Gauthier Baptiste, Painchaud-April Guillaume, Le Duff Alain, Bélanger Pierre
PULÉTS, École de Technologie Supérieure (ÉTS), Montréal, QC H3C 1K3, Canada.
Olympus NDT Canada, Québec, QC G1P 0B3, Canada.
Sensors (Basel). 2021 Jan 22;21(3):730. doi: 10.3390/s21030730.
Time of flight diffraction (TOFD) is considered a reliable non-destructive testing method for the inspection of welds using a pair of single-element probes. On the other hand, ultrasonic phased array imaging has been continuously developed over the last couple of decades, and now features powerful algorithms, such as the total focusing method (TFM) and its multi-view approach to rendering detailed images of inspected parts. This article focuses on a different implementation of the TFM algorithm, relying on the coherent summation of the instantaneous signal phase. This approach presents a wide range of benefits, such as removing the need for calibration, and is highly sensitive to defect tips. This study compares the sizing and localization capabilities of the proposed method with the well-known TOFD. Both instantaneous phase algorithm and TOFD do not take advantage of the signal amplitude. Experimental tests were performed on a ¾″-thick steel sample with crack-like defects at different angles. Phase-based imaging techniques showed similar characterization capabilities as the standard TOFD method. However, the proposed method adds the benefit of generating an easy-to-interpret image that can help in localizing the defect. These results pave the way for a new characterization approach, especially in the field of automated ultrasonic testing (AUT).
飞行时间衍射（TOFD）被认为是一种可靠的无损检测方法，用于使用一对单元素探头检测焊缝。另一方面，超声相控阵成像在过去几十年中不断发展，现在具有强大的算法，如全聚焦方法（TFM）及其多视图方法，可用于生成被检测部件的详细图像。本文重点介绍了TFM算法的一种不同实现方式，该方式依赖于瞬时信号相位的相干求和。这种方法具有广泛的优点，例如无需校准，并且对缺陷尖端高度敏感。本研究将所提出方法的尺寸测量和定位能力与著名的TOFD进行了比较。瞬时相位算法和TOFD都没有利用信号幅度。在一个3/4英寸厚的带有不同角度裂纹状缺陷的钢样品上进行了实验测试。基于相位的成像技术显示出与标准TOFD方法相似的表征能力。然而，所提出的方法还有一个优点，即能生成易于解释的图像，有助于缺陷定位。这些结果为一种新的表征方法铺平了道路，特别是在自动超声检测（AUT）领域。
