Computational modeling of tissue damage preceding aortic dissection: a coupled biphasic and reactive viscoelastic framework.

Aortic dissection is a life-threatening pathology characterized by the progressive delamination of adjacent lamellar units within the aortic media. Because this internal damage propagates predominantly along the radial direction of the arterial wall, radial tensile testing has emerged as a particularly relevant experimental configuration to reproduce the mechanical conditions associated with dissection. Several experimental studies have reported the mechanical response of arterial tissues under radial tension, highlighting pronounced viscoelasticity, fluid-driven effects, and progressive damage. However, despite these advances, a coherent constitutive framework capable of reproducing the full mechanical response of arterial tissue subjected to radial tensile loading is still lacking. In this study, we propose a computational model specifically designed to describe arterial tissue behavior under radial tensile testing. The model combines a biphasic formulation, accounting for fluid-solid interactions, with a reactive viscoelastic damage framework to capture time-dependent response and progressive mechanical degradation. Implemented within the FEBio environment, the model is calibrated using experimental radial tensile tests on aortic tissue. The proposed formulation accurately reproduces key experimental features, including stress relaxation, nonlinear stiffening, and damage progression. These results demonstrate that the model provides a physically consistent description of arterial tissue behavior under radial tension and represents a relevant tool for investigating the mechanical mechanisms preceding aortic dissection.