一种新的三维四步编织复合材料几何模型及其在宏观弹性性能预测中的应用

 为了准确预测三维四步(1×1)编织复合材料的宏观弹性常数，提出了一种考虑纤维束三维几何结构和纤维束与基体相互作用、便于有限元网格划分的单胞几何模型，该模型精确地反映了纤维体积比。以该几何模型为基础，用六面体单元分别对纤维束和基体进行了网格划分，满足了纤维束与基体界面间的位移连续条件。采用有限元模型计算了编织复合材料的宏观弹性常数，与其他计算结果和实验结果的比较表明，该几何模型和有限元模型比较合理。

A New Geometric Model of 3D 4-Step Braided Composites and Its Applications in Macroscopic Constant Predictions

In order to predict the macroscopic elastic constants of 3D braided composites a ccurately, first, a unit cell geometric model is presented. In this model the 3D geometric structure of the yarn is considered in detail and the corresponding f inite element model can be built easily. Then the yarn and matrix are meshed usi ng solid hexahedral elements respectively. So there is only one material in one element and this finite element model can reflect the fiber volume fraction exac tly, moreover, it satisfies the displacement continuous conditions of the yarn/m atrix interface. Finally, the macroscopic elastic constants are obtained using t his finite element model. The comparisons of the results with those of other met hods and experiments show that the model of this paper is more reasonable.