Parameters Optimization Study On Restraint System Development For The Rear Seat Female Passenger In Vehicle Frontal Impact

Generally, the fatality of female passenger has achieved a certain degree of improvement in recent 20 years, and the added fatality risk for female decreases greatly. However, adult women have higher fatality risk, given similar physical insults, than men of the same age. The early safety technologies and design changes tended to benefit young adult males somewhat more than other groups, consequently augmenting slightly the relative risk increases for females. More recent technologies such as air bags, pretensioners, and load limiters which were developed with a deeper understanding of biomechanic and human tolerance limits, have substantially reduced the excess risk of females relative to male occupants. For the rear seat, the technologies design didn’t get good- performance for women occupants. While the using frequency of vehicles rear seat is very high in our country, and it is estimated that the rear passenger’s account for a large proportion of deaths in 10 million people each year in China’s road death toll is 1 million people. Further research on the safety of rear seat passengers need us to do.In this paper, the star rating in the Euro-NCAP of 2015 version was used to study the safety performance of rear passenger restraint system. The sum total of study on the subject is contained as follows:1. By a lot of literature data, the research content and method of car passive safety was summarized focusing on rear seat passenger safety research and development. The passenger restraint system simulation model of fontal impact including 5th% Hybrid III dummy was established by MADYMO software. And the model was verified according to the test results.2. The sensitivity analysis was carried out on the parameters of restraint system, by applying MODEFRONTIER software to selecting the sensitive parameters. Using the validated model, the influence of passenger restraint system parameters on the passenger injuries was researched, including seat belts, seat and the car body to make the optimization goal.3. According to the sensitivity analysis of the restraint system parameters and the influence of various parameters on the occupant injury trends, select belt strength, preloaded time limit, cushion stiffness, cushion friction coefficient as the design parameters, and the chest compression as the optimization goal. Using Kriging algorithms and the test data to create the response surface model, Genetic Algorithm NSGA-II(Non-dominated Sorting based Algorithm-II) was applied to make the parameters of the design model restraint system optimization, obtain the optimized group, then simulate the optimized model in MADYMO. And the effect is good compared with the original model.The optimization result is the star-rating score in Euro-NCAP of 2015 version was improved by 3.73%, effectively improving the safety performance of the restraint system for the rear female occupant.