Optimization of passive head restraint for IIHS low speed rear impact

Abstract

Research and/or Engineering Questions/Objective: Active headrest is usually utilized to mitigate the whiplash injury to the occupant from the rear impact by way of moving forward during the collision to shorten the distance and the contact duration between the occupant head and the headrest thus reduce the neck injury index. But the spread application of the active headrest is limited due to its high cost. This paper explore the approach of applying a passive head restraint to alleviate the whiplash injury during the rear impact. Methodology: Aimed at earning high rating of GOOD in the rear impact condition in IIHS through minimize the neck injury, this paper presents the method of development and optimization of head restraint insert/surface and seat back suspension and the by way of simulation and vehicle test. Results: The rigidity distribution of seat back suspension, and quality of the integration design of head restraint foam and insert have great impact to the neck injury resulted from the rear collision. In order to keep the seat comfort, a space between the occupant head and the head restraint surface has to be maintained. In the premise of satisfying the seat comfort to the greatest extend, by way of adjusting seat back suspension and the head restraint insert/surface, the head restraint can rapidly contact the occupant head in the collision, thus reduce the shear load and tension to the neck, and earning highest rating of GOOD in IIHS. Limitations of this study: This paper study the rear impact load case of IIHS only, does not consider 2012 version CNCAP and Euro NCAP. But the approach set forth in this article can be applicable for mitigate the neck injury in the rear impact. What does the paper offer that is new in the field in comparison to other works of the author This paper study the development and optimization of passive head restraint to improve the occupant protection performance of the head restraint in the rear impact with the minor cost increase. The paper offers the active contribution in lower the cost and the vehicle mass. Conclusion: In the premise of satisfying the seat comfort to the greatest extend, by way of adjusting head restraint insert/surface and seat back suspension, the headrest can rapidly contact the occupant head in the collision, thus reduce the shear load and tension to the neck, and earning highest rating of GOOD in IIHS. This paper study the development and optimization of passive head restraint to improve the occupant protection performance of the headrest in the rear impact without increase the cost. The paper offers the active contribution in lower the cost and the vehicle mass. © Springer-Verlag 2013.