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Journal ArticleDOI

SHM of pipes using torsional waves generated by in situ magnetostrictive tapes

01 Dec 2007-Smart Materials and Structures (IOP Publishing)-Vol. 16, Iss: 6, pp 2505-2515
TL;DR: In this article, an improved magnetostrictive sensors (MsSs) were used for structural health monitoring (SHM) of hard-to-inspect pipes using polymeric magnetic tape material that is suitable for use in a variety of industries.
Abstract: Long-range, torsional guided waves generated in pipes using magnetostrictive sensors (MsSs) have great potential for applications to the structural health monitoring (SHM) of hard-to-inspect pipes. This paper reports an improved MsS technique (when compared to related techniques currently used for the NDT of pipes) that uses polymeric magnetic tape material that is suitable for use in a variety of industries as an SHM tool for pipes. Improvements include increased efficiency, reduced cost and increased long-term survivability of the sensor system. Transduction efficiency was increased by reducing the sensor eddy current losses and by using a field concentrator strip. For long-term monitoring, a low-cost magnetic oxide based MsS material (video recording tape) having the required magnetic properties was used. The MsS strips were oriented to generate non-dispersive torsional guided ultrasonic waves that propagate long distances with minimal mode conversion. Further, considering both safety and long-term survivability of the sensor, low-power ultrasonic instrumentation was developed and tested. Measurements reported here demonstrate the sensitivity of this sensor to both radial notches (saw cuts) and drilled holes. Results also show that magnetic anisotropy of the strip plays a role in generating torsional waves. It is envisioned that results obtained from the present study will significantly enhance the ability to monitor the long-term structural health of piping systems.
Citations
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Proceedings ArticleDOI
16 Feb 2017
TL;DR: In this paper, a new design of Electromagnetic Acoustic Transducer (EMAT) that can generate a T(0, 1) as a single transducer, rat...
Abstract: Guided waves inspection is a well-established method for the long-range ultrasonic inspection of pipes. Guided waves, used in a pulse-echo arrangement, can inspect a large range of the pipe from a single point as the pipe structure carries the waves over a large distance due to the relatively low attenuation of the wave modes. However, the complexity of the dispersion characteristics of these pipe guided wave modes are well known, and can lead to diffculty interpreting the obtained results. The torsional family of guided wave modes are generally considered to have much simpler dispersion characteristics; especially the fundamental T(0,1) mode, which is nominally non-dispersive, making it particularly useful for guided wave inspection. Torsional waves have been generated by a circumferential ring of transducers to approximate an axi-symmetric load to excite this T(0, 1) mode. Presented here is a new design of Electromagnetic Acoustic Transducer (EMAT) that can generate a T(0, 1) as a single transducer, rat...

10 citations

Dissertation
11 Jun 2008
TL;DR: Several aspects of the instantaneous baseline damage detection method are explored in this work including the implementation of sensor diagnostics, determination of the features best used to identify damage, development of signal processing algorithms used to analyze data, and the comparison of two sensor/actuator deployment schemes.
Abstract: The research presented in this thesis is based on improving current structural health monitoring (SHM) technology. Structural health monitoring is a damage detection technique that involves placing intelligent sensors on a structure, periodically recording data from the sensors, and using statistical methods to analyze the data in order to assess the condition of the structure. This work focuses on improving two areas of SHM; baseline management and energy supplies. Several successful SHM methods have been developed in which prerecorded baseline measurements are compared to current measurements in order to identify damage. The need to compare new data to a prerecorded baseline can present several complications including data management issues and difficulty in controlling the effects of varying environmental conditions on the data. Another potential area for improvement in SHM systems deals with their energy supplies. Many SHM systems currently require wired power supplies or batteries to operate. Practical SHM applications often require inexpensive, stand alone sensors, data acquisition, and processing hardware that does not require maintenance. To address the issue of baseline management, a novel SHM technique is developed. This new method accomplishes instantaneous baseline measurements by deploying an array of piezoelectric sensors/actuators used for Lamb wave propagation-based SHM such that data recorded from equidistant sensor-actuator paths can be used to instantaneously identify several common features of undamaged paths. Once identified, features from these undamaged paths can be used to form a baseline for real-time damage detection. This method utilizes the concept of sensor diagnostics, a recently developed technique that minimizes false damage identification and measurement distortion caused by faulty sensors. Several aspects of the instantaneous baseline damage detection method are explored in this work including the implementation of sensor diagnostics, determination of the features best used to identify damage, development of signal processing algorithms used to analyze data, and the comparison of two sensor/actuator deployment schemes. The ultimate goal in the development of practical SHM systems is to create autonomous damage detection systems. A limiting factor in current SHM technology is the energy supply required to operate the system. Many existing SHM systems utilize wired power supplies or batteries to power sensors, data transmission, data acquisition, and data processing hardware. Although batteries eliminate the need to run wires to SHM hardware, their periodic replacement requires components to be placed in easily accessible locations which is not always practical, especially in embedded applications. Additionally, there is a high cost associated with battery monitoring and replacement. In an effort to eliminate replaceable energy supplies in SHM systems, the concept of energy harvesting is investigated. Energy harvesting devices are designed to capture surrounding ambient energy and convert it into usable electrical energy. Several types of energy harvesting exist, including vibration, thermal, and solar harvesting. A solar energy harvesting system is developed for use in powering SHM hardware. Integrating energy harvesting technology into SHM systems can provide autonomous health monitoring of structures. All images and figures are property of Steven R. Anton and captured or created between June, 2006 and June, 2008.

10 citations


Cites background from "SHM of pipes using torsional waves ..."

  • ...Several types of sensors can be used to perform SHM. Common sensor types in the literature include magnetostrictive, fiber optic, and piezoelectric devices....

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  • ...Several studies have been conducted in which magnetostrictive materials are used for SHM. Kannan et al. (2007) describe a SHM system for pipe monitoring in which magnetostrictive tape was bonded to a pipe and used as both a sensor and an actuator....

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  • ...Today, there are several journals and conferences throughout the world that include sections devoted to SHM....

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  • ...Sohn et al. (2004) use a grid of PZT transducers on a 48-ply, 6.35 mm thick composite plate to perform pitch-catch SHM. Putty applied to the surface of the composite is used to simulate delaminations on the plate....

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  • ...Giurgiutiu and Cuc (2005) also present a review of wave propagation-based SHM....

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Journal ArticleDOI
TL;DR: In this paper, rapidly quenched ribbons prepared by a melt spinning technique have been used as a magnetostrictive sensor (MsS) element for the generation and detection of guided waves traversing through a pipe.
Abstract: In this investigation, rapidly quenched ribbons prepared by a melt spinning technique have been used as a magnetostrictive sensor (MsS) element for the generation and detection of guided waves traversing through a pipe. The materials we have used in the present study are the rapidly quenched Fe80Si8B12 and Fe40Ni40B20 which have a high magnetostriction constant. The experiments were conducted on a bare Al tube after generating proper dispersion curves. The experiments were carried out using as-spun and annealed ribbons. After optimizing the AC magnetizing field, DC bias field and frequency (from software), longitudinal guided waves were generated in the tubes using MsS ribbons. Measurements were carried out to test the sensitivity of this sensor to both circumferential discontinuity (saw cut) and defect free bare aluminum tubes at a frequency of 76?kHz. The effect of defect size on the sensor signal was also investigated. Using the present technique, the defects were not only identified but their location in the pipe was also estimated.

9 citations


Cites background or methods from "SHM of pipes using torsional waves ..."

  • ...8 kOe [17] FeCoV Tube OD: 114 mm DC bias current: 150 A [19] Present investigation: Fe80Si8B12, Fe40Ni40B20 melt spun ribbons Tube OD: 48 mm DC bias field (current) Fe80Si8B12 annealed: 12....

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  • ...Kannan et al [17] explored the use of magnetic videotapes as MsS elements for inspection of an aluminum pipe of outer diameter 76 mm, wall thickness 6 mm and length 4 m using biasing permanent magnets generating a strong magnetic field in the range of 0....

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Journal ArticleDOI
Zhe Wang1, Songling Huang1, Shen Wang1, Qing Wang2, Wei Zhao1 
28 Feb 2020
TL;DR: In this paper, a transducer is developed using permanent magnets and arc-coil based on the principle of electromagnetic-acoustic conversion to generate helical Lamb wave with concentrated beam.
Abstract: Guided wave is advantageous to inspect pipe-like structures because of its long-distance propagation. Due to the curved structure of pipeline, guided wave can spread spirally with a helix angle. However, the current transducers focus more on the narrow or omni-directional beam than the helical form. This work presents the designed transducer to generate helical Lamb wave with concentrated beam. The transducer is developed using permanent magnets and arc-coil based on the principle of electromagnetic-acoustic conversion. The numerical analysis applying finite element method is conducted to verify the theoretical model of the transducer. The angular profiles are obtained to study the propagation of helical Lamb wave. Further, experiments are designed to demonstrate the performance of proposed transducer. The results from the experiments show good agreement with the numerical simulations. Besides, the parameter of central width is investigated and the half-angle of divergence is calculated. The results are compared with that from traditional transducers. The comparison indicates the superiority of the proposed transducer in generating helical Lamb wave. Therefore, the designed transducer could be a potential alternation for pipeline inspection based on guided wave.

8 citations


Cites background from "SHM of pipes using torsional waves ..."

  • ...The guided wave transmitter and receiver can be placed in the two ends of pipeline to accomplish the inspection [10]....

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References
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TL;DR: The concept of sensor networks which has been made viable by the convergence of micro-electro-mechanical systems technology, wireless communications and digital electronics is described.

17,936 citations

Book ChapterDOI
01 Jan 1997
TL;DR: In this article, a general-purpose program that can create dispersion curves for a very wide range of systems and then effectively communicate the information contained within those curves is presented, using the global matrix method to handle multi-layered Cartesian and cylindrical systems.
Abstract: The application of guided waves in NDT can be hampered by the lack of readily available dispersion curves for complex structures. To overcome this hindrance, we have developed a general purpose program that can create dispersion curves for a very wide range of systems and then effectively communicate the information contained within those curves. The program uses the global matrix method to handle multi-layered Cartesian and cylindrical systems. The solution routines cover both leaky and non-leaky cases and remain robust for systems which are known to be difficult, such as large frequency-thicknesses and thin layers embedded in much thicker layers. Elastic and visco-elastic isotropic materials are fully supported; anisotropic materials are also covered, but are currently limited to the elastic, non-leaky, Cartesian case.

485 citations

Journal ArticleDOI
TL;DR: Magnetic crystal anisotropy and magnetostriction have been measured in various single crystals of ferrites having compositions represented approximately by $M{\mathrm{Fe}}_{2}{\mathrm{\O}}_{4}$, where $M$ stands for Mn, Fe, Co, Ni, and Zn in various proportions.
Abstract: Magnetic crystal anisotropy and magnetostriction have been measured in various single crystals of ferrites having compositions represented approximately by $M{\mathrm{Fe}}_{2}{\mathrm{O}}_{4}$, where $M$ stands for Mn, Fe, Co, Ni, and Zn in various proportions. Special attention is given to heat-treatment in a magnetic field.The magnetic anisotropy of cobalt ferrite at room temperature is as high as 4\ifmmode\times\else\texttimes\fi{}${10}^{6}$ ergs/${\mathrm{cm}}^{2}$. Magnetostriction is as high as 800\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$. Magnetic anneal is effective at temperatures as low as 150\ifmmode^\circ\else\textdegree\fi{}C, and causes the hysteresis loop to become square. In polycrystalline material the response to magnetic anneal is a maximum at compositions intermediate between Co${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ and ${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$.The constants for the various specimens are tabulated. Values of the anisotropy constants of Mn${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ at 20\ifmmode^\circ\else\textdegree\fi{}C and -196\ifmmode^\circ\else\textdegree\fi{}C are the same as those determined from ferromagnetic resonance experiments. At -196\ifmmode^\circ\else\textdegree\fi{}C the constant for ${\mathrm{Ni}}_{0.75}$${\mathrm{Fe}}_{2.25}$${\mathrm{O}}_{4}$ differs markedly from that determined by ferromagnetic resonance; this is to be expected from the relaxation phenomena observed by Galt, Yager, and Merritt.

446 citations