ДО ВИЗНАЧЕННЯ УРІВНОВАЖУВАЛЬНОЇ НАВАНТАГИ НА ШПАНГОУТ ОДНОПАЛУБНОГО ФЮЗЕЛЯЖУ

Abstract

With the optimal design of the fuselage, a very important issue is the choice of the optimal position of the load-bearing floor in the cross-section of the fuselage.Depending on the relative position of the load-bearing floor, the reduced thickness of the floor, the scheme of fastening the floor to the frames and the ratio of the reduced thicknesses of the fuselage skin and the floor, the position of the center of stiffness of the fuselage cross-section changes, the torsional stiffness of the fuselage. This leads to a change in torque, a redistribution of shear flows, a redistribution of flattening loads on the frame from the bending of the fuselage.In this work, two schemes of fastening the floor to the frame are considered - a rigid, torque connection and a hinged one. In this case, the frame takes up additional load from the floor. The fuselage is considered as a thin-walled rod, loaded with horizontal and vertical shear forces, torque and flattening forces from the fuselage bending.For reliability, the calculation of the position of the center of stiffness in a double-closed cross-section was carried out by two methods: a fictitious force and a fictitious moment. The influence of various parameters on the location of the center of rigidity was investigated. The influence of the vertical position of the floor, the ratio of the reduced thicknesses of the floor and the fuselage skin and the cross-sectional area of the beams of the floor attachment to the fuselage on the position of the center of stiffness was evaluated. Diagrams of these dependencies were constructed based on the results of calculations. The dependence of the torsional stiffness on the position of the floor and the ratio of the reduced thicknesses of the floor and the fuselage skin was investigated. Based on the calculation results, a diagram of these dependencies was built. Various constructive solutions were considered for fastening the floor to the fuselage skin: with their direct connection and with the floor support only on the beam. The floor loading from flattening loads caused by the bending of the fuselage was studied. The diagram of the loading of the frame and the floor from flattening loads is shown.According to the diagrams, you can choose the optimal vertical position of the floor, the reduced floor thickness and the cross-sectional area of the beam