A study on the countermeasure method for gauge corner cracking by applying the worn profiles of rail

Abstract

A study on the countermeasure method for gauge corner cracking by applying the worn profiles of rail AbstractIn Japanese railway networks, the gauge corner cracking (GCC) occurs to the head hardened rail of the high rail in curved sections of R600 to R800m. In case of the GCC propagates deeply, it will be a possibility of causes rail broken. Therefore, the appearance of GCC is considered a serious problem from the viewpoint of safety transportation. Since GCC appears mixed with head checks, it is very difficult to find GCC in the early stages. Furthermore, GCC appears in the cluster conditions, it is very difficult to remove all cracks of GCC. Hence, it is very important to control the initiation of GCC. However, the countermeasure method for GCC initiation has not been developed. The aim of this study is to examine the reduction method for GCC initiation due to the relief of the contact pressure between wheel/rail. Therefore, the wear development of rail was focused, the influence of the worn profiles of rail on wheel/rail contact condition was examined. In the beginning of this study, rolling contact fatigue (RCF) test were conducted by use of the twin disc test equipment. Secondly, wear analysis of rail with multibody dynamics which was modeled the locations of GCC appearance was conducted. Finally, the effect of the worn profiles of rail on wheel/rail contact and the suppression of RCF initiation was examined by the wheel/rail contact analysis. In summary, the worn profiles of rail were confirmed the suppression effect for RCF by reducing the contact pressure between wheel/rail.

<b>Rail Profile Selection Method to Reduce Gauge Corner Cracking Initiation</b>

“…The crack initiation prevention effect is assumed by the reduction of the value of FI which is described above. As for preventive methods for crack initiation, previous research includes the following methods [1] • The reduction of the contact stress by controlling the contact geometry • Increasing the material resistance k s by introducing materials with a higher yield limit •The reduction of friction loads by lubrication In a previous paper [2], the authors proposed a method for reducing wheel/rail contact pressure and the occurrence of GCC by applying a worn profile to high rails in curved sections with a radius of 800 m where GCC is likely to occur. T is paper presents he de el pment and ap licat o s of aseismic countermeasures for earth retaining stru tures such as bridg abu ments and retaining w lls.…”

“…Secondly, the details of the wheel/rail contact conditions are calculated for each section of the track model. According to the results of the contact conditions, the wear volume of the rail at each section are calculated by Archard's wear law in (2). The wear profiles of the rail are obtained from the wear depth and the rail profiles in the track model.…”

“…Previous research [1] has reported that the risk of fatigue crack initiation can be reduced by reducing wheel/rail contact pressure. In addition, the authors have proposed a countermeasure method for suppressing the occurrence of GCC by applying rail wear profiles to the high rail of curved sections to suppress wheel/rail contact pressure [2]. Since wear development is closely related to wheel/rail contact conditions, prediction of rail wear profiles is complex due to the variety of contact conditions Therefore, to implement this method on an actual line in service, it is necessary to predict the wear profile for each location individually.…”