Characteristics of longitudinal modes in symmetric mode conversion for defect characterization in guided waves-based pipeline inspection

2021 ◽  
pp. 102490
Author(s):  
Xiaojuan Wang ◽  
Heming Gao ◽  
Kai Zhao ◽  
Cuo Wang
Keyword(s):  
Guided Waves ◽  
Mode Conversion ◽  
Defect Characterization ◽  
Symmetric Mode ◽  
Pipeline Inspection ◽  
Longitudinal Modes

MODE CONVERSION OF SH GUIDED WAVES AT DEFECTS FOR PIPELINE INSPECTION

2009 ◽  
Author(s):  
S. A. Uribe ◽  
N. Nakamura ◽  
H. Ogi ◽  
M. Hirao ◽  
Donald O. Thompson ◽  
...  
Keyword(s):  
Guided Waves ◽  
Mode Conversion ◽  
Pipeline Inspection

scholarly journals Longitudinal Guided Wave Inspection of Small-Diameter Elbowed Steel Tubes with a Novel Squirrel-Cage Magnetostrictive Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Yao Liu ◽  
Xiucheng Liu ◽  
Chehua Yang ◽  
Wenxin Guo ◽  
Bin Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Guided Waves ◽  
Mode Conversion ◽  
Small Diameter ◽  
Longitudinal Mode ◽  
Guided Wave ◽  
Wall Defect ◽  
Squirrel Cage ◽  
Simulation Results ◽  
Magnetostrictive Sensor

In the study, ultrasonic longitudinal mode guided waves were employed to detect defects in elbowed tubes (without welds) with a diameter of 10 mm. Finite element simulation results highlighted that the emitted L(0,1) mode guided waves experienced strong reflection and mode conversion at the elbow region to generate F(1,1) mode, followed by slow and weak F(2,1) mode. The guided wave reflected from the elbow with a through-wall defect was manifested as two overlapped wave packets, which were good indicators of a defective elbow. To conduct L(0,1) mode guided waves inspection on the small-diameter elbowed tubes, a novel tailored squirrel-cage magnetostrictive sensor was employed in the experiment. The new sensor employed the configuration of segmental iron-cobalt strips and small-size permanent magnet arrays. The entire sensor is composed of two identical C-shaped sensor elements and can be recycled and installed conveniently. Experimental results obtained from healthy and defective tubes were consistent with the conclusions obtained from finite element simulations. An artificial through-wall defect at the elbow and a notch defect at the straight part of the tube could be simultaneously detected by L(0,1) mode guided waves through comparing experimental signals with simulation results.

scholarly journals Water Level Sensing in a Steel Vessel Using A0 and Quasi-Scholte Waves

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Peng Guo ◽  
Bo Deng ◽  
Xiang Lan ◽  
Kaili Zhang ◽  
Hongyuan Li ◽  
...  
Keyword(s):  
Water Level ◽  
Guided Waves ◽  
Mode Conversion ◽  
Experimental Studies ◽  
Low Frequency ◽  
Steel Vessel ◽  
Theoretical Predictions ◽  
Travelling Time ◽  
The Comparative Study ◽  
Group Velocities

This paper presents a water level sensing method using guided waves of A0 and quasi-Scholte modes. Theoretical, numerical, and experimental studies are performed to investigate the properties of both the A0 and quasi-Scholte modes. The comparative study of dispersion curves reveals that the plate with one side in water supports a quasi-Scholte mode besides Lamb modes. In addition, group velocities of A0 and quasi-Scholte modes are different. It is also found that the low-frequency A0 mode propagating in a free plate can convert to the quasi-Scholte mode when the plate has one side in water. Based on the velocity difference and mode conversion, a water level sensing method is developed. For the proof of concept, a laboratory experiment using a pitch-catch configuration with two piezoelectric transducers is designed for sensing water level in a steel vessel. The experimental results show that the travelling time between the two transducers linearly increases with the increase of water level and agree well with the theoretical predictions.

Circumference Damage Identification in a Pipe Using Mode Conversion of Longitudinal Guided Wave

2013 ◽  
Vol 395-396 ◽  
pp. 787-791
Author(s):  
Jing Wu ◽  
Wei Wei Zhang
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Mode Conversion ◽  
Guided Wave ◽  
Symmetric Mode ◽  
Axially Symmetric ◽  
Mode Transformation ◽  
Damage Location

This paper aims to develop a method to identify the damage location in circumference direction of a pipe using mode transformation of longitudinal guided wave. The corrosion-like damage in bimetal pipe is considered. Case study that damage detection for a bimetal pipe is used to show the validity and advantage of the proposed method. It can be found that the axially symmetric mode guided wave encounter the damage and the three modes were received in reflection. The damage location in circumferential directions could be identified by conversed modes measured at one position. The simulation shows a good performance.

Effect of an Internal Open Crack on Pipes Wave Propagation

2011 ◽  
Vol 488-489 ◽  
pp. 375-378
Author(s):  
Alessandro Marzani ◽  
Marco Miniaci ◽  
Erasmo Viola
Keyword(s):  
Cross Section ◽  
Guided Waves ◽  
Dispersion Curves ◽  
Internal Crack ◽  
Open Crack ◽  
Axially Symmetric ◽  
Pipe Length ◽  
Pipeline Inspection ◽  
Non Invasive ◽  
The Waves

Stress guided waves in the sonic and ultrasonic regime are acknowledged as a powerful too lto inspect pipes in a non-invasive manner.A key point of the inspection procedure is related to the dispersive behavior of guided waves, that for agiven pipe is defined by the so-called dispersion curves. Such behavior, is generally predicted bymeans ofanalytical formulations. However, when the geometry of the pipe cross-section is not axially symmetric,such as in the presence of an open internal crack running along the pipe length, analytical formulations fail. Here, the computation of the guided waves properties for such a scenario is addressed via a SemiAnalytical Finite Element (SAFE) formulation in which the open crack is modeled at the mesh level.Different crack depths are considered and their effect on the waves dispersion curves are highlighted.The results could be of interest in pipeline inspection and monitoring.

A Wall Thinning Detection and Quantification Based on Guided Wave Mode Conversion Features

2006 ◽  
Vol 321-323 ◽  
pp. 795-798 ◽  
Author(s):  
Youn Ho Cho ◽  
Won Deok Oh ◽  
Joon Hyun Lee
Keyword(s):  
Long Range ◽  
Guided Waves ◽  
Velocity Dispersion ◽  
Mode Conversion ◽  
Group Velocity Dispersion ◽  
Wave Mode ◽  
Guided Wave ◽  
Wall Thinning ◽  
Theoretical Analyses ◽  
Data Calibration

This study presents a feasibility of using guided waves for a long-range inspection of pipe through investigation of mode conversion and scattering pattern from edge and wall-thinning in a steel pipe. Phase and group velocity dispersion curves for reference modes of pipes are illustrated for theoretical analyses. Predicted modes could be successfully generated by controlling frequency, receiver angle and wavelength. The dispersive characteristics of the modes from and edge wall-thinning are compared and analyzed respectively. The mode conversion characteristics are distinct depending on dispersive pattern of modes. Experimental feasibility study on the guided waves was carried out to explore wall thinning part in pipe for data calibration of a long range pipe monitoring by comb transducer and laser.

scholarly journals Quantitative mapping of thickness variations along a ray path using geometrical full waveform inversion and guided wave mode conversion

2022 ◽  
Vol 478 (2257) ◽  
Author(s):  
Peng Zuo ◽  
Peter Huthwaite
Keyword(s):  
Guided Waves ◽  
Mode Conversion ◽  
Waveform Inversion ◽  
Guided Wave ◽  
Direct Access ◽  
Thickness Variation ◽  
Full Waveform Inversion ◽  
Large Area ◽  
Wave Inversion ◽  
Full Waveform

Quantitative guided wave thickness mapping in plate-like structures and pipelines is of significant importance for the petrochemical industry to accurately estimate the minimum remaining wall thickness in the presence of corrosion, as guided waves can inspect a large area without needing direct access. Although a number of inverse algorithms have been studied and implemented in guided wave reconstruction, a primary assumption is widely used: the three-dimensional guided wave inversion of thickness is simplified as a two-dimensional acoustic wave inversion of velocity, with the dispersive nature of the waves linking thickness to velocity. This assumption considerably simplifies the inversion procedure; however, it makes it impossible to account for mode conversion. In reality, mode conversion is quite common in guided wave scattering with asymmetric wall loss, and compared with non-converted guided wave modes, converted modes may provide greater access to valuable information about the thickness variation, which, if exploited, could lead to improved performance. Geometrical full waveform inversion (GFWI) is an ideal tool for this, since it can account for mode conversion. In this paper, quantitative thickness reconstruction based on GFWI is developed in a plate cross-section and applied to study the performance of thickness reconstruction using mode conversion.

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