Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

D7a: Validated frontal test procedure proposal (TRL)

One of the aims of the CHILD project was to develop a sled test procedure for determining the effectiveness of Child Restraint Systems (CRSs) in frontal impacts and that was representative of the accidents in the CHILD database. This report is providing details on the CREST frontal test procedure and on the work conducted in the CHILD project to ensure that the testing conditions were reasonably similar in CREST and CHILD accident reconstructions to be still the best compromised to evaluate by the performance of a single sled test the efficiency of child restraint systems in frontal impacts.

The test procedure was expected to specify the geometrical arrangement of the test seat, together with the impact conditions, which needed to be replicated. Although the CREST procedure did not aim first to be used in CRS certification legislation, it is based on ECE Regulation 44 (R44; Economic Commission for Europe; 1981, as amended). However, changes to the R44 procedure were proposed in order to meet the objectives of the CREST project.

The profile for the CREST deceleration corridor was developed around the pulses recorded during accident reconstructions, which lead to a higher plate for the deceleration of the sled, with a change in velocity of 55 km/h and a stopping distance of 650 to 700mm. Modifications were proposed for the test bench shape in order to make it more representative recent cars, this included an anti-sub-marining device. The CHILD frontal test procedure is based on the use the Q-series dummies, which were to be used in the evaluation of the injury criteria that had been developed in another CHILD project Work-Package.

Whilst differences may have existed between the geometry of the vehicles in the CREST and CHILD accident databases, these were not considered within the development of a CHILD frontal sled test procedure. The differences were thought to be of only very minor consequence at the CRS and occupant level. Instead, the key element was considered to be the deceleration pulse. As noted with the development of the CREST test procedure, the accidents in the CHILD accident database tended to be quite severe on account of the selection criteria used and the acceleration profile to be typical of modern vehicles. This means that the accident cases are not representative of the whole real-world accident situation. On this basis, the acceleration profile developed for use in the CHILD project, would not be comparable to the levels of the current legislation used for the certification of child restraints.

A few of the accident reconstruction cases conducted in the CHILD project had considerably different deceleration pulses compared with the CREST corridor profile. The most significant of these differences were explained through consideration of the accident scenario. In the majority of cases, the reconstruction pulse was close to the corridor. However, even for these cases, the pulses did not meet the corridor exactly and a general trend was observed for the decrease from peak value to occur later than was suggested by the corridor. Following consideration of the test conditions and in particular the impact pulse, and on the basis that only little differences would be observed at the CRS and occupant level in sled tests using either the CREST acceleration profile or a new CHLD profile, the CREST corridor can be considered to represent the CHILD accident reconstruction cases. It was accepted that some differences would be expected in the occupant response at this time, the CHILD project partners considered that little difference would be observed up to this point. Therefore peak excursion and instrumentation values used in injury risk prediction would show little difference in tests conducted with either the CREST or a CHILD acceleration profile, assuming that other conditions were consistent.

It is then possible to recommend that the CREST frontal impact test procedure would be appropriate for investigating the injury criteria being developed in another CHILD WP.

Verwandte Informationen

Reported by

TRL Limited
Crowthorne House, Nine Mile Ride
RG40 3GA Wokingham
United Kingdom
See on map
Folgen Sie uns auf: RSS Facebook Twitter YouTube Verwaltet vom Amt für Veröffentlichungen der EU Nach oben