Analytical and Numerical Solution for Auxetic Stent with Re-entrant Geometry and its Multi-Objective Optimization

The present study examines the mechanical properties of auxetic stents with Re-entrant structure. Geometries were parametrically modeled, and the design of experiments (DOE) was developed by defining the elastic properties of the stents and using the response surface method (RSM). Finite element (FE) analysis was performed in order to find a polynomial relationship between the geometric parameters as inputs and the elastic parameters as the outputs. Then, the optimal stent was obtained in terms of elasticity parameters by using RSM method. As a result, the optimal parameters of the Re-entrant stent including flexural stiffness, axial elasticity modulus, radial elasticity modulus and Poisson’s ratio were obtained as 40 mPa.m4, 253 MPa, 752 MPa and -0.58, respectively. Moreover, a method was proposed to find an analytical solution for metal elastic stents in order to verify the FEM results. Finally, the blood vessel compliance of the optimal stent was evaluated, showing a good compliance for practical usage.