基于三胞模型的三维五向编织复合材料刚度性能预测
Prediction of Stiffness Properties of 3D Five-Directional Braided Composites Based on Three-Cell Model

三维五向编织复合材料空间拓扑结构复杂，为了对其刚度性能进行准确预测，本文首先研究了三维编织工艺中纱线的运动规律，根据空间纱线轨迹在角部、表面和内部的分布情况确定了角胞、面胞和内胞组成的三胞实体模型。然后对三胞模型划分对称网格并施加合理的周期性边界条件，通过有限元分析分别计算单胞的刚度性能后，采用体积平均法获得宏观材料的整体刚度，并与试验结果进行比对。研究结果表明，本文构建的三胞结构模型可以准确反映三维五向编织复合材料的细观结构，刚度性能预测结果较好，为组分材料的选择及编织工艺的改进提供了理论依据。
The spatial topology of the 3D five-directional braided composite material is complex. In order to accurately predict its stiffness performance, this paper firstly studies the motion law of the yarn in the 3D braiding process, which is determined according to the distribution of the spatial yarn trajectory at the corner, surface and interior. A three-cell solid model consists of corner, face and inner cells. Then, the three-cell model is divided into symmetrical meshes and reasonable periodic boundary conditions are applied. After calculating the stiffness properties of the unit cells through finite ele-ment analysis, the overall stiffness of the macroscopic material is obtained by the volume average method and compared with the experimental values. The research results show that the three-cell structure model constructed in this paper can accurately reflect the microstructure of the 3D five-directional braided composite material, and the stiffness performance prediction results are good, which provides a theoretical basis for the selection of component materials and the improve-ment of the weaving process.