Title: Effects of pre-impact body orientation on traumatic brain injury in a vehicle–pedestrian collision

Authors: Atsutaka Tamura, Yuko Nakahira, Masami Iwamoto, Kazuaki Nagayama, Takeo Matsumoto

Addresses: Biomechanics Laboratory, Toyota Central R&D Labs, Inc, Yokomichi Nagakute, Aichi-gun 480 1192, Japan; Biomechanics Laboratory, Nagoya Institute of Technology, Gokiso-cho Showa-ku, Nagoya 466 8555, Japan; Toyota Research Institute of North America, 1555 Woodridge Ave., Ann Arbor, MI 48105, USA. ' Biomechanics Laboratory, Toyota Central R&D Labs, Inc, Yokomichi Nagakute, Aichi-gun 480 1192, Japan. ' Biomechanics Laboratory, Toyota Central R&D Labs, Inc, Yokomichi Nagakute, Aichi-gun 480 1192, Japan. ' Biomechanics Laboratory, Nagoya Institute of Technology, Gokiso-cho Showa-ku, Nagoya 466 8555, Japan. ' Biomechanics Laboratory, Nagoya Institute of Technology, Gokiso-cho Showa-ku, Nagoya 466 8555, Japan

Abstract: A series of minivan-pedestrian collisions was simulated, and pre-impact body orientation was found to considerably affect the mechanical responses of injury predictors for traumatic brain injury (TBI). The maximum average traction force generated in the cervical spinal cord prior to head strike took its peak value when the pedestrian was subjected to purely lateral head rotation in a sideways collision and decreased by up to one-half in a symmetric manner as the pedestrian changed his direction toward or away from the vehicle. The intracranial strain concentration and the cumulative strain damage measure following the head strike increased by more than 60% as the initial pedestrian configuration changed from the backward to frontal collision. Since the outcome of injury predictors is closely associated with an initial body facing angle to the striking vehicle, regulatory impactor tests should consider the effects of pre-impact body orientation for accurately assessing real-world TBIs in the future.

Keywords: cumulative strain damage measure; CSDM; effective head mass; pedestrian accidents; traction force; TBI; traumatic brain injury; pre-impact body orientation; minivan-pedestrian collisions; cervical spinal cord; intracranial strain concentration.

DOI: 10.1504/IJVS.2008.025076

International Journal of Vehicle Safety, 2008 Vol.3 No.4, pp.351 - 370

Published online: 11 May 2009 *

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