Detection of a Defect on the Back of a Pipe by Noncontact Remote Measurements
Detection of a Defect on the Back of a Pipe by Noncontact Remote Measurements
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通过非接触式远程测量检测管道背面的缺陷
DOI：
10.1115/1.4041433
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Takahiro Hayashi
中科院分区：
文献类型：
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作者：
別府万寿博;相澤武揚;市野宏嘉;郷原将哉，濵田匠李，別府万寿博，市野宏嘉，相澤武揚;相澤武揚，別府万寿博，市野宏嘉;三浦賢卓，濵田匠李，別府万寿博，市野宏嘉，相澤武揚;三浦賢卓，濵田匠李，別府万寿博，市野宏嘉，相澤武揚;相澤武揚，別府万寿博，市野宏嘉;寺澤拓真，濵田匠李，別府万寿博，市野宏嘉，相澤武揚;相澤武揚， 別府万寿博，市野宏嘉;Hayashi Takahiro;Takahiro Hayashi
管道检测通常采用超声波脉冲回波测试，其中超声波换能器下的小范围管壁可以在一次测量中进行评估。如果要检查管道的整个范围，则需要进行昂贵且费力的逐点测试。作者研究了板状结构的快速缺陷成像使用扫描激光源（SLS）技术作为一种有效的缺陷检测技术。虽然成像技术在非接触式远程测量中是可行的，但只能评估激光照射表面下的板横截面。本研究描述了检测壁变薄的管道背面使用共振的导波在管道圆周上传播的非接触式远程测量与SLS技术。利用光纤激光器对激光脉冲进行调制，在管道中产生窄带弹性波。当调制频率与周向导波的谐振频率一致时，利用SLS技术获得的频谱峰值的分布变得与周向导波模式的谐振图案相同。分布是扭曲的管壁变薄的背面，表明该技术具有潜在的检测缺陷的背面的管道。
Pipe inspection is generally executed with ultrasonic pulse echo testing where a small range of pipe wall under an ultrasonic transducer can be evaluated in one measurement. Costly and laborious point-by-point testing is required if a whole range of a pipe should be inspected. The author has investigated fast defect imaging for a plate-like structure using a scanning laser source (SLS) technique as an efficient defect inspection technique. Although the imaging technique is feasible in noncontact remote measurements, only a plate cross section under the laser irradiation surface can be evaluated. This study describes detection of wall thinning on the back of a pipe using resonance of guided wave propagating in a pipe circumference by noncontact remote measurements with the SLS technique. The narrowband elastic waves are generated in a pipe by modulating laser pulses with fiber laser equipment. When the modulation frequency is in harmony with the resonance frequency of a circumferential guided wave, the distribution of the frequency spectrum peak obtained with the SLS technique becomes identical to the resonance pattern of the circumferentially guided wave mode. The distributions are distorted for a pipe with wall thinning on the back indicating that this technique has a potential for detection of defects on the back of a pipe.