食管支架变形数值模拟与疲劳寿命的分析研究

Research on Numerical Simulation and Structural Fatigue Life for Esophagus Stent

分析了食管支架在工作中的非线性行为,提出了适合支架有限元分析的假设条件和简化方法,完成了食管支架有限元模型的创建、材料模型的选取和边界条件的设置,并采用牛顿-拉斐逊迭代法完成了食管支架的数值模拟。分析得出支架工作中产生的非对称交变应力是引起支架疲劳断裂的一个主要原因,并用有限元软件对不同头数食管支架的疲劳寿命进行了分析,分析结果显示支架头数越多其疲劳寿命就越长。体外加速模拟疲劳试验的试验结果与有限元计算结果一致。

The nonlinear behavior of stent at work was analyzed.Some assumptions and simplifications were proposed for finite element analysis.Based on that,finite element model creation,selection of material models,boundary conditions and loads of settings were implemented,and the Newton-Raphson method was adopted to complete numerical simulation of stent.Unsymmetrical alternating stress was found that was the major reason for esophagus stent rupture.The fatigue life of different head number of stents were computed by using finite element software.The results show that the more the head number of stent,the longer the fatigue life.The accelerative fatigue experiment in vitro of stent was expressed.The experimental results are consistency with the simulation ones.