Elastic properties of lightweight rotating square structures

This paper studies three lightweight rotating square structures, and analytical formulas for Poisson's ratio, Young's modulus, and shear modulus are given. Numerical simulations and experiments demonstrate the high accuracy of the analytical formulas. The structures have a large regulatory range of negative Poisson's ratio and strong shear resistance, with a shear modulus even greater than Young's modulus. Secondly, there are two mechanisms to achieve negative Poisson's ratio, that is, bending of the rod and rigid rotation of the square. The rod's bending dominates the auxetic effect when the overlapping area is relatively large. If the overlapping area is gradually reduced, the bending of the rod transitions to the rigid rotation of the square, which dominates the auxetic effect. Due to such structures' excellent auxetic behavior and strong shear resistance, they have potential applications in the engineering field.