A kind of unit cell for 2.5 dimension C/SiC composites was established by extracting the boundary of warp

fitting the curve using robust least square and simplifying the fitted curve.The elastic properties of 2.5 dimension C/SiC composites were predicted using dual-scale model;the dual-scale model was micro-scale which considered the scale of matrix/fiber/pore

and also meso-scale which considered the scale of warp/weft/cavity.The method for predicting the elastic properties of 2.5 dimension C/SiC composites was stiffness average method and energy method;finally the relationship between the porosity in the micro-scale and the elastic properties of 2.5 dimension C/SiC composites was discussed.Numerical results show that the theoretical results using energy method and stiffness average method have little difference;when considering the micro-scale porosity

the theoretical results can fit the experimental results better.