The computational LCF-analyses of chiral and Re-entrant auxetic structure using the direct cyclic algorithm

Abstract

This study presents the computational analysis for determining the fatigue life of two conventional 2D auxetic cellular structures: (i) A chiral auxetic structure, (ii) A re-entrant auxetic structure. The low-cycle fatigue analysis using a damage initiation and damage evolution law was performed, where the needed material parameters were obtained previously from the experimentally determined stabilised hysteresis loop of inelastic strain energy. The direct cyclic algorithm implemented in the Abaqus/Standard software was used for the computational analyses to obtain the stabilised response of a model subjected to the cyclic loading. In order to examine the damage evolution paths, finite elements with severe damage were detected, and then removed from the finite element model in the subsequent numerical simulations.The computational fatigue analyses have shown that the chiral auxetic structure demonstrates a higher fatigue strength than the re-entrant auxetic structure which is probably due to the fact that, in the chiral structure, the stresses are distributed more uniformly along the individual cells. To confirm the computational results, the cyclic experimental testing has been performed for both auxetic structures. The comparison between computational and experimental results shows a reasonable agreement.