An Optimization Study of Occupant Restraint System for Different BMI Senior Women in Vehicle Frontal Impact

Accident statistics have shown that older and obese occupants are less adaptable to existing vehicle occupant restraint systems than ordinary middle-aged male occupants, and tend to have higher risk of death and injury in vehicle crashes.However, the current research on the mechanism of injury in vehicle frontal impact for aging and obese occupants is scarce. This paper mainly focuses on the optimization design method of occupant constraint system parameters for specific body type characteristics. The damage attributes of vehicle crash on elderly female with different BMI (body mass index) was analyzed. The design variables in the constraint system were screened for DOE analysis. We selected five parameters for optimization, namely the force limiter force limit value of the seat belt, the pretensioner preload of the seat belt, the preload time of the seat belt, the ignition time of the airbag, the proportionality coefficient of the mass flow rate of the airbag. The objective of this study is to minimize the risk of comprehensive injuries, and the constraints are that indicator values for head injury, neck injury, chest injury and lower extremity injury do not exceed the US-NCAP values. The approximate model was established and the optimal combination of parameters was selected by NSGA-II genetic algorithm. The results were substituted into the finite element simulation model, which proven that the optimization results was effective. The results showed that by optimizing the key parameters of the occupant restraint system, the risk of comprehensive injury of senior women with lean body size was reduced by 6.08%, the risk of comprehensive injury of aging senior women was reduced by 7.77%, and the risk of comprehensive injury of obese senior women was reduced by 10.17 %.