Investigation of energy absorption concepts for a transport aircraft fuselage section on various soil impact surfaces

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Potagani, Anoop Goud
Lankarani, Hamid M.
Crashworthiness of fuselage section has been and will continue to be the main concern in aviation safety. A vertical drop test of the fuselage section of a Boeing 737 aircraft was conducted at the FAA William J. Hughes Technical Center in Atlantic City, NJ (1999). During this test, the auxiliary fuel tank is punctured causing a fuel leakage, and the crushing of the fuselage skin is observed. As per Federal Aviation Administration (FAA) advisory circular 25-30, fuel spillage from auxiliary fuel tank is recognized as a hazard for occupant safety during a sudden crash. It is recommended to eliminate the fuel tank in or near the fuselage section. This study focuses on conversion of a detailed full-size fuselage model into the simplified full-size model using energy absorption and supporting structure concepts. The drop test simulations are performed using LS-DYNA, which is a non-linear finite element analysis (FEA) explicit code. Two issues are found during the development of computational finite element (FE) fuselage model after the elimination of the auxiliary fuel tank from the fuselage section. The first is the crushing of passenger floor due to poor dynamic performance of auxiliary fuel tank. The second being the uncertainty in deformation of the fuselage skin cross-section. The Dynamic response of the simplified full-size fuselage model is evaluated providing rigidity by incorporating hollow cylinders and lambda (λ) - shaped struts. The developed simplified full-size fuselage model with supporting structures is dropped at different velocities at 10.17 m/s and 12.19 m/s and their performance is analyzed. The model is vertically dropped onto various soil surfaces, and the results are compared with those of a rigid surface. To trigger deformations, structural defects are also introduced to the simplified fuselage section at maximum stress regions. Overall, the study demonstrates that the inclusion of lambda (λ) struts and hollow cylinders provides structural integrity and energy absorption to the fuselage section.
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Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering