Research On Child Head Injury Mechanism And Protection For Child In Vehicle Side Impact

Side impact is one of the most important causes of child casualities.The head of a child occupant is the most serious injury position in the collisions.However,due to the lack of material property data of the child head,it is difficult to explore the injuries of the child occupants in the side impact.Besides,the child restraint system parameters matched for the children of the single age can't guarantee the same protection effect to the children of the other age at present.So it is a hot issue to attain material property data of the child head and improve the protection effect of the child restraint system to the children of different ages in the side impact.First of all,child head injury mechanism was studied,and the results of skull injury test for children of different ages and animal skull test were compared and analyzed.Secondly,based on a built-in child safety seat,the simulation model of 6 year old dummy's restraint system in side impact was established by using the multi rigid body and finite element coupling method.And then the accuracy of the model was verified by sled impact test data.Thirdly,the height of handrail,scaling factor of side wings stiffness and angle of side wings were found to be the factors that had a great influence on child occupant head's injury by using parameter sensitivity analysis,and then these three factors were selected as variables,while the head peak resultant acceleration and chest peak resultant acceleration were selected as optimization objectives,and then the protection effect of child restraint system on the child occupants of 3,6,10 years old were optimized.Furthermore,based on the optimal design parameters for three age groups of 3,6,10 year old child occupants,an adaptive control strategy was proposed for protection of children with different height and weight.Finally,In view of the limitations of the three point safety belt,a "X" type four point safety belt was modeled.And a comparative analysis of the protection effect on child occupants of the three point safety belt and four point safety belt was carried out.And then,the influence of the restraint system parameters on the four point safety belt to protect the head of the child occupant was analyzed by simulation.The result of this research shows that the acquisition of material property data of child head can be carried out from the study of skull.And it is necessary to cooperate with clinical medicine and find appropriate animals as surrogates of human to carry out biomechanical experiments in the future.And the child occupants of 3,6,10 years old can attain good protection effect by optimizing the restraint system parameters in side impact,respectively.Besides,the protection design of adaptive control strategy for restraint system parameters can provide effective protection for most children.Furthermore,the simulation analysis shows the four point safety belt is superior to the three point safety belt in the absence of side wings,and optimization combination of restraint system parameters can provide good protection for the head of child occupant.