Chest injuries in small overlap impacts: field data and full-scale vehicle tests

Frontal crashes can be classified as full, offset, or small overlap impacts. Although the former two impacts have received considerable attention in crashworthiness and promulgation of worldwide standards, small overlap crashes have undergone limited analyses from field and laboratory investigation perspectives. The objective of the present study was to analyze small overlap impacts using data from the Crash Injury Research and Engineering Network database and determine the head-neck-torso kinetics from full-scale vehicle tests. Head-neck kinematics and loads, and chest deflections from four cruxes were obtained from the Test Device for Human Occupant Restraint (THOR – NT version without modifications), positioned in the driver seat. Head contact occurred with the forward and outboard interior components of the vehicle; traditional crash metrics are inadequate descriptors; and less than full structural engagement contributes to increased vehicle deformations, enhanced occupant motions, and injury susceptibility. The mechanism of head and torso injuries was hypothesized to be due to the asymmetric loading and kinematics of the thorax and head-neck complex, resulting in sagittal and coronal motions with less than optimal interaction with the frontal airbag. Acknowledging that these impacts have not been systematically analyzed for injuries, mechanisms, occupant kinematics, and dummy measures such as multi-point sensing and head-neck trajectories and loads, the present study sheds light in these areas..