Traumatic rupture of the aorta (TRA) remains the second most common cause of death associated with motor vehicle crashes (MVC), only less prevalent than brain injury. On an average, nearly 8,000 people die annually in the United States due to blunt injury to the aorta. It is observed that over 80% of occupants who suffer an aortic injury die at the scene due to exsanguination into the chest cavity. There have been numerous hypotheses for aortic injury in the literature but it is imperative to draw a distinction between the injury mechanisms in different directions of impact.
Eight real world crashes were reconstructed in two stages using a combination of accident investigation data from the Crash Injury Research and Engineering Network (CIREN) database, finite element (FE) vehicle models, and Wayne State Human Body Model (WSHBM). Further, 16 design of computer experiments (DOCE) simulations were carried out to understand the effect of key factors (Principle Direction of Force (PDOF), impact position, impact angle, velocity of impact, and the bumper profile of striking vehicle) on average maximum principal strain (AMPS) and maximum pressure in the aorta. In order to get a better understanding of the mechanism of TRA, a sensitivity study was performed using a combination of WSHBM and a variation of PDOF. The AMPS and maximum pressure due to longitudinal stretch of the thoracic aorta was the highest at a PDOF of 270 degrees of impact and the occupant seated adjacent to the B-pillar. As the PDOF increased from 250 degrees to 310 degrees, the aortic arch transitioned from a caudomedial motion of the thoracic spine relative to the sternum (owing to thoracic deformation from the intruding B-pillar) to posterior-anterior motion of the thoracic aorta relative to the ascending aorta due to thoracic compression (greater than 300-degree impact).