Evaluation of the Hybrid III and Q-Series Pediatric ATD Upper Neck Loads as Compared to Pediatric Volunteers in Low-Speed Frontal Crashes

Abstract

Debate exists in the automotive community regarding the validity of the pediatric ATD neck response and corresponding neck loads. Previous research has shown that the pediatric ATDs exhibit hyper-flexion and chin-to-chest contact resulting in overestimations of neck loads and neck injury criteria. Our previous work comparing the kinematics of the Hybrid III and Q-series 6 and 10-year-old ATDs to pediatric volunteers in low-speed frontal sled tests revealed decreased ATD cervical and thoracic spine excursions. These kinematic differences may contribute to the overestimation of upper neck loads by the ATD. The current study compared upper neck loads of the Hybrid III and Q-series 6 and 10-year-old ATDs against size-matched male pediatric volunteers in low-speed frontal sled tests. A 3-D near-infrared target tracking system quantified the position of markers on the ATD and pediatric volunteers (head top, nasion, bilateral external auditory meatus). Shear force (F x ), axial force (F z ), bending moment (M y ), and head angular acceleration ([Formula: see text]) were calculated about the upper neck using standard equations of motion. In general, the ATDs underestimated axial force and overestimated bending moment compared to the human volunteers. The Hybrid III 6, Q6, and Q10 exhibited reduced head angular acceleration and modest increases in upper neck shear compared to the pediatric volunteers. The reduction in axial force and bending moment has important implications for neck injury predictions as both are used when calculating N ij . These analyses provide insight into the biofidelity of the pediatric ATD upper neck loads in low-speed crash environments.

Evaluation of Pediatric ATD Biofidelity as Compared to Child Volunteers in Low-Speed Far-Side Oblique and Lateral Impacts

“…Previously, we quantified the dynamic responses of pediatric volunteers (6-14 years) in low-speed (<4 g) frontal crash conditions (Arbogast et al 2009;) and compared the responses of pediatric volunteers to the Hybrid III and Q-Series 6-and 10-year-old ATDs, noting differences in head and spine kinematics, seating environment reaction loads, and upper neck loads (Seacrist et al 2010(Seacrist et al , 2013. In general, the ATDs exhibited reduced excursions, increased belt loading, and increased upper neck bending moment, resulting in an overestimation of the neck injury criteria.…”

Comparison of Q3s ATD Biomechanical Responses to Pediatric Volunteers

“…Though the adjusted back rest was successful in providing an appropriate posterior environment for the Q3s, the seat belt angles were not able to prevent seat belt slip up the Q3s rounded thorax. Seat belt slip up the rounded thorax has also been observed in other Q-series ATDs and has been highlighted as a biofidelity issue in itself (Lubbe 2009;Seacrist et al 2012Seacrist et al , 2014. We acknowledge that though observed differences between the Q3s and PVs may be attributed to nonbiofidelic aspects of the Q3s, these differences could also be due to the difference in seat belt loading.…”

“…Recently, several studies have taken advantage of pediatric volunteer (PV) data to evaluate the biofidelity of ATDs (Seacrist et al 2010(Seacrist et al , 2013(Seacrist et al , 2014. PV data are more readily attainable compared to pediatric PMHS and are emerging as a valuable tool for evaluation of ATD whole-body kinematic responses.…”

Modeling spatial trajectories in dynamics testing using basis splines: application to tracking human volunteers in low-speed frontal impacts

“…Previously, we have limited comparisons between human volunteer and ATD response to the few children in the data-set who correspond to the ATD size (Seacrist et al 2010(Seacrist et al , 2012 and age (Seacrist et al 2014). The results are consequently more robust to sample size limitations which are common in biomechanical testing.…”