Determining Effects of Wagon Mass and Vehicle Velocity on Vertical Vibrations of a Rail Vehicle Moving with a Constant Acceleration on a Bridge Using Experimental and Numerical Methods

C. Mızrak,İ. Esen

doi:10.1155/2015/183450

Abstract

Vibrations are vital for derailment safety and passenger comfort which may occur on rail vehicles due to the truck and nearby conditions. In particular, while traversing a bridge, dynamic interaction forces due to moving loads increase the vibrations even further. In this study, the vertical vibrations of a rail vehicle at the midpoint of a bridge, where the amount of deflection is expected to be maximum, were determined by means of a 1 : 5 scaled roller rig and Newmark-βnumerical method. Simulations for different wagon masses and vehicle velocities were performed using both techniques. The results obtained from the numerical and experimental methods were compared and it was demonstrated that the former was accurate with an 8.9% error margin. Numerical simulations were performed by identifying different test combinations with Taguchi experiment design. After evaluating the obtained results by means of an ANOVA analysis, it was determined that the wagon mass had a decreasing effect on the vertical vibrations of the rail vehicle by 2.087%, while rail vehicle velocity had an increasing effect on the vibrations by 96.384%.

Highlights

Design and production of high-speed trains require a thorough understanding of the dynamic behaviour of these vehicles moving on ground and flexible structure
When the root mean squares (RMS) values of the vertical vibrations obtained from the rail vehicle bridge model with 5 degrees of freedom and from the 1 : 5 scaled roller rig are compared to each other, it can be seen that the dynamic model and experimental methods bear the same results by a maximum error margin of 7.423% for a vehicle
Effects of the wagon mass and vehicle velocity of a rail vehicle on the vertical vibrations of the quarter vehicle model have been determined by means of ANOVA analyses that were carried out for the averages and the S/N using the method of Taguchi’s design of experiment

Summary

Introduction

Design and production of high-speed trains require a thorough understanding of the dynamic behaviour of these vehicles moving on ground and flexible structure. In order to determine the vibrations occurring on rail vehicles on flexible structure under different loading conditions, a number of numerical and experimental studies have been presented in literature. Determination of driving comfort in high-speed trains passing over a bridge has been performed [17] To this end, the rail vehicle, rail, rail pad, sleeper, ballast, and the bridge have been modelled interactively. Considering realistic test conditions, a fully realistic experimental study cannot be performed since the rail vehicles and other units of railway systems may be costly From this point of view, some economic small scale test equipment and numerical models have been generally used to estimate the dynamic behaviour of the rail vehicle within the desired scenarios. The obtained results are assessed using ANOVA analysis; effects of the wagon mass and the vehicle velocity on the vertical vibrations of a rail vehicle crossing over the midpoint of the bridge

Bogie-Bridge Interaction Model

Validation

Taguchi and ANOVA Analysis

Findings

Conclusion and Discussion