薄膜反射面结构新型折展方案设计

基于薄膜结构模拟方式的对比分析，选用VUMAT子程序修改了考虑褶皱问题的膜单元的本构关系，解决了膜单元不能承受压应力的问题。采用三维数字图像相关（3D-DIC）方法对聚酰亚胺薄膜材料进行性能测试，试验表明带折痕的薄膜材料的等效模量比无折痕的薄膜材料低15%左右。在考虑折痕弹性模量差异的基础上采用显式计算方法对Miura折纸的展开过程进行了仿真，并基于平面度和最大应力2个指标对不同数量加载点的情况进行了对比，结果表明，加载点数量增多对结构的平面度和最大应力指标均是有利的。最后，基于薄膜结构找形和Miura折纸概念提出一种新的薄膜折叠方案。

Design of fold-development program for film reflective surface structures

Based on a comparative analysis of the simulation methods for membrane structures, the constitutive relationship of the membrane elements considering the wrinkle problem was modified using the VUMAT subroutine to overcome the difficulty that the membrane elements cannot withstand the compressive stress. The performance of the polyimide film material was tested by Three Dimensional Digital Image Correlation (3D-DIC). The test shows that the equivalent modulus of the folded film material was about 15% lower than that of the film material without crease. Based on the difference of flex modulus of elasticity, the deployment process of Miura origami was simulated. The situations with different number of loading points are compared in terms of the two indicators of flatness and maximum stress. The results show that increase in the number of points is beneficial to flatness and maximum stress of the structure. Finally, a new film folding program is proposed based on the concept of structure forming finding and Miura origami.