Development of a New Crack Identification Technique Based on Near-Tip Singular Electrothermal Field Measured by Lock-in Infrared Thermography
Development of a New Crack Identification Technique Based on Near-Tip Singular Electrothermal Field Measured by Lock-in Infrared Thermography
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DOI：
10.1299/jsmea.44.528
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发表时间：
2001-10
期刊：
影响因子：
--
通讯作者：
T. Sakagami;S. Kubo
中科院分区：
文献类型：
--
作者：
T. Sakagami;S. Kubo
提出了一种新的热成像无损检测技术，即利用红外热成像技术结合锁相数据处理技术，测量周期调制电流作用下裂纹尖端的奇异磁场。实验研究了该方法在识别钢和铝合金板试样中的穿透人工裂纹和疲劳裂纹时的分辨率和适用性。通过感应线圈将调制电流施加到破裂的样品。同步于参考电流调制信号的锁定热图像由锁定热成像拍摄。在锁相热像中，在裂纹尖端观察到显著的奇异磁场。疲劳裂纹以及人工裂纹被发现是敏感地识别所提出的技术在良好的分辨率相比，奇异的方法，使用传统的热成像温度测量。
A new thermographic NDT technique was proposed, in which singular electrothermal field near crack tips under the application of periodically modulated electric current was measured using an infrared thermography combined with lock-in data processing technique. Experimental investigations were made on the resolution and the applicability in the identification of through-thickness artificial cracks and fatigue cracks embedded in steel and aluminum alloy plate samples. Modulated electric current was applied to the cracked sample by an induction coli. Lock-in thermal images synchronized to the reference current modulation signal were taken by the lock-in thermography. Significant singular electrothermal field was observed at the crack tip in the lock-in thermal image. The fatigue cracks as well as artificial cracks were found to be sensitively identified by the proposed technique in good resolution compared with the singular method using a conventional thermographic temperature measurement.