A Study of Standards for Child Restraint System Sled Tests

Abstract

A method is developed for finding the best and worst possible responses of a child dummy in a child seat sled test where the sled deceleration pulse must follow a prescribed corridor. Constrained optimization techniques are applied to a two-degree-of-freedom lumped mass model of the sled test to determine the best and worst sled deceleration pulses, within the prescribed corridor, that produce the minimum and maximum child chest decelerations. A three-dimensional multi-body model is used to predict the values of the peak child chest g's in sled tests with the best and worst sled deceleration pulses. The results are useful as a measure of the variability of child dummy response that can be expected for a prescribed sled deceleration corridor. The standards for child seat safety testing can be evaluated and compared quantitatively using this sensitivity information. Results indicate that some prescribed sled deceleration corridors are too wide, allowing extreme variations in occupant responses, and some are too narrow, or perhaps unnecessarily complex.