Optimization Of The Airbag Parameters Based On6-year-old Children Out-of-position Passengers

With the increasing numbers of vehicles inventory and traffic accidents, it hasattracted much attention due to the occupant restraint system not matching the sizes ofpassengers which had caused much injuries and death. At present, most of the restraintsystems were designed and developed based on normal position and adult body. But forthe children, it could be resulted to additional injuries when collision occurred. Inother countries, the study of passenger airbag for out-of-position children was morespecialized, but these researches were less in China because of absence of regulations.The object of this thesis was6-year-old child whose bodies were differentout-of-position states. Two positions which could cause serious injuries according asSAE J1980-2008and FMVSS208are selected. The two positions includingmulti-body and finite element model were developed which were used for dynamicpassenger airbag systems tests. The accuracy and effectiveness of the models werevalidated by static tests for passenger airbag systems. Then, the airbag mountingangle(θ), scale factor for exhaust orifice(CDEX), scale factor for airbag volume(SS),scale factor for mass flow rate(IS), initiation time of inflator(T) and the variable rangeswere selected, and the objective function was built. Subsequently,30sampling pointswere selected by Latin Hypercube method and its responses were simulated byMADYMO, and kriging surrogate model was chosen. Final, the parameters of airbagwere optimized by multi-island genetic algorithm based on the kriging surrogate model,and the result was validated and analyzed by simulation method.The results of optimization and simulation show that the injury values of childrenhead, neck and chest were less than FMVSS208regulations when the dummy thoraxwas contacting with passenger airbag model. It is indicated that the children whichwere set in this position could be effectively protected by airbag parameters byoptimized method. When the dummy head was contacting with passenger airbag model,the head of children was protected effectively at the first74ms, but in the74ms-83.4ms,peak acceleration was produced because of children’s head impacting with thewindshield. It was indicated that the five variables in the thesis were not enough forchildren protection effectively when the dummy head was contacting with passengerairbag model. More variables and/or other protective measures were needed to acquirebetter children protection. In this thesis, the method of airbag optimization was established for children out-of-position passenger. The results show that the modelingand airbag parameters optimization methods are also apply to6-year-old children whoare posed in other out-of-positions, and to the children who are in different ages andout-of-positions.