Numerical Simulation of Mechanical Coupling for Low-Back Booster with a 6-Year-Old Child during a Crash Test

This research assessed a mechanical coupling for the ISOFIX Child Restraint System using the Finite Element Method (FEM) in a critical condition (simultaneous frontal and lateral collision). The mechanism was designed according to the R129 standard, and it consists of a set of springs and dampers that allows displacements in the three Cartesian axes (x, y, z) to dissipate a portion of the energy produced by a traffic accident. Two case studies are presented. The first one evaluates the behavior of the mechanism by applying the equivalent weight of a child and the LBB during a frontal and lateral impact according to the FMVSS 213 standard. The second evaluates the injuries generated in the head, neck, and thorax with a six-year Hybrid III model during a frontal impact when implementing the coupling system. The outcomes show that both axes reach a maximum deceleration of 23 G, and it remains from 17 G to 21 G in 30 ms. After 65 ms, it decreases from 17 G to 0 G. Overall, the injury rates are compared when using mechanical coupling with LBB and only LBB to analyze the system’s efficiency, showing a significant reduction in head and neck injuries, obtaining a 24% variation in the HIC_36, and reducing the neck range motion by 19.3°.