Assessment of Acclimation of 5th Percentile Female and 50th Percentile Male Volunteer Kinematics in Low-Speed Frontal and Frontal-Oblique Sled Tests

In order to accurately represent the response of live occupants during pre-crash events and frontal crashes, computational human body models (HBMs) that incorporate active musculature must be validated with appropriate volunteer data that represents a wide range of demographic groups and potential crash conditions. The purpose of this study was to quantify and compare occupant kinematic responses for unaware (relaxed) small female and midsize male volunteers during low-speed frontal and frontal-oblique sled tests across multiple test conditions, while recognizing, assessing, and accounting for potential acclimation effects due to multiple exposures. Six 5th percentile female and six 50th percentile male volunteers were exposed to multiple low-speed frontal and frontal-oblique sled tests on two separate test days. Volunteers experienced one test orientation and two pulse severities (1 g and 2.5 g) on each test day. A Vicon motion capture system was used to quantify the three-dimensional (3D) kinematics of the volunteers. Peak forward excursions of select body locations were compared within a test day and between test days for the same test condition to determine if and how acclimation occurred. Differences between demographic groups were also compared after accounting for any observed acclimation. Acclimation was not observed within a test day but was observed between test days for some demographic groups and some test conditions. In general, head, neck, and shoulder responses were affected, but the elbow, hip, and knee responses were not. Males generally moved farther forward compared to females during the frontal tests, but both groups moved forward similarly during the frontal-oblique tests. Overall, this study provides new female and male biomechanical data that can be used to further develop and validate HBMs that incorporate active musculature in order to better understand and assess occupant response and injury risk in pre-crash events and frontal crashes.