Multi-scale finite element analyses on the thermal conductive behaviors of 3D braided composites

The thermal conductive behaviors of 3D braided composites along in-plane and out-of-plane directions were characterized and analyzed by multi-scale finite element analyses (FEA) and also validated by experimental. Micro-scale representative volume element (RVE) was used to calculate the thermal conductivities of braiding yarns, and the meso-scale RVE and full-scale braided model were developed to research the thermal conductive behaviors of the whole braided composites. The differences of the two models are also analyzed in this paper. Another attention of this paper was focused on revealing the thermal conductive structural effects of braided composites. It is found that the thermal conductivities along out-of-plane direction are larger than that of in-plane direction. The temperature distribution and heat flux transmission are mainly along fiber orientation direction. With the increment of temperature, the thermal conductivities of the braided composites are increased. As the existence of surface and corner regions, the thermal conductivities calculated from full-scale model are closer to experimental by comparison with meso-scale RVE. In addition, the temperatures in interior regions are slightly higher than those in surface and corner regions of the braided composites. This paper could make for further understanding the thermal conductive behaviors of braided composites.