Numerical prediction of the effective coefficient of thermal expansion of 3D braided C/SiC composite

This paper is focused on the microstructure modeling and evaluation of effective coefficient of thermal expansion (CTE) of 3D braided carbon fiber-reinforced silicon carbide composites (C/SiC). Regarding the multi-scale characteristics of the composite, the microstructure modeling is carried out sequentially from the fiber scale to tow scale. Effective elastic properties are obtained based on the sequential homogenization from the fiber scale to the tow scale. A stain energy model is developed for the prediction of the effective CTE of composite materials. This model is based on the relationship established between the strain energy of the microstructure and that of the homogenized equivalent model under specific thermo-elastic boundary conditions. Expressions of closed-form are derived for the effective CTE in terms of the strain energy and effective elastic tensor. Numerical results obtained by the proposed model show a good agreement with the results measured experimentally