多轴向经编复合材料预制件的几何模型

摘要

为更好地了解复杂多轴向经编复合材料预制件的细观结构,在对多轴向经编复合材料预制件结构特征进行研究的基础上,通过合理假设,从细观几何角度出发,建立了带有短切毡的多轴向经编复合材料预制件单元结构模型.利用这个模型推导几何结构特征参数和加工工艺参数之间的关系,得出多轴向经编复合材料预制件理论纤维体积分数公式.以不同规格的多轴向经编复合材料预制件为样品,借助CAD软件快速实现对纤维体积分数理论值的计算,并将理论值与实测值进行比较.结果表明,二者吻合良好,证明该模型是有效的.对理论值和实测值产生误差的原因进行分析,认为主要是由于模型假设的理想化以及复合成型后材料上存在树脂聚集区引起了误差.%With a view of better understanding the microstructure of complex multi-axial warp knitted composite preform,a modular construction geometric model of multi-axial warp knitted composite preform with chopped strand mat was developed based on the further research on the structure of multi-axial warp knitted composite preform and the analysis of its microstructure by reasonable hypothesis. According to the model,the relation between geometric parameters and process variables was derived, and the theoretical fiber volume fraction formula of the preform was worked out. Furthermore, using multi-axial warp knitted composite preforms of different specifications as samples,the theoretical value of fiber volume fraction was calculated rapidly by using CAD software. Comparing the theoretical value with the experimental value,it indicated that they were in good agreement, which means that the model was practical. Finally, the factors leading to deviations between theoretical value and experimental value were analyzed, they were mainly attributed to the ideal assumption of the preform, the resin-rich zones in the composites after molding and so on.