Modelamiento y simulación numérica de un ensayo de presurización

ABSTRACT

In order to reliably assess the rupture-risk of the aorta – along with the hazardousness index of cardiovascular diseases or other extreme conditions, and the effect of possible treatments – it is necessary to know the damage mechanisms that lead to it. In this work, the mechanical damage of hypoxic aortic tissue is characterized, numerically predicting its response when subjected to a bulge-test type of pressurization state. The mechanical behavior of the aortic wall, is described using a hyperelastic material model with two transverse-isotropy directions and an isotropic damage model; both experimentally calibrated, from previously reported uniaxial tensile-test results, performed on thoracic aorta samples of lambs exposed to chronic hypobaric hypoxia. A melatonin-treated group is studied in contrast to a control group. Once the constitutive model is calibrated, its performance is evaluated via the numerical simulation of the bulge-pressurization test; in which the quasi-static response of a quarter-disk shaped structure, fixed along its curved perimeter, and loaded out of its plane by a pressure, or force per unit area permanently normal to the loaded area, its analyzed.

Keywords
hyperelasticity; isotropic mechanical damage; aortic wall; bulge test; hypoxia