三维多向编织复合材料纤维束细观结构拓扑优化

Topology optimization of the fiber microstructure of 3-D multidirectional braided composites

三维多向编织复合材料中近似空间网格状的纤维束增强骨架为复合材料及其结构件的性能提供了灵活的可设计性,为充分利用这类复合材料的优越性能,选用遗传算法优化纤维束拓扑结构、纤维束线密度和节矩长度,使三维编织复合材料既满足轴向弹性模量的下限要求,又能使材料的质量和横向泊松比最小。研究结果表明,在建立复合材料空间桁架结构单胞模型与其细观结构几何等价关系的基础上,利用遗传算法不断调用单胞模型刚度有限元计算子程序,可以在满足弹性要求的前提下,为三维多向编织复合材料找到最优的纤维束拓扑结构和细观结构参数。

The space grid of fiber microstructure of 3-D multidirectional braided composites provides more tailor flexibility in respect of the performance of the composites and their structures. To utilize the tailorability, genetic algorithm is adopted to optimize the topology parameters of fiber microstructure, linear density and pitch length so that the 3-D braided composites satisfy the lower limit requirement of stretch modulus and the minimum ratio of material mass to lateral Poisson. Research results show that on the base of the geometric equivalents between the space truss unit cell and the composites microstructure, the optimal topological microstructure can be found for the elastic demands of the composites by the methodology in which the genetic algorithm is combined with the finite element stress analysis of the space truss model of unit cell.