“平面支架”实验验证支架力学行为公式

Verification of Stent Mechanical Formulas by“Planar Stent”Experiment

为了验证支架弹性径向刚度公式和塑性极限压力公式的准确性,提出了"平面支架单元"的概念,并根据血管支架真实弯曲单元的结构,制作了相同结构的平面形式支架单元试件.利用MTS材料试验机对平面支架单元试件进行拉伸试验,将试件实验测量的压力-半径曲线与弹性径向刚度和塑性极限压力公式预测的压力曲线对比.结果显示,支架撑开的弹性阶段,实验测量的弹性径向刚度和公式计算的弹性径向刚度差值在3%以内,进入塑性阶段,实验得到的曲线与公式接近.实验验证了这两个公式准确且精度较高.

To verify the formulas of elastic radial stiffness and plastic limit pressure of stents, the conception of ＂planar stent cell＂ was proposed and a planar stent specimen was produced according to the real curved structure of an intravascular stent. Tensile experiments of ＂planar stent cell＂ were then performed using MTS （material test system） equipment, and the experimental pressure-radial curves were compared with the ones predicted by formulas of elastic radial stiffness and plastic limit pressure. The results show that at the elastic stage of stent expansion, the difference of elastic radial stiffness between experimental measurements and formula-calculated values was less than 3% ; at the plastic stage, the two curves obtained by experiment and formula were close. The experiments confirmed the accuracy and precision of the two formulas.