Injury Analysis And Optimization For The Passenger Under Different Postures Of A Certain Vehicle

With the development of autonomous driving technology,the layout of vehicle interior changes greatly,with a greater variety of occupant positions.Passenger occupants are not required to perform driving duties and non-standard seating positions are more common for the passenger seat.Occupant posture is an important factor for the occupant protection effectiveness of restraint systems,and the complex and varied occupant postures present unique challenges in terms of occupant protection.This paper carries out research related to the analysis and optimization of occupant injury under different postures by means of simulation.Firstly,a passenger side restraint system model for a frontal 100% overlap rigid barrier crash and a frontal 40% overlap deformable barrier crash of a certain vehicle was established,and the simulation model was validated against the data obtained from the crash tests.Then,the occupant posture and injury protection analysis was carried out for the restraint system design in which the upper-anchor point of the safety belt is integrated into the seat back.Finally,the Kriging model and the MOGA-II genetic algorithm combined with the Weighted Injury Criterion（WIC）are used to optimize the restraint system design parameters in order to improve the protection performance of the restraint system for passengers under different initial postures among the two load-cases.The simulation results showed that as the angle of the seat back increases,the distance between the upper torso and the center of the dashboard increases,the injury indexes of dummy’s head and neck increase and the peak values occur later.By comparing the traditional seat belt with the integrated seat belt,it is found that the integrated seat belt can effectively reduce the head and neck injury of the dummy when the backrest angle increases,but the partial injury of the dummy under the normal backrest angle was increased.The final integration optimization shows that: increasing the cushion angle,seat belt limit force,seat belt pretensioner force,reducing the cushion stiffness,delaying the seat belt pretensioner time,increasing the height of the seat belt fixation point,etc.It can enhance the overall protection performance of the restraint system for different occupant postures in multiple collision load-cases.For the frontal 100% overlap rigid barrier crash load-case,the dummy WIC value was decreased by 4.76% at 20° seatback angle,9.4% at30° seatback angle,and 5.76% at 45° seatback angle.For the frontal 40% overlap deformable barrier crash load-case,the dummy WIC value was decreased by 6.06% at 20°seatback angle,5.7% at 30° seatback angle and 4.31% at 45° seatback angle.