Simplifications in modelling of dynamical response of coupled electro-mechanical system

Darula, Radoslav; Sorokin, Sergey

doi:10.1016/j.jsv.2016.08.036

Cited by 3 publications

(2 citation statements)

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“…To obtain the analytic solution for these equations is not an easy task. Various solving methods for the two mass systems with two degrees of freedom [3][4][5][6][7][8][9] are developed (see [10]): the energy balance method [11], the He's frequency-amplitude procedure [12], the He's variation approach [13], the higher order Hamiltonian approach [14] etc. For all of them it is common that the result is unable to give an exact reprea e-mail: cpinter.livia@uni-obuda.hu (corresponding author) sentation in the complex plane of the dynamic balance between inertia, stiffness, damping and external forces [15].…”

Section: Introductionmentioning

confidence: 99%

Rotating vector solving method applied for nonlinear oscillator

Cvetićanin

Suchy

Bíró

et al. 2021

Eur. Phys. J. Spec. Top.

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Significant number of procedures for solving of the finite degree-of-freedom forced nonlinear oscillator are developed. For all of them it is common that they are based on the exact solution of the corresponding linear oscillator. For technical reasons, the aim of this paper is to develop a simpler solving procedure. The rotating vector method, developed for the linear oscillator, is adopted for solving of the nonlinear finite degree-of-freedom oscillator. The solution is assumed in the form of trigonometric functions. Assuming that the nonlinearity is small all terms of the series expansion of the function higher than the first are omitted. The rotating vectors for each mass are presented in the complex plane. In the paper, the suggested rotating vector procedure is applied for solving of a three-degree-of-freedom periodically excited oscillator. The influence of the nonlinear stiffness of the flexible elastic beam, excited with a periodical force, on the resonant properties of the system in whole is investigated. It is obtained that the influence of nonlinearity on the amplitude and phase of vibration is more significant for smaller values of the excitation frequency than for higher ones.

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Section: Introductionmentioning

confidence: 99%

Rotating vector solving method applied for nonlinear oscillator

Cvetićanin

Suchy

Bíró

et al. 2021

Eur. Phys. J. Spec. Top.

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“…An electro-magneto-mechanical model of the track brake is essential for numeric analysis of the stability and the dynamic behaviour of the system. The contribution from Darula and Sorokin 9 give an overview on modelling electro-mechanical systems. Jirout et al 5 used an electro-magneto-mechanical model of a track brake to simulate the brake activation process.…”

Section: Introductionmentioning

confidence: 99%

Modelling, analysis and mitigation of self-excited vibrations of a magnetic track brake

Tippelt

Edelmann

Plöchl

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part F:

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Magnetic track brakes work independently of the wheel–rail contact as an additional braking system in railway vehicles. In the past, magnetic track brakes were usually deactivated at velocities below 25 km/h in mainline applications to avoid stopping jerks. However, current demands on braking performance require activation until full stop. During field tests on this subject, severe self-excited vibrations were measured at velocities below 25 km/h. This study analyses the oscillations observed by focusing on the stability behaviour of a simplified linear coupled electro-magneto-mechanical model of the track brake. Key parameters are identified by applying established criteria of linear stability theory. To account for essential nonlinear effects, a detailed multibody dynamics model with flexible bodies including a more enhanced electro-magnetic model is introduced and parameterised by using measurement data. Simulation results reveal two separate (or combined) mechanisms that may lead to self-excitation. On the one hand, friction-induced vibrations between the magnets and the rail; on the other hand, coupling effects between the electro-magnetic and the mechanical subsystems of the track brake may be the cause of the self-excited vibrations observed. Stability behaviour is influenced by various design parameters and in particular by the contact conditions between track brake and rail. Finally, a few passive methods are briefly discussed that may help to mitigate or reduce self-excited vibrations at low velocities in future designs of track brakes.

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