EVALUATION OF THE EFFECTIVENESS OF SIDE IMPACT PROTECTION OF CHILDREN IN CHILD RESTRAINT SYSTEMS A MADYMO STUDY

摘要

Current Federal Motor Vehicle Safety Standards (FMVSS) regulations do notmandate testing of child dummies in child restraint systems (CRS) in a sideimpact configuration for assessing their performance. In the absence of anyregulations, child seat manufacturers use alternative methods of testing in combinationwith more structure in the CRS like “side wings” or inserting differentenergy absorbing foam materials like Expanded Polystyrene (EPS), etc. to ensuresafety of the child. However, there is a lack of detailed understanding of theeffect of these countermeasures on the performance of the child restraints andthere is need to quantify their performance. The objective of this study was tounderstand the protection offered to the child when using foam inserts and sidewings in child restraint systems during an intrusion type side impact. The studywas conducted using mathematical models developed in MADYMO. Parametricstudies were conducted to understand the effect of various densities and thicknessof EPS foam and structural increases in side wing design on mitigation ofhead injuries. Examining values for the Head Injury Criterion (HIC15) obtainedfrom simulation runs showed that an increase in foam density resulted in a 21percent decrease of HIC15, whereas the pelvis and chest accelerations did notshow substantial change. Similar trends were also observed when foam thicknesswas increased from the baseline model. Extending the side wing structurefrom the baseline model did not show substantial change in the HIC15 values.Results of the study show that an increase in density and thickness of the EPSfoam used could help mitigate injuries to the head as seen by reduction in HIC15.Further parametric studies need to be conducted to understand the extent ofthese benefits. The models can further be employed to optimize foam densityand thickness, not only for head impact, but also on other impact areas like theshoulder and pelvis. The study could be further extended to conduct simulationsin different offset impact directions, or to change and optimize the impactor designand material.