Parameter Study for Child Booster Seats in Frontal Collisions

To improve the safety of middle-aged and older child occupants, this paper proposes a framework to effectively design the layout parameters of child booster seats. The layout parameters of the child booster seat include both the three-point seat belt restraint path parameters and the structural design parameters. First, based on a validated frontal collision simulation model with the sled test, a parametric study of child booster seats for different injury indices is performed based on ECE R129 regulations in terms of a Q6 child dummy. To evaluate the effects of each parameter on the overall injury for children, the modified Weighted Injury Criterion (WIC) is proposed. Then, a parameter sensitivity based on the modified WIC is conducted to screen out parameters that have a significant impact on the response of injury indices. The position of the shoulder belt guide and the stiffness of the backrest have dominant effects on the WIC. Finally, a full factorial experiment is conducted for the above selected design variables based on the newly proposed WIC. The identified design position of the shoulder belt guide is 48 mm and its value corresponds to 30 mm of the relevant headrest position, which is explicitly utilized in the design process. The identified stiffness of the backrest is 30,400 Nm/rad. The corresponding WIC is decreased significantly, and the value is reduced by 19.6% compared with the reference model.