3-year-old Child Occupant Injury In The Car Side Collision Risk Analysis And Protection Studies

In an accident of car to car side collision the door intrusion of struck car is the cause of relatively high risk of serious or fatal injuries to child passengers. Child restraint system (CRS) used correctly has been proved to be an effective method to mitigate the risks of injury and death for children in motor vehicle crashes. However, the car safety performance for child occupant protection was influenced by not only child restraint system but also automotive interior system. So that it is significant to improve the car design through the research on protection system of CRS and interia for child occupants in side impact.The CRS model and the rear door assembly model were developed by means of dynamic simulation of multi-body code coupling with finite element method. The whole simulation model was validated in accordance with test results. On the base of validated model, four simulation models were developed. These models included, (1) child dummy is not restrained by CRS or side airbag, (2)child dummy is not restrained by CRS but side airbag, (3)child dummy is restrained by CRS but not side airbag, (4)child dummy is restrained by CRS and side airbag. Kinetic and dynamic responses of child dummy were analyzed to compare effectiveness of side airbag and CRS for reduction of injury risks of 3 years old child passengersin vehicle side impact.Current research on CRS is focused on improvement of child seat design parameters, comparing of various anchorage devices. Optimization design of child restraint system was carried out as it was not condidered before in configuration of child seat and vehicle interior system. Design of experiments and parameter sensitivity analysis were conducted to confirm the primary design parameters. Regression equations of optimization objective were obtained. Optimization of the equations was finished using non-dominated sorting genetic algorithm (NSGA-Ⅱ).The results showed that CRS in combinnation with side airbag could effectively mitigate injury risk of child passenger in side impacts. CRS was more effectively than side airbag when used individually. However, side airbag did not increase head injury risk of child occupant in side impact. Child passenger had highest injury risk when they were not restrained in car.Optimization results indicated that main design parameters of child restraint system were material permeability 0.06 of side airbag, location-0.25m of top tether in x-direction, stiffness coefficient 0.5 of lower anchorage. In the optimized condition, the peak value of the head acceleration was reduced by 38 percent, peak value of thorax acceleration was also reduced.