A Numerical Investigation into the Injury Potential of Three-year-old Children Seated in Forward Facing Child Safety Seats During Side Impact Crashes in Far Side Configurations

This research focuses on the injury potential of children seated in forward facing child restraint seats during side impact crashes. Side dynamic sled tests were conducted by NHTSA using the existing FMVSS 213 seat fixture oriented at both 90° and 45° relative to the motion of the sled buck. A half sine pulse and a scaled FMVSS 213 pulse were used in the tests. All the tests were conducted at a test velocity of 32 km/h (20 mph) and a peak acceleration of 17 g’s. A forward-facing Hybrid III 3-year-old child dummy positioned in a child restraint seat (CRS) with LATCH and the top tether in far side configurations were used in the tests. Details of the sled tests were stated in FMVSS 213 ANPRM. A finite element model of the child restraint seat was developed using FEMB for simulation in LS- DYNA. The child seat model, which included all CAD surfaces provided by Century/Graco Corporation, was fully deformable and was previously validated for frontal impacts. Three side impact simulations were completed for data comparison. (i) using the half sine acceleration pulse with the seat oriented at 90° relative to the motion of the sled, (ii) using the half sine acceleration pulse with the seat oriented at 45° relative to the motion of the sled, and (iii) using scaled FMVSS 213 acceleration pulse with the seat oriented at 90° relative to the motion of the sled. Validation of the numerical model was completed by comparing the head injury criteria (HIC) values and chest accelerations from the experimental and numerical tests. The simulation results were generally 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 blocks in the head region of the CRS. It was observed from the simulation results that foam padding was effective in reducing the injury potential of the child dummy.