Numerical Study On Wrinkling Mechanical Behavior Of Stretch Membrane

The exploration of human in the outer space has been more and more frequent due to the development of science and technology in recent decades. Membrane, due to its light-weight, small-volume and easy-fold properties, has become an indispensable part in the aerospace filed, but the small bending stiffness makes the membrane unstable in the local region and have the wrinkle deformation when under load, the deformation will affect its accuracy. To avoid the undesired influence of wrinkle in membrane, a lot of researches have been carried out to study the evolution mechanism, condition, propagation law and how to resist the occurrence of wrinkle.Membrane wrinkle can be described by nonlinear differential equaiton as large deformation problem. There are many theoretical work on membrane wrinkle, most of them are based on tension filed theory, initially the membrane is believed to have zero bending stiffness, but the following research propose the small bending stiffness for membrane. The analytical model can be used to characterize the wrinkle in membrane with regular structure, but invalid for complex structure and boundary condition. Thus, we need to perform numerical simulation for the complex structure. In this paper, the shell element in the nonlinear finite element package ABAQUS is used to model the wrinkle in membrane under tension.This paper focuses on the eigenvalue-buckling and post-buckling of membrane under tension. With the eigenvalue-buckling of membrane with different sizes, the critical buckling strain contour can be obtained and it is found that the most unstable case is when the aspect ratio is2. The parameter analysis of membrane size illustrates that the critical buckling strain has a decrease-increase trend with the increase of the aspect ratio of membrane, the critical buckling strain decrease with the increase of width, and also the critical buckling strain increase with the increase of thickness. From the first-mode eigen-value buckling analysis for membranes with different aspect ratios, it is found that the buckling region is in the center and end of membrane when the aspect ratio is smaller and larger than3, respectively. The plane stress analysis for the same membrane suggests that the compressive stress has the increase-decrease trend as the tensile strain increase, also the maximum compress stress has the increase-decrease trend with the increase of aspect ratio. The post-buckling analysis of membrane proposes that with the increase of tensile strain, the wrinkle amplitude first increases and then decrease, while the wave length decreases monotonically. Also, it is found that the maximum wrinkle amplitude has the increase-decrease-stable trend with the increase of aspect ratio. Based on the analysis on membrane with different size, we here give three suggestions to resist the wrinkle:(1) using thick membrane,(2) taking appropriate aspect ratio for same thickness;(3) stretching membrane beyond the limit.