Multi-scale modeling of thermal expansion coefficients of C/C composites at high temperature

In-plane and out-of-plane coefficients of thermal expansion (CTEs) are important parameters for thermodynamic analysis of Carbon/Carbon (C/C) composite. In this study, CTEs of a high performance 3D orthogonal woven C/C composite at high temperature are studied by multi-scale mechanical modeling using the finite element method. Two representative volume element (RVE) models at different length scales are used to evaluate the CTEs of the C/C material. Micro-scale model predicts the CTEs at the fibre tow scale in the three orthogonal directions (x, y and z). The output results from the micro-scale model are then incorporated in the meso-scale model to obtain the in-plane and out-of-plane CTEs of the 3D C/C composite. The modeling results have good agreement with the experimental results reported in references. Based on the numerical approach, global CTEs of the 3D C/C composite are calculated from 300 to 2500 K, and their temperature dependences are discussed. The current applied multi-scale models provide an efficient approach to predict the CTEs of 3D textile materials, which will give some highlights for thermodynamic analysis and structures design of the C/C composite.