ABSTRACT Rolling contact fatigue (RCF) cracks are the predominant reason for rail grinding maintenance and replacement on all types of railway system, as they can potentially cause rail break if not removed. To avoid excessive material removal, accurate crack sizing is required. Alternating current field measurement has been used as an electromagnetic method for RCF crack sizing, incorporating with modelling results for single RCF cracks with large vertical angles (>30°). No study using this knowledge to size shallow angled crack clusters has yet been reported. A novel method, the pocket length compensation method, is proposed to determine the length and depth of RCF cracks with shallow vertical angles. For shallow crack clusters, vertical angle predictions are close to the measured values with a deviation of less than 13.6%. Errors in crack pocket length prediction are greatly reduced when the pocket length compensation was included. The predicted vertical depth using the approach developed for clustered angled cracks is accurate with errors <8.3%, which compares to errors of up to 60% if the single RCF crack approach is used and errors of up to 21.4% if a non-compensated prediction for crack clusters is used.

中文翻译：

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使用 ACFM 传感器预测 RCF 簇状裂纹尺寸以及裂纹长度和垂直角度的影响

摘要 滚动接触疲劳 (RCF) 裂纹是所有类型铁路系统磨削维护和更换钢轨的主要原因，因为如果不去除，它们可能导致钢轨断裂。为避免过度去除材料，需要精确的裂纹尺寸。交流场测量已被用作 RCF 裂纹尺寸的电磁方法，结合具有大垂直角 (>30°) 的单个 RCF 裂纹的建模结果。还没有研究使用这些知识来确定浅角裂纹簇的大小。提出了一种新的方法，即袋长补偿法，用于确定具有浅垂直角的RCF裂缝的长度和深度。对于浅裂纹簇，垂直角预测值接近实测值，偏差小于 13.6%。当包含口袋长度补偿时，裂纹口袋长度预测的误差大大减少。使用针对成簇角裂纹开发的方法预测的垂直深度准确，误差 <8.3%，相比之下，如果使用单个 RCF 裂纹方法，误差高达 60%，如果使用非补偿预测，误差高达 21.4%用于裂纹簇。