单叶式主动脉瓣流固耦合仿真与力学性能分析

Simulation and Mechanical Properties Analysis of Unicuspid Aortic Valve Fluid-structure Interaction

目前,单叶式主动脉瓣(unicuspid aortic valve,UAV)的研究大多集中在对患者的相关疾病进行统计分析,而对其力学性能的研究较少。通过COMSOL有限元软件,建立了基于任意拉格朗日-欧拉法的三维UAV流固耦合模型,分析了不同条件下的UAV在整个收缩期的血流动力学特征。首先,通过对Poiseuille流和圆柱体后弹性梁流致振动的仿真,验证了所建立模型和算法的有效性。随后,对UAV问题进行了流固耦合仿真和较为深入地力学性能分析。结果显示,UAV相较于正常主动脉瓣表现为狭窄,具有过高的跨瓣压差以及流体剪切应力;低血流流量下的UAV在具有低血流速度和低跨瓣压差的同时表现为狭窄;钙化程度的加剧会造成UAV再狭窄,形成一个恶性循环。

At present,studies on the mechanical properties of unicuspid aortic valve(UAV)were rare as most of the research works were focused on the statistical analysis of related diseases in patients.A 3D fluid-structure interaction model based on the arbitrary Lagrangian-Eulerian method was established by utilizing the COMSOL finite element software and the hemodynamic characteristics of UAV throughout the systolic period under different conditions were analyzed.Firstly,the effectiveness of the proposed model and algorithm was verified by simulating the Poiseuille flow and the flow-induced vibration of an elastic beam behind a cylinder.Then,fluid-structure interaction simulation was performed for UAV problems and its mechanical properties were analyzed.The results show that UAV is narrower and has higher transvalvular pressure gradients and fluid shear stress when compared to the normal aortic valve;under the condition of low blood flow,UAV is narrow and has a low blood flow velocity and low transvalvular pressure gradients;the aggravation of calcification can make UAV narrow again,which forms a vicious cycle.