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Fatigue assessment of EA4T railway axles under artificial surface damage
International Journal of Fatigue ( IF 5.7 ) Pub Date : 2021-01-21 , DOI: 10.1016/j.ijfatigue.2021.106157
Jie-Wei Gao , Guang-Ze Dai , Qiu-Ze Li , Min-Nan Zhang , Shun-Peng Zhu , José A.F.O. Correia , Grzegorz Lesiuk , Abílio M.P. De Jesus

Foreign object damage (FOD) introduced in service, indentations, and nicks encountered during maintenance are typical defects leading to pre-scrap of high-speed railway axles. A comprehensive assessment of the influence of these defects on the structural integrity of axles is critical for ensuring their operation safety with low maintenance costs. Three types of defects were produced artificially on specimens extracted from EA4T axles, electronic discharge machine (EDM) crater, indentation via compressing balls, and FOD by tungsten steel balls and cubes. Rotating bending fatigue tests were performed for fatigue strength evaluation of smooth and defected specimens. Morphologies of defects and fracture surfaces were studied. EDM defect surface is rough and the secondary notches are the fatigue crack initiation sites, while fatigue crack of indented and impacted specimens initiates from the sharp point of defect rims. Fatigue strength of specimens with indentation or tungsten ball impact damage is superior to that of EDM specimens and cubical projectile impacted specimens under the same depth. A large dispersion was found in the shape of impact damages by cubic projectiles and scattered fatigue strength as a consequence. Except for the defect depth, other parameters including produce modes and shape of the defect, should be considered to give a reliable evaluation on the fatigue strength of defected specimens.



中文翻译:

人为表面损伤下EA4T铁路车轴的疲劳评估

服务中引入的异物损坏(FOD),压痕和维护期间遇到的划痕是导致高速铁路车轴预先报废的典型缺陷。全面评估这些缺陷对车轴结构完整性的影响,对于确保其运行安全和低维护成本至关重要。在从EA4T车轴,电火花放电机(EDM)弹坑,压缩球压痕以及钨钢球和立方体的FOD提取的样品上人工制造了三种类型的缺陷。进行了旋转弯曲疲劳试验,以评估光滑和缺陷试样的疲劳强度。研究了缺陷和断裂表面的形态。EDM缺陷表面粗糙,次要缺口是疲劳裂纹的起始点,而凹痕和受冲击试样的疲劳裂纹是从缺陷边缘的尖端开始的。在相同深度下,带有压痕或钨球冲击损坏的试样的疲劳强度要优于电火花加工试样和立方弹丸冲击的试样。结果发现,立方弹丸的冲击破坏形状和分散的疲劳强度分布很大。除缺陷深度外,还应考虑其他参数,包括缺陷的产生方式和形状,以对缺陷试样的疲劳强度进行可靠的评估。结果发现,立方弹丸的冲击破坏形状和分散的疲劳强度分布很大。除缺陷深度外,还应考虑其他参数,包括缺陷的产生方式和形状,以对缺陷试样的疲劳强度进行可靠的评估。结果发现,立方弹丸的冲击破坏形状和分散的疲劳强度分布很大。除缺陷深度外,还应考虑其他参数,包括缺陷的产生方式和形状,以对缺陷试样的疲劳强度进行可靠的评估。

更新日期:2021-01-31
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