Abdominal Response to High-Speed Seatbelt Loading

UNLABELLED: This study was conducted to address injury risk due to high-speed loading of the abdomen by a seatbelt during the pretension phase. Indeed, a better coupling of occupants to the structure of the vehicle in frontal impact can be achieved by a strong pretension of the lap belt. However, out of position considerations have to be taken into account in the development of pretension systems. In particular, when the lap belt is on the abdomen instead of the pelvis at the time of pretension, the penetration of the belt into the abdomen should not lead to injuries. Given the sensitivity of pyrotechnic pre-tensioners to the resistance that they encounter, it is important to have an understanding of the behaviors of both human and dummy abdomens in order to evaluate injury risk. These data are indispensable for the evaluation, with dummy tests, of the effects of pre-tensioners on occupants and for the estimation of the levels of injury risk. New experiments were necessary to obtain data on abdomenbehavior in the pretension range of velocity. Six fixed-back cadavers were tested in two configurations: the belt was placed just above the iliac crest and tensed either symmetrically or not from 11 m/s to 23 m/s. Belt forces and kinematics were measured. Autopsies were performed. Tests were duplicated on the THOR dummy. RESULTS: Load penetration characteristics and injury outcomes are provided and compared to other published data. A spring-damper equivalent model of the abdomen is provided in order to give a means by which to evaluate dummies. The stiffness is 12.9 kN/m and the damping is 765 Ns/m. Static stiffness for the THOR dummy is too high, while the viscous component is four times too low when compared to the tested cadavers.