Ultrasonic isolation of buried pipes
Ultrasonic isolation of buried pipes
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DOI：
10.1016/j.jsv.2015.10.018
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发表时间：
2016-02-17
影响因子：
4.7
通讯作者：
Cawley, Peter
中科院分区：
文献类型：
--
作者：
Leinov, Eli;Lowe, Michael J. S.;Cawley, Peter
远程导波检测（GWT）通常用于监测和检测地面管道中的腐蚀缺陷。由于能量泄漏到埋地土壤中，与地面配置相比，埋地涂层管道中的GWT测试范围大大减小。本文以提高埋地管道导波检测范围为目的，研究了管道涂层对导波衰减的影响。T（0.1）和L（0.2）导波模式的衰减测量使用全尺寸的实验装置中的熔融粘结环氧树脂（FBE）涂层8英寸。管道，埋在松散和压实的沙子中。在10-35 kHz的GWT中通常使用的频率范围内进行测试，并与模型预测进行比较。结果表明，在FBE层和砂之间施加低阻抗涂层有效地消除了砂对埋地管道超声泄漏的影响。埋地管道的超声波隔离是通过在管道上涂上聚乙烯（PE）泡沫层来证明的，该泡沫层的阻抗比管道和沙子都小，并且能够承受来自沙子的过载。与在没有PE泡沫的埋地FBE涂覆管中测量的1.7-4.7 dB m（-1）的衰减相比，发现在埋地PE泡沫FBE涂覆管中测量的衰减显著降低，对于松散和压实的砂条件在0.3-1.2 dB m（-1）的范围内。使用超声干涉法独立测量PE泡沫的声学特性，并将其纳入埋地涂层管中导波传播的模型预测中。良好的协议之间的实验测量和模型预测。衰减在对应于涂层的全厚度共振频率的频域中呈现周期性峰值。PE涂层管道导波衰减的大幅减少将导致GWT测试范围的大幅增加;这种涂层对新管道安装具有吸引力。(C)2015年，作者。爱思唯尔有限公司出版
Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0.1) and L(0.2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8 in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10-35 kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3-1.2 dB m(-1) for loose and compacted sand conditions, compared to measured attenuation of 1.7-4.7 dB m(-1) in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such coatings would be attractive for new pipeline installations. (C) 2015 The Authors. Published by Elsevier Ltd.