Modification of hexachiral unit cell to enhance auxetic stent performance

Abstract

Stents possess disadvantages such as foreshortening and dogboning. Material selection alongside topological modifications are two main approaches to overcome these issues. Stents with negative Poisson’s ratio, also known as auxetic property, can lead to promising performance improvement. Therefore, in this study, three stents were designed by improving a hexachiral unit cell and underwent numerical and experimental investigations using CoCr 605 L and SS 316 L alloys. The modified auxetic stents presented higher auxeticity and NPR of −0.64 and −0.69. Higher radial expansion, stress tolerance and yield strain of these modified stents help them overcome drawbacks of non-auxetic stents.