A Comparison of the Kinematics of a Child Finite Element Model and the HYBRID III 3-Year-Old Dummies in Frontal Crashes 2007-01-0977

The THUMS (Total HUman Model for Safety) 3-year-old child finite element (FE) model was developed by Toyota Central R&D Labs (TCRDL) by model-based scaling from the AM50 (50 percentile male) human FE model. The objective of this paper is to present a comparison between the kinematics of a child FE model developed from the adult THUMS model and a HYRID III 3-year-old child dummy using observations from numerical simulations of a CMVSS 208 frontal crash. Both the child models were positioned in a forward facing, five point child restraint systems (CRS). An acceleration pulse acquired from a vehicle crash test in accordance with Canadian Motor Vehicle Safety Standards (CMVSS) 208 was applied to the seat buck supporting the CRS. Numerical simulations with both the child model and the Hybrid III child dummy were conducted using LS-DYNA version 970.

Through a quantitative analysis of the head accelerations, it was observed that the 3-year-old child model experienced greater magnitudes of head accelerations in the global x-direction as compared to the Hybrid III three-year-old child dummy. In addition, the child model exhibited an increased flexibility of the neck and a greater degree of deformation in the thorax. The child model exhibited an 18% greater magnitude of head rotation about the y-axis compared to the Hybrid III child dummy. The head injury criteria values calculated over a 36 ms window were observed to be 480 for the child model and 576 for the Hybrid III child dummy respectively. By comparing the head trajectories of the two FE models with an experimentally completed crash test using a child cadaver it was observed that the child model is more capable of predicting the kinematics believed to be experienced by a child body. The results of this study may act as a reference to aid in improving the accuracy of numerical simulations for child safety in vehicle crashes.