Research On Protective Performance Of Child Restraint System Based On Dummy,Simulation And Animal Experiment

With the increase of car ownership and motor vehicle drivers,as well as the opening of the second child policy and the development and enforcement of relevant national laws and regulations,the safety of child occupants has been paid more and more attention.Child occupants belong to the special vulnerable groups,whose self-protection awareness is relatively poor,in the traffic accident,the probability of casualties is much larger than adults.The accident data shows that the correct use of child restraint system(CRS)can effectively prevent child occupant damage.In this paper,two child safety seats(impact shield CRS and five-point harness CRS)are used as the research object.The frontal sled collision simulation model is established and validated by using HyperMesh pre-processing modeling software.The establishment of the simulation model includes the trolley test seat model,the child safety seat model,the five-point harness model,the three-point car seat belt model and the dummy model,among them,the establishment of the child safety seat model is introduced in detail,including the reverse scanning acquisition of the child seat geometry model and the establishment of the finite element model.Finally,based on the above model,the LS-DYNA solver is used to calculate and the kinematic response,the damage curve and the corresponding kinetic response and damage parameter of the practical sled test are tracked by LS-Prepost,and the simulation results all meet the good agreement with the sled test results,which can be used as the basic model for the future study.The chest and abdomen soft tissue injury risk to 3YO child occupant in a child restraint system(CRS)was studied using finite element(FE)simulations and animal experiments.The research was done for impact shield CRS and five-point harness CRS.Based on the UN R129 dynamic test,in the FE simulations,two types of frontal collision numerical analysis CRS models were established using Q3 dummy and THUMS 3YO Occupant Model Academic Version 4(THUMS 3YO V4AC)and the kinematic response,chest injury parameters and visceral soft tissue organ damage of 3YO child occupant in a child restraint system(CRS)was analyzed;in the animal experiments,seventeen experiments were performed using Tibetan miniature pigs with weights ranging from 9.7 kg to 16.5 kg and The chest and abdomen soft tissue injury of the pigs was analyzed by autopsy and ISS after the collision.The simulation results show that the kinetic response and the chest deformation of Q3 dummy and THUMS 3YO V4 AC FE model has significant difference;because of trunk flexibility,and the Chest deformation rate of THUMS 3YO V4 AC FE model in the impact shield CRS was 39.25%,reaching AIS grade 4 damage;the stress and strain of chest and abdomen visceral soft tissue organs of THUMS 3YO V4 AC in the two CRSs is beyond the damage threshold,which in the impact shield CRS is relatively large in both the area and the numerical value,so the risk of injury in the thoracic soft tissue is also greater.From the pig tests,it is found that the inner organ injuries can be occur to child occupants sitting in the CRS equipped with an impact shield even no rib fracture observed.And the liver laceration and lung contusion were the common injury occurred in the impact shield CRSs on the chest and abdomen.