Vertical impact simulations of a full-size and simplified scaled models of an aircraft fuselage section
Computer simulations of aircraft crashworthiness of aircraft using validated models have provided insight into the nature of the energy-absorption of structures and allow parametric studies in evaluation of different crash energy management designs. In this study, the dynamic responses of scaled aircraft fuselage models in comparison with a detailed full-size fuselage model in vertical impact are investigated. The detailed full-size model, constructed from a Boeing 737 mid-section fuselage, consists of a rigid auxiliary fuel tank and a cargo door. The detailed full-size model is dropped from a height of 4.26 m (14 ft) onto a rigid surface, which corresponds to a vertical impact speed of 9.14 m/s (30 ft/s). The drop test simulations are performed using the non-linear explicit code, LS-DYNA. Correlation of the detailed full-size model with the experimental test conducted by the Federal Aviation Administration is presented and demonstrated. The scale modeling technique applied to the aircraft fuselage section is then utilized and for this purpose, a simplified full-size model is first constructed without the auxiliary fuel tank and cargo door. The crash responses of the simplified full-size models in relation to the detailed full-size model are examined. 1/5th, 1/10th and 1/20th scaled models are constructed utilizing the scaling techniques on the simplified full-size model. The vertical impact simulations of the scaled models are carried with identical impact speed as that of the detailed full-size model. General scaling laws for geometry, mass, velocity, acceleration and forces are utilized to predict the output parameters for different scaled models. The results from this study on scaling technique demonstrate a cost-effective and innovative method on the design and crashworthiness analysis of an aircraft structure.