Novel hybrid 3D-printed auxetic vascular stent based on re-entrant and meta-trichiral unit cells: Finite element simulation with experimental verifications

Abstract

In this study, a novel re-entrant meta-trichiral auxetic (RMCA) vascular stent with improved mechanical properties was designed by combining three auxetic unit cells: re-entrant, trichiral, and anti-trichiral. The in-plane tensile behavior of RMCA structure was investigated through finite element analysis and experimental tests were performed to verify the finite element analysis (FEA) results. 3D printing was employed to fabricate the samples. The effect of various geometric parameters on the in-plane behavior of RMCA structure, including the stress-strain curve and Poisson’s ratio, were studied using FE analysis. The highest value of negative Poisson's ratio obtained for RMCA structure was equal to − 4.91, which is a stunning value among auxetic structures. After that the vascular stent was proposed using the most appropriate structure determined by the parametric investigation. Finite element analysis (FEA) was conducted to evaluate the behavior of the stent during the deployment process (angioplasty), and interaction between the vascular stent, artery, and plaque. The dogboning, foreshortening, and recoil of the vascular stent were evaluated using the FEA results. Also, bending flexibility of the vascular stent was investigated based on FEA and three-point bending tests.