as function of load. These relationships were then incorporated in the real area and load expressions of the rough surface model. It is found that a dimensionless surface energy parameter γ{sup}* = γ/(E'β) and three other surface parameters were required to implement the model. Most of the surface parameters are strongly dependant on the sampling interval. Hence a methodology is developed to incorporate the effect of sampling interval. The results of the surface adhesion model were then incorporated into the Thermal Contact Conductance (TCC) and Electrical Contact Resistance Models (ECR). Then the TCC model is used to predict experimental results for Ni200 and SS304 interfaces. Comparison of model against data shows that Ni200 data is closer to γ{sup}* = 10{sup}(-3) and SS304 data is closer to γ{sup}* = 10{sup}(-6). In general there is a trend for low load data to lie closer to the larger value γ{sup}* than the higher load data. One important conclusion is that low load may not refer to low contact pressure or load but refers to higher interface separation. A second important conclusion is that the surface parameter variation due to sampling interval plays a larger role than the adhesion parameter itself.