A Study On The Restraint Systems Of 6YO Child Occupants In Vehicle Frontal Impacts Using Mathematical Models

In pediatric population, the fatality rate in automotive crash in China is about 2.5 times that of European countries and the United States of America. It is therefore the protection of child occupant should give a high priority in vehicle safety field. For 6-year-old child occupant, booster seats have been shown to be the most effective means to improve child safety. Unfortunately, there are two major problems associated with the use of booster seat. First, the usage rate is rather low, especially in China. Second, children are often not correctly restrained in booster seats. In order to improve the safety of children in cars, it is necessary to analyze the responses of a child in vehicle impacts.In this study a rigid body dynamics code MADYMO and the 6-year-old P-dummy model from database was used to simulate the responses of a 6-year-old child occupant restrained properly in frontal impacts, and to investigate the influence of the booster seat design parameters to injury risks. The 6 years old child in incorrect restraint conditions was analysed in terms of that a booster seat was improperly or not used in frontal impacts.A total of 14 simulations were conducted. The injury related parameters specified in FMVSS213 and ECER44 were analysed, including the resultant head acceleration(aRes), HIC value(36ms), the resultant chest acceleration(aRes), the vertical chest acceleration(az), the neck z-component force(Fz) and neck y-component moment(My).The results show that all three configurations: the back support, arm rest, and shoulder belt guide, resulted in significant effect on the model for head, neck, thorax, and lumbar spine injuries in frontal impact. It is mainly due to different positioning of the seat belt. A reduction of peak force in the x- and y-component of the lumbar spine was seen when comparing the integrated booster seat with that of the non-integrated booster seat without back and armrest.For those child occupants without usage of the restraint system or, the misuse case that results in the highest injury risk. Whether a child is in vertical sitting and slanted sitting positions, the case with adult seat belt only causes strangulating the child neck. When the shoulder belt is routed behinds the back, the lumbar spine suffers higher loads whether with a booster seat or not. The case with the shoulder...