نتایج جستجو برای: rail fracture
تعداد نتایج: 104627 فیلتر نتایج به سال:
rails fracture by the growth of fatigue crack or critical crack is one of the prevalent defects in railway. the rail fracture, failure and stress analysis should be studied in order to prevention of rail fracture. in this paper, new formulation of contact stress for two rolling bodies is presented, where the results are closed to the hertz stress formulation. moreover, stress analysis is done b...
The wide-gap aluminothermic rail welds with root opening of 50-70 mm were produced using plain carbon steel rail and non-alloy aluminothermic charge. Mechanical properties and micro-structure of the weld metal and HAZ as well as the impact energy and the fracture toughness of the welds were investigated. The yield and tensile strength of wide-gap welds were about 98% and 95% of the base metal, ...
Abstract: To ensure the rail transportations safety, evaluation of fatigue behavior of the rail steel is necessary. High cycle fatigue behaviour of a rail steel was the subject of investigation in this research using fracture mechanics. Finite element method (FEM) was used for analyzing the distribution of the stresses on the rail, exerted by the external load. FEM analysis showed that the ...
in this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. two parallel rails of the track have been modeled as euler-bernoulli beams on elastic points as rail pads. also sleepers have been modeled as visco-elastic euler-bernoulli beams. it is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. the...
The paper presents the development of an intelligent image processing algorithm capable of detecting fatigue defects from images of the rail surface. The links between the defect detection algorithm and 3D models for rail crack propagation are investigated, considering the influence of input parameters (materials, vehicle characteristics, loading conditions). The dynamic behaviour at the wheel-...
Increased traffic speeds and axle loads on modern railways enhance rail track degradation. To eliminate track failure due to rail defects, a condition monitoring system requires methods for the early detection of defects which grow in service. Acoustic emission (AE) monitoring is the only non-destructive technique which might be applied online to study the defect growth under traffic loading. H...
This thesis proposes a quantitative method to optimize inspection/repair intervention in rail defect management. Rail defect management is important for track maintenance, since rails are the most significant and basic component of the track systems. Rail inspection is a fundamental intervention to prevent rail failure. Railroads have evolved the rail inspection interval based on their empirica...
Various stresses add to the railway rails and accumulate fatigue damage due to daily use. Fracture mechanics clarification concerning the growth behavior of cracks is needed, in order to decide the inspection period and the cycle [1], . Though the crack progression and influence of residual stress on fatigue strength has been researched [3] for many years, they are not clear now. The aims of th...
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