1. Science and Technology Innovation Research Institute, Civil Aviation University of China, Tianjin 300300, China;
2. College of Safety Science and Engineering, Civil Aviation University of China, Tianjin 300300, China
Abstract：To study the vertical water-entry impact characteristics of civil aircraft typical fuselage section, the cylinder water-entry impact test was firstly carried out by using the water-entry impact test system. Secondly, the uniform grid fluid model and locally refined grid fluid model were established based on the LS-DYNA ALE method, and were verified by comparing the water-entry impact test results. Finally, the water-entry impact characteristics of fuselage section at 6.02m/s were studied based on the verified fluid domain model and fuselage section model, the difference between water-entry impact characteristics and rigid ground impact characteristics, and the water-entry impact response of fuselage section at different speeds were further analyzed. The results show that the ALE method has higher accuracy for the structure water-entry impact simulation, and the fluid model grids numbers and the water-entry impact calculation time can be greatly reduced when using the locally refined grid fluid model. The water-entry impact failure mode of fuselage section is consistent with the rigid ground impact failure mode, but the overall deformation degree of fuselage section decreases, and the deformation degree of cabin floor beam increases. The frames are still the most energy-absorbing structural components, and a large amount of impact energy are absorbed by the water, resulting in the acceleration at the floor rail is always smaller. With the increase of the water -entry impact velocity, the degree of bending and upturning of fuselage frames increases.
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