Bending behavior of auxetic tubular intersecting lattice metamaterials

Auxetic metamaterials have gained substantial attentions because of their unique deformation mode and outstanding mechanical behavior. This paper proposed a new tubular lattice structure realized by rolling up a flat lattice structure with has a negative Poisson’s ratio. And the bending properties under large deformation were studied by finite element simulations. The simulation results reveal that the stress on the TIL-A (arcuated tubular intersecting lattice structure) structure is concentrated around the indenter. Contrarily, the stress on the TIL-S (star-shaped tubular intersecting lattice structure) structure spreads more evenly distributed across the span. Thus, the TIL-A structure has higher stability. Additionally, it was found that increasing the beam thickness and the beam depth improved the stiffness and maximum load, while the ductility declined moderately as the beam depth and beam thickness grow. In general, aggrandizing the beam depth is better than increasing the beam thickness to obtain the ideal maximum load and stiffness. Besides, compared with other geometric parameters, the internal cell angle θ only have limited effect on the bending properties. The results of this work instructive for the design and optimization of tubular lattice structure for applications in biomedicine, soft robots, protective engineering, etc.