Dynamic model of stationary contacts based on random variations of surface characteristics

A statistical model was developed to characterize surface profiles and calculate the density of contact spots produced when rough surfaces are pressed together. This model incorporates contact force, microhardness, and real and apparent contact area as parameters which can be varied. The effects these variables have on the number of contact spots and asperity deformation were calculated. These results were subsequently used to evaluate the impact on electrical performance of aged contacts. This was accomplished using a previously developed degradation model that utilizes the concept of a third level of constriction to simulate aging. The results indicate that both contact force and geometry play important roles in the electrical performance of aging contacts. The connection between geometry and apparent pressure was estimated using Hertz theory and indicates that one pressure can also be viewed as an important variable.<>