FEM analysis of cement-concrete pavements loaded by the SUPER JUMBO aircraft landing gears

The airport pavement project requires, in general, the mass of the critical take-off aircraft; particularly it uses the load transmitted by one of the main landing rear gears; in fact the contemporary presence of two main gears on the same plate is rare. The anterior or secondary gear has essentially directional functions, it is not considered in the calculation because the load that transmits to the aircraft pavement is negligible. In this research all the landing gears, isolated and in couple, are examined. They have been situated in particular positions on the slab; as a critical airplane has been selected the greatest jet of the world: the Airbus 380, nicknamed Super Jumbo. It has a Maximum Take Off Weight of 600 tons around. The Airbus 380 has all the typologies of landing gear with which the modern commercial aircrafts are equipped: directional anterior twin wheels (Nose Landing Gear), rear double tandem bearing wheels (Wing Landing Gear) and rear tridem bearing wheels (Body Landing Gear). The details are: the 22 wheel Goodrich landing gear consists of two underwing struts each with four wheels, two central under-fuselage struts each with six wheels and a twin nose wheel. Through a computational code fem and the predisposition of numerous models, two objectives have been reached: 1. to show that, for particular conditions of load, the Nose Landing Gear NLG, often neglected in the airport pavement design, determines tensions of traction more elevated than those activated by the bearing rear gears Wing Landing Gears WLG and Body Landing Gears BLG; 2. to calculate the tensions and deformations in the pavement with two main gears on an only slab. Then such loading condition has been compared with that product by the single gear. From the examination of the results has emerged that the most elevated characteristics of the stress depend above all from the geometry of the gears and from the way of transmission of the loads; in subordination, from their entity.