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Research Papers

# Development of Vehicle Dynamics Simulation for Safety Analyses of Rail Vehicles on Excited Tracks

[+] Author and Article Information
Kazuhiko Nishimura, Tsutomu Morimura

Department of Technology Research and Development, Central Japan Railway Company, 1545-33 Ohyama, Komaki, Aichi 485-0801, Japan

Yoshiaki Terumichi, Kiyoshi Sogabe

Department of Mechanical Engineering, Sophia University, 7-1 Kioi-cho, Chiyodaku, Tokyo 102-8554, Japan

J. Comput. Nonlinear Dynam 4(1), 011001 (Nov 11, 2008) (9 pages) doi:10.1115/1.3007901 History: Received June 08, 2007; Revised May 08, 2008; Published November 11, 2008

## Abstract

Considerable numbers of earthquake disasters have been experienced in Japan. Thus the study and research of earthquake disaster prevention are highly aware in Japan. In a railway industry, for instance, infrastructures have been reinforced, and a new alert system has been employed to regulate the operating system to stop trains immediately if a great earthquake occurs. A railway is organized by a variety of individual technologies and functions safely and properly as a system; therefore it is beneficial for the system safety to study and examine the individual potential cases of disasters caused by earthquakes from various different viewpoints. Recent reports imply that rail vehicles could derail solely by the ground motions of earthquakes without fatal damages of vehicles and tracks. Therefore, in this paper, the vehicle safety in terms of the dynamic stability and the possibility of derailment directly caused by the track excitations of great earthquakes is specifically studied. The rail vehicles are supposed to involve severe vehicle body motions, wheel lifts, and derailing behaviors. In this study, such extreme responses of the vehicles are focused on; thus at the start, a new vehicle dynamics simulation is developed with unique modeling specifically taking account of internal slide forces between the vehicle body and the bogie resulting from large motions of vehicles. Then, the simulation is employed to assess the safety of vehicles on excited tracks with sinusoidal displacements, and the numerical results are analyzed. Through the assessment and the analyses, four major outcomes are obtained. First, the limit excitation amplitudes for the wheel lift of flange height, defined as safety limits in this paper, are presented in the frequency range of $0.5–2.5Hz$. Second, two types of critical vehicle motions are captured; one is a rocking motion involving large wheel lift observed in lower frequency excitations and the other is a severe horizontal impact of a wheel to a rail observed in higher frequency excitations. In the latter cases, the vehicles derail with slightly larger excitations than those of the wheel lift of flange height. Third, the roll characteristic of a vehicle body is demonstrated as a dominant factor for the vehicle dynamic motions in terms of large wheel lift and derailment. Finally, the unique modeling in the developed simulation is evaluated, and its advantages for precise prediction of the extreme vehicle responses are confirmed.

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## Figures

Figure 1

The half car model for the 13 DOF vehicle dynamics model

Figure 2

The diagram of the forces acting on the half car model

Figure 3

The lateral slide force acting at the contact area inside of the air suspension

Figure 4

The vertical slide force acting at the contact area between the vehicle body and the bump stop rubber on the bogie

Figure 5

The track model for the 13 DOF vehicle dynamics model

Figure 6

Shape of the sine excitation input

Figure 7

Definitions of 30mm wheel lift and derailment

Figure 15

Comparison of 30mm wheel lift limits between Model (a) and Model (b)

Figure 16

Vertical and lateral travels of air suspension during the excitation

Figure 10

Calculated vehicle motions at 0.8Hz excitation

Figure 11

Calculated vehicle motions at 1.5Hz excitation

Figure 12

Roll responses of vehicle body and bogie at 0.5Hz

Figure 13

Roll responses of vehicle body and bogie at 1.5Hz

Figure 14

Calculated vehicle motions of derailing case

Figure 8

Limit amplitudes for 30mm wheel lift and derailment

Figure 9

Calculated vehicle motions at 0.5Hz excitation

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