Contact Pressure and Current Density Distribution in a Circular Contact Surface

The influence of the axisymmetric contact pressure distribution on the current density in the circular contact surface between two conducting semi-infinite bodies was theoretically analyzed by using the newly proposed mechanical asperity contact model and the electrical current flow model. The results of this study revealed that the shape of the nominal current density distribution approximates to the distribution shape of the contacting pressure but the current density on a microcontact approximates to the inverted shape of the contacting pressure, and that the effect of the pressure distribution shape on the overall contact resistance is not negligible and must be considered, when the mean pressure level is lower than several percentages of the hardness (i.e., contact hardness or Meyer's hardness) of contacting materials. On the other hand, increasing mean pressure level causes both the current densities to increase, as approaching the contact surface margin, and the effect of the pressure distribution shape on the overall contact resistance to weaken.