3D residual stress field in arteries: a method combining optical full-fields measurements and finite element reconstruction

Arterial tissue consists of multiple structurally important constituents which have individual material properties and associated stress-free configurations that evolve over time. This gives rise to residual stresses contributing to the homeostatic 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 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 paper 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