Design of low-porosity auxetic tessellations with reduced mechanical stress concentrations

Published on Oct 1, 2021in Extreme Mechanics Letters4.806
· DOI :10.1016/J.EML.2021.101401
M. Barillas Velásquez (Central American University), L. Francesconi8
Estimated H-index: 8
,
Michael Taylor13
Estimated H-index: 13
(Santa Clara University)
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Abstract
Abstract null null Two-dimensional tessellations of alternating high-aspect ratio voids, such as ellipses, are known to induce auxetic behavior in engineering materials. An undesirable side effect of using high-aspect ratio shapes is an increased stress concentration at the ends of the voids. A novel rational process for designing auxetic tessellations with reduced stress concentration using Gielis’ Superformula and Nelder–Mead optimization is presented in this work. Results lead to an end-shape with a peak stress nearly 40% less than that of a comparable baseline circular stop-hole end-shape at the same porosity.
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4 Authors (Hui Wang)
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An experimental and numerical investigation of fatigue life and crack propagation in two-dimensional perforated aluminum structures is presented. Specifically, the performance of positive Poisson’s ratio (PPR) geometries using circular holes is compared to that of auxetic stop-hole and straight-groove hole geometries. Mechanical fatigue testing shows that the considered auxetic structures have more than 20% longer life than the porous PPR structure at the same porosity and peak effective maximum...
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