Load carrying capacity analysis and gradient design of new 3D zero Poisson's ratio structures

Abstract

Mechanical metamaterials offer a wide range of potential applications in the load-bearing structures of deformed wings due to their characteristics like light weight and high stiffness. In this paper, four 3D zero Poisson’s ratio structures are proposed. The modified concave hexagon structure is verified by quasi-static compression experiment, which shows that the finite element analysis is correct. The load-bearing capacity of the four structures is compared using experiments and finite elements, the concave hexagonal structure with oblique bar embeddings (CHSO) has a higher load-bearing capacity. The effect of cell wall thickness on the energy absorption capacity is investigated, the larger the wall thickness, the higher the energy absorption capacity of the structure, but there is the disadvantage of excessive peak stress. Therefore, a gradient design is carried out for CHSO. The effects of the number of gradient layers, gradient rate and gradient distribution mode on the peak stress, plateau stress and specific energy absorption of the structure are also investigated. The optimal gradient design mode is finally obtained by comparison with the goal of increasing the plateau stress and specific energy absorption of the structure and reducing the peak stress. It provides a good design idea for the design of the load-bearing structures of deformed wings to meet lightweight requirements.