Simulation of ultra-thin membranes with creases

Abstract

Two dimensional nature of thin membranes has led to their evolution as an essential component in space structures that demand lighter mass and compact packaging. Origami based folding patterns are used to fold these membranes into compact configurations by introducing plastic deformations along the predetermined fold-lines referred to as creases. Creases have been observed to alter the material state and the mechanical response of highly compacted thin membranes, leading to changes in their deployment behaviour outer space. This paper proposes an idealised connector element based method which introduces rotational stiffness associated with the creases while eliminating the requirement for a large number of small shell elements to capture accurate deployment behaviour. First, an experiment is carried out to quantify the fold-line rotational stiffness of Kapton polyimide film. Then, the technique is implemented in a commercially available finite element package ABAQUS simulating the deployment of a single-folded thin membrane, and is identified to capture in-plane and out-of-plane displacements with a better approximation than the other existing crease modelling techniques. Then the applicability of the proposed technique is validated against a quasi-static deployment experiment of a solar sail model available in the literature. The use of the proposed technique has proven to be qualitatively effective in terms of inducing a quasi-static deployment that achieves fair quantitative agreement as well.