The scaled test method has the advantages of low testing cost, short testing time and low risk, and has been widely used in aerospace and other fields. Taking the lower structure of a typical civil aircraft fuselage as the research object, this study conducted theoretical analysis and experimental method research on the impact scaling of civil aircraft structures. Using dimensional analysis, the complex dynamics of the fuselage crash were simplified to identify key physical quantities and processes. The main research objects, critical physical parameters, and physical processes involved in the aircraft crash were clarified, leading to the extraction of key basic physical quantities and the derivation of primary dimensionless numbers that control the crash response of the fuselage structure. Based on the Buckingham π theorem, the scaling factor for civil aircraft crashes was derived, establishing the scaled experimental methodology. A 1/4 scale model was designed and fabricated, and an impact test at a speed of 6 m/s was performed. The velocity, acceleration, ground impact load, deformation, and failure modes of key components in both full-scale and scaled crash tests were obtained and compared. The applicability and accuracy of the scaled-down theory in the crash experiment of the civil aircraft fuselage frame section were verified. The results show that the deformation and failure modes of the 1/4 scaled test piece and the full-scale test piece are consistent at the frame and column. Structural response prediction deviation analysis shows that the prediction deviation of the maximum crash load is 14.4%, the prediction deviation of the maximum seat acceleration is 14.8%, and the prediction deviation of the maximum acceleration at the beam is 13.1%. Scaled tests can effectively predict the deformation, failure process and dynamic response of key parts of the prototype structure. The scaled test could be used to verify and evaluate the crash performance of civil aircraft structures.
DownLoad: