Determination of initial conditions for the problem of aircraft dynamics after its lift-off from the elastic rail beam

Аuthors

Russkikh S. V.

Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

e-mail: sergey.russkih@rambler.ru

Abstract

Problems related to the movement of the aircraft or missile on the sliding bearings along the elastic rail beam arise at the present time in aviation engineering. For example, the launch of modern unmanned aircrafts in some cases is carried out by the rails.
The aim of this work was to research the process of aircraft lift-off from the beam and kinematic parameters determination. While considering the final stage of movement when the first bearing descents, it was taken into account that an extra grade of freedom appears at the expense of aircraft rotation towards the second bearing which hasnt left yet. The evaluation of accuracy of numerical algorithms and the estimation of convergence results were carried out.
In the process of problem solving there were considered transverse unsteady vibrations of elastic rail beam along which an absolutely rigid machine moves under the traction force. The forces acting on the beam from the bearings sides are found from the equations of motion taking into account the displacement of the beam. The displacements of the beams were presented by the Ritz method. The initial deflection of the beam is presented in the form of a springboard. There were obtained the equations of beam unsteady vibrations in generalized coordinates at all stages of the aircraft movement along the rail. The problem of machine kinematic parameters finding during the lift-off from the beam was solved for different variants of movement final stage.
The example of calculation is considered. The influence beam and machine of various parameters on the beam displacement, the transverse velocity and angular velocity of machine rotation when leaving the rail was investigated.
The result of the work is an estimation of beam and machine different parameters influence on aircraft lift- off ballistic parameters taking into account the particularity of movement final stage.

Keywords:

: elastic vibrations, transverse unsteady vibrations, the rail beam, the Ritz, leaving the rail beam, sliding bearing

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