Bending Flexibility of Negative Poisson's Ratio Structural Vascular Stent

The mechanical properties of the stent have a direct impact on the therapeutic effect after vascular intervention surgery. The flexibility of bending is an important performance to ensure that the vascular stent can adhere to the blood vessels and plaques, reduce vascular damage, and improve the cure rate. A negative Poisson's ratio structural vascular stent with arrow shaped cell is proposed in the paper, and three shapes of connecting bars, namely U-shaped, S-shaped, and linear, are designed. The influence of stent structural parameters on the bending performance of the stent is studied using finite element method and experimental methods. 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 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.