This paper studies the crashworthiness characteristics of a fuselage section and its improvement. A full-scale three-dimensional finite element model of the fuselage section is developed using a nonlinear finite element code, PAM-CRASH. The simulation is implemented to determine the structural deformation and impact response in terms of peak loads and acceleration peaks at the floorlevel, deformation mode, energy absorption, and structural integrity, and then to assess the crashworthiness of the fuselage section. By partitioning the total energy dissipated, it is shown that the frames and the supports of the cargo floor play important roles in the process of energy dissipation. Based on the results, an effective approach to improve the crashworthiness of the fuselage section is presented. The paper also provides an in-depth analysis in the deformation mechanism of the fuselage section under a vertical crash, which will be helpful to effectively prevent the cabin floor from heavily damage and maintain the integrity of the fuselage section.

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Aircraft fuselage and struts under the cabin floor play important impact resisting roles in the crashworthiness of an aircraft. This study first investigates the performance of the struts which support floor beams in a typical fuselage section, and compares the energy absorption characteristics of two typical struts—C shape and Wide-flange shape. Then, the vertical drop numerical test of a fuselage section at a velocity of 9 m/s is conducted. The performances of the aircraft fuselage with different struts in cross section and orientation angle are compared. The results show that the specific energy of Wide-flange is higher than that of C shape when subjected to axial impact load. However, in a fuselage section, the struts are subjected to a complex loading condition, resulting in complex impact energy dissipation process in the vertical crash process. The bending rigidity of Wide-flange is greater than that of C shape, as a result that the initial acceleration peak transferred by the strut with Wide-flange shape to the seat is greater than that transferred by C shape strut. The orientation angle of the struts also affects the crashworthiness of the fuselage section.