A cross-scale method for predicting equivalent elastic constants of needled C/SiC composite considering manufacturing defects

For the ceramic matrix composites, manufacturing defects are the key issues that make their elastic constants difficult to predict. A method is proposed to predict equivalent elastic constants of needled C/SiC composite. This method consisted of multiscale model construction and cross-scale analysis. In the model construction, two types of manufacturing defects, pore and fiber deflection, were analyzed and characterized in two scale models. In the cross-scale analysis, theoretical prediction method was used to link the microscopic and mesoscopic scales. The periodic boundary condition method was used to link the mesoscopic and macroscopic scales. The comparison between the predicted results and the experimental data showed that the method considering manufacturing defects was in great agreement with experiment. By discussing the effects of different manufacturing defects on the elastic constants of needled C/SiC composite, it was demonstrated that manufacturing defects in needled C/SiC composite played an important role in dispersion of material properties. Reducing the number of manufacturing defects by optimizing the relevant process parameters can improve the dispersion of material properties.