Electro-thermo-mechanical Contact Analysis Considering Temperature Dependent Material Properties and Electrical Contact Resistance Determination

Electrical contact mechanics behaves in a complex way and the effect of temperature makes the contact behavior more complicated. To analyze the temperature dependent contact behavior an axisymmetric sinusoidal asperity model of tin has been developed using Finite Element method. The axisymmetric sinusoidal model reduces computational expenses and can effectively consider the asperity interaction, which is an important factor for large elastic-plastic deformation. The model considers temperature dependent yield strength, thermal conductivity and resistivity. Effect of thermal expansion co-efficient is also included. For material modeling, Johnson-Cook material model has been used which can model the temperature dependent material behavior from room temperature to melting temperature. Results show that temperature dependent resistivity and thermal conductivity are the key factors that govern the contact mechanism and temperature dependent yield strength has negligible effect on the electrical contact behavior. The finite element results have been validated comparing the results with the closed form solutions available for voltage-temperature relation. Later an equation has been suggested for the electrical contact resistance (ECR) determination, modifying the current equation derived by Greenwood and Williamson. The equation should be able to predict the contact resistance from room temperature to high temperature cases.