Темир йўл транспорти: долзарб масалалар ва инновациялар 6-том 2-нөмір (2025) · 178-186-беттер
VIBRATIONS OF A PRESTRESSED BEAM UNDER OSCILLATORY MOTION: VIBRATIONS OF A PRESTRESSED BEAM UNDER OSCILLATORY MOTION
Мирзаев, И., Аскарова, Д.С., Хожахматов, С.Ш.
Аңдатпа
This work considers the specific aspects of calculating vibrations of reinforced concrete railway bridges under moving loads and moving oscillators. Finite element and finite difference methods are used. Considering the symmetry of the process, a single beam of the intermediate device was considered, which was modeled with a Timoshenko beam taking into account prestressing. The point of contact of the beam with the support part, as well as fixed and movable hinges at the points of contact with the support, were taken into account. The 23.6 m long spans were taken as an example for the study of a railway bridge. In the numerical solution of the problem of oscillations of a system with distributed parameters under the action of a moving concentrated force and mass, “parasitic oscillations” were established by selecting the time step depending on the speed of load movement. Calculations were performed using an implicit Newmark scheme for a moving concentrated force at a velocity of 25 m/s with a time step of 0.008 s; at 50 m/s with a time step of 0.004 s; at 75 m/s with a time step of 0.00267 s; at 100 m/s with a time step of 0.002 s; and at 200 m/s with a time step of 0.001 s. As an example, the mass of a Talgo locomotive was taken as a moving load or mass. The mass has such a speed that a force model moving at a lower speed can be used, otherwise an oscillator model must be adopted. As the horizontal speed of the oscillator increases, the beam's deflection increases, and the vertical oscillations of the mass also increase. This process cannot be accurately reflected in a concentrated force model.
железобетон, балка, арматура, сосредоточенная сила, осциллятор.reinforced concrete, beam, armature, concentrated force, oscillator.
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