冠脉支架用CoCr合金的弹塑性变形行为

对冠脉支架用CoCr合金材料的弹塑性变形行为进行研究,提出了支架有限元分析与体外实验研究方案;进行压握-扩张实验,揭示了压握对支架力学性能影响的规律,分析了压握-扩张变形时材料应力/应变变化规律。结果表明,支架压握-扩张方案与直接扩张方案相比,最大等效应力和最大残余应变分别上升16.55%和41.18%;材料抗拉强度、延伸率和安全系数分别下降25.73%、32.11%和14.38%。支架数值模拟与体外性能测试实验结果基本一致,其生物力学性能预测误差在10%以内。

Research on elastic and plastic deformation of CoCr alloy used for coronary stents

Study of elastic-plastic deformation of CoCr alloy material used for coronary stents was conducted.The finite element analysis and vitro experimental scheme of stent were proposed.The effect of regularity on stent mechanical properties by constriction was revealed and the variation of material stress/strain in stretch-expansion deformation was analyzed by carrying out constriction-expansion experiments.Results showed that compared with direct expansion,the maximum equivalent stress and residual strain of stent in constriction-expansion increased by 16.55% and 41.18% respectively and the tensile strength,elongation rate and safety factor decreased by 27.73%,32.11% and 14.38% respectively.The numerical simulation results agreed with vitro test results and the predictive error of biomechanical performance was less than 10%.