球囊扩张式冠脉支架扩张变形机理数值模拟方法

研究支架耦合扩张过程三维数值分析的弹塑性大变形基本理论和耦合接触处理算法,采用更新拉格朗日方法,基于动力虚功率原理,给出支架耦合扩张变形的动力显式算法有限元列式和求解步骤.研究支架耦合扩张过程数值模拟关键技术,提出适合支架耦合扩张的有限元建模方法,重点研究支架压握收缩、自由扩张和与血管接触的耦合扩张全过程有限元模拟中的几何建模、材料模型选取、网格划分、边界条件、载荷定义、接触处理等关键技术.阐述冠脉支架样件在试验测试平台上进行实物扩张试验过程,并将试验测试数据与支架扩张数值模拟获得的数据进行分析比较,结果表明支架数值模拟与实物扩张试验之间的误差在许可范围之内,从而证明所建立的支架耦合扩张过程三维数值分析方法是合理的.为支架的优化设计及其扩张过程的有限元模拟提供有力的支持.

Numerical Simulation Method of Balloon-expandable Coronary Stents Expansion Mechanism

The foundational theory of large plastic deformation and contact algorithm for finite element numerical analysis of stent coupling expansion are studied. Based on the principle of virtual power, the finite element formulation for the dynamic explicit analysis of stent coupling expansion and the solving process were presented by using updated Lagrangian method. The key technologies of numerical simulation for stent coupling expansion are studied. The finite element modeling method adapting to stent coupling expansion is proposed. The key issues including geometry modeling, materials selection, meshing, boundary conditions, loads definition, and contact disposal are studied. Moreover, a sample of tubular coronary stent was expanded on the testing platform and its testing data in the experiment were analyzed compared with the result of numerical simulation. The experimental result showed that the error, between numerical simulation and the expansion experiment are in the permission spectrum. Consequently, the 3D numerical analysis method for stent coupling expansion is proved reasonable, and provided a powerful support for the stent optimization design and finite element simulation of stent expansion.