Citation

Muller JT. Proc. Am. Assoc. Automot. Med. Annu. Conf. 1966; 10: 135-140.

Copyright

(Copyright © 1966, Association for the Advancement of Automotive Medicine)

DOI

unavailable

PMID

unavailable

Abstract

Sometimes it seems puzzling to fit together the injuries sustained in a car crash where the passenger survives and the fact that the belt is broken by the impact. Dynamic injuries or injuries caused by forces which act only for a limited period of time appear to be much milder when considering the peak forces which are involved. The relationship of the impulse or the transient force operating over the impulse time interval and the reaction of some parts of the human body are the subject of this paper. The specific section considered here is the hip section of a male passenger. The conclusions seem to indicate that it is possible for the human body to sustain dynamic loads far in excess of those administered statically and that the amount of bodily injury is dependent upon the time interval of the action. The failure of the belt is simply a case of overloading and except for the dynamic change in response behavior of the webbing material, once a critical value is exceeded, the belt resistance will collapse. The area and mass involved are so small that this will occur in a few milli-seconds -- usually less than one or two. Nevertheless, though the injury was of a severe nature, it is still far more acceptable than the residual velocity due to the breaking of the belt. The passenger in this case was fortunate enough to be jammed in the car and thus avoid being thrown out. It must be realized that the velocity at the time of failure was still considerable (approximately 70% of the initial velocity) and would have caused further fatal injuries like those received by another passenger in this car who was not fortunate enough to be constrained and was thrown through the windshield fracturing his skull. All this seems to point to the desirability to increase the breaking strength of present day belts. It is suggested that loop loads of at least 10,000 lbs. should be required. It is quite evident that the injuries due to belt pressure are to be preferred to those caused by collision after belt failure.