Research On Injuries Of The Airbag Parameters For OOP Children

It is counted that about fifty percent parents hold their children in their arms onthe bus in the country. Meanwhile, many parents have habits of tak ing their childrensitting in the co-pilot position because of the wide vision. However, most of thecurrent occupant restraint systems are designed based on the body size of adultssitting in normal position, which may cause serious injuries to out-of-position （OOP）children. The study of OOP children is few in China, and the corresponding researchof the parameter design for the corresponding passenger airbags is not sufficient. Inthis paper, the injuries of OOP children aged6and3caused by the passenger airbagwere studied according to the regulations of SAE J1980-2008and FMVSS208.The restraint system models were developed respectively when the chests ofOOP6-year-old and3-year-old children were close to the dashboard. The FE model ofthe airbag was established by using Initial Matrix Method. The deployment of airbagwas validated by the results of drop tower test. The effects of Uniform Pressure andGas Flow algorithms on the deployment of airbag were compared. It was showed thatthe Gas Flow model could simulate the real deployment of the airbag especially theearly stage of deployment.The effects of the energy variations of inflator partitions and delay time of thedual-stage airbags on the injuries of OOP children were investigated. It was indicatedthat the injuries of6-year-old children were unchanged when gas ration of doublestage airbag was50:50and the deployment delay time was40ms. For3-year-oldchildren, the injuries were unchanged when gas ration of double stage airbag was50:50and deployment delay time was50ms. The present model was prepared for thefollowing airbag parameters optimization.The parameters of dual-stage airbag were optimized based on the above studies,and the combined injury index I_c1(I_c2)was chosen as object function. Coefficient ofdiscouraged hole, scaling coefficient of volume, and fire time were chose n as thedesign variables. The Quadratic Response Surface model was constructed withsampling points generated by Latin Hypercubes. Meanwhile, Sequential QuadraticProgramming NLPQL was used for optimizing the approximate model using ISIGHTsoftware. The results showed that the I_c1was improved by17.97%for6-year-old OOPchildren, and the the I_c2was improved by14.25%for3-year-old OOP children. An adaptive airbag with three straps arranged parallel was proposed anddeveloped based on the study of protection of intelligent airbags for OOP children. Toreduce the injuries of head, neck and chest of6-year-old children, strap length,coefficient of discouraged hole, scaling coefficient of mass-flow rate, fire time, andmounting angle of instrument panel were optimized by integrating MADYMO withLS-OPT. It was showed that the new developed airbag could protect children well andthe corresponding parameters could be easily implemented by executive mechanismof the smart airbag. The analysis results could provide the reference for thedevelopment of smart airbags.