Numerical and experimental studies on the car body flexible vibration reduction due to the effect of car body-mounted equipment

Abstract

To study the effect of car body-mounted equipment on the car body flexible vibration, a vertical rigid-flexible coupling model of a high-speed vehicle is established, which includes a flexible car body, rigid bodies for two bogie frames, four wheelsets, and the car body-mounted equipment. The car body is approximated by an elastic beam, with dimensions selected to give similar mass and vertical bending frequency to an existing car body. Model validation is then carried out by comparing results from numerical simulation and on-track test. Using frequency response analysis and ride comfort analysis, parametric studies are undertaken in order to investigate the respective effect of equipment mounting systems on the car body flexible vibration and ride comfort perceived by the passenger. It is found that the equipment behaves as a dynamic vibration absorber on account of its elastic connections to the car body. The stiffness, damping, mass, and installing position of the equipment have a significant influence on the car body flexible vibration. The optimal parameters of the dynamic vibration absorber are given, which can contribute much to the vibration absorption of the car body flexible vibration. Finally, extensive tests on a high-speed test vehicle are conducted to represent a part of results obtained in the numerical study, including modal tests on the car body, component tests on rubber springs used in the equipment mounting systems, and roller rig tests on the vibration absorption performance of the equipment. It is shown that the car body flexible vibration can be effectively suppressed by reasonably suspending the car body-mounted equipment.

Numerical study on the influence of suspended equipments on the ride comfort in high speed railway vehicles

“…The vehicle is represented by a rigid-flexible coupled model ( Fig. 1), used on a regular basis for such studies, thanks to the fact that it displays a good agreement between the numerical simulations and the field tests [2]. The carbody rigid vibration modesbounce z c and pitch θ c , and the first carbody bending eigenmode in a vertical plansymmetrical bending, will be taken into account.…”

“…The motions of each body can be numerically solved using compiled MATLAB codes. For the model with one equipment, the selection will be for the equipment with the largest mass (m e1 = m e = 3960 kg), mounted at the centre of the carbody (l e1 = l e = L c /2), according to the usual models in the literature review [2,7,9,14,16].…”

“…One of the basic criteria involved in designing the high-speed railway vehicles is the reduction in the vehicle weight, particularly of the carbody that is the most relevant component for the total vehicle mass. A lighter weight of the vehicle brings a significant contribution to a higher speed, lower energy consumption, reduction in the ground vibration and construction-cost saving [1,2].…”

“…The carbody elastically suspended equipment can be looked at as a DVA, whose help counts in the control of the amplitude in the carbody flexible vibrations. The DVA theory was implemented by Huang et al [2], Ye et al [6] and Shi et al [7], to restrain the flexible vibration of the carbody for EMU. Based on DVA theory, Shi et al [7,15] calculated the optimal frequencies of the various suspended pieces of equipment.…”

“…bounce, pitch and flexible bending modes) influencing the vertical ride comfort are included. [2,7,9,14,16]. A more complex representation of the carbody would use 3D rigid-flexible coupled models built in compliance with the multi body system (MBS) theory and the finite element method (FEM) [3,6,7,8,12,17].…”