A multi-scale iterative approach for finite element modeling of thermal contact resistance

Abstract

Surface topography has long been considered a key factor in the performance of many contact applications including thermal contact resistance. However, essentially all analytical and numerical models of thermal contact resistance and thermal contact conductance either neglect surface topography or make simplifications and assumptions about the nature of the surface. This work combines measured surface geometry with an iterative thermal/structural finite element model to more accurately predict microscopic and macroscopic thermal contact resistance. A commercial power electronics module which exhibits both macroscopic surface form and micro scale surface roughness is analyzed using three different macro scale surface models to verify the accuracy of the model and to demonstrate the impact of geometric surface assumptions. Finally, the factors influencing the thermal/structural behavior of bolted plates are examined and recommendations for reducing both contact resistance and the overall thermal resistance of bolted plate systems are presented.