Numerical evaluation of effective elastic properties of CVI-C/C composites considering anisotropic matrix

The elasticity of carbon/carbon (C/C) composites is strongly dependent on the properties of pyrocarbon. Carbon planes of pyrocarbon prepared by the chemical vapor infiltration (CVI) method orient along the axial direction of fibers, leading to the anisotropy of pyrocarbon. This paper proposes a novel numerical model to accurately predict the effective elastic properties of C/C composites with anisotropic pyrocarbon. At first, the porepyrocarbon system is homogenized as an equivalent matrix. The equivalent matrix is then partitioned using a pyrocarbon micromorphology-based modified Voronoi tessellation method. Meanwhile, the cohesive elements are introduced to capture the interphase effect on the effective elastic properties of C/C composites. Regarding the prediction of the effective elastic properties of unidirectional C/C composites and short carbon fiber reinforced pyrocarbon (Csf/C) composites, the proposed model is validated by analytical and experimental results. Additionally, the results show that increasing interphase stiffness improves the effective elastic properties of C/C composites while an increase in porosity reduces the effective elastic properties of C/C composites.

Automated summary

This paper proposes a novel numerical model to accurately predict the effective elastic properties of C/C composites with anisotropic pyrocarbon. The model homogenizes the pore-pyrocarbon system as an equivalent matrix and divides it using a modified Voronoi tessellation method based on pyrocarbon micromorphology. Cohesive elements are introduced to capture the interphase effect on the effective elastic properties of C/C composites.