Evaluation of thermal conductivity of CNT composites using a modified representative volume element (RVE) approach

Thermal conductivity is considered to be an important property in selecting heat transfer devices. In composite materials, the thermal properties can be improved substantially by changing process parameters, type and orientation of the reinforcing materials. One of the best candidate as a reinforcing material is carbon nanotubes (CNT). Utilizing the superior properties of CNTs offers exciting opportunities for new composites. Based on the reported values of CNT, 10% is enough to produce a composite product with heat conductivity coefficient comparable to many metallic counterparts. In the proposed work, the main focus will be on the numerical modeling of nanocomposites using a modified RVE approach. In this approach the CNT is modeled as FE line elements instead of the traditional way of modeling the CNT as a cylindrical volume. The air trapped inside the CNT is accounted for using the rule of mixture. The proposed approach is more effective and allows the simulation of more complex components by reducing the number of FE elements while maintaining the same level of accuracy. The modified RVE approach is validated and used to predict the thermal conductivity of various cases with different dispersions and number of CNTs.