Estimating Thermal Contact Resistance Using Sensitivity Analysis

Characterization of the thermal contact resistance is important in modeling of multi-component thermal systems which feature mechanically mated surfaces. Thermal resistance is phenomenologically quite complex and depends on many parameters including surface characteristics of the interfacial region and contact pressure. In general, the contact resistance varies as a function of pressure and is non-uniform along the interface. A two dimensional model problem is solved analytically for a known contact resistance between two mated surfaces. The results from the analytical solution are compared with a boundary element solution to the same problem, thus verifying the implementation of the boundary element method code. An inverse problem is formulated to estimate the variation of the contact resistance by using a boundary element method to determine sensitivity coefficients for specific temperature measurement points in the geometry. Temperature measured at these discrete locations can be processed to yield the contact resistance between the two mating surfaces using a simple matrix inversion technique. The inversion process is sensitive to noise and requires using a regularization technique to obtain physically possible results. The regularization technique is then extended to a genetic algorithm for performing the inverse analysis. Numerical simulations are carried out to demonstrate the approach. Random noise is used to simulate the effect of input uncertainties in measured temperatures at the sensors. Copyright © 2004 by ASME