NUMBER-SHAPED TENSEGRITY STRUCTURES: CONFIGURATION DESIGN AND MECHANICAL PROPERTIES ANALYSIS

Due to the novel mechanical properties, tensegrity structures have found various applications in science and engineering, and the design of large-scale tensegrities becomes a vital issue. In this paper, a series of number-shaped tensegrity structures are proposed by assembling the cylindrical and spherical tensegrity elementary cells. Specifically, the quadruplex prismatic tensegrities and the truncated regular octahedral tensegrities are selected as the elementary cells and then connected by using the node-on-node assembly scheme. Furthermore, structural stiffness matrix-based numerical method is employed to simulate the mechanical responses of the assembled tensegrities. Our results show that the obtained number-shaped tensegrities are self-equilibrated and stable when the elementary cells satisfy their self-equilibrium and stability conditions, respectively. A physical sculpture is also constructed using the aluminium alloy bars and nylon strings. Taking the eight-shaped tensegrity structure as an example, the static mechanical responses of the structure subjected to self-weight loading and uniaxial tension/compression are simulated, as well as the structural natural frequencies and modes of its free vibration. The simulations show that the tensegrity could have enough rigidity to bear the self-weight when the structural pre-stress level, the mass density of the compressed bars, and the stiffness of the tensioned strings match well. The load-displacement curves of the tensegrity under uniaxial loading are nonlinear, that is, the tensile stiffness increases with the tensile deformation, while the compressive stiffness decreases with the compressive deformation. The structural natural frequencies are dependent on the pre-stress level, while the vibration modes change little. The present work enriches the shapes of large-scale tensegrities and would promote their applications in civil and material engineering.