DEVELOPMENT OF A CRASHWORTHY SYSTEM: INTERACTION BETWEEN CAR STRUCTURAL INTEGRITY, RESTRAINT SYSTEMS AND GUARDRAILS 2001-06-0052

In the development of a crashworthy road transport system, guard-rails could play an important role in preventing frontal collisions on roads without separated lanes and in avoiding collisions with roadside objects. Crash pulses in crashes into guard rails may differ from e.g. car-to-car collisions, concerning the duration and mean acceleration. If the characteristics of crash pulses into guard-rails differ from those used in the design of vehicle interior restraint systems, it may influence the performance of these systems.. Collisions with soft guardrails, such as wire ropes, may often have pulse duration of 200 ms or more. The performance of e.g. airbag systems in collisions with such duration is rarely studied.

This study presents the results of six crash tests, carried out with identical vehicles running into three types of guard rails at two different test speeds, 80 and 110 km/h, and at two different impact angles, 45° and 20° respectively. The three tested guard-rails were: a flexible barrier - a wire rope, a semi-rigid barrier - a W-beam guard rail and a rigid type - the concrete barrier. The characteristics of these types of guardrails were found to vary a lot concerning the transferred crash severity and physical behavior. The airbags did not deploy in either of the two wire-rope tests, whereas they deployed in the tests with concrete barriers and W-beam barriers at 45°, 80 km/h. Severe car deformations occurred in the 45°, 80 km/h test with the concrete barrier, while no interior deformation occurred in the wire rope and W-beam tests. The tests demonstrated the wide range of crash behavior with different barriers and guard-rails. Furthermore they demonstrated the importance of choosing the right barrier for a particular need in road construction.