Experimental Investigation of Effect of Initial Geometry Condition of Shape Memory Polymer Convex Shell on Self-Deployment Characteristics

Abstract

This research investigates a low impact stable self-deployment of a shape memory polymer convex shell. The convex shell generates a self-deployment force. After deployment, it has a higher bending stiffness with a reduced thickness. The self-deployment force depends on the initial geometry, such as the degree of flatness or curvature of the convex shell when it is stowed. To examine the effect of the initial condition, we investigate the three different forces required to prepare the flat shape before stowing. Theoretical analysis is performed to derive the work required by the weight to flatten the shell. Then, the deployment behaviors for each condition are compared by determining the deployment ratio. As a result, the deployment ratio and rate depended on the force used to make the stowed condition. In addition, repeatability of the deployment is discussed with multiple deployment tests. Furthermore, theoretical analysis is presented to discuss the required force and work done by weights used to flatten the shell. Finally, some nonlinear finite element analyses of a single convex shell are also presented to show the predicted deformation of the convex shell.