CALCULATION OF F/A-18 FATIGUE LOADS AND WING DEFORMATION USING COMPUTATION FLUID DYNAMICS

摘要

Aerodynamic loads on the F/A-18 aircraft were an important subject during the execution of the Swiss F/A-18 full scale fatigue tests performed at RUAG Aerospace, because only few relevant fatigue load cases for the entire airplane were obtained from The Boeing Company in St. Louis, the F/A-18 Original Equipment Manufacturer (OEM). These load cases were used originally within the ASIP studies in the 1990s, before the construction of the RUAG full scale fatigue test facility. In the ASIP studies the structural integrity of the entire airframe based on the Swiss flight spectrum was analyzed and a service life of 5000 Swiss flight hours had to be demonstrated. However to reach this goal some structural modifications had to be made to the aircraft, as for instance the change of material from aluminium alloy to titanium for the three carry through bulkhead in the centre fuselage. Furthermore fatigue life improvement technologies (beef-up, cold working, interference fit fasteners) were applied on the wing and the centre fuselage.