Numerical Analysis Of Influencing Factors On Head HIC Of Airline Seat Occupants

In the process of certification and installation of the aviation seat,the relevant compliance verification of occupant head injuries is mainly achieved through full-scale sled test.But this kind of test has poor economical efficiency,high personnel requirements,and low repeatability,which would greatly increase the seat design research and development costs and certification cycle.This paper takes a certain type of aviation seat as the research object and adopts numerical analysis methods to establish a numerical model that can support or partially replace the full-scale sled test to provide certain support for the design,development,and certification of the aviation seat.At the same time,the model is used to analyze the factors affecting occupant damage,and to provide suggestions and references for occupant protection under crash conditions.Firstly,a horizontal impact model of double-row seats and occupants is established,and full-scale sled tests for double-row seats are carried out according to the airworthiness requirement of CCAR 25.562 so as to verify the accuracy of the model.According to the verification requirements of FAA AC 20-146 A for the aviation seat model,the comparison between the test and the simulated head acceleration,HIC,femoral axial load,etc.shows the accuracy of the model.Secondly,based on the validated numerical model,the sensitivity analysis is carried out by changing the seat belt parameters,and the significance and regularity of the influence of different seat belt parameters on the occupant injury response are studied.This paper found that the axial load of the femur and the compressive load in the Z-direction of the neck of the dummy restrained by the high-rigidity seat belt are significantly reduced compared with the small rigidity;the position of the seat belt anchor will cause the change of the restraint angle of the seat belt and the acceleration of the center of gravity of the dummy’s head;the peak value and HIC value are positively correlated with the seat belt angle;compared with the two-point seat belt,the Y-type seat belt has a better restraint effectiveness in the X-direction,but has a slightly worse restraint effect in the Z-direction,which can effectively reduce the dummy neck partial axial load and head HIC value,but will increase the dummy’s neck load.Subsequently,the influence of different impact conditions on the occupant’s injury response is studied.Compared with no yaw condition,the femur load of the dummy is reduced in the yaw state,but the Z-direction compression load of the neck and the head HIC are also higher;the Z-direction compression load and HIC of the dummy neck decrease with the increase of the row pitch;the femoral axial peak load and the neck Z-direction compression peak load of the 5th percentile female dummy are both smaller than the male dummy,but the head HIC is much larger than the two male dummy,indicating that under the same impact conditions,the petite female occupants are more severely injured.Head-mounted and hand-mounted sitting positions will increase the axial load of the dummy’s femur and the Z-direction compression load of the neck,but it is still far below the requirements of CCAR 25.562.At the same time,these two sitting positions can greatly reduce the head injury of the dummy,and the sitting posture has the most significant effect.