钴铬合金靶向药物洗脱支架疲劳强度的有限元分析

Fatigue strength analysis of Co-Cr alloys targeted drug eluting stent by finite element method

药物洗脱支架(drug eluting stent,DES)植入血管后的疲劳性能,对冠状动脉支架植入术的成功有着重要影响。利用有限元方法分析支架在使用过程中的应力分布,通过绘制Goodman曲线图分析支架的疲劳强度,并通过计算支架的安全系数来反应支架的安全性。分析发现,支架变形过程中的大应力分布区始终位于支撑体的圆弧部位。Ⅰ型支架和Ⅱ型支架的所有特征点在Goodman曲线图中均位于疲劳极限以下,不会造成支架在使用过程中的疲劳失效。此外,支架的安全系数与支架槽的长、宽、高均成负相关。该分析可为支架的设计提供参考依据。

After the implantation,the fatigue performance of the drug eluting stent has significant influence on the success of coronary stent implantation.The finite element method was used to analyse the stress distribution of the stent during the process of using,and the fatigue strengh was analysed according to the Goodman curve.The security of the stent was described by the safety factor.It could be found from the analysis that the high-stress area always located in the arc parts during the deformation process.However,all the feature points of the two kinds of stents located under the fatigue limit line.So the failure by fatigue of the stents will not happen during the using process.Moreover,there was a negative correlation between the safety factor of the stent and the length,width,and thickness,respectively.The results prove that the fatigue strength of the stent can be analysed successfully through the finite element method,which provides the reference for the stent design.