关键词: 薄膜材料, VUMAT用户子程序, 三维数字图像相关, Miura折叠, 平面度指标, 找形设计

Abstract: 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.

Key words: thin film material, VUMAT user subroutine, three dimensional digital image correlation, Miura folding, flatness index, form finding design