Two-dimensional Finite Deformation Experiments on Dog's Arteries and Veins

Résumé du livre

Most published data on the blood vessel elasticity were obtained either in simple elongation or in simple inflation, but not simultaneously. For finite deformations, such data are insufficient to formulate a three-dimensional stress-strain law even if the material is isotropic and incompressible. Since the blood vessels are highly nonlinear, the Young's modulus for a specimen varies continuously from almost zero at the undeformed state to a large final value, and a starement of the modulus without the corresponding stress level is meaningless. The purpose of the experiments reported in this paper is to illustrate a scheme remedying these difficulties. The tests consist of (1) a longitudinal stretching while the diameter of the vessel was maintained, (2) a lateral distension with the length of the vessel fixed, (3) stress relaxation at fixed strain, and (4) cyclic deformation. Two Lagrangian stresses (stresses based on the vessel's undeformed state) and two extension ratios are used to describe the deformed state of the vessel under a symmetric loading. The nonlinearity in the elasticity, and the dependence of the stress on the strain-history is demonstrated. (Author).