Bending Flexibility of Negative Poisson's Ratio Structural Vascular Stent

A negative Poisson's ratio structural vascular stent with arrow-shaped cell is proposed in the paper. In order to improve the bending flexibility of the stent, three shapes of connecting bars, namely, U-shaped, S-shaped, and linear, are designed. The influence of structural parameters of the stent connecting bars on the bending performance of the stent is studied using the finite element method and experimental method. The research results show that compared to S-shaped stents, U-shaped stents have better bending flexibility. In addition, the influence of the parameters of the connection bars of a U-shaped stent on its flexibility is also explored. The longer the length of the U-shaped connection bars, the lower the corresponding bending stiffness and better bending flexibility. The larger the width of the U-shaped connecting bar, the greater the bending stiffness of the stent, and the worse its bending flexibility. And some experiments are conducted using the four points bending method. The deformation of the S-shaped stent and U-shaped stent under bending is very similar, and the bending stiffness of the U-shaped stent is lower than that of the S-shaped bracket, which also verified the correctness of the finite element calculation.