Directional snapping instability in a bistable tensegrity under uniaxial loads

Abstract

Multistable structures possess fascinating shape reconfigurability and property programmability, which have been applied in various scenarios. Multistable tensegrities are a novel class of compliant prestressed structures with different stable states. However, how structural transitions occur among these states remains an interesting challenge. Here we investigate a continuous configuration transition of bistable quadrangular prismatic tensegrity under uniaxial loads. A theoretical model is proposed to determine the deformation behavior of the structure starting from different stable states clamped by structural height or axial forces. The obtained structural mechanical responses exhibit multi-value curves, leading to the occurrence of snapping instability and bistable states. Interestingly, the transition of these two stable states is directional and one-way irreversibility, i.e., the structure can only jump from one stable state to another, but not vice versa. Finally, displacement and force-clamped loading experiments are carried out under these two stable states, and the test results agree well with our theoretical predictions. This work shows that applying uniaxial loads can directionally trigger a specific stable-state transition of the tensegrity, which holds great applications in the precise configuration programming of metamaterials and advanced devices.