Harnessing the path-dependent bistability of non-prismatic foldable truss modules for self-lockability

Abstract

Deployable structures, including origami-inspired and truss-based designs, offer innovative solutions for portable structural systems across various disciplines, with origami structures providing larger folding ratios but limited stiffness, and truss-based structures offering higher strength and stiffness at the expense of folding ratio. The existing technologies for earth-based deployable structures have inherent limitations in terms of stiffness and packaging efficiency. To address these limitations, there is a need to enhance the longitudinal stiffness while maintaining optimal packaging efficiency, enabling the utilization of these structures as high-capacity towers for multiple earth-based applications. This study presents a novel design of a self-lockable non-prismatic foldable truss module that offers high-end structural performance while simultaneously maintaining optimal packaging efficiency. The proposed module exhibits two distinct modes of motion: the folding/deployment mode and the operational loading mode. The mathematical models for both modes are presented to investigate respective motion characteristics followed by a novel algorithm to calculate the folding ratio of physical model. Parametric studies are conducted to comprehensively characterize various folding deployment characteristics, folding ratio and load carrying capacity of the SLFT module while considering different design parameters. Moreover, a physical model of a SLFT module is developed to demonstrate its compression behavior under symmetric and unsymmetrical loading conditions experimentally.