Theoretical and experimental study on vertical dynamic characteristics of six-axle heavy-haul locomotive on curve

Abstract

This paper presents a method to study the vertical dynamic characteristics of a heavy-haul locomotive in curve. A quasi-static analysis model based on the static force equilibrium relationship is established to investigate the load bearing characteristics of suspension system when the locomotive runs through the curve. Then a locomotive–track coupled dynamics model is used to analyse the dynamic characteristics of wheel load in curves. Finally, a field test in curve is carried out to validate the simulated results. The theoretical analysis results indicate that due to the different twist shapes of track on the entry and exit transition curves, for some specific position in the suspension system or wheel arrangements, the corresponding vertical load along the curve length presents an asymmetry about the section of circular curve. The asymmetry is predominantly caused by the Superelevation Angle Differences (SADs) between car body, bogie frames and wheelsets. A distinct phenomenon is that the outer wheel–rail vertical load of the first axle increases when the locomotive enters the transition curve and then reduces when it exits. These results are expected to provide theoretical guidance to the design of the heavy-haul railways. It is suggested that the asymmetric characteristics of the wheel loads can be improved by some measures, such as adopting a low vertical stiffness in the secondary suspension and increasing the transition curve length.

Dynamic Finite Element Simulation of Wheel–rail Contact Response for the Curved Track Case

“…The results of experiments agreed well with the Kalker's linear theory (Kalker 1967(Kalker , 1973, and it revealed that a small change in the lateral displacement of wheelset may lead to a great change in creep characteristics of wheelrail system. Recently, Liu et al (2018a) conducted the field experiment of heavy-haul locomotive on a curved track to investigate the vertical dynamic loads, verifying the validation of the proposed theoretical model. As for theoretical analyses, based on the linear creep theory (Kalker 1967), Newland (1968) and Boocock (1969) put forward the mechanism of creeping force guidance, and a quasi-static method was employed to examine curve negotiation mechanism.…”

“…By accounting for more realistic contact condition, the FE method has been demonstrated to be effective and accurate for solving wheel-rail contact problem. As the train speed improves, the strain rate effect of materials cannot be ignored (Jing et al , 2022a(Jing et al , 2022bLiu et al 2018aLiu et al , 2018bSu et al 2020;Zhou et al 2022). Hence, in the present work, the wheel-rail dynamic interaction of curve negotiation was investigated by employing the FE model of a wheelset in contact with double rails, where the strain rate effect of wheel/rail materials, superelevation, the roll angle and initial lateral displacement were fully considered.…”

Effect of vehicle-track vertical coupling vibrations on frame-mounted traction motor dynamics

“…Chen et al [15,16] studied the effect of the locomotive dynamic characteristics on the root crack of the transmission system under traction drive conditions by establishing a heavy-haul electric locomotive-track vertical longitudinal coupling dynamic model with considering the dynamic effect of gear transmission. Liu et al [17] analyzed the dynamic force of the wheel and the rail under curve driving conditions by using the locomotive-track vertical coupling dynamic model.…”

Testing of modified primary stiffness for heavy-haul locomotives operating on sharper-radius curves

“…Liu et al. and Liu and Wang 15,16 investigated the vertical wheel load distributions of locomotive in the transition curves, and discussed the curving performance of railway vehicle subjected to the braking force and coupler forces. Luo et al.…”

“…The scheme of vertically inclined radius link could effectively steer the wheelsets to the radial alignment in curves, and also improve the locomotive load distribution rather than depending on spring deflections. Liu et al and Liu and Wang 15,16 investigated the vertical wheel load distributions of locomotive in the transition curves, and discussed the curving performance of railway vehicle subjected to the braking force and coupler forces. Luo et al 17 analyzed the bifurcation characteristics of vehicle hunting motion and presented the matching range of primary longitudinal and lateral stiffness to increase the nonlinear critical speed.…”