Numerical prediction of effective thermal conductivities of 3D four-directional braided composites

The temperature distribution in a representative volume element of three-dimensional and four-directional braided composites is studied with appropriate boundary conditions by the finite element method (FEM) to predict the effective thermal conductivity of the composite. Models with elliptical, circular and hexagonal cross-section of braiding yarns are considered. The model is validated by experiments based on hot disk thermal constant analyzer. The influences of fiber volume fraction Vf, and interior braiding angle γ, on heat transfer of the composite are studied with Vf equal to 0.40, 0.50 and 0.58, and γ from 15° to 50°. The results show that for the composite studied increasing fiber volume fraction results in higher thermal conductivity in both axial and transverse direction, while a larger interior braiding angle leads to higher transverse thermal conductivities but lower axial ones.