Makhijani V B, Yang H Q, Dionne P J, Thubrikar M J
CFD Research Corporation, Huntsville, Alabama 35805, USA.
ASAIO J. 1997 Sep-Oct;43(5):M387-92.
A computational, three-dimensional coupled fluid-structure dynamics model was developed for a generic pericardial aortic valve in a rigid aortic root graft with physiologic sinuses. Valve geometry was based on that of the natural valve. Blood flow was modeled as pulsatile, laminar, Newtonian, incompressible flow. The structural model accounted for material and geometric nonlinearities and also simulated leaflet coaptation. A body fitted grid was used to subdivide the flow domain into computational finite volume cells. Shell finite elements were used to discretize the leaflet volume. A finite volume computational fluid dynamics code and finite element structure dynamics code were used to solve the flow and structure equations, respectively. The fluid flow and structural equations were coupled using an implicit "influence coefficient" technique. Physiologic ventricular and aortic pressure waveforms were prescribed as the flow boundary conditions. The aortic flow field, valve structural configuration, and leaflet stresses were computed at 2 msec intervals. Model predictions on aortic flow and transient variation in valve orifice area were in close agreement with corresponding experimental in vitro data. These findings suggest that the computer model has potential for being a powerful design tool for bioprosthetic aortic valves.
针对具有生理窦的刚性主动脉根部移植物中的通用心包主动脉瓣，开发了一种计算三维流固耦合动力学模型。瓣膜几何形状基于天然瓣膜。血流被建模为脉动、层流、牛顿、不可压缩流。结构模型考虑了材料和几何非线性，还模拟了瓣叶贴合。使用适体网格将流动域细分为计算有限体积单元。壳有限元用于离散瓣叶体积。分别使用有限体积计算流体动力学代码和有限元结构动力学代码求解流动和结构方程。使用隐式“影响系数”技术耦合流体流动和结构方程。将生理心室和主动脉压力波形规定为流动边界条件。以2毫秒的间隔计算主动脉流场、瓣膜结构配置和瓣叶应力。关于主动脉血流和瓣膜孔面积瞬态变化的模型预测与相应的体外实验数据密切一致。这些发现表明，该计算机模型有潜力成为生物人工主动脉瓣的强大设计工具。
