Huthwaite Peter, Ribichini Remo, Cawley Peter, Lowe Michael J S
IEEE Trans Ultrason Ferroelectr Freq Control. 2013 Jun;60(6):1165-77. doi: 10.1109/TUFFC.2013.2679.
Guided wave tomography offers a method to accurately quantify wall thickness losses in pipes and vessels caused by corrosion, using ultrasonic waves transmitted over distances of approximately 1 to 2 m, and measured by an array of transducers. These measurements are then used to reconstruct a map of wall thickness throughout the inspected region. To achieve accurate estimations of remnant wall thickness, it is vital that a suitable Lamb mode is chosen. This paper presents a detailed evaluation of the two most suitable modes, S0 and A0, to compare their performance using both numerical and experimental data. The sensitivity of A0 to thickness variations was shown to be superior to S0; however, the attenuation from A0 when a liquid loading was present was much higher than S0. A0 was less sensitive to the presence of coatings on the surface than was S0. Finally, it was shown that both modes could achieve a similar level of resolution in the plane of the plate surface.
导波层析成像提供了一种方法，可利用在大约1至2米距离上传输并由换能器阵列测量的超声波，精确量化管道和容器中由腐蚀导致的壁厚损失。然后，这些测量值被用于重建整个检测区域的壁厚图。为了准确估计剩余壁厚，选择合适的兰姆波模式至关重要。本文对两种最合适的模式S0和A0进行了详细评估，使用数值和实验数据比较它们的性能。结果表明，A0对厚度变化的灵敏度优于S0；然而，存在液体负载时A0的衰减远高于S0。A0对表面涂层的存在不如S0敏感。最后，结果表明两种模式在板表面平面内均可实现相似的分辨率水平。
