Large deformation and collapse analysis of re-entrant auxetic and hexagonal honeycomb lattice structures subjected to tension and compression

Abstract

Additively manufactured auxetic structures exhibit exceptional mechanical properties, such as lightweight design, enhanced energy absorption, high shear stiffness, and excellent indentation resistance. Unlike conventional materials, auxetic structures feature a negative Poisson’s ratio, enabling unique deformation characteristics through tailored geometries. This study investigates the mechanical behavior of two lattice designs: re-entrant auxetic and conventional hexagonal honeycomb structures. Finite element analyses in both 2D plane strain and 3D were performed using multi-field displacement-pressure elements. The structures were modeled using hyperelastic and rate-independent plasticity constitutive laws calibrated with experimental uniaxial tensile test data. The simulations involved loading in both longitudinal and transverse directions, incorporating self-contact between the struts and contact with the loading plates by the contact domain method. The results demonstrated a strong agreement with the experimental findings. The re-entrant auxetic structure exhibited a negative Poisson’s ratio and superior energy absorption efficiency compared to the hexagonal honeycomb. These insights contribute to a reliable theoretical framework for designing high-performance lattice materials with direction-dependent mechanical properties.