Frequency Dependence of the Defect Sensitivity of Guided Wave Testing for Efficient Defect Detection at Pipe Elbows
Frequency Dependence of the Defect Sensitivity of Guided Wave Testing for Efficient Defect Detection at Pipe Elbows
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DOI：
10.2320/matertrans.m2015319
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发表时间：
2016-03
影响因子：
1.2
通讯作者：
Toshihiro Yamamoto;T. Furukawa;H. Nishino
中科院分区：
文献类型：
--
作者：
Toshihiro Yamamoto;T. Furukawa;H. Nishino
导波检测是一种有效的管壁减薄筛选方法，因为它的检测范围长，而且能够检测进出受限的管道。然而，管道中弯头的存在使得回波信号的解释变得困难。本文研究了导波检测在管道弯头缺陷检测中的灵敏度问题。为了检验弯头上不同位置存在缺陷时的缺陷敏感性，在每个铝合金管件的弯头外表面的12个不同位置中的一个制造了人工缺陷。在每个缺陷位置，随着缺陷深度的逐渐增加，观察缺陷信号，获得缺陷灵敏度。发射导波频率依次设置为30khz、40khz和50khz。在30 kHz时，肘部的内腔获得了高灵敏度值，而在40 kHz和50 kHz时，肘部的外腔获得了高灵敏度值。本文还给出了用与实验中相同配置的计算机模拟结果来分析导波通过弯头的传播行为。除实验结果外，仿真结果还表明，缺陷敏感位置受导波频率的控制。因此，适当选择导波检测的激励频率可以有效地检测管道弯头处的缺陷。(doi: 10.2320 / matertrans.M2015319)
Guided wave testing offers an efficient screening method for thinning of pipe walls because of its long inspection range and its ability to inspect pipes with limited access. However, the existence of an elbow in pipes makes the interpretation of echo signals difficult. The present study investigates the sensitivity of defect detection when guided wave testing is applied to detect a defect at a pipe elbow. To examine the defect sensitivity when a defect exists at different locations on an elbow, an artificial defect was produced at one of 12 different locations on the outer surface of the elbow of each aluminum alloy piping specimen. The defect signals were observed as the defect depth was gradually increased at each defect location to obtain the defect sensitivity. The transmitted guided wave frequency was in turn set to 30 kHz, 40 kHz, and 50 kHz. At 30 kHz, high sensitivity values were obtained at the intrados of the elbows, whereas at 40 kHz and 50 kHz, high sensitivity values were obtained at their extrados. This paper also shows the results of computer simulations that used the same configuration as that used in the experiments to analyze the propagation behavior of guided waves passing through the elbow. In addition to the experimental results, the simulation results indicate that the defect-sensitive locations are controlled by the guided wave frequency. Thus, proper selection of the excitation frequency for guided wave testing enables efficient defect detection at pipe elbows. [doi:10.2320/matertrans.M2015319]