Servicio de Información Comunitario sobre Investigación y Desarrollo - CORDIS

FP5

CHILD Informe resumido

Project ID: G3RD-CT-2002-00791
Financiado con arreglo a: FP5-GROWTH
País: France

D8c: Reconstruction Quality Score (INRETS)

In order to identify injury mechanisms and to establish injury risk curves, accident analyses are carried out and afterwards accident reconstructions performed in laboratories. Crash test conditions such as equivalent energy speed (EES), overlap, angulations and body vehicle heights are assessed by experts and partly based on empirical methods. Moreover, particularly in the case of injured children using CRS's, parameters such as adjustment of belt or harness and especially misuses are difficult to determine. Consequently, it seemed necessary to develop methods aiming at eliminating those approximations leading to weak correlations. It is the case of accident speed, overlap and angulations, which have an effect on the car(s) deformations and consequently on the loads sustained by the occupants. Over the years, a lot of effort has been devoted to increase the accuracy of the evaluation of these accident parameters from accident scene evidences (see for instance McHenry et al., 2003 or Moser et al., 2003). But in the evaluation of the quality of the reconstruction, the deformation sustained by the vehicle(s) in the reconstruction cannot play an important role, either because they are calculated by simulation or they are considered globally. It seems that no systematic approach based on the study of the deformation of well- identified vehicle structural points has been tried so far. The use of this new method requires that vehicle deformations has been measured on the crushed parts, compared and submitted to basic statistical functions such as average value, standard deviation and variance in order to establish a quality score of the reconstruction.

This method is intended to help experts to assess the quality of the reconstruction of a real world accident in terms of correlation of dissipated energy between a vehicle involved in a real world accident and its homologue used for the reconstruction. For this purpose, a "Reconstruction Quality Score" based on the deformations of the main relevant vehicle body parts -- longitudinal members, damper housing, A pillar, foot well, etc, is calculated. There is an infinite number of ways to calculate a reconstruction quality from the comparison of vehicle deformations. The present software, after an extensive comparison of various candidate indicators and score weighing methods, led to define a composite score based on the absolute values of the deformation differences, the relative values of the deformation differences. Weighing factors depending on the deformation variability at each considered point and depending on its position with respect to the impact point.
For each point, a score is computed from an absolute and a relative deformation indicators and then, all scores are weighted and mixed in order to give a global quality score.

At present, a software developed under Java and a database developed under MySQL are available for the partners of the CHILD consortium for frontal crash analysis. Further development will be undertaken for the lateral crash configuration

Reported by

INRETS LBHM
25 AVENUE FRANCOIS MITTERAND
69675 BRON
France
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