Robust Optimization Design Of A Vehicle Frontal Impact Occupant Restraint System

More and more attention has been paid to vehicle collision safety performance,occupant restraint system is an important safety device in vehicle,and its performance directly affects the degree of injury to the occupants when the collision occurs.The traditional parameter matching process of occupant restraint system usually ignores the influence of uncertain factors,and optimizes the parameters of airbags,seat belts and seats directly.When the design variables fluctuate,the performance of the occupant constraint system may change significantly,resulting in the failure of the design.Therefore,in the parameter matching of occupant restraint system,it is necessary to take full consideration of the influence of uncertain factors to improve the safety performance of the occupant restraint system while ensuring its robustness.Based on the analysis of the development status of occupant restraint system at home and abroad,a robust optimization design method of occupant restraint system based on parameter grouping global sensitivity analysis and 6σ design theory is proposed in this dissertation.The main contents and research methods are as follows:Firstly,an automotive frontal impact occupant restraint system model is established,and simulation model is verified according to the results of real car crash test,the response of head,chest,pelvis,leg and other parts of the dummy are basically identical with the experiment,which indicates that the simulation model can be used for subsequent optimization design.According to Sobol sensitivity analysis method and Monte Carlo sampling,a method based on parameter grouping was proposed to analyze the global sensitivity,the design parameters are preselected and divided into two independent groups according to correlation,The weighted injury criterion(WIC)is used as the evaluation index to analyze the sensitivity of each group,and then the weight coefficient is determined according to the contribution of each parameter group to the total variance of the system.On this basis,the parameters with high sensitivity are selected for subsequent optimization.Based on the theory of 6σ robust design,using the WIC as the optimization objective,take the head,chest and leg injury criteria as constraints,and consider the impact of design variable fluctuation on the optimization results,the occupant restraint system is robust optimized through the comprehensive application of design of experiments,approximate model technology and Multi-Island Genetic Algorithm.Through the analysis of the optimization results,it is proved that this method improves the protection effect of the restraint system to the occupant and improves the robustness of the result.