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Showing 4 results for Younesian

D. Younesian, A.a. Jafari, R. Serajian,
Volume 1, Issue 3 (5-2011)

Nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using Hopf bifurcation theory in this paper. The railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. Linear and nonlinear critical speeds are obtained using Bogoliubov method. A comprehensive parametric study is then carried out and effects of different parameters like the magnitudes of lateral clearance, damping values, wheel radius, bogie mass, lateral stiffness and the track gauge on linear and nonlinear hunting speeds are investigated.
F. Javid, E. Esmailzadeh, D. Younesian,
Volume 1, Issue 4 (12-2011)

D. Younesian, M. S. Fallahzadeh,
Volume 4, Issue 3 (9-2014)

Nonlinear vibration of parabolic springs employed in suspension system of a freight car has been studied in this paper. First, dynamical behavior of the springs is investigated by using finite element method and the obtained results are then used in vibration analysis of a railway freight car. For this purpose, dynamics of a parabolic spring subjected to a cyclic excitation has been studied in the frequency range of 2 to 15 Hz. By utilizing an experimental setup, equivalent static and dynamic stiffness and damping of the spring have been obtained and compared with theoretical results. Different classes of rail irregularities are taken into account to excite the vehicle. Bond Graph method is employed to extract the equations of motion of the system and validity of the obtained equations is investigated. Finally, a parametric study is carried out and the influence of vehicle velocity and rail irregularity on vertical acceleration of the freight car has been examined.
D. Younesian, S. Hamzavi, M.r Rostam,
Volume 4, Issue 4 (12-2014)

In recent years, need to increase the convenience of trips in railway vehicles causes that train operators and manufacturers focus on reducing the noise level which is sensed by passengers. In this paper, first the state of modeling acoustic noise in cab train is discussed and natural frequencies and acoustic mode shapes are derived and then formulation of acoustic pressure in the cab will be obtained. By utilizing field testing, the noise produced by diesel engine in the cabin of Pardistranset train (source of undesirable noise), has been measured and is used in simulating. In order to reduce the acoustic pressure, a secondary noise source is used which its Stimulation signal is obtained by phased PID controller. Then, active noise control will be investigated in two cases of single-channel and multi-channel. The result of actuating the controller shows that in central frequencies of one octave band, there is a reduction in the sound pressure level, loudness, and sound loudness level.

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