Citation

Zeidler F, ichelmann F. Int. J. Crashworthiness 1998; 3(1): 7-16.

Copyright

(Copyright © 1998, Informa - Taylor and Francis Group)

DOI

unavailable

PMID

unavailable

Abstract

In the last two decades the front end structures of all cars were optimized in crashes against rigid barriers in order to guarantee the highest level of self protection. As a consequence, the stiffness of the front end structure was directly related to the own mass of the car. This effect is independant of the crash test speed if safety standards demand the same test speed for all cars. Although German accident statistics still indicate that twice as many fatalities of car occupants occur in single vehicle accidents as in car-to-car collisions, the problem of compatibility has to be taken into account because of the high number of injuries in car-to-car collisions. Therefore, for compatibility reasons, for years experts have recommended higher crash speeds for small cars and lower crash speeds for large cars; a demand which of course is not in accordance with the safety standards. Based on the state-of-the-art cars, experts agree that the stiffness of the front end of a small car should be increased and the stiffness of the front end of a large car should be decreased. This energy-balance concept is briefly described in this paper. Unfortunately, the offset test procedure according to ECE-R 94/01, which is a structural test, is now used as a rating system with an increased test speed. This paper describes the consequences of these tests for cars of different weight which were especially designed for compatibility. With the increase of the test speed as a side effect, which is completely unreasonable, the energy unbalance is of more and more significance: large cars are tested at a higher crash severity level than small cars. This effect is totally contradictory to the basic demand for compatibility. As a consequence, a mass-dependent test speed is proposed to avoid this special disadvantage of the offset test procedure using a deformable barrier.