Thermal Conductivity Prediction of SiC/Silicone Rubber Composites Using Combined Separate Axis Theorem-Finite Element Model

High thermal conductive composites are widely used for heat dissipation, where suitable filling schemes are needed to meet the application requirements. In this study, a thermal conductivity prediction model with higher accuracy is developed to guide the preparation of composites. With experimental tests and simulations, the impacts of fillers on the overall thermal conductivity are investigated. Separation axis theorem is introduced to calculate the filler contact probability, with the aim of further explaining the impact mechanism of the filling scheme. It is found that increasing the filling volume fraction can promote the formation of inter-filler thermal conductivity pathways. The filler contact probability is approximately proportional to the composites thermal conductivity in our research, based on which the multiple connection mechanism prediction model is built. The average prediction accuracy of the new model considering the log-normal distributed size fillers is 96.8%.