Abstract
As a main part of continuously welded rail track, rail weld widely exists in high-speed railway. However, short-wave irregularities can easily initiate and develop in rail weld due to the limitation of welding technology and thus rail weld has been a main high-frequency excitation and is responsible for deterioration of track components. This work reports a 3D finite element model of wheel-rail rolling contact which can simulate dynamic wheel-rail interaction at arbitrary contact geometry up to 400 km/h. This model is employed to investigate dynamic response of wheel-rail interaction at theoretical and measured rail weld, including wheel-rail force and axle-box acceleration. These simulation results, combined with Quality Index (QI) method, are used to develop a quantitative expression, which can be easily applied for evaluating rail weld deterioration based on measured rail profiles and axle-box acceleration.
Highlights
Rails of standard length can be welded into required length in the continuously welded track to eliminate the joint gaps [1, 2]
Steenbergen and Esveld [9, 10] evaluated the quality of rail welds using a geometric gradient which can be used for considering any weld geometric forms
The stiffness coefficient of the normal contact spring used in the traditional vehicletrack coupling dynamics model is generally derived from the Hertz theory based on the static hypothesis, which contains some differences when dynamic interaction between wheel and rail is taken into account [19]
Summary
Rails of standard length can be welded into required length in the continuously welded track to eliminate the joint gaps [1, 2] (see Figure 1). The geometrical profiles of rail welds are hardly to maintain due to the limitation of the welding process and the improper operation [3], the phase transformation between welding materials and base metals [4], and the influence of residual stress [5] and fatigue crack [6] This phenomenon has been recently observed by Gao et al [1] who conducted detailed measurement and statistics on the geometric irregularity of rail welds in Chinese high-speed lines and found that short-wave irregularity is a main form of surface defects in the rail weld zones. In China, the straightness shall not exceed 0.3 mm and 0.2 mm at the operating speeds of 200 km/h and 300 km/h, respectively, within the straightedge measuring range of 1 m in Chinese maintenance regulation for high-speed nonballast track lines This standard ignores the influence of geometrical wavelengths on wheel-rail force. These thresholds of [11]
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