Papers by Keyword: Rail

Abstract: The paper presents the importance of the sustainable development of means of transport. The biggest challenge facing the transport sector is to significantly reduce emissions and become sustainable. The sustainable development of transport also leads to a sustainable development of human society, by ensuring the circulation of goods, which has become a distinct, independent branch of the national economies and the European economy. For the EU, it is very important that Europe's economy grows sustainably and sustainably – a central aspect of its policies. The EU also plays a key role in promoting sustainable development worldwide.

Abstract: The aim of the work was to find out the causes of cracking of the A120 crane track rail. Although the track was regularly inspected by defectoscopic techniques, after five years of operation, the rail was broken at the weldment. The elemental composition of the welded joint materials was verified and the mechanical properties were determined. A fractographic description of the fracture surface was performed and the structure of the material was evaluated. Several factors contributed to the formation of crack, the combination of which led to a rail failure. Defects of the welded joint, acting as notches, from which they initiated fatigue cracks, unfavourable microstructure of the weld metal, low toughness of the base material and operating environment and conditions were dominant.

Abstract: The most common reason of the fatigue crack appearance is the presence of stresses in the rail. The process of stress strain state simulation for the R65 rail is presented in the paper. Values of residual stresses were modeled and chosen to be maximum allowed by GOST (State Standard): -77 MPa in the rail head, -125 MPa in the web and 106 MPa in rail foot. These stresses match the value-77 MPa measured by the acoustoelastic method from the center of the rolling surface of the rail. The influence of the crack at the highest level of the stress strain state was studied in cases of the maximum train load and its absence. According to results of modeling, stresses in the sharp edge of the crack can exceed the lowest acceptable by GOST (State Standard) value of the yield strength by more than 5 times in case of the presence of the train load. In case of the absence of the train load, the crack does not have a significant influence on the stress strain state. The modelling process was also used to study the influence of the installation temperature difference on the operational lifetime of the rail. The paper presents the description of the influence between the installation temperature difference and the crack initiation. According to modeling results and the rail defect catalogue, rails with the lowest acceptable mechanical characteristics are prohibited to be used after 300∙10⁹ kg and higher tonnage.

Abstract: Dynamic force that strains on the rail and the wheel occurs. In case of wheel flats, during wheel and rail interaction, exposure time of dynamic forces acting in contact is very short and depends on the railway vehicle speed and the length of flat.Results obtained from a method that uses mathematical model of a system “Railway Vehicle Wheel-Track” and the simplified method to determine a vertical impact force of wheel with flat and rail interaction are presented in this article.The results of the mathematical and physical results of this system are analysed and presented.

Abstract: Flash butt welding (FBW) of railway rails was investigated in this work. For this purpose samples of R260 rail steel and 60E1 profile were instrumented and subsequently welded on a Schlatter GAA 100 welding machine under industrial conditions. The intention is to gain in depth process knowledge by more accurately depicting thermal cycles for an entire welding sequence in the immediate proximity of the weld as well as in the heat affected zone (HAZ). A detailed characterization of the single stages of the heat up phase of the process is important. Additionally, the secondary welding voltage was measured simultaneously during the experiments to characterize the transient heat input. Moreover, these data were used in the analysis of the temperature signals to better cope with electrical interferences. Additionally, a finite element (FE) model of this FBW process was developed in the present work. Its implementation and solution is realized with the help of ESI’s FE-software SYSWELD. A strong coupled thermo-electrokinetical and metallurgical calculation routine was used. The model comprises the transition resistance at the welding surfaces as the main heat source to the process. Temperature dependent material properties and a corresponding metallurgical model based on an experimental CCT diagram of the rail steel R350HT are implemented in the simulation as well.

Abstract: This paper is focused on systems which enables transportation of semi-trailers by rail. The selected systems are evaluated from the economical point of view. These systems which meets today's requirements, with simple technical solutions, suitable for existing infrastructures, free of constraints for users and requiring only limited investment. The main objective of this article consists of the operational costs calculating and their comparison. The selected systems are CargoBeamer, Modalohr, ISU and Megaswing.

Abstract: Because of the non-uniformity of the section shape of rail and complexity of its temperature changing, the degree of thermal expansion and contraction of section must be different which leads to the interior stress is produced inevitable in it. The residual stress in rail is elastic stress and its maximum value is elastic limit stress. They affect the dimension stability, mechanical property, deformation and etc. And it is the important factor of rail quality. This paper builds a finite element model of temperature field through the MSC.Marc software during the process of heating and cooling of 55Q rail, which simulates the rail stress field of air cooling and water cooling. Our paper conducts the experiments on the rails of same material and condition and also selects the temperature and stress of appointed nodes to analyze them. The results of experiments and simulations are very identical. Simulating the residual stress of air cooling and water cooling, the result is that residual stress of water cooling is bigger than that of air cooling. This consequence gives the reference for planning the suitable heat treatment and improving the service life.

Abstract: Considering the initial straightened residual stress of rail and the actual geometrical , we established a three-dimensional contact model of real wheel-rail rolling using ANSYS software. The variation of internal residual stress effected by the wheel repeated rolling was numerically simulated and computed by the explicit dynamic software ANSYS/LS-DYNA, and the variation rules of residual stress during the manufacturing process are obtained. Results show that The longitudinal residual stress decrease with the increase of rolling times, which changed significantly in rail head after 5 repeats, and reached a stable state after 10 repeats

Abstract: In order to improve the accuracy and reliability of the defect recognition in rails, the new principle and methods of NDT should be explored, and the safety of railway operation and guiding the repair can be guaranteed. The study is aiming at comparing and analyzing the characteristics of destructive data signals with non-destructive ones. The damage and defect can be judged by the differences of the processed data in the frequency domain and energy spectrum. The location of the defect and damage can be obtained by the singularities of destructive signals using wavelet data processing method: continuous wavelet transform, Mallat algorithm and à Trous algorithm. Based on the above consequence, à Trous algorithm is found that its result is more similar to the real damage location, which proves that the method can be used in the real damage detection and provide us more precise defect location information for early warning.

Abstract: The study on dynamical model of wheel and rail of high-speed train has attracted many researchers nowadays. According to the damping force and the dry friction between wheel and rail, the dynamical model of wheel and rail of high-speed train is constructed and the Hamilton dynamical system of this model is analyzed to discuss its nonlinear dynamical behaviors, which will benefit the practical engineering of high-speed train.