Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences ( IF 2.741 ) Pub Date : 2021-01-13 , DOI: 10.1098/rspa.2020.0380 Andreas A. E. Zimmermann; Peter Huthwaite; Brian Pavlakovic
Quantifying corrosion damage is vital for the petrochemical industry, and guided wave tomography can provide thickness maps of such regions by transmitting guided waves through these areas and capturing the scattering information using arrays. The dispersive nature of the guided waves enables a reconstruction of wave velocity to be converted into thickness. However, existing approaches have been shown to be limited in in-plane resolution, significantly short of that required to accurately image a defect target of three times the wall thickness (i.e. 3 T) in each in-plane direction. This is largely due to the long wavelengths of the fundamental modes commonly used, being around 4 T for both A0 and S0 at the typical operation points. In this work, the suitability of the first-order shear-horizontal guided wave mode, SH1, has been investigated to improve the resolution limit. The wavelength at the desired operating point is significantly shorter, enabling an improvement in resolution of around 2.4 times. This is first verified by realistic finite-element simulations and then validated by experimental results, confirming the improved resolution limit can now allow defects of maximum extent 3T-by-3T to be reliably detected and sized, i.e. a long-pursued goal of guided wave tomography has been achieved.
量化腐蚀破坏对石化行业至关重要，而导波层析成像可以通过将导波传输通过这些区域并使用阵列捕获散射信息来提供此类区域的厚度图。导波的色散特性使波速的重构可以转换为厚度。然而，现有方法已经显示出在平面内分辨率上受到限制，大大低于在每个平面内方向上精确成像三倍壁厚（即3 T）的缺陷目标所需的分辨率。这主要是由于通常使用的基本模式的长波长，在典型的工作点上，A0和S0的波长都约为4T。在这项工作中，一阶剪切水平导波模式SH1的适用性 已进行研究以提高分辨率极限。所需工作点处的波长明显更短，分辨率提高了约2.4倍。这首先通过现实的有限元模拟进行验证，然后通过实验结果进行验证，确认改进的分辨率极限现在可以可靠地检测和确定最大范围3T x 3T的缺陷，即长期追求的导波目标层析成像已实现。