Fatigue cracks have appeared as a significant issue for joints and connections in existing steel structures in the last decades. Therefore, those are a major inspection and maintenance matter for any steel structure's operator. This emphasises the importance of using a reliable detection method to determine the crack size and assessing the severity of such a crack on the structural integrity of a structure. In this article, the effectiveness of strain measurement in detecting fatigue cracks in transversal non-load carrying welded attachment subjected to out of plane axial loading is studied. Numerical analysis and experimental investigations allowed to correlate the decrease in strain measured by attached gauges to the crack depth at the weld toe. In addition, different strain evolution patterns were found during fatigue testing, and the fracture surfaces of the specimens were observed to interpret these patterns. Moreover, the crack position with respect to the weld toe surface was predicted via strain measurements.

中文翻译：

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通过疲劳测试中的应变测量来检测裂纹

在过去的几十年中，疲劳裂纹已成为现有钢结构中接头和连接的一个重要问题。因此，对于任何钢结构操作人员来说，这些都是一项重大的检查和维护事项。这强调了使用可靠的检测方法来确定裂缝大小并评估此类裂缝对结构结构完整性的严重程度的重要性。本文研究了应变测量在检测平面外轴向载荷下横向非承载焊接附件疲劳裂纹中的有效性。数值分析和实验研究允许将附加应变计测量的应变减少与焊趾处的裂纹深度相关联。此外，在疲劳测试过程中发现了不同的应变演化模式，并观察试样的断裂表面来解释这些图案。此外，通过应变测量预测相对于焊趾表面的裂纹位置。