Abstract: Aiming at the prediction of mechanical properties of 3D four-directional carbon/carbon composites, a microstructure model was established based on the multi-scale analysis method of parameter transfer, and the prediction of basic mechanical properties was realized by combining micromechanics. Firstly, the yarn representative volume element (RVE) model was constructed by using the random disturbance algorithm at the microscopic scale, and the effective performance parameters of the fiber bundle were predicted. At the same time, the 3D four-directional carbon/carbon composite meso-RVE model was constructed by observational test method. Finally, the elastic performance parameters of composites were accurately predicted by homogenization theory, and the influence of yarn filling factor on the elastic performance parameters of 3D four-directional carbon/carbon composites was discussed. The results show that the error between the tensile simulation prediction results and the experimental results of the multi-scale finite element model established in this paper is about 5.5%; the sensitivity of elastic properties of composites to yarn filling factor is different.

Key words: 3D four-directional carbon/carbon braided composites, multi-scale analysis, RVE model, elastic performance parameters, yarn filling factor