Construction parametric model and stress analysis of the biopresthetic heart valve

In order to improve long-term durability of bioprosthetic heart valve, stress distribution of bioprosthetic heart valve leaflets with different shapes under the same load is analyzed and compared based on finite element method. Combining traditional design theories and modern design methods, we create the cylindrical, spherical, paraboloidal and ellipsoidal curved surfaces in accordance with the geometrical equations in the appropriate frame ordinal. Based on the stress analysis of two kinds of curved surfaces, we take turns to create relative inverse conic curved surfaces which satisfy the actual condition. Meanwhile, the space positions of boundary curves and important points are determined by the intersected curves and axis of revolution. Geometrical design and the finite element analysis could provide direct and useful information for the bioprosthetic heart valve designer. The experimental results of the finite element analysis reveal that stress distribution of different bioprosthetic heart valve leaflets is quite different in diastole time. Ellipsoidal valve leaflets have the following advantages over spherical, paraboloidal and cylindrical valves leaflets: one is that the peak stress area of ellipsoidal valve leaflets is comparatively far from seam position, the other is that the maximal primary stress of ellipsoidal valve leaflets is lower than that of spherical, paraboloidal and cylindrical valves leaflets. Therefore, mechanical properties of ellipsoidal valves leaflets are superior to those of spherical, paraboloidal and cylindrical valves leaflets.