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目的评估血流作用下冠脉支架的疲劳寿命,并在此基础上对支架的疲劳寿命进行优化设计。方法采用Pro/Engineer建立包含植入支架、血液、血栓以及动脉壁的简化组合模型,使用ANSYS有限元分析程序,利用有限元法模拟支架在动脉壁中受血流的周期性作用,并根据支架内的血流动力学分析结果对评估支架的疲劳寿命。以支架的几何参数作为设计变量,通过拉丁超立方抽样方法选取样本点并得到对应的响应值,建立Kriging代理模型,对冠脉支架的疲劳寿命进行优化。结果 Goodman图显示优化后支架是安全的;累积损伤法表明支架最大损伤点处于支架血流流入端的第2交叉面上,优化后支架的疲劳寿命提高30.55%。结论有限元法可对冠脉支架疲劳寿命进行有效的评估,建立Kriging代理模型对支架进行优化设计可以有效地提高支架的使用寿命。
Objective To evaluate the fatigue life of coronary stent under blood flow and to optimize the fatigue life of stent. Methods The simplified combined model of implanted stent, blood, thrombus and arterial wall was established by Pro / Engineer. The ANSYS finite element analysis program was used to simulate the cyclical effect of blood flow in the artery wall by using finite element method. The hemodynamic analysis within the assessment of stent fatigue life. Taking the geometrical parameters of the stent as the design variables, the sample points were selected by the Latin hypercube sampling method and the corresponding response values were obtained. The Kriging agent model was established to optimize the fatigue life of the coronary stent. Results The Goodman diagram showed that the optimized stent was safe. The cumulative damage method showed that the maximum injury point of the stent was on the second cross-section of the stent blood flow inflow end. The fatigue life of the stent was improved by 30.55%. Conclusion The finite element method can effectively evaluate the fatigue life of coronary stent. To establish the Kriging agent model to optimize the stent design can effectively improve the service life of the stent.