3-DIMENSIONAL COUPLED FLUID-STRUCTURE SIMULATION OF PERICARDIAL BIOPROSTHETIC AORTIC-VALVE FUNCTION

A computational, three-dimensional coupled fluid-structure dynamics mo del was developed for a generic pericardial aortic valve in a rigid ao rtic root graft with physiologic sinuses. Valve geometry was based on that of the natural valve. Blood flow was modeled as pulsatile, lamina r, Newtonian, incompressible flow. The structural model accounted for material and geometric nonlinearities and also simulated leaflet coapt ation. A body fitted grid was used to subdivide the flow domain into c omputational finite volume cells. Shell finite elements were used to d iscretize the leaflet volume. A finite volume computational fluid dyna mics code and finite element structure dynamics code were used to solv e the flow and structure equations, respectively. The fluid flow and s tructural equations were coupled using an implicit ''influence coeffic ient'' technique. Physiologic ventricular and aortic pressure waveform s were prescribed as the flow boundary conditions. The aortic flow fie ld, valve structural configuration, and leaflet stresses were computed at 2 msec intervals. Model predictions on aortic flow and transient v ariation in valve orifice area were in close agreement with correspond ing experimental in vitro data. These findings suggest that the comput er model has potential for being a powerful design tool for bioprosthe tic aortic valves.