Bifurcation analysis of 4-axle rail vehicle models in a curved track

Abstract

The article presents authors' recent results on nonlinear lateral stability of rail vehicles in a curved track. The theories of self-exciting vibrations and bifurcation are the key elements here. The general objective is presentation of extended use of the earlier worked out authors' method to more complex rail vehicle models. Two 4-axle vehicle models were created. The first one represents coach MKIII described with multibody software by the first author. The second one represents coach 127A described with use of engineering multibody software VI-Rail. The models are described, and method of the analysis is shortly reminded. Then, results for both models are presented. They include verification of the limit cycle possible passage from straight track to circular curve and stability maps for regular curves of different radii and straight track. Next influence of selected suspension parameter and wheelrail coefficient of friction on vehicle stability is shown. The more general objective is the authors' say in the hot polemics on the advisability of rail vehicle stability analysis in curves and on the advantages of the nonlinear methods of such analysis over the linear ones.

An investigation into multi-domain simulation for a pantographcatenary system

“…Other geometrical parameters as well as mass and inertial properties of the car body and bogies were taken according to the model from ref. [9]. Those values are consistent with the parameters of rail electric multiple units (EMU) utilized in Poland, therefore the authors consider that proposed rail vehicle model represents realistic constrains of a pantograph on high-speed trains.…”

“…Therefore, it allows us to take into account the most important directions of pantograph excitation from car body (vertical, lateral vibrations and tilt). The model of the rail vehicle was built according to [9]. The parameters of the two-level suspension system in the model are shown in Table 3.…”

Investigation into nonlinear phenomena for various railway vehicles in transition curves at velocities close to critical one

“…Similar figures can be found, e.g. in [9][10][11][12] while analogous figures for vehicle motion in CC can be found in [13,14]. In this approach linear v c and nonlinear v n critical velocities are recognised as generally different quantities.…”

“…This stop can be caused by unbounded growth of the solution (called sometimes numerical derailment, but not physical one) or arbitrarily by the software operator, e.g. due to unnaturally big velocity values [11,14,15]. As shown, e.g.…”

The Impact of Primary Suspension Stiffness of 2-Axle Bogie of Mkiii Passenger Car on Its Dynamical Behaviour

“…The authors used approach applied in the earlier publications, e.g. [12]. This publication shows different values of v n in straight track (ST) and circular curves (CC) and dependence of v n on suspension stiffness parameters.…”