Optimal design of pre-triggering airbag system for occupant protection performance during frontal crashes

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2022

Two kinds of knee airbags and dummy crash simulation models are established, and the accuracy of the models is verified by comparing the knee module impact test data and CAE simulation data. A knee airbag and dummy crash simulation system is established, and the frontal collision finite element simulation of the Chinese 50th percentile dummy is carried out under the three conditions of no knee airbag, bottom-mounted knee airbag, and rear-mounted knee airbag. According to the regulations of China-New Car Assessment Program (CNCAP), the injury data of major body parts such as the head, chest, femur, and legs are compared and analyzed, and the differences in damage to the dummy caused by the bottom-mounted knee airbag, the non-knee airbag and the rear-mounted knee airbag are focused on. Conclusion: Compared with the HIII dummy with knee airbag, the chest compression and tibia compression force of the Chinese dummy with knee airbag are larger, and the compression force of femur is smaller; compared with the condition without knee airbag, the value of head acceleration, tibial index, chest deformation, etc of Chinese dummy can be reduced with knee airbag, but the tibial axial force and knee side displacement have increased; compared with the condition of the rear-mounted knee airbag, the bottom-mounted knee airbag has better protection performance for the dummy’s head, chest, upper leg, and lower leg, but the knee side displacement of bottom-mounted knee airbag is greater, and the axial compression of the tibia is greater. This paper can provide a theoretical basis for the design of knee airbag in the Chinese market and the development of Chinese human dummy.

Section: Results Analysis Of Dynamic Parameters Of Crash Dummymentioning

confidence: 99%

Injury effects of knee airbags on Chinese human dummy

Huang

Proceedings of the Institution of Mechanical Engineers, Part D:

et al. 2022

“…It was discovered that all errors between the test values and simulation values were less than 10%.Therefore, the simulation model can be used as a basic model for further research. 26…”

Section: Methodsmentioning

confidence: 99%

Optimal design of rear-seat restraint system based on new safety seat during frontal collisions

Hong

Proceedings of the Institution of Mechanical Engineers, Part D:

2022

Owing to the narrow rear-row space of compact cars, the head of a rear-seat occupant can easily hit against the headrest or the seatback of the front seat in frontal collisions, thereby causing injuries to the occupant. A prototype design of a new safety seat is proposed to increase the safety of rear-seat occupants. The aim of this study is to investigate the protective effects of the new safety seat and further optimise the rear-seat restraint system in 100% and 40% overlapped frontal collisions. First, a simulation model of the restraint system is developed and validated. Second, the effects of the original seat and the new safety seats with different torsional stiffness of the torsion spring on the injuries to a female rear-seat occupant are compared. Finally, the design parameters of the rear-seat restraint system are optimised globally to minimise injuries to the female rear-seat occupant. Compared with the original seat case, the head injury criterion HIC15 and thorax 3 ms resultant acceleration T3MS of the female rear-seat occupant in the new safety seat case reduce, whereas the neck injury criterion Nij increases. When the torsional stiffness of the torsion spring decreases gradually, HIC15 and T3MS decrease. The optimum torsional stiffness of the torsion spring determined via analysis is 10 N m/°. The optimal combination of the design parameters of the rear-seat restraint system is obtained. After optimisation, for the 100% overlapped collision, HIC15 and T3MS decrease by 40.20% and 5.75%, respectively, Nij decreases by 35.94% and the peak left and right femur forces ( FL and FR, respectively) decrease by 9.65% and 12.26%, respectively. For the 40% overlapped collision, HIC15 and T3MS reduce by 39.92% and 11.64%, respectively, and Nij, FL and FR decrease by 8.89%, 7.50% and 6.09%, respectively.

“…The simulation model of the driver restraint system was developed based on one car through crash simulation software MADYMO. The developed simulation model contained the driver seat, the floor, the instrumental panel, the windshield, the steering wheel, the airbag, the three-point safety belt, the Hybrid III 50th percentile male dummy which was used to simulate the driver and so on, 17 as shown in Figure 1. In addition, the simulation model defined the acceleration fields, the contact surfaces and the other features.…”

Section: Model Development and Validationmentioning

confidence: 99%

Analysis on the driver’s upper and lower neck injury in the three stages of the frontal collision

Hong

Proceedings of the Institution of Mechanical Engineers, Part D:

2020

According to the driver’s moving posture in the frontal collision, the movement process of the driver could be divided into the three stages. At present, the researchers mainly focused on the neck injuries in the first stage of the driver movement, seldom involve the neck injuries in the second and third stage of the driver movement. The aim of this study is to investigate the neck injuries in the three stages comprehensively to expand the protective scope of the neck. Firstly, the simulation model of the driver restraint system was developed and validated. Secondly, parametric studies were conducted to investigate the influences of the design parameters of the driver restraint system on the occurrence times and the variation trends of the upper and lower neck injuries. Finally, the driver restraint system design parameters were optimized globally using the whole injury criterion of the neck WICN. The results indicate that the driver restraint system should be designed with the moderate vent leakage coefficient, inflator mass-flow rate and fabric permeability coefficient of airbag, and the smaller recliner rotational stiffness of seatback for reducing the neck injuries. After optimization, the peak anterior shear force of lower neck F3 reduces by 27.2%, the peak extension bending moment of upper and lower neck Mupper, Mlower decline by 22.4% and 22.2% respectively, WICN decreases by 15.2%, and the other neck injury values also show a declining trend. At the moment, both the peak anterior shear force of lower neck F3 and the peak extension bending moment of lower neck Mlower appear in the second stage, the peak extension bending moment of upper neck Mupper appears in the third stage, the other neck injury values appear in the first stage.