Influence of intersected fold-lines on thin-folded membranes

Abstract

Concept of solar sailing which uses solar energy to propel a spacecraft is becoming popular as a low-cost spacecraft propulsion system. These solar sails require larger area while in operation and are stored in the limited space available in launch vehicles by introducing series of fold-lines. Therefore, precise prediction of deployment behaviour is important in designing tear-free deployment configurations. Physical testing of such applications is difficult due to presence of gravity, air drag and friction which prevent such structures from deploying on Earth. Hence deployment of solar sails has to be tested under vacuum and zero gravity conditions. Virtual simulations are being used to overcome these challenges. This paper attempts to understand deployment behaviour of highly compacted thin membranes and highlight the importance of incorporating fold-line properties in finite element modelling. The effects of membrane thickness and creased geometry for the deployment behaviour and deployment force were also studied through force–displacement relationship of the membrane opening. It is shown that the connection with rotational stiffness gives better idealization for the fold-line in virtual environment. Further it is evident that the deployment force and shape have a significant influence from membrane thickness and fold-line geometry.