# Influence of Cargo Luggage on the Vertical Drop Crashworthiness of Aircraft Mid-Fuselage Section
## 6 Conclusions  
In this study, compression tests on cargo compartment luggage were performed, and an FEM of cargo luggage was established using HYPERMESH. The material model was crushable foam from LS-DYNA. Then, an FEM of the fuselage segment with and without cargo luggage was established. By comparing and analyzing the deformation, acceleration, displacement, and energy absorption of the fuselage section, as well as the overload response of the cabin seat rail of the fuselage section, of the two models during a vertical crash, the impact of cargo luggage on the fuselage section crash response was studied. The following conclusions are drawn.  
1. The vertical crash simulation process of the fuselage section agreed well with the test results. The FEM accurately simulated the fracture of the cargo floor beams. Moreover, plastic hinges were generated in the connection area between the cabin stanchion and the fuselage frame. When the velocity curve of the simulation and test reached 0 m/s, the times were 115 and 122 ms, respectively, with a difference of only 7 ms. The initial peak acceleration values of the simulation at C1 and C4 were 8.6% and 0.5% higher than those of the test, respectively;
2. During the vertical crash, the cargo floor without cargo luggage was lifted to come in contact with the cabin floor and could easily penetrate the cabin floor, consequently threatening passenger safety. However, including cargo ensured that the deformation of the cargo floor with the cargo luggage was less than that of the cargo floor without cargo luggage; the deformation of the cargo floor did not affect passenger safety. Cargo luggage has a certain energy absorption and buffering effect, and the vertical displacement of the fuselage section with cargo luggage is less than that without it, thereby effectively ensuring the integrity of the living space of passengers in the cabin structure;
3. Cargo luggage, fuselage frames, fasteners, and skin were the main energy absorption components, and the absorption of energy of cargo luggage was the largest of all components, accounting for 39.2% of the total energy absorption. The energy absorption of the fuselage frames, fasteners, and skin accounted for 13.9%, 11.4%, and 10.3%, respectively.  
Conceptualization, S.Z. and M.T.; methodology, K.L. and X.X.; validation, S.Z., Y.Z., and Y.L.; formal analysis, K.L.; investigation, X.X.; resources, X.L.; data curation, S.Z.; writing--original draft preparation, K.L.; writing--review and editing, K.L. and S.Z.; visualization, Y.Z.; supervision, Y.L.; project administration, M.T.; funding acquisition, M.T. All authors have read and agreed to the published version of the manuscript.  
This research was supported by a research grant for MJ-2017-F15 civil aircraft crashworthiness for a basic research project.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
The authors gratefully acknowledge the reviewers for their careful work and thoughtful suggestions, which have helped improve this paper substantially. Special thanks to [PERSON]'s guidance and [PERSON]'s revision.  
The authors declare no conflict of interest.