Study On Dynamic Characteristics Of 3D C/SIC Composite Structures

As a kind of advanced composite material, the three-dimensional braided carbon fiber reinforced silicon carbide matrix composite (3D-C/SiC) has many excellent properties. The ability of 3D-C/SiC composite to maintain its strength and stiffness at high temperatures as well as low density make it an attractive candidate for many applications in future aerospace vehicles. Nowadays researches about 3D-C/SiC composite on micro-structure analysis and micro-structure model are becoming more and more important.The purpose of this paper is to establish and develop a cell model to simulate the micro-structure of 3D four-direction C/SiC composite. 3D-C/SiC composite is considered as a spatial structure, which is made up of cyclic and repeating cell models and contain matrix and fibers. In this paper, a 3D- C/SiC composite beam is analyzed. The cell models are used for meshing the beam. Based on the cell model, dynamic properties of the composite cantilevered beam are calculated using finite element method. The theoretical dynamic property result of the beam is also obtained. Results show this model is suitable for analyzing dynamic properties of a C/SiC composite structure.There are lots of voids in 3D-C/SiC composite. The voids are one of the most formidable obstacles to the mechanical properties of 3D-C/SiC composite. It's therefore necessary to analyze the effect of voids on composite structure dynamic property. In this paper, the random voids are simulated by MONTE CARLO method. The cell model with voids is constituted geometrically and used for meshing a 3D-C/SiC composite beam. The modal parameters are obtained through modal analysis in finite element software ANSYS. Analysis results present that the natural frequencies of the beam decrease because of the voids in it.The mechanical performances of 3D-C/SiC composite correlate with many influencing factor. In this paper, 3D-C/SiC composite beam model with random physical parameters is set up. The problem of dynamic analysis based on reliability for the composite structure is studied. Considering the randomness of both elastic...