1.School of Aeronautics and Astronautics,Sun Yat-sen University,Guangzhou,510000;2.China
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan)
目的 基于合理假设,推导冠脉支架位移及应力分布解析解；结合有限元分析结果,探究支撑筋数目n对其应力大小的影响。方法 解析解：利用弹性力学理论推导出矩形波型冠脉支架一个周期支撑筋在血管收缩压作用下的位移和应力分量解析解；数值解：利用ANSYS有限元分析软件建立支架支撑筋模型,求解得到应力数值分析结果。分析两种方法应力曲线的一致性,验证解析解正确性和适用性；再利用解析解探究支撑筋波峰数量对收缩压作用下应力的影响。结果 解析解与数值解应力曲线一致性极强；波峰数n=6时,横杆环向既有拉应力又有压应力。结论 波峰数n=6时,横杆存在环向应力为零的区域。这样的支架在血管中工作时,能有效避免血管中再狭窄情况的发生。推导的解析解能适用于分析矩形波型支架一个周期支撑筋的力学性能,给深入认识和研究冠脉支架的应力分布以降低介入治疗再狭窄率提供了一种新思路。
Objective To deduce the analytic solution of displacement and stress distribution of coronary stent based on reasonable assumptions, as well as investigate the influence of wave number of support bars on the stress distribution by combining the results of finite element analysis. Methods Establishing a local cylindrical coordinate system to deduce the analytical solution of the displacement and stress components of the periodic support bar of rectangular wave type vascular stent under the action of vascular systolic pressure. Using ANSYS to establish the model of the support bar and calculate the numerical results of stress analysis. By analyzing the consistency of stress curves between two methods, the accuracy and applicability of the analytical solutions were verified. The influence of the number of wave crests of supporting ribs on the stress under systolic pressure was explored by analytic solution. Results The analytical stress curves were basically in conformity with that from the results of ANSYS. It was found that when the number of wave crests was 6, there were both tensile and compressive stresses in the circumferential direction of the cross bar. Conclusions There were stress free position in the circumferential direction of the cross bar when the number of wave crests was 6. Such stents can effectively prevent restenosis in the blood vessels when working. The analytical solution derived can be used to analyze the mechanical properties of one-period support bars of rectangular wave supports, which provides a new idea to cognize and study the stress of coronary stent to reduce the restenosis rate of interventional therapy in the future.