1. Fatigue behaviour of different chiral auxetic structures using a numerical approachBranko Nečemer, Patrik Lampret, Srečko Glodež, 2025, original scientific article Abstract: This study presents the computational analysis for determining the fatigue life of different chiral auxetic structures made of aluminium alloys 5083-H111. The influence of Poisson's ratio on the loading process was investigated to determine which structures exhibited the auxetic effect and how intense it was. Finally, the fatigue life calculation was performed using the strain life approach in the framework of the ANSYS software. The fatigue life determination was evaluated using the approach of amplitude strains, amplitude forces, and strain energy density per cycle. The computational results were described and presented according to predefined approaches, from which it was determined which chiral structure can withstand the highest number of loading cycles at the prescribed load, and which structure shows the most favourable combination of mechanical and physical properties. Keywords: advanced metamaterials, chiral auxetic structures, fatigue behaviour, numerical simulations, aluminium alloys Published in DKUM: 20.05.2025; Views: 0; Downloads: 4
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4. High strain rate hardening of metallic cellular metamaterialsNejc Novak, Matej Vesenjak, Zoran Ren, 2024, original scientific article Abstract: Strain rate hardening caused by the changed deformation mode is a fascinating phenomenon in cellular metamaterials where the material’s stiffness and energy absorption capabilities increase as the strain rate increases. This unique behaviour is attributed to a combination of micro-inertia effects, base material’s strain rate hardening and inertia effects. At high strain rates, the metamaterial’s inertia influences its deformation response, which changes to shock mode. This work briefly presents the geometry and fabrication of different metallic metamaterials. Then, it evaluates their mechanical response at different strain rates, ranging from quasi-static to intermediate dynamic and shock, determined by experimental and computational investigation. The three deformation modes can be separated into two critical loading velocities, unique for each metamaterial, which are also presented and compared in this work for various metamaterials. The investigations show that the deformation mode change in metallic metamaterials depends on their porosity. The critical velocities separating the deformation modes decrease with increasing porosity, i.e., decreased density of the metamaterial results in reduced critical loading velocities. The shock deformation mode in cellular metamaterials is thus attainable at much lower loading velocities than in homogeneous (nonporous) materials. Keywords: metamaterials, cellular structures, high strain rate, experimental testing, computational modelling, compression loading, mechanical properties Published in DKUM: 22.05.2024; Views: 204; Downloads: 25
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