Self-deployable Space Structure using Partially Flexible CFRP with SMA Wires

This article deals with a self-deployable composite structure using a partially flexible composite (PFC) with shape memory alloy wires and reveals the fabrication process of the PFC. Two different matrices are used in the PFC: epoxy resin for the normal part, and silicone rubber for the folding line. Since the fibers are continuous, the PFC has the same strength as a normal composite. We investigate carbon fiber breakages during the folding process by considering changes in electrical resistance, and cyclic tests are performed to confirm the availability even after long-term cyclic folding. An SMA wire is embedded in the PFC to keep the folded configuration without loading and self-deployment is achieved using Joule heating. The results confirm that a flexible part of adequate length enables foldable composite structures without causing carbon fiber breakages, while the cyclic folding tests reveal that the PFC is reliable when a long flexible part is used. The embedded SMA wire realizes compactly folded composite panel structures without loading and Joule heating of the SMA wires enables self-deployable composite structures.