New Insights into the Short Pitch Corrugation Enigma Based on 3D-FE Coupled Dynamic Vehicle-Track Modeling of Frictional Rolling Contact

Rolf Dollevoet,Shaoguang Li,Alfredo Núñez,Zili Li

doi:10.3390/app7080807

Abstract

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine the system responses in terms of vibration modes, contact forces and the resulting wear with smooth rail and corrugated rail with progressively increasing amplitude to infer the conditions for consistent corrugation initiation and growth. Wear is assumed to be the damage mechanism, and short pitch corrugation is modeled using wavelengths from field observations of a Dutch railway. The contribution of this paper is a global perspective of the consistency conditions that govern the evolution of short pitch corrugation. The main insights are as follows: (1) the longitudinal vibration modes are probably dominant for short pitch corrugation initiation; (2) during short pitch corrugation evolution, the interaction and consistency between longitudinal and vertical modes should determine the development of short pitch corrugation, and once a certain severity is reached, vertical modes become dominant; and (3) in the case simulated in this paper, corrugation does not grow probably due to not only the different resulting main frequencies of the vertical and longitudinal contact forces, but also the inconsistency between the frequencies of the vertical and longitudinal vibration modes and the resulting wear. It is inferred that in the continuous process of initiation and growth of the corrugation, there should be a consistency between them, and this could be done by the control of certain track parameters.

Highlights

Rail corrugations are periodic defects commonly observed in all types of railway tracks
We must identify the causes of the dynamic forces that result in differential wear and differential plastic deformation, which remain in phase for the many different passing wheels such that the wear and deformation accumulate and corrugation can initiate and grow
In [42], the relative longitudinal vibration of the two rails of a track is considered for corrugation initiation, for which each half track is modelled as an inertia, and longitudinal vibration modes of the rail as a flexible body are not considered

Summary

Introduction

Rail corrugations are periodic defects commonly observed in all types of railway tracks. Resonance [22] or the stick-slip process [23], the randomness of passing wheels and the track can lead to phase variations of the contact force so that the total effect of many wheel passages may cancel out or suppress the differential wear and deformation Regarding the latter situation, we must identify the causes of the dynamic forces that result in differential wear and differential plastic deformation, which remain in phase for the many different passing wheels such that the wear and deformation accumulate and corrugation can initiate and grow. To account for plasticity, the method of [28] can be readily incorporated, which will be our future research focus

FE Model

Normal Contact

Tangential Contact

Wear and Corrugation Simulation

Prediction of Major

Analysis of Longitudinal and Vertical Rail Modes

Additional Comments

Relationship between Contact Forces and Wear as well as New Insights

Preferred Frequency of Contact Forces

Frequencies Converge to Develop Uniform Corrugation

Importance of the Proposed Modeling Approach and Track Parameters

Additional Discussions