Child restraint seat design considerations to mitigate injuries to three-year-old children in side impact crashes

Abstract

This research focuses on the injury potential of children seated in forward-facing child safety seats during side impact crashes in a far-side seated position. Side impact dynamic sled tests were conducted by Transportation Research Center Inc. (TRC) using two Hybrid III 3-year-old child dummies in convertible forward/rearward child safety seats. The seats were equipped with a LATCH and a top tether and the dummies were positioned in forward-facing/far-side configuration. The tests were completed using an acceleration pulse with a closing speed of 32.8 km/h, and the seat fixture with vehicle body oriented at 270° relative to the motion of the sled. A fully deformable finite element model of a child restraint seat, for side impact crash investigations, has been developed which has also been previously validated for frontal impacts. A numerical model employing a similar set-up as the experimental sled test was generated and simulated using LSDYNA. The numerical model was validated by comparing the head and the chest accelerations, resultant upper and lower neck forces and moments from the experimental and numerical tests. The simulation results were observed to be in good agreement to the experimental observations. Further studies were conducted to confine lateral movement of the dummy's head by adding energy absorbing foam on the side wings in the vicinity of the contact region of the CRS. It was observed from the simulation results that the addition of foam padding and foam blocks was effective in reducing the head injury criteria of the Hybrid III 3-year-old dummy by approximately 30%, and the upper neck lateral shear and lateral bending by approximately 45%.