Flexible Performance Prediction Of Three-dimensional Woven C / Sic Composites

As a kind of advanced composite materials, three-dimensionally braided structural composites have distant structure that is fully integrated, continuously spatial fiber-network impregnated with matrix material. Because of their enhanced stiffness and strength in the thickness direction, near-net-shape design and manufacturing, superior damage tolerance and specified aerospace function, the braided composites are gaining more and more attention of industry and academia. In this dissertation I research the geometric structure of three-dimensionally braided composites and more build the unit cell (the obliquity model). According the theory of layer board we can obtain equations to calculate elastic constants. Three-dimensionally braided C/SiC composite materials differ from resin matrix composites. Firstly, the modulus of fiber is lower than that of matrix. Secondly, the moduli of carbon fiber have much drop after sedimentated by pyrolytic carbon and pyrolytic silicon carbon at high temperatures. The last, much cavity lies without forecast. To a certain extant, these factors influence the elastic of three-dimensionally braided C/SiC composites. The relevant computer procedure is programmed that can forecast the elastic constants of three-dimensionally braided structural composites(CVSiC); at the same time I analyze and discuss the result. In addition, we try a lot of mechanics experimentations that can validate the dependability of theoretic analysis.