2.5维C/SiC复合材料单胞模型及刚度预测

通过提取2.5维C/SiC复合材料经纱边界曲线,采用鲁棒最小二乘拟合得到了经纱轴向函数表达式,对拟合后的曲线进行合理简化,建立了参数化的2.5维C/SiC复合材料的有限元模型.采用双尺度模型对2.5维C/SiC复合材料进行刚度预测,分别为考虑纤维/基体/孔隙的微观尺度和考虑经纱/纬纱/孔隙的单胞尺度模型,刚度预测的方法采用刚度平均法和能量法.最后讨论了微观尺度的孔隙率对2.5维C/SiC复合材料弹性模量的影响.结果表明,刚度平均法和能量法的计算结果差异较小,考虑微观孔隙率后,计算结果与试验结果吻合得更好. 

Unit cell of 2.5 dimension C/SiC and its stiffness prediction

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.