Magnetostrictive Guided Wave Technique Verification for Detection and Monitoring Defects in the Pipe Weld

Abstract

During inspection of piping in nuclear power plants or other industries, it is difficult to implement conventional nondestructive techniques due to limited accessibility or obstacles such as pipes with insulation, pipes buried underground, structural complexity, or radiation environments. In addition, since the defects mainly occur in the weld region or support area, it is not easy to separate defect signals from those of structural components. To solve these problems, we developed a technique to detect and monitor the formation and growth of defects, using a magnetostrictive guided wave sensor. This sensor has advantages (such as sharp and clear signal patterns and ability to easily eliminate the signal from the geometric structure) over the conventional piezoelectric transducer. To verify our technique, signals from actual pipe welds with defects were acquired and processed with our phase matching/subtraction program. The proposed technique shows a superior capability for detection and monitoring of defects, compared to the conventional guided wave methods.

High-Sensitivity Ultrasonic Guided Wave Monitoring of Pipe Defects Using Adaptive Principal Component Analysis

“…As shown in the straight pipe experiment conditions in Figure 10 a, the transducer based on magnetostrictive effect [ 41 ] was installed 0.2 m from the beginning. A hole defect 1 m away from the transducer was expanded from small to large.…”