Compressive mechanical behavior for surface auxetic structures

Auxetic structure is a typical metamaterial, whose mechanical behaviors of two-dimensional and threedimensional structures are widely studied. However, reports on surface auxetic structure (SAS) are rare. As a consequence, two types of SAS were designed by reversing and crimping the concave hexagonal plane auxetic structure (PAS) composed of double arrows, which were known as RAS and CAS, respectively. The theoretical equations to calculate the deformation of the representative volume cell structure (RVCS) were derived, and the relationships between energy and work were established based on the plastic wrinkle. The compressive simulations of the plane and surface auxetic structures were conducted through the use of finite element method (FEM) verified by experiment, and the mechanical behaviors and energy absorption characteristics were obtained. By comparing the simulation results of different structures, it was found that RAS not only realized the auxetic effect of compression shrinkage but also realized the supermechanical effect of compression twist. The auxetic effects of these structures were realized by the deformation of beams. The auxetic effect only appeared in the local positions of these structures, and other positions still belonged to the positive Poisson's ratio effect. The crimped CAS had the biggest maximum load peak, and PAS possessed the highest specific energy absorption (SEA). The supermechanical effects of compression shrinkage and compression twist in RAS have great potential in some distinctive engineering applications. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

Auxetic structures, including surface auxetic structures, were studied regarding their mechanical behaviors and energy absorption characteristics through compression simulations and experimental verification. The design of reversed and crimped structures showed both auxetic effect and supermechanical effect in compression.