Experimental analysis of three tetra-anti-chiral auxetic honeycomb structures

Abstract

Recent advances in manufacturing macro/micro/nano-structures led to the development of metamaterials, a new class of materials, which have exceptional properties, not easy to observe in nature, in terms of mechanical response, heat transport performance and energy absorption. In this study, a specific auxetic structure called anti-tetra-chiral, ATC (the adjective "chiral"means physical property to spin, "anti"is the effect, and the "tetra"represents their number of ligaments) is investigated and it was manufactured by laser cutting from 3 mm thick S320 mild steel plates with three different horizontal to vertical ligament ratios of 1:1, 1.5:1 and 1:1.5. The elastic properties of raw material, obtained by tensile testing regular S320 mild steel specimens, have been used in a numerical simulation algorithm using LS-DYNA in order to identify the loading capabilities of the structure. Then, an experimental setup for compression and tensile testing of A, B, and C types of ATC structures, have been appropriately planned and performed, assisted by with Digital Image Correlation (DIC) analysis using GOM-Correlate in order to obtain the deformation field evolution and calculate the average Poisson's coefficients for all three ACT structures. Future research work is targeted for the development and optimization of both ATC structure design and numerical simulation algorithm targeting shock absorbers applications.