3D Residual Stress Field in Arteries: Novel Inverse Method Based on Optical Full-field Measurements

Arterial tissue consists of multiple structurally important constituents that have individual material properties and associated stress-free configurations that evolve over time. This gives rise to residual stresses contributing to the homoeostatic state of stress in vivo as well as adaptations to perturbed loads, disease or injury. The existence of residual stresses in an intact but load-free excised arterial segment suggests compressive and tensile stresses, respectively, in the inner and outer walls. Accordingly, an artery ring springs open into a sector after a radial cut. The measurement of the opening angle is commonly used to deduce the residual stresses, which are the stresses required to close back the ring. The opening angle method provides an average estimate of circumferential residual stresses but it gives no information on local distributions through the thickness and along the axial direction. To address this lack, a new method is proposed in this article to derive maps of residual stresses using an approach based on the contour method. A piece of freshly excised tissue is carefully cut into the specimen, and the local distribution of residual strains and stresses is determined from whole-body digital image correlation measurements using an inverse approach based on a finite element model

Caractérisation des propriétés mécaniques d'un tronçon d'aorte par méthode inverse basée sur une mesure ex-vivo du champ de déformations

National audienceCette contribution a pour objectif de caractériser les propriétés hyperélastiques du tissu composant l'aorte humaine. Pour cela, un nouveau dispositif de mesures ex vivo du champ de déformations est employé en parallèle avec une méthode inverse reposant sur des simulations éléments finis

Regional identification of mechanical properties in arteries

International audienceAortic aneurysms are often characterized by localized changes in aortic wall composition and structure that result from the degradation of elastin, loss of smooth muscle cell function, and remodeling of collagen. Correlations between wall composition and local mechanical properties can potentially provide insight into conditions that render a vessel susceptible to failure. Previous work has shown that chronic angiotensin-II infusion in ApoE-/- mice often results in dissecting aneurysms (Bersi et al. 2012). The objective of this work is to establish a new protocol able to characterize in vitro the local mechanical properties of arteries on the murine model

Caractérisation des propriétés mécaniques d'un tronçon d'aorte par une méthode inverse basée sur des mesures ex-vivo du champ de déformations

Cette contribution a pour objectif de caractériser les propriétés hyperélastiques du tissu composant l'aorte humaine. Pour cela, un nouveau dispositif de mesures ex-vivo du champ de déformations est employé en parallèle avec une méthode inverse reposant sur des simulations éléments finis