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

• Coefficients of thermal expansion of C/C composites were calculated from 300 K to 2500 K.
• A multi-scale thermomechanical simulation approach to obtain desired coefficients of thermal expansion of textile composites was proposed.
• Architecture of a 3D woven C/C composite was investigated by μCT and SEM, manufacture defects inner the composite were statistically studied.
• Multi-scale model of the C/C composite with void defects was constructed, which will be helpful for thermomechanical properties analysis of textile composites.

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.

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