中文摘要：

复合材料几何模型可用于计算其物理性能和力学性能. 对于随机分布的椭球颗粒复合材料和三维编织复合材料提出几何建模方法. 首先针对随机分布颗粒为椭球的情况进行了阐述, 对现有生成椭球颗粒分布样本的方法进行改进, 消除了随机颗粒重叠的情况; 为了应用多尺度有限元方法, 对单胞边界之外的椭球进行处理, 得到基体和增强体的边界. 另外, 针对三维四向编织方法, 在纤维束不重叠并尽可能排列紧密的情况下给出了构建每根纤维束的运动规律. 最后通过实例验证了该方法的有效性.

英文摘要：

Geometry model of composites materials could be used to calculate its physical and mechanicalproperties. In this paper, a geometry modeling algorithm for composite materials with randomly distributedellipsoidal grains and three dimensional braided composites is proposed. Firstly, we use ellipsoids to representgrains and modify the original samples of randomly distributed grains to remove overlapped ones. Then,in order to apply multi-scale finite element method, the ellipsoids outside the boundaries of the unit cell ishandled to obtain the boundaries of matrix and reinforcement. For 4-step rectangular three-dimensionalbraided composites, we analyze the motion law of each yarn to obtain tightly packed yarns without intersection.Examples have been given to demonstrate the validity of algorithms.