Understanding aortic dissection through phase field fracture modeling in curved geometries

Aortic dissection is a fracture problem where a tear in the intima propagates helically along the aorta’s axial direction. This leads to delamination between layers of the aortic wall and the creation of the false lumen where blood can enter and cause potential problems like rupture. The mechanism for aortic dissection is unclear due to the complex coupling of the loading, the curved geometry and the anisotropy of the aortic wall. In this work, we implement a phase field fracture modeling with a fiber-reinforced material model for the aortic wall using ABAQUS material subroutine VUMAT. The model is tested through benchmark fracture problems. It is then used to study how crack propagates in idealized curved geometries such as along a bended cylinder with varying degrees of Gaussian curvature. This provides insight on how curvature and the initial tear’s location affect the crack path, which is critical to understand aortic dissection propagation. Through modeling the aortic wall as a multi-layer composite, the model will also help to understand how the delamination occurs along layers of the aortic wall. Furthermore, our implementation opens the way to integrate solid-fluid interactions through Abaqus and Xflow to study how the false lumen is developed in the dissection process.