Kinematics and shoulder belt position of child volunteers when exposed to steering manoeuvres in different restraint systems

Abstract

In car crash scenarios, the head is the most frequently injured body region among children. The main injury mechanism for rear seated restrained children, aged 3-13, who sustained head injuries rated AIS2+, has been found to be the contact of the head with the seat back or with other parts of car interior. Previous studies showed that pre-crash manoeuvres could influence the injury outcome. This thesis quantifies the static belt measurement and the kinematics of child volunteers exposed to steering manoeuvres when restrained on different types of booster cushion. A study was conducted on a test track with 18 children divided into two groups based on their stature. Each child was tested for the static belt measurement on three different booster cushions and performed two steering manoeuvres on each of two of these boosters. Cameras were used to monitor the child during the event. Different parameters were extracted from the videos in order to analyse the kinematics of the child. From the static belt measurement arose that tall children can achieve a better belt fit than short children, especially in terms of shoulder belt position and its “grabbing” effect.The analysis of the kinematics showed that head and torso moved inboard in different ways. The position of the belt on the shoulder was also considered throughout the steering event. The belt slip off the shoulder in 11 trials out of 18 for short children when restrained on the accessory booster, while the slip off occurred only in 2 trials when restrained on integrated booster. For tall children no belt slip off occurred regardless of the type of booster cushion.