title: Aortic valve mechanics. Part II: a stress analysis of the porcine aortic valve leaflets in diastole.
abstract: The stress analysis of the porcine aortic valve leaflets in diastole at 80 mm Hg pressure in-vitro is presented. Incorporation of local geometrical asymmetry, material inhomogeneity, anistropy and non-linearity are applied. The stress theory used is a modified form of the thin membrane stress theory for a homogeneous linearly elastic and orthotropic lamina. Modifications are made so that the Hooke's law constitutive equations of stress may be applied to the inhomogeneous, non-lineary elastic and orthotropic thin (membrane) aortic valve leaflets. Stress calculations are made on the premise that the valve is in pre-transition (i.e. low elastic modulus) in the circumferential direction and post-transition (i.e. high elastic modulus) in the radial direction. It is shown that sigmaCIR less than 1 gm/mm2, and for most of the noncoronary leaflet, 0 less than sigmaRAD less than 30 gm/mm2. The areas of highest stress concentrations are in the areas of mutual leaflet coaptation near the Node of Arantii. A progressive increase of radial stresses from the sinus-annulus edge toward the node is observed.
mesh_terms: D000818:Animals; D001021:Aortic Valve / Q000502:physiology*; D001705:Bioprosthesis; D003971:Diastole; D006350:Heart Valve Prosthesis; D066298:In Vitro Techniques; D009200:Myocardial Contraction; D013314:Stress, Mechanical; D013552:Swine