Multi-Scale Modeling and Tensile Failure Prediction of 3d Needled C/C-Sic Composites Considering Real Microstructure

Abstract

Three-dimensional (3D) needled C/C-SiC composites have the significant advantages of low density, high strength, and long lifespan, which are widely used in aerospace and other industrial fields. In this paper, based on the microstructure of the composites, a multi-scale finite element model is established to predict their mechanical properties and failure behaviors under the tensile load. The multi-scale model has been validated by the static tensile test and the microstructure of fracture. With this model, the effects of the fiber volume fraction, the interfacial bonding strength, the content of residual Si elements, and the porosity on the mechanical properties of needled C/C-SiC composites are systematically analyzed. The results show that the stress-strain curve of the composites under the longitudinal tensile load has two nearly linear segments. The final failure strength of the composites increases with the increase of the interfacial bonding strength, the fiber volume fraction and residual Si elements, while decreases with the increase of the porosity. In addition, based on the established multi-scale finite element model, the damage evolution process and failure mechanism of the needled composites are investigated in detail. The proposed scheme could effectively predict the mechanical properties of the needled C/C-SiC composites and capture the microscopic damage evolution, which would help to optimize the design of composites.

Keywords: 3D needled C/C-SiC composites, Multi-scale approach, Mechanical properties, Failure analysis, Finite element analysis, Progressive damage