Reza Serajian

University of California, Merced | UCM · Department of Mechanical Engineering

This paper is an outcome of an international collaborative research initiative. Researchers from 24 institutions across 12 countries were invited to discuss the state-of-the-art in railway train air brake modelling with an emphasis on freight rains. Discussed models are classified as empirical, fluid dynamics and fluid-empirical dynamics models. Em...

In this paper, an exact analytical solution for free vibration analysis of thick laminated annular circular plates is presented.

The nonlinear damping characteristics of friction wedges in the secondary suspension of a freight bogie are investigated considering unidirectional contact and non-smooth frictional forces. In the proposed MultiBody System model, each wedge has six Degrees of Freedom with corresponding inertial properties. The geometry of wedge, as well as, wedge a...

It needs some seconds for a signal, which is created from brake application, to travel from the first part of the train system (locomotive) to the end part of it (last wagon). Delay in time of all parts of the system (train) brake is seen which might deteriorate the longitudinal dynamic interaction of the long trains. For instance, this results in...

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For long freight trains, the pneumatic brake systems are still used. In these situations, the cars at the end of the train brake a few seconds later than those wagons at the front. This variable braking action along the train may cause large longitudinal forces and impacts. Beside brake system parameters, auto coupler characteristics parameters hav...

Conventionally a railway vehicle has stable motion in low speeds, when it reaches to high speeds stability changes to unstable form. The main purpose of this article is to show the authors' view of analytical investigation of bifurcation, nonlinear lateral stability and hunting behavior of rail vehicles in a tangent track. The paper includes non...

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...