Traumatic rupture of the aorta (TRA) is a leading cause of fatality in motor vehicle crashes. However, its injury mechanisms are still unknown since it is difficult to replicate and evaluate such ruptures experimentally. In this study, the mechanisms of aortic rupture in dynamic pressure loading were investigated using Finite Element (FE) Analysis.

A hyperelastic material model with linear viscoelasticity was used to characterize the mechanical behavior of aorta based on oscillatory biaxial tests and literature data. It was shown that the previous data led to contradictory uniaxial and biaxial responses. A set of new material properties were identified which closely described all the available experimental data.

Furthermore, a Finite Element model of aortic arch was studied under pressure impulse as seen in cadaveric sled tests. Four approaches were used to model the fluid namely, Lagrangian, Eulerian, Arbitrary Lagrangian-Eulerian (ALE), and Smoothed Particle Hydrodynamics (SPH). The Eulerian approach, in which the mesh is fixed in space through which the material flows, was the most complete one in terms of modeling the flow and interaction with the wall, though it required relatively large computational time. In the ALE approach, a Lagrangian material deformation was considered followed by an advection cycle for smoothing the mesh. The result of the ALE approach compared to the Eulerian approach showed less flow and localized deformation. In the SPH formulation, the fluid was represented by particles which interact with one another and the surroundings through specific potential energy functions. The SPH approach exhibited rather idealized behavior of the fluid flow with less computational time. The TRA models were validated against in vitro tests and predicted the most probable location of rupture at the isthmus as indicated in the experiments.