Abstract: In the certification test of aircraft seat, the occupant’s peak lumbar load can reflect the protective effect of the aircraft seat on occupants, besides, it is also a crucial indicator to judge whether the seat has passed the airworthiness certification test. Based on numerical dummy models and vertical crash test of fuselage section, an one-dimensional lumped parameter model of a seated occupant including seat is established. Comprehensive evaluation indicators and genetic algorithms is used to complete the identification and verification of the model. Based on the verified model, the study investigates the effect of peak floor acceleration, loading duration, and loading waveform on the lumbar load of the occupant. The results indicate that the peak force of the occupant's lumbar is positively correlated with the overall change in speed, and is not related to the loading waveform. The sensitivity of occupant's lumbar force peak to loading duration and acceleration peak varies depending on the variation in speed. The study proposes a rapid method for evaluating occupant lumbar load, forming a response envelope of occupant lumbar force peak based on floor acceleration, which can provide support for the design of crashworthiness of transportation civil aircraft.

Key words: crashworthiness, lumped parameter model, occupant protection, floor acceleration, peak lumbar load