SICF/SIC stiffness prediction, thermal residual stress and progressive damage simulation by micro-mechanics model

Ceramic matrix composites (CMCs, e.g.SiCf/SiC) are applied widely in hot-section components of aeronautics and astronautics. The macroscale mechanical properties of CMCs can be easily obtained by standard tests. Likewise, the thermal residual stress created during preparation can be monitored by experimental means. However, in the material design stage, it will result in waste only through testing validation, and especially a few parameters need to be optimized and determined. Precise virtual simulation technology (VST) is extremely useful on predicting materials' performance and giving optimal strategies to materials designers. Under this mean, the present work is mainly focusing on predicting the macro-stiffness and thermal residual stress (TRS) for SiCf/SiC composites. 3D micro-structure finite element analysis (FEA) methods are applied to representative volume elements (RVE). Period boundary condition (PBC) is adopted in the RVE to make stiffness prediction, which cannot be utilized in the deformation of thermal expansion. The microscale RVE model can be used to calculate the elastic modulus in fiber direction and two fiber's normal directions, as well as shear modulus of in-plane and out-plane. Distributions of radial, hoop, axial and shear TRS in fiber, interphase and matrix are analyzed profoundly. Besides, in the 3D microscale FEA model specialized for TRS calculation, parameters effects of homogeneous and anisotropic interphase modulus and interphase thickness are investigated. The models are not only adapted to SiCf/SiC composites, but also to the other fiber toughened CMCs foremost.