Numerical simulation for evaluating child occupant behaviour in the case of a rear impact

Surcel, Marius-Dorin; Buzatu, Marius-Petrino; Vadean, Aurelian

Affiliations

¹FPInnovations

²École Polytechnique de Montréal, Canada

Abstract

This project uses dynamic simulations to assess the effectiveness of child restraint systems in the case of rear impact, in various installation configurations and for different acceleration pulses.

The model was mainly based on a multi-body method, using the MADYMO software. However, the side wings of the child restraint system have been modelled by the finite-element technique, to ensure a better representation of the contacts between the child dummy and the restraining device.

The study shows that the neck is the most exposed part of the body and in some situations the neck injury criteria overpass the limit values. Thus, the case of the neck injury criteria in tension-extension for the installation using vehicle safety belts, when the result is more than double than the limit value. The simulations employed two triangular pulses, with speed variation of 16 km/h and 25 km/h, and one trapezoidal pulse, with speed variation of 25 km/h. In all cases, the results are proportional with the speed variation. Furthermore, the two triangular pulses give higher values for injury criteria than the trapezoidal pulse.

Installation of a child restraint using rigid anchorages and lower straps offers the best protection for the child passenger in the case of rear-end collision. The acceleration pulse is a crucial factor for the accuracy of tests and the realism of simulations. The principal limitation of the study refers to the injury criteria that are not yet well defined and for which does not exist a consensus in the case of a rear impact.

The paper presents an approach for simulating rearend collision involving child passengers, which could be used for comparative studies of different rear-impact scenarios, such as different acceleration pulses or installations.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv21/09-0029.pdf

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