Circumferential SH Wave Piezoelectric Transducer System for Monitoring Corrosion-Like Defect in Large-Diameter Pipes

Abstract

The fundamental circumferential shear horizontal (CSH0) wave is of practical importance in monitoring corrosion defects in large-diameter pipes due to its virtually non-dispersive characteristics. However, so far, there have been limited CSH0 wave transducers which can be used to constitute a structural health monitoring (SHM) system for pipes. Moreover, the CSH0 wave’s capability of sizing the corrosion-like defect has not yet been confirmed by experiments. In this work, firstly, the mechanism of exciting CSH waves was analyzed. A method based on our previously developed bidirectional SH wave piezoelectric transducers was then proposed to excite the pure CSH0 mode and first order circumferential shear horizontal (CSH1) mode. Both finite element simulations and experiments show that the bidirectional transducer is capable of exciting pure CSH0 mode traveling in both circumferential directions of a 1-mm thick steel pipe from 100 to 300 kHz. Moreover, this transducer can also serve a sensor to detect CSH0 mode only by filtering circumferential Lamb waves over a wide frequency range from 100 to 450 kHz. After that, a method of sizing a rectangular notch defect by using CSH0 wave was proposed. Experiments on an 11-mm thick steel pipe show that the depth and circumferential extent of a notch can be accurately determined by using the proposed method. Finally, experiments were performed to investigate the reflection and transmission characteristics of CSH0 and CSH1 waves from notches with different depths. It was found that transmission coefficients of CSH0 mode decrease with the increasing of notch depth, which indicates that it is possible to monitor the depth change of corrosion defects by using CSH0 wave.

Nondestructive Testing for Corrosion Evaluation of Metal under Coating

“…Therefore, more advanced signal processing algorithms are needed to further improve the sensitivity and quantification ability of NDT system. control/monitoring room often located at a significant distance, unlike NDT (often scheduled inspection); thus, it can help identify corroded areas and plan condition-based structural repairs [77]. In [78], structural integrity monitoring of corroded steel marine structures with the use of NDE and SHM approach was presented.…”

Piezoelectric Transducer-Based Diagnostic System for Composite Structure Health Monitoring

“…Schematic representation of boundary conditions is presented in Figure 4 a. The application of piezoelectric sensors in damages or different type of defect detection was used by other authors [ 20 , 21 , 31 ]; as for a structural health monitoring (SHM) system, this method is of great significance [ 32 ].…”

A circumferential SH wave piezoelectric transducer array for damage detection in large-diameter pipes

“…However, there appears no attempt to develop a CSH0 wave phased array, which is mainly attributed to the difficulty of generating pure CSH0 wave. Recently, Miao et al [36] designed a bidirectional SH wave piezoelectric transducer (BSH-PT) based on dual face-shear d24 PZT wafers, which is capable of exciting pure CSH0 wave by suppressing all the axial guided waves and circumferential Lamb waves over a wide frequency range [37]. Moreover, the proposed BSH-PT can also be served as a sensor to receive CSH0 wave only by filtering circumferential Lamb waves.…”