An Optimization Study of Occupant Restraint System for Different BMI Senior Women Protection in Frontal Impacts

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 injury risk in vehicle crashes. However, the current research on injury mechanism of aging and obese occupants in vehicle frontal impacts is scarce. This paper focuses on the optimization design method of occupant restraint system parameters for specific body type characteristics. Three parameters, namely the force limit value of the force limiter in the seat belt, pretensioner preload of the seat belt and the proportionality coefficient of mass flow rate of the inflator were used for optimization. The objective was to minimize the injury risk probability subjected to constraints of occupant injury indicator values for various body regions as specified in US-NCAP frontal impact tests requirements. The approximate model was established and the optimal combination of parameters was selected by NSGA-II genetic algorithm. The optimization results were verified via the finite element simulation model, showing that when the key parameters of the occupant restraint system were optimized, the joint injury risk probabilities of the senior women with a BMI of 24.5, 33.4 and 36.3 were reduced by 7.73%, 7.45%, and 9.48 %, respectively.