Effect of Head Restraint Position and Neck Injury Criteria in Rear Impact

2002 ◽  
Author(s):  
John DeRosia ◽  
Narayan Yoganandan ◽  
Frank A. Pintar
Keyword(s):  
Motor Vehicle ◽  
Vehicle Safety ◽  
Bending Moments ◽  
Safety Standards ◽  
Acceleration Pulse ◽  
Head Restraint ◽  
Rear Impact ◽  
Injury Criteria ◽  
Hybrid Iii ◽  
Impact Acceleration

The objective of this study was to determine the forces and bending moments at the top of the Hybrid III dummy neck secondary to rear impact acceleration and evaluate the various proposed injury criteria. Rear impact sled tests were conducted by applying the Federal Motor Vehicle Safety Standards FMVSS 202 acceleration pulse. Differing positions of the head restraint in terms of height (750 and 800 mm) and backset (zero, 50, and 100 mm) were used to determine the axial and shear forces, bending moments, and injury criteria (NIC, Nij, and Nkm). The time sequence of attainment of these parameters was determined along with peak values.

Use of Upper and Lower Neck Load Cell Data From the Hybrid III Dummy to Assess Whiplash Injury Risk

2002 ◽  
Author(s):  
Liming Voo ◽  
Michael Kleinberger ◽  
Andrew Merkle
Keyword(s):  
Injury Risk ◽  
Motor Vehicle ◽  
Safety Evaluation ◽  
Human Head ◽  
Impact Testing ◽  
Vehicle Safety ◽  
Rear Impact ◽  
New Findings ◽  
Hybrid Iii ◽  
Motor Vehicle Safety

Whiplash associated disorders (WAD) of the neck continue to represent a significant societal problem with associated costs estimated at over $5 billion annually. Recent dramatic increases in whiplash-related research has produced some interesting new findings related to its injury mechanism. It has been shown in human volunteer and cadaver experiments that the human head-neck structure often exhibits a transient S-shape during the initial kinematic response (Grauer et al. 1997; Luan et al. 2000; Ono et al. 1997; Yoganandan et al. 1998). Such a finding has significant impact on the injury risk assessment using the instrumented anthropomorphic test dummies in vehicular or sled testing. Unlike the recently developed dummy necks for rear impact testing, such as BioRID and TRID, the Hybrid III neck does not exhibit an S-shape curvature or the so-call “retraction” motion in rear impact testing. Numerous studies have reported that the Hybrid III neck is too stiff for low-speed rear impact testing (Svensson et al. 2000; Yoshida and Tsutsumi, 2001). Nevertheless, the Hybrid III is still being used for motor vehicle safety evaluation in rear impact as it is the only dummy neck that has been incorporated in the US Federal Motor Vehicle Safety Standards (FMVSS).

Passive Seat Belt Design and Standards

1978 ◽  
Vol 22 (1) ◽  
pp. 528-531
Author(s):  
Wesley E. Woodson ◽  
Thomas L. Black
Keyword(s):  
Motor Vehicle ◽  
Seat Belt ◽  
Vehicle Safety ◽  
Writing Performance ◽  
Safety Standards ◽  
The Public ◽  
Passive Restraint ◽  
Motor Vehicle Safety

Recently mandated passive restraint requirements raise the question of how to minimize the possible resistance of the public by putting comfort and convenience requirements into Federal Motor Vehicle Safety Standards. This paper discusses methods for determining potential public complaints and presents some of the problems of writing performance rules that deal with the subjective reactions of the public to discomfort and inconvenience.

Biomechanics of Roof Crush and Rear Impact-Related Neck Injuries

2008 ◽  
Author(s):  
Nicholas Perrone
Keyword(s):  
Public Health ◽  
Public Health Problem ◽  
Vehicle Safety ◽  
Global Public Health ◽  
Neck Injuries ◽  
Injury Biomechanics ◽  
Safety Standards ◽  
Rear Impact ◽  
Roof Structure ◽  
Global Public Health Problem

The importance of vehicle safety as a critical and global public health problem is discussed. Crashworthiness principles are enumerated and reviewed as relevant to this problem. Injury biomechanics in rollover and rear impact cases are considered next. Pertinent vehicle safety standards are discussed. The importance and feasibility of improved roof structure, seatbacks and windows is examined. Some selected pertinent case studies are reviewed and finally conclusions are drawn.

Evaluation of Rear Impact Seat System Performance Using a Combined Load Neck Injury Criteria and Hybrid III Surrogates

2001 ◽  
Author(s):  
Kenneth J. Saczalski ◽  
Joseph Lawson Burton ◽  
Paul R. Lewis ◽  
Todd K. Saczalski ◽  
Peter E. Baray
Keyword(s):  
System Performance ◽  
Dynamic Tests ◽  
Actual Case ◽  
Combined Load ◽  
Occupant Protection ◽  
Rear Impact ◽  
Injury Criteria ◽  
Vehicle To Vehicle ◽  
Hybrid Iii

Abstract Vehicle to vehicle rear impact crash tests and sled buck tests were run to evaluate seat system performance related to Hybrid III surrogate response and comparison with NHTSA proposed combined load injury assessment values, as well as standard injury criteria. The crash and sled buck test impact conditions were modeled after actual case study incidents where changes in the rear impacted vehicle speeds ranged from about 25 to 50 kph. With the exception of one baseline vehicle-to-vehicle rear impact test, the dynamic tests provided side-by-side comparisons, and test-to-test evaluations, of surrogate response in conventional yielding front seats versus much stronger seat systems such as the belt integrated seat designs. Head, neck and chest injury criteria were used in the evaluations, including both the proposed NHTSA combined load neck criteria and SAE J 885 injury values. The surrogate response injury levels for the conventional yielding seats correlated well with the actual case study injury results. The seat comparison response generally indicated much reduced head and neck injury potential to surrogates seated in the stronger seat designs. The dynamic tests also demonstrate the importance of testing within the full vehicle interior structure to insure that floor strength is compatible with seat strength, so as to attain optimum occupant protection in stronger seat designs, and to assess injury risk to occupants in yielding or collapsing seat designs, as well as rear seated occupants, such as children. The tests indicate that quasi-static seat strength measurements made with more realistic “torso body block” load devices can provide reasonable estimates on the ultimate failure modes and dynamic load capabilities of the seat systems if the seat systems are properly mounted to the vehicle. Quasi-static seat strength results are presented for a variety of conventional collapsing seat designs and stronger seat systems like the belt integrated designs. One sled buck test was run with a rear-seated child surrogate to demonstrate the hazard of front seat collapse into the rear seat occupant area. The results of these tests further demonstrate the need for dynamic testing to assess total seat system performance and full occupant protection in rear impacts.

Biomechanical Analysis of Side Release and Top Release Seat Belt Buckles

2003 ◽  
Author(s):  
Anthony Sances ◽  
Srirangam Kumaresan ◽  
Richard Clarke
Keyword(s):  
Motor Vehicle ◽  
Seat Belt ◽  
Large Male ◽  
Biomechanical Analysis ◽  
Vehicle Safety ◽  
Safety Standards ◽  
Emergency Situations ◽  
Motor Vehicle Safety ◽  
European Standards ◽  
Release Force

Various articles suggest that the maximum release force for buckle according to Federal Motor Vehicle Safety Standards (FMVSS) 109 of 133 N is beyond the capability of a large percentage of our population [1, 2]. Inversion studies with a large male in a three-point production belt showed he could not open a side release buckle [3]. Numerous articles and patents reference the potential for entrapment of inverted occupants unable to release the seat belt buckle [4–11]. Various articles and patents discuss the problems associated with entrapment of individuals in fires, water or emergency situations or where the occupant is deprived of oxygen due to positional asphyxia [12]. While the use of seat belts has increased markedly over the years [13], investigations indicate that rollover accidents showed fatally injured occupants in their seats which were entrapped in their vehicle. The forces to release the buckles under full load of the inverted occupants were beyond the physical capacities of the occupants involved. Canadian motor vehicle safety standard 209 (CMVSS 209) requires that a buckle must release with a force of 133 N to the button with a restraining loop force of 666 N. About 80 % of driver’s could not release a buckle that requires 133 N of force on the button [1]. Females could exert about 80 N with their fingers when opening child restraint buckles [14]. Females were generally found to have about half the physical capacity to open buckles compared to males. The maximum buckle release force of 133 N is not found in literature. Dreyfuss in his book indicates various forces for females and males [15]. European standards require that latch plate be ejected, therefore side release buckles are not allowed.

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