Papers by Keyword: CWR

Abstract: Wubei-Xiaohuangshan railway was characterized by the large local temperature difference, and high density of heavy haul train traffic. Reasonably determining the rail stress-free temperature has an important role on the line traffic safety and stability. Combined with the actual situation of the line, this paper researched some key technical issues of laying CWR in alpine and large temperature difference region, from determining the reasonable allowable temperature rise, allowable temperature drop, the rail stress-free temperature, and its allowable ranges, etc. Look forward to give some reference to the similar engineering problems.

Abstract: With economic development, China’s railway construction is also rapidly developing and its technical requirements are also increasing. In recent years, CWR technology is most used in railway construction, the railway built using this technology is not only smooth, comfortable, but also long life and low maintenance costs, being widely used in railway construction. However, due to restrictions on the production technology and construction conditions, CWR will also be worn, broken, bent, etc., which requires people to continue to study techniques to prevent crawling or off the seam value of rail gauge, to ensure that rail transport safety. This article focuses on the finite element method-based bridge vertical plate non-ballasted track CWR mechanical properties.

Abstract: In this paper, combine with specific projects of Dahe railway design to study the key technical problems of laying CWR in large temperature difference alpine region, including stress-free temperature design, stability analysis of heavy haul CWR, heavy haul rail design in special sections, etc. The result has vital significance to guide the similar project design.

Abstract: Longitudinal seismic responses of CWR on bridges with high-piers and long-spans under uniform excitation and traveling wave effect were studied. Results are shown as follows: Under seismic action, rail longitudinal forces near beam joints increase greatly than rail expansion forces (due to beam expansion); Designing CWR on bridges with high-piers and long-spans needs to consider influences of traveling wave effect and wave spreading derection; With the increase of the apparent velocity of seismic waves, rail longitudinal force tends to decrease; We suggest that designing of CWR on bridges crossing high-intensity earthquake zone should consider impact of seismic action, and establish a reasonable check method.

Abstract: In the design of long-span bridge , it is necessary to lay the expansion regulator in order to reduce the beam-track interaction. Take the Zhengzhou-Xi’an high-speed railway as an example, the paper created a CWR mechanical model on the bridge using the finite element software ANSYS, proposed the deformation law of the structure and its stress characteristics. Based on the fiber grating testing technology, many monitoring points were laid on the Weihe bridge, to make a long-term monitoring. Processed the monitoring data about rail temperature and temperature force of the regulator, the CWR service conditions were assessed. The study shows that the scheme laying a set of regulator on the longest span Weihe bridge has greatly decreased the beam-rail interaction. All of its design parameters are reasonable. The operation safety indexes can completely meet the need of limits.

Abstract: 4Cr9Si2 Martensitic heat-resistant steel is inlet valve and the exhaust tappet materials. This paper is based on the constitutive relationship of 4Cr9Si2 Martensitic heat-resistant steel obtained by isothermal compression; a finite element model of Cross Wedge Rolling was build up for 4Cr9Si2 Martensitic heat-resistant steel. In the model the heat conduction between billet and the die, the convection of heat transfer, and the thermal conversion of plastic work and friction work were taken in account, the value of damage was obtained in the rolling and central porosity was analysis. Then verify the correctness of the FEM and feasibility of simulation results by the experiment

Abstract: Stress contained in rails, mainly due to thermally-induced expansion and contraction, results in large longitudinal loads which lead to broken rails and track buckling. According to the beam bending theory of structural dynamics with a consideration of the influence of axial load, a CWR track model is developed in the present study to be used for extensive buckling analysis of CWR tracks. The model discusses CWR track vibration characteristics with a length of unsupported rail subjected to the longitudinal force due to fluctuation of temperature. From the result, it can be gotten that the critical point of the temperature which may cause the rail have the danger of unstable. This model would help to evaluated and measure the real temperature in rail by analyzing the dynamic response of CWR track.

Abstract: Aimed at preventing the problems of axial movement, step blemish and rolling overlap piece of skins which make from the imbalance of axial and tangential force because of asymmetry of parts in size and shape, the paper adopted finite element method (FEM) to simulate CWR technique of typical asymmetric shaft part, and analysis systematically axial force and axial displacement. Then we can judge axial offset by axial displacement of central point of billet. The results of the study indicate that FEM can manifest the axial deformation of asymmetric shaft parts in CWR, which provides theoretical foundation for the promotion of CWR technology in the application of asymmetric shaft parts manufacture.

Abstract: Axial force in CWR is an important force and energy parameter for stable rolling, which plays an important role in studying the forming quality of asymmetric shaft-parts, section shrinkage of rolled parts and rolling of heavy area reduction. By simplifying boundary conditions of solving axial projected area in this paper, and considering the effects of frictional force generated by contact surfaces between the tools and shaped shaft-section, the formula of the axial force has been derived by analytical method; by comparison of axial force values simulated by ANSYS/LS-DYNA FE software and measured through experiment, the formula of the axial force is verified correctly. The analyzing results provide useful reference for solving process problems caused by axial force.