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Head Excursion of Seat Belted Cadaver, Volunteers and Hybrid III ATD in a Dynamic/Static Rollover Fixture
ISSN: 0148-7191, e-ISSN: 2688-3627
Published November 12, 1997 by SAE International in United States
Annotation ability available
In rollovers, belted occupants sustain a lower fatality rate compared to unbelted occupants primarily due to lower risk of partial or full ejection. However, seat belt and occupant compartment designs found in most current vehicles do not prevent head contact with the vehicle interior during a rollover because of occupant torso and head excursion that result from the rollover dynamics. An experimental study was conducted to simulate the airborne phase of a rollover. The goals of this study were to: 1) quantify the effect of restraint anchor locations and belt component designs in reducing head excursion, and 2) to better correlate the response between humans and an Anthropomorphic Test Device (ATD) during the high angular roll rate of the airborne phase of a rollover.
A Head Excursion Test Device was designed to rotate a restrained occupant about an axis to approximate the inertial loading experienced during the airborne phase of a rollover. Overall occupant kinematics were recorded with onboard video cameras and analyzed to determine vertical and lateral head displacements. Static tests were carried out using human volunteers, and both static and dynamic tests were conducted with a Hybrid III ATD and a human cadaver. In addition to the test subject, webbing length and angle, latch plate design and restraint pretensioning were used as control variables for evaluation of head excursion.
A total of 80 excursion tests were conducted: 51 tests with a Hybrid III 50th percentile male ATD (20 static and 31 dynamic), 18 tests with a cadaver (7 static and 11 dynamic) and 11 static tests with two male volunteers. In tests using a two-point lap belt, belt angle was more significant than overall belt length in reducing head excursion. Results indicated that vertical head excursion was minimized with a steep lap belt angle and short webbing length. Tests utilizing a three-point lap and torso restraint demonstrated that the torso belt reduced vertical head excursion primarily by restricting forward torso rotation. Furthermore, increasing the belt webbing pretension load reduced vertical and lateral head excursion. Comparison of results from human volunteers, cadaveric and Hybrid III ATD subjects in static tests indicated that the Hybrid III ATD had the least vertical excursion. Dynamically, the Hybrid III ATD had less vertical and lateral excursion than the cadaver.
Results from this study may be useful in future seat belt design. Results also suggest that while the currently available Hybrid III ATD is a useful tool in testing the effectiveness of restraint system parameters, it may not fully simulate vertical and lateral head excursion of humans in rollover conditions.
CitationMoffatt, E., Cooper, E., Croteau, J., Parenteau, C. et al., "Head Excursion of Seat Belted Cadaver, Volunteers and Hybrid III ATD in a Dynamic/Static Rollover Fixture," SAE Technical Paper 973347, 1997, https://doi.org/10.4271/973347.
- Traffic Safety Facts, 1993, NHTSA, US DOT, October 1994.
- Cohen, D. and Digges, K., “Rollover Crashworthiness Classification and Severity Indices,” 12th International Technical Conference on Experimental Safety Vehicles, NHTSA, 1989.
- Digges, K.H., Malliaris, A.C., Ommaya, A.K., and McLean, A.J., “Characterization of Rollover Casualties,” 1991 International Conference on the Biomechanics of Impact, Berlin, 1991.
- Evans, L., “Restraint Effectiveness, Occupant Ejection from Cars, and Fatality Reductions,” Accident Analysis and Prevention, Vol. 22, No. 2, 1990.
- Bahlina. G.S.. Bundorf. R.T.. Kaspzyk, G.S.. Moffatt. E.A.. Orlowski, K.O. and Stocke, J.E., “Rollover and Drop Tests - The Influence of Roof Strength on Injury Mechanics Using Belted Dummies,” SAE 902314, 34th Stapp Conference, Orlando, 1990.
- Shoemaker, N.E., “Study of Human Kinematics in a Rolled Over Automobile,” Cornell Aeronautical Laboratory, Inc., Report No. YM-1246-D-1, June 1959.
- Stone, K., “Occupant Protection During Vehicle Rollover,” 5th International Technical Conference on Experimental Safety Vehicles, June 1974.
- Johnson, A.K. and Knapton, D.A., “Occupant Motion During a Rollover Crash,” DOT HS 806 646, November 1984.
- Obergefell, L.A. and Kaleps, I., “Prediction of an Occupant's Motion During Rollover Crashes,” 30th Stapp Car Crash Conference, October 1986.
- Arndt, M.W., Mowry, G.A., Dickerson, C.P. and Arndt, S.M., “Evaluation of Experimental Restraints in Rollover Conditions,” SAE 952712, 39th Stapp Car Crash Conference, Coronado, CA, 1995.
- Herbst, B., Forrest, S., Wang, P., Chng, D., Friedman, D. and Friedman, K., “The Ability of Three-Point Safety Belts to Restrain Occupants in Rollover Crashes,” 15th International Conference on the Enhanced Safety of Vehicles, Melbourne, 1996.
- Friedman, K., Friedman, D., Forrest, S., Meyer, S., Herbst, B., Chng, D. and Wang, P., “Restraint Effectiveness During Rollover Motion,” 1996 International IRCOBI Conference, Dublin, 1996.
- Arndt, M.W., Mowry, G.A., Baray, P.E. and Clark, D.A., “The Development of a Method for Determining Effective Slack in Motor Vehicle Restraint Systems for Rollover Protection,” SAE 970781, 1997.
- James, M.B., Allsop, D.L., Nordhagen, R.P. and Decker, R.L., “Injury Mechanisms and Field Accident Data Analysis in Rollover Accidents,” SAE 970396, 1997.
- Orlowski, K.F., Bundorf, R.T. and Moffatt, E.A., “Rollover Crash Tests - The Influence of Roof Strength on Injury Mechanics,” 29th Stapp Car Crash Conference, SAE 851734, 1985.