三维五向编织复合材料弹性性能的数值预报

Numerical prediction for the elastic properties of three dimensional and five directional braided composites

基于三维五向编织复合材料细观结构模型,通过假设挤压固化后编织纱线和轴纱分别具有六边形和正方形横截面以及分析纱线之间的空间几何关系,建立了该类材料的有限元模型.并且,采用有限元方法计算得到了三维五向编织复合材料的弹性性能,分析了编织角和纤维体积含量对弹性性能的影响规律,并与三维四向编织复合材料的相应结果进行对比,同现有的实验数据进行了比较,验证了数值预测的有效性.结果表明:三维五向编织复合材料具有良好的力学性能,轴纱的加入使得轴向力学性能得以增强.

The finite element model is established based on the micro-structure of three dimensional and five directional braided composites and the assumption of the braiding yarn with the hexagon section and the axial yarn with the square section and the analysis of geometrical relationship of yarns in three dimensions. The elastic constants of three dimensional and five directional braided composites are calculated by the finite element method and compared with the corresponding results of three dimensional and four directional braided composites. The influences of the braiding angle and fiber volume fraction on the elastic constants are also analyzed. In addition, the predictions were compared with the experiment results which verified the validity of the finite element analysis. The results show that three dimensional and five directional braided composite has good mechanical properties and it improves the axial mechanical performance of the material by joining the axial yarns.