Stress Analysis of Normal Human Aortic Valve Leaflets during Diastole

Abstract

Geometry of the normal human aortic valve leaflets during diastole were measured carefully by several different techniques. It was found that each of the three semilunar valve leaflets can be closely approximated by two principal radii of curvature with a limited range of subtending angles. Membrane theory is applied to analyze the stress distribution in the valve leaflets. The computed results are presented to cover ranges of the subtending angle $tH₁ between 180 and 230°, for subtending angle $tH₂ between 70 and 260°, and for radii of curvature ratio R₂/R₁ between 0.6 and 0.9. An alternative method applying the theory of thin shells is also comprehensively discussed. Since the method involves extremely complicated computation procedures, and yet the actual thickness of the valve leaflets is so thin that they behave more like membranes than shells, no effort was made to compare the two methods numerically.