Buckling of Tensegrity-Based Metamaterials for Dynamic Applications

Tensegrity structures are promising building blocks for metamaterials, due to their tolerance to deformation and strength at low density. Recent theoretical studies show that a truncated octahedron tensegrity cell can be used to tessellate multidimensional lattices. These studies suggest that buckling of the struts greatly improves energy absorption, showing potential for impact mitigation and wave management. Here, finite element models and experiments are used to design and characterize tunable, 3D printed unit cells, with equivalent strain energy capacity as a pin-jointed, “ideal” tensegrity structure. A drop weight setup is employed to characterize individual cells and 1D lattices under dynamic impacts. Experiments on individual cells show resilience to increasing impact speed and deformation, exhibiting load limitation and high energy absorption. The structure’s effective wave speed ranges from 25-40 m/s, an order of magnitude lower than speeds in common foams. We model the dynamics of arrays of these unit cells with discrete numerical simulations. Results show dispersive and asymmetric wave propagation in 1D lattices. This study expands the fundamental understanding of energy absorption in buckling tensegrity metamaterials and provides design tools for applications.