Preliminary design and validation of a hybrid triangular rollable and collapsible boom based on high strain and shape memory polymer composites

Shape memory polymer composites (SMPCs) are attractive for space deployable structures, yet their deployment is often limited by insufficient recovery moment. To address this challenge, this work proposes a bilayer hybrid composite strategy that integrates a high strain composite (HSC) layer with an SMPC layer. In this configuration, the SMPC enables thermally activated self locking and shape recovery, while the HSC serves as an elastic energy storage component to boost actuation. Mechanical characterization under varied thermal conditions shows the SMPC undergoes more pronounced stiffness reduction with increasing temperature while exhibiting greater failure strain compared to the HSC. A basalt-aramid hybrid fabric is employed to improve toughness and provide an ISRU-informed design perspective by increasing the fraction of mineral based reinforcement. Experimental validation confirms that the hybrid structure retains the shape memory capability of SMPCs while significantly increasing the recovery moment. Under constrained displacement recovery with the SMPC thickness fixed at 0.5 mm, increasing the HSC thickness to 0.35 mm raises the normalized recovery moment by 15-fold. Using 18 W electrothermal actuation, the boom achieved deployment with a recovery time of 63 s. Although some discrepancies in transient response were observed between simulations and experiments, mainly due to boundary condition idealization, the model captures the steady-state recovery moment, which is a practically relevant parameter for engineering applications. This study demonstrates that the proposed hybrid composite approach offers a viable pathway to develop high performance self deployable structures that combine substantial recovery moment with commandable thermal actuation.