A study on the design, framework, experimental arrangement, data acquisition, and subsequent analysis of cold crack detection using fiber Bragg grating (FBG) sensors during welding is presented. Cold crack induced acoustic emission (AE) events are detected by multiple FBG sensor configurations and using a commercial FBG AE interrogation system. The crack locations are theoretically predicted using a method of linear localization based on the differences in the time of arrival of the AE events at different FBG sensors. The approach is experimentally validated by employing packaged and unpackaged FBG sensor arrays in a welding experiment with gas tungsten arc welding on ultrahigh toughness high hardness armor steel. Frequency analysis of the AE events is also carried out to understand the cold crack characteristics. The weld region of the steel plate is diced into 1-mm cross-sectional pieces, and the positions of the cold cracks are identified using scanning electron microscope imaging and then cross correlated with the measured AE events, and thereby confirming the correct identification of cold crack location using the FBG sensing method.

中文翻译：

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使用光纤布拉格光栅传感器进行焊接冷裂纹监测和定位

介绍了在焊接过程中使用光纤布拉格光栅 (FBG) 传感器进行冷裂纹检测的设计、框架、实验安排、数据采集和后续分析的研究。冷裂纹诱发声发射 (AE) 事件由多个 FBG 传感器配置和使用商用 FBG AE 询问系统检测。基于AE事件到达不同FBG传感器的时间差异，使用线性定位方法在理论上预测裂纹位置。该方法通过在超高韧性高硬度装甲钢上采用钨极气体保护焊的焊接实验中采用封装和未封装的 FBG 传感器阵列进行了实验验证。还进行了 AE 事件的频率分析，以了解冷裂纹特征。