The Design Simulation And Optimization Of The Integral Composite Child Safety Seat

The child safety seat can effectively protect children crews in the process of carcollision. Accompanied by a boom in the automotive industry over these years, thenumber of traffic accidents increases. According to the survey, the traffic accident hasbecome the second leading cause of death of children. Therefore, the child safety seatsmust be designed and used properly in order to effectively reduce injury of childrencrews in the accident.The Children safety during the car collision has been an important topic inthe study of vehicle passive safety research. This thesis firstly introduces themechanism of children injury in the process of collision damage, and thenanalyzes the related content about child restraint systems in the regulations ofECE-R44and FMVSS213. China’s vehicle child restraint system rules andregulations basically adopt the ECE-R44, so this thesis uses the ECE-R44as theregulatory requirement.Based on experiments on the child safety seat in Automotive Crash Lab inTsinghua University, this thesis finds that the torn seat backrest, seat belt offand unqualified buckle open force are the main reasons which lead to theunqualified experimental data. Overall, during the subsequent design ofintegrated child safety seats, how to design the seat backrest structure properly,how to ensure the belt and seat joint reinforcement reasonable, how to reducethe stress concentration to prevent partial tear, and how to ensure buckles openforce qualified are the keys of the design. This child safety seat should complywith the ECE-R44and be suitable for9-36kg,9months to12years oldchildren.During the process of design and development, this thesis firstly chooses oneunqualified child seat as the research object, and then sets up the CAE simulation modelin the environment of MADYMO to simulate vehicle frontal crash test, and compareswith the actual crash test results, including the motion and dummy damage data forstandard to fully demonstrate the effectiveness of the CAE simulation model. After thatthis thesis conduct the part structure optimization improvements, including the design of the adult seat belt positioning device, the convex buckle design，the thickening of seatback edge and the strengthen of joint parts of the back and the base, finally meeting thebasic requirements of the ECE-R44regulations. On the above basis, this thesis conductoverall improvement for this qualified seat. Firstly a set of simulation data is obtainedby orthogonal test and the influence of structure parameters on the dummy injuries isgot by extreme difference analysis. And then the logarithm model is established formulti-objective optimization design, and its pareto optimal solutions are obtained byusing the NSGA-Ⅱ algorithm which make it have a more good collision protectioneffect. In conclusion, the study method of child seat has a guiding significance for thedesign, development and optimization of integrated child seats.