Extracting Quantitative Information on Pipe Wall Damage in Absence of Clear Signals From Defect

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Amit Shelke ◽  
Umar Amjad ◽  
Milos Vasiljevic ◽  
Tribikram Kundu ◽  
Wolfgang Grill
Keyword(s):  
Guided Waves ◽  
Pipe Wall ◽  
Low Frequency ◽  
Time History ◽  
Quantitative Information ◽  
Guided Wave ◽  
Long Distance ◽  
Acoustic Transducers ◽  
Small Defect ◽  
Electro Magnetic

It has been well established that guided waves are sensitive to structural damages encountered on their path of propagation and for this reason this technique is very efficient for distinguishing defective structural components from defect-free ones. Although the guided wave technique can identify a specimen having a distribution of defects, detecting and quantifying a small defect on its path from a long distance, as required for structural health monitoring (SHM) applications, is not an easy task for the guided wave inspection technique even today, especially when the transducers cannot come in direct contact with the pipe wall. The current technological challenges for pipe inspection by generating guided waves using noncontact transducers are to detect a small defect on the pipe wall and estimate its location and size from a long distance when the reflected signal from the defect cannot be clearly identified as is the case for low frequency guided waves that can propagate long distances. Electro-magnetic acoustic transducers (EMATs) are used here to generate guided waves in the pipe by the noncontact technique. This paper shows how small a defect in a pipe wall can be detected and its location and dimension can be estimated using relatively low frequency guided waves generated and received by EMATs even when the defect signal is not clearly visible in the time history plot because various wave modes reflected from the defect and pipe ends overlap.

EMAT-Based Inspection of Concrete-Filled Steel Pipes for Internal Voids and Inclusions

2002 ◽  
Vol 124 (3) ◽  
pp. 265-272 ◽  
Author(s):  
Won-Bae Na ◽  
Tribikram Kundu
Keyword(s):  
Guided Waves ◽  
Acoustic Method ◽  
Guided Wave ◽  
Long Distance ◽  
Steel Pipes ◽  
Acoustic Transducers ◽  
Bending Resistance ◽  
Good Potential ◽  
Internal Volume ◽  
Electro Magnetic

Concrete-filled steel pipes have been used as piles for supporting civil and marine structures. These piles provide good bending resistance, and can be easily spliced for long depth installation. However, these piles are usually exposed in hostile environments such as seawater and deicing materials. Thus, the outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. In addition, the void that can possibly exist in the pipe reduces the bending resistance. To avoid structural failure due to this type of deterioration, appropriate inspection and repair techniques are to be developed. The acoustic method is attractive for this inspection since it is relatively simple and versatile. Especially, guided wave techniques have strong potentials for this inspection because of long-distance inspection capability. There are different transducer-coupling mechanisms available for the guided wave inspection techniques. Electro-magnetic acoustic transducers (EMATs) give relatively consistent results in comparison to piezoelectric transducers since they do not need any couplant. EMATs are used for transmitting and receiving cylindrical guided waves through concrete-filled steel pipes. It is shown that EMAT-generated cylindrical guided wave techniques have good potential for the interface inspection of concrete-filled steel pipes.

Inspection of Concrete-Metal Rod Interface Using Guided Waves

2000 ◽  
Author(s):  
Won-Bae Na ◽  
Tribikram Kundu ◽  
Mohammad R. Ehsani
Keyword(s):  
Lamb Wave ◽  
Guided Waves ◽  
Lamb Waves ◽  
Guided Wave ◽  
Ultrasonic Transducers ◽  
Interface Debonding ◽  
Long Distance ◽  
Steel Rebar ◽  
Steel Bars ◽  
Steel Rebars

Abstract The feasibility of detecting interface degradation and separation of steel rebars in concrete beams using Lamb waves is investigated in this paper. It is shown that Lamb waves can easily detect these defects. A special coupler between the steel rebar and ultrasonic transducers has been used to launch non-axisymmetric guided waves in the steel rebar. This investigation shows that the Lamb wave inspection technique is an efficient and effective tool for health monitoring of reinforced concrete structures because the Lamb wave can propagate a long distance along the reinforcing steel bars embedded in concrete as the guided wave and is sensitive to the interface debonding between the steel rebar and concrete.

Detection of Defects in Titanium Using Shear Horizontal Guided Waves

2021 ◽  
Author(s):  
Christian Peyton ◽  
Rachel S. Edwards ◽  
Steve Dixon ◽  
Ben Dutton ◽  
Wilson Vesga
Keyword(s):  
Guided Waves ◽  
Wave Mode ◽  
Guided Wave ◽  
Inspection System ◽  
Wave Direction ◽  
Finite Element Software ◽  
Small Defect ◽  
Back Face ◽  
The Relationship ◽  
Shear Horizontal

Abstract This paper investigates the interaction behaviour between the fundamental shear horizontal guided wave mode and small defects, in order to understand and develop an improved inspection system for titanium samples. In this work, an extensive range of defect sizes have been simulated using finite element software. The SH0 reflection from a defect has been shown previously to depend on its length as the total reflection consists of reflections from both the front and back face. However, for small defect widths, this work has found that the width also affects this interference, changing the length at which the reflection is largest. In addition, the paper looks at how the size of the defect affects the mode converted S0 reflection and SH0 diffraction. The relationship between the SH0 diffraction and defect size is shown to be more complex compared to the reflections. The mode converted S0 reflection occurs at an angle to the incident wave direction; therefore, the most suitable angle for the detection has been found. Simultaneous measurement of multiple waves would bring benefits to inspection.

An improved design of shear horizontal guided wave electromagnetic acoustic transducer

2020 ◽  
Vol 62 (8) ◽  
pp. 494-497
Author(s):  
Xu Zhang ◽  
Sheng Feng ◽  
Jun Tu ◽  
Xiaochun Song
Keyword(s):  
Guided Waves ◽  
Cost Effective ◽  
Guided Wave ◽  
Experimental Investigations ◽  
Electromagnetic Acoustic Transducer ◽  
Rectangular Array ◽  
Acoustic Transducers ◽  
Acoustic Transducer ◽  
Improved Design ◽  
Shear Horizontal

This work proposes the use of a Halbach magnet structure to enhance the generation efficiency of shear horizontal (SH) guided waves on a plate. SH waves are normally generated using periodic permanent magnet (PPM) electromagnetic acoustic transducers (EMATs). Two PPM configurations are designed using a Halbach magnet array and the enhancements of the static magnetic fields of the two magnet arrays are validated by the finite element method, indicating that these configurations can increase the peak flux density compared with the conventional configuration. Numerical analysis and experimental investigations indicate that a racetrack coil combined with either a rectangular or triangular Halbach magnet array can enhance the amplitude of the SH guided wave by factors of ∼1.2 and ∼1.1, respectively, and that the rectangular array performs better and is more cost effective.

Flaw Detection in Aluminum Plate by Shear Horizontal Guided Wave Based on Magnetostriction EMAT

2014 ◽  
Vol 614 ◽  
pp. 287-290
Author(s):  
Le Chen ◽  
Yue Min Wang ◽  
Hai Quan Geng
Keyword(s):  
Guided Waves ◽  
Flaw Detection ◽  
Test Sample ◽  
Guided Wave ◽  
Sh Waves ◽  
Electromagnetic Acoustic Transducers ◽  
Acoustic Transducers ◽  
Non Destructive ◽  
Viable Method ◽  
Shear Horizontal

Shear horizontal (SH) guided waves have been proved to be a viable method in the Non-Destructive Evaluation (NDE). Electromagnetic acoustic transducers (EMAT) can excite SH waves easily. By bonding the Fe-Co alloy to the test sample, the SH guided waves based on magnetostriction effect can be used to detect the flaw in nonferromagnetic material. The principle of exciting and receiving SH waves is introduced, and an experiment is carried out to validate the result.

scholarly journals THE MAIN CHARACTERISTICS AND FEATURES OF THE LOW-FREQUENCY WAVE PROCESS IN THE STRETCHED PIPELINES

2019 ◽  
pp. 5-23
Author(s):  
O. G. Bondarenko
Keyword(s):  
Solid Medium ◽  
Pipe Wall ◽  
Wave Process ◽  
Low Frequency ◽  
Technical Condition ◽  
The Body ◽  
Technical State ◽  
Long Distance ◽  
Pipe Surface ◽  
Frequency Wave

The problem of determining the technical condition of various pipeline systems, ensuring their reliable аnd safe operation has recently become the subject of geopolitics. In this situation, constant monitoring of their technical condition is essential for the maintenance of pipelines. However, it is technically difficult to monitor the technical state of pipelines by conventional methods of non-destructive testing (NDT). An analysis of the essence of the wave process in diagnosing the technical condition of long pipelines by low-frequency ultrasound directed waves is performed. The types of modes of directed waves and peculiarities of the wave process in the solid medium of the pipeline are given. Dispersed diagrams of  ound velocities for different modes of directed waves are considered, on the basis of which their main features are formulated in the diagnosis of the technical state of extended pipelines. The analysis of the wave process in the long pipeline from the position of the acoustic location of its solid medium by low-frequency directional waves is made, the model of the active localization system is developed in diagnosing the technical state of the pipeline, the principles of excitation and displacement of the particles of the medium of the pipe wall are considered in the distribution of longitudinal, twisted and bending mods of low-frequency ultrasonic directed waves. When choosing the frequency and mode of the directed wave to diagnose the technical state of long pipes, it is necessary to take into account that the directed wave is the result of the interaction of the vibrations generated by the transducers with the pipe surface. A significant factor determining the efficiency of energy transfer from the antenna to the body of the drainage pipeline is the harmonization of the internal resistance of the converter and the load due to the static force of pressing the piezoelectric transducers to the pipe surface. When creating systems of low-frequency ultrasonic diagnostics of long-distance pipelines directed waves it is necessary to take into account the main features of the wave process, which has a complicated mechanism of propagation over the thickness of the pipe wall.

scholarly journals Nondestructive Inspection of Corrosion and Delamination at the Concrete-Steel Reinforcement Interface

2002 ◽  
Author(s):  
Tri Miller ◽  
Christopher J. Hauser ◽  
Tribikram Kundu
Keyword(s):  
Guided Waves ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Reinforcing Steel ◽  
Electromagnetic Acoustic Transducer ◽  
Long Distance ◽  
Steel Bar ◽  
Acoustic Transducer ◽  
Steel Bars ◽  
Aging Infrastructure

This paper explores the feasibility of detecting and quantifying corrosion and delamination at the interface between reinforcing steel bar and concrete using ultrasonic guided waves. The problem of corrosion and delamination of the reinforcing steel in the aging infrastructure has increased significantly in the last three decades and is likely to keep on increasing. Ultrasonic cylindrical guided waves that can propagate a long distance along the reinforcing steel bar are found to be sensitive to the interface conditions between steel bar and concrete. Ultrasonic transducers are used to launch and detect cylindrical guided waves along the steel bar. The traditional ultrasonic testing methods, for instance the pulse-echo method, where reflection, transmission, and scattering of longitudinal waves are used for detecting large voids in concrete, are not very efficient for detecting corrosion and delamination at the interface between concrete and steel bar. For this study four sets of specimens were prepared. They are rebars and plain steel bars with corrosion and physical separation. Transducers used during the experiment are the Electromagnetic Acoustic Transducer (EMAT) and the Piezoelectric Transducer (PZT). The experiment suggests that the guided wave inspection technique is feasible for the health monitoring of reinforced concrete structures. It also reveals that the ultrasonic guided waves are sensitive to the type of steel used and to the rib patterns on the reformed steel bars.

scholarly journals Core–skin debonding detection in honeycomb sandwich structures through guided wave wavefield analysis

2018 ◽  
Vol 30 (9) ◽  
pp. 1306-1317 ◽  
Author(s):  
Lingyu Yu ◽  
Zhenhua Tian ◽  
Xiaopeng Li ◽  
Rui Zhu ◽  
Guoliang Huang
Keyword(s):  
Guided Waves ◽  
Sandwich Structures ◽  
Lamb Waves ◽  
Laser Doppler Vibrometer ◽  
Low Frequency ◽  
Guided Wave ◽  
Honeycomb Sandwich ◽  
Debonding Detection ◽  
The Waves ◽  
Detection And Quantification

Ultrasonic guided waves have proven to be an effective and efficient method for damage detection and quantification in various plate-like structures. In honeycomb sandwich structures, wave propagation and interaction with typical defects such as hidden debonding damage are complicated; hence, the detection of defects using guided waves remains a challenging problem. The work presented in this article investigates the interaction of low-frequency guided waves with core–skin debonding damage in aluminum core honeycomb sandwich structures using finite element simulations. Due to debonding damage, the waves propagating in the debonded skin panel change to fundamental antisymmetric Lamb waves with different wavenumber values. Exploiting this mechanism, experimental inspection using a non-contact laser Doppler vibrometer was performed to acquire wavefield data from pristine and debonded structures. The data were then processed and analyzed with two wavefield data–based imaging approaches, the filter reconstruction imaging and the spatial wavenumber imaging. Both approaches can clearly indicate the presence, location, and size of the debonding in the structures, thus proving to be effective methods for debonding detection and quantification for honeycomb sandwich structures.

scholarly journals Improving accuracy through density correction in guided wave tomography

2016 ◽  
Vol 472 (2186) ◽  
pp. 20150832 ◽  
Author(s):  
P. Huthwaite
Keyword(s):  
Guided Waves ◽  
Low Frequency ◽  
Region Of Interest ◽  
Density Variation ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Wave Tomography ◽  
Wall Loss ◽  
Improving Accuracy ◽  
The Waves

The accurate quantification of wall loss caused by corrosion is critical to the reliable life estimation of pipes and pressure vessels. Traditional thickness gauging by scanning a probe is slow and requires access to all points on the surface; this is impractical in many cases as corrosion often occurs where access is restricted, such as beneath supports where water collects. Guided wave tomography presents a solution to this; by transmitting guided waves through the region of interest and exploiting their dispersive nature, it is possible to build up a map of thickness. While the best results have been seen when using the fundamental modes A0 and S0 at low frequency, the complex scattering of the waves causes errors within the reconstruction. It is demonstrated that these lead to an underestimate in wall loss for A0 but an overestimate for S0. Further analysis showed that this error was related to density variation, which was proportional to thickness. It was demonstrated how this could be corrected for in the reconstructions, in many cases resulting in the near-elimination of the error across a range of defects, and greatly improving the accuracy of life estimates from guided wave tomography.

A Non-Contact Guided Wave Technique for Defect Thinning Monitoring

2006 ◽  
Vol 326-328 ◽  
pp. 681-684 ◽  
Author(s):  
Ik Keun Park ◽  
Yong Kwon Kim ◽  
Tae Hyung Kim ◽  
Yong Sang Cho
Keyword(s):  
Guided Waves ◽  
Guided Wave ◽  
Velocity Change ◽  
Accelerated Corrosion ◽  
Ultrasonic Guided Wave ◽  
Acoustic Transducer ◽  
Thin Aluminum ◽  
Wave Technique ◽  
Electro Magnetic ◽  
Flow Accelerated Corrosion

This paper capitalizes on recent advances in the area of non-contact ultrasonic guided wave techniques. The present technique provides a decent method for nondestructive testing of defect thinning simulating a hidden corrosion or FAC(Flow Accelerated Corrosion) in a thin aluminum plate. The proposed approach is based on using EMAT(Electro-magnetic Acoustic Transducer) to generate guided waves and detect the wall thinning without any coupling. Interesting features in the dispersive behavior of selected guided modes are used for the detection of plate thinning. It is shown that mode cut-off measurement allows us to monitor a defect thinning level while a group velocity change can be used to quantify the thinning depth.

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