Research On Dynamic Performance Prediction Model And Experiment Of Child Safety Seat

With the increase in the number of cars and the increase in the awareness of protecting child occupants in road traffic,more attention has been paid to the safety of children in vehicles,and there are more and more researches on child restraint systems.The research on the sensitivity of CRS layout parameters and dynamic damage prediction are still insufficient.The main purpose of this thesis is to establish a dynamic damage prediction model of CRS and explore the sensitivity of many damage indicators specified by ECE R129 with respect to the changes in the layout parameters of CRS,and in order to find the layout parameter of CRS that can achieve the best protection effect for child occupants.Based on the ECE R129 regulation,the Q3 dummy frontal impact simulation model is established and the validity of the model is verified.After that,A conceptual model based on the simulation model was established to adjust the parameters of the seat arrangement conveniently.On the basis of the conceptual model,a single factor analysis method was used to explore the impact of CRS seatback stiffness,CRS cushion angel,Seat belt stiffness,CRS Cushion height,CRS backrest thickness,position of the seat belt outlet,Coefficient of friction between dummy,seat and Coefficient of friction between sled and safety seat and upper strap stiffness on 3ms acceleration of the chest,3ms acceleration of the head,head excursion,head injury criterion,maximum abdominal pressure,upper neck tension and upper neck bending moment is studied.Based on the experimental data obtained from the single factor study,the sensitivity of the above seven damage indexes to the layout parameters is determined.The effect of the seat back stiffness on the head excursion,3ms acceleration of the head and head injury criterion under the misuse of the upper strap is studied,and the results show that the damage indexes without the upper strap have a greater increase compared with the case with the upper strap.The results show that the 3ms acceleration of chest and the head injury criterion can reach a relatively good level with lower seat back stiffness under the premise that the head excursion is less than the legal requirements.Through the sensitivity analysis results,selected four main parameters that have the highest sensitivity to Child injury index : CRS cushion angel、seat belt stiffness、CRS Cushion height and position of the seat belt outlet.RSM tests were carried out on the selected layout parameters and damage index to find the layout parameter of CRS that can achieve the best protection effect for child occupants.