Validation of the structural integrity of an aircraft external fuel tank through a structural test under flight-load conditions

Abstract

An external fuel tank, one of the main components of an aircraft, is a component that extends the range of the aircraft and that should be separable from the aircraft in emergency situations. During flight, if structural damage occurs in an external fuel tank, the survivability of the aircraft may be catastrophically affected. Therefore, the structural integrity of such external fuel tanks must be proven under flight-load conditions applied to the external fuel tank during flight. This study presents the results of a structural test conducted to verify the structural integrity of an external fuel tank for flight-load conditions. In the main text, the process of converting the six-component flight load into a test load is described, and a whiffle tree application plan is presented for efficient testing. Then, the reliability of the test load was confirmed by comparing it with the required flight load. As a result of the structural test, the test loads were stably controlled. It was also confirmed that the internal pressure of the test specimen measured in real time during the test was maintained well within the required pressure range and that the behavior of the EFT was suitably predicted through a numerical analysis. After the structural test, it was found through an inspection that the test specimen did not undergo serious structural damage under the required flight-load condition. In conclusion, through structural testing, it was validated that the newly developed external fuel tank had sufficient structural integrity under all required flight-load conditions.