Abstract
This study stems from a real-world far-side side impact collision that produced severe cervical spinal cord injury to a 46-month-old girl appropriately positioned in a High Back Booster (HBB). The objective of this study was to introduce and examine Pelvis Acceleration Amplification (PAA) as a potential biomechanical factor to assist the design and evaluation of booster seats in a far-side side impact scenario. MADYMO model is employed to demonstrate the relationship between the Pelvis Acceleration Amplification and the neck distractive load and head excursion values. The validated HBB MADYMO model assembled with a Q3 Side impact ATD and the vehicle rear compartment is utilized for the study. The assembled model is used to run the parametric study, to analyze the influence of seatbelt pretensioner and rigid ISOFIX on the neck response in far-side side impact scenario. MADYMO model shows a good kinematics correlation with the side impact sled test. The velocity-time diagram facilitated a better understanding of relative motion between the vehicle seat, booster seat and the Q3 Child ATD. Pelvis velocity exceeded the lateral vehicle velocity with seatbelt slack and no rigid ISOFIX increasing the pelvis acceleration amplification. The study shows the proportional relationship between the pelvis acceleration amplification, neck distractive load, and, head excursion values. Pelvis acceleration amplification is a useful biomechanical indicator to assess booster seat performance in a far-side side-impact collision. This indicator offers a potential method to improve the booster design, especially for far-side side impact scenario. The vehicle seatbelt pretensioner and the booster seat rigid ISOFIX work together to increase the level of child protection in far-side impact configurations. However, there is no benefit of rigid ISOFIX alone in the absence of seatbelt pretensioner; the pelvis velocity overshoots the lateral vehicle velocity increasing the pelvis acceleration amplification factor. The neck tensile loads and lateral head excursions show a proportional relationship with the pelvis acceleration amplification factor.