The Rear Seat Occupant’s Mechanical Response Analysis And Occupant Restraint System Design Of Passenger Car In Frontal Crash

It is considered generally the passenger in the rear seat is safer than others in vehicle.And the rear seat has a wide range of applications in daily life. However, the real world datasuggests that the fatality and serious injury risk of the occupant in rear seats is significantlyincreased, and more serious than for those in front seats. It is because that the vehicles withstiffer front-end structures experience more severe crash pulses. It is more dependent on theoccupant restraint system to protect the passenger. However the rear restraint systemconfigurations those are not including airbags, knee boards and others, which are simplerthan those in front seats. In addition, the rate of rear occupants wearing seat belts is lower.Both reasons result the safety of the rear occupants experience less protection. Therefore,the study of the safety of the rear occupants should be payed highly attention by thegovernment, enterprises and the occupants. The new version of C-NCAP evaluationprocedure is formally implemented on July1,2012，and adds the injury evaluation of therear5th%female dummy. Referring to the global published study results, the foreignresearch is mainly focused on the development of the new restraint system, such asinflatable seat belts, but because of the cost and other factors, that have not been widelyused. The domestic research is mainly about some parameters analysis of the rear occupantrestraint systems by the simulation or testing. In general, the study of rear occupant safetysystems is not global and systematic. In addition, most enterprises in the developmentprocess are lack of relevant work experience. All that result cause the blindness in the rearoccupant restraint system development process.Based on the rear dummy evaluation requirements of C-NCAP in this paper, thegeneration pattern of the rear dummy injury response (Upper neck tension Fz and chestcompression) is analyzed deeply. Then the dummy’s ideal movement trends are obtained.On the other hand, based on the statistics datas of occupant restraint system configuration and design parameters of the subsystem, the relationship between of the dummy’s mainparts’ motion (head, chest and pelvis) and rear seat restraint system design parameters isestablished. Then the rear occupant restraint system design regular is built.Finally, based on a domestic A class vehicle (253model), the rear occupant restraintsystems simulation model of two conditions are developed, involving frontal impact testagainst a rigid barrier with100%overlapping and frontal impact test against a deformablebarrier with40%overlapping. Both models are applied to valid the design regular of rearseat occupant restraint system.