Design and analysis of quadruple Waterbomb origami with multi-stability

In this paper, after investigating the folding behavior and bistable positions of the sixfold Waterbomb, we propose a novel origami structure, multi-stable quadruple Waterbomb origami (QWO), which is designed as a composition of four sixfold Waterbombs. QWO exhibits three stable configurations under axial symmetric conditions. By controlling the pushing inward and popping outward of the Waterbomb center, two alternative folding paths can be generated, which achieves easy folding and high-stiffness in the axial direction, respectively. When the structural symmetry is disrupted, QWO exhibits four stable configurations in axial bending. We develop a truss model of QWO, and the energy landscape derived from it confirms the tri-stable property under symmetric deformation along its axis. Moreover, the high stiffness of the third stable state of QWO is verified by physical compression experiments. A novel QWO tube is fabricated by connecting QWO units in series. Each QWO in the tube can be deformed independently, which avoids the problem of interlayer motion coupling that commonly occurs in existing Waterbomb origami tubes. Our QWO tube offers diverse spatial configurations and mechanical properties that can be potentially used in mimicking the deformation of strip-shaped soft organisms.