人工机械心瓣启闭过程的ALE有限元分析*
ALE Finite Element Analysis of the Opening and Closing Process of the Artificial Mechanical Valve
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摘要: 本文采用任意拉格朗日-欧拉(ALE)有限单元法,将血液视为不可压缩粘性流体,同时将人工机械瓣简化为定轴转动刚体,建立了机械心瓣-血液耦合运动二维计算模型,解决了人工机械瓣启闭过程的计算问题。对St.Jude瓣启闭过程的数值分析表明:1.St.Jude瓣启闭过程包括四个阶段,即:Ⅰ.开启相;Ⅱ.开启保持相;Ⅲ.关闭相;Ⅳ.关闭保持相。2.St.Jude瓣关闭时回流明显,伴有显着水击效应。3.在启闭过程中,高剪力区位于两瓣叶间及瓣环附近。本文的研究突破了以非耦合的方法研究心瓣启闭过程的局限性。Abstract: Employing arbitrary Lagrangian-Eulerian (ALE) finite element method, this poper studies the opening and closing process of a St. Jude medical valve through a two-dimensional model of the mechanical valve-blood interaction in which the valve is regarded as a rigid body rotating around a fixed point, and the blood is simplified as viscous incompressible Newtonian fluid. The numerical analysis of the opening and closing behaviour of as St. Jude valve suggested that: 1. The whole opening and closing process of an artificial mechanical valve is consisted of four phases: Ⅰ Opening phase; Ⅱ Opening maintenance phase; Ⅲ Closing phase; Ⅳ Closing maintenance phase. 2. The St. Jude medical valve closes with prominent regurgitat which results in waterhammer effect. 3. During the opening and closing process of the St. Jude valve,high shear stresses occur in the middle region of the two leaflets and on the valve ring. The present model has made a breakthrough on the coupling computational analysis considering the interactive movement of the valve and blood.
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