Anisotropic Thermal Conductivity of Carbon-fiber/epoxy Composites

In this paper, the anisotropic heat transfer property of carbon-fiber/epoxy plain woven and twill woven composites is studied experimentally and numerically. In the experiment aspect, the steady-state "sandwich" structure based on the electric heating film is used to measure the out-of-plane and in-plane thermal conductivity at different temperature. In terms of simulation, a representative unit cell is established according to observation of the interior micro-structure of composite, and then anisotropic thermal conductivity along different principal axis can be obtained by simulating the 1D steady-state heat transfer process within the model in the three-dimensional direction, respectively. The results show that both the out-of-plane and in-plane thermal conductivity of carbon-fiber/epoxy composites increase linearly with the hot surface temperature of composites, and the in-plane thermal conductivity is approximate 2.8 times as high as the out-of-plane thermal conductivity. The thermal conductivity deviation between the plain woven and twill woven composites along different main axis is less than 10% due to the similar density. The numerical prediction result agrees with the experimental result and the sources of leading to the deviations are also discussed.