Euro NCAP is planning to use a 6 and a 10 year-old anthropomorphic test device (ATD) in rear seats for frontal and side impact assessments. A candidate for the 10 year-old ATD is the in-development Q10. This paper compares the sensitivity of Q10 and HIII-10 year old (HIII) ATDs to pretensioner and force-limiter equipped 3-point belts, and to high back booster child restraint systems (CRS).
Q10 and HIII were placed on the rear bench of a compact vehicle body-in-white. Sled tests were performed with a compact car 64kph ODB acceleration pulse under 4 different test situations:
Using a CRS resulted for both ATDs in a reduction of head acceleration 3msec and an increase of head longitudinal displacement compared to without CRS. Video analysis suggests that additional stroke originates from seatbelt moving out from the CRS belt guide. Without CRS, pretensioner/force-limiter seatbelt usage resulted for both ATDs, in a reduction of head acceleration 3msec and head forward displacement. For both ATDs, usage of CRS increased the chest deflection (average: Q10=+45%, HIII=+10%). HIII responded to pretensioner/force-limiter with a decrease of chest deflection (average -10%), irrespectively of CRS use. Notably Q10 without CRS experienced chest deflection increase (+28%) when using pretensioner/force-limiter seatbelt, possibly due to a smaller shoulder belt migration towards the neck. For Q10 dummy, usage of CRS significantly reduced the left abdomen pressure (-27% for no pretensioner/no force limiter seatbelt, -52% for pretensioner/force limiter one) by preventing the lap belt migration towards the abdomen.
Reported results are based on sled tests. Neither pitch nor yaw are represented despite being showed as potentially relevant for ATD kinematics [Deguchi et al., 2012]. In line with the results of the present study, belt migration to abdomen and neck have been reported for HIII 10 year-old to be less common when using CRS and chest deflection was reported to be higher when using a CRS [Tylko and Bussières, 2012].
In this study, differences in the chest deflection sensitivity to restraint systems were observed between Q10 and HIII dummies. Those differences presumably originate from the difference of behaviour of the shoulder belt on the dummies’ chest. It was also observed for both dummies that the chest deflection was decreasing when the lap belt was sliding up towards the abdomen.
At this point, given the limited scope of this study, it cannot be concluded whether these belt sliding phenomena represent human characteristics or if it is a dummy artefact. Further investigation is needed.
Based on this study herein, the authors recommend using the abdomen pressure sensor when assessing restraint system performance as it seems to be able to identify differences in the phenomenon of lap belt migration.