Research On Safety Of Built-in Child Safety Seat In Different Collision Condition

Children safety protection is one of the most important topics in the field of car crash safety.Proper use of child safety seat can reduce children's fatalities effectively in accidents.However,only one collision situation was considered in the design of child safety seats.Child restraint systems designed only in one collision situation can't provide effective protection for children in other collision situations,and may lead to a more serious injury.According to the current shortcomings in design of child safety seats,an optimization method was proposed based on front impact and rear impact condition for a built-in child safety seat.The influence of different seat parameters for child dummy was also studied.Firstly,the model of built-in child restraint was set up and sled test was adopted to validate the model.The seat height,the cushion length and the force limiter value of the seat belt were chosen as optimization variables,and children,s comprehensive damage evaluation ? and neck injury threshold Njkm were chosen as optimization objectives.The methods of approximate model of polynomial regression and Non-dominated Sorting Genetic Algorithm ? were combined to conduct multi-objective optimization.A matching method for built-in child safety seat was proposed based on height and weight.Secondly,a simulation model was set up used the method of coupling between MADYMO and LS-DYNA.The influence of different seat parameters(armrest,the type of armrest,stiffness and angle of the armrest and flank,armrest height)for child dummy was also studied using the validated model.Finally,a method of side impact for built-in child safety seat was established and carried out by drawing lessons from test methods of child test method worldwide.The result of this research shows that the child occupant in built-in child safety seat can get a better protection in both front impact and rear impact through multi-objective optimization.Built-in child safety seat which matching strategy based on height and weight can provide better protection for most children.After studied on the influence of children's injury with different safety seat parameters,we found that built-in safety seat with armrest and flank combined can provide children a better protection.Stiffness and angle of the flank and armrest has great influence to children's injury.