Magnetostrictive sensor technology and its applications

Kwun, H.; Bartels, Keith A.

doi:10.1016/s0041-624x(97)00043-7

Cited by 200 publications

(80 citation statements)

References 3 publications

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“…In the most common implementation, a non-dispersive torsional T(0,1) signal is introduced into a pipe using a ring of piezoelectric transducers [3]; alternatively a system with magnetostrictive transducers can be used [4] [5]. The walls of the pipe act as a one dimensional waveguide, allowing the signal to travel tens of meters in each direction from the measurement location [3].…”

Section: Introductionmentioning

confidence: 99%

Reflection of torsional T(0,1) guided waves from defects in pipe bends

Heinlein

Cawley

Vogt³

2018

NDT & E International

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This paper investigates the reflection of the torsional T(0,1) mode from defects in pipe bends. The effect of varying circumferential and angular position along the pipe bend, as well as the influence of the bend radius, is investigated via 3D finite element simulations. The results show that the reflection expected from a small defect varies significantly with position, the minimum reflection coefficient being about 10% of that from a comparable defect in a straight pipe, while maxima of around four times the straight pipe value are seen. The areas of low detectability are mainly found on the bend intrados and those of high detectability close to its extrados; similar effects are seen in bends with radii varying from one to twenty pipe diameters. It is shown that the reflection from a defect at a given location is roughly proportional to the square of the von Mises stress produced by the transmitted wave at that position. This holds for defects such as circumferential cracks, the detailed subject of this investigation, and is also expected to be valid for corrosion patches; it will not hold for axial cracks. The results explain the low reflection seen from a simulated corrosion defect at a bend in a previous investigation.

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Section: Introductionmentioning

confidence: 99%

Reflection of torsional T(0,1) guided waves from defects in pipe bends

Heinlein

Cawley

Vogt³

2018

NDT & E International

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“…These investigations focused only on assessment using the king wire. To explore acoustoelastic measurement, Washer (2001), Kwun and Bartels (1998), and Kwun and Teller (1994) employed magnetorestrictive sensors for guided wave transduction in seven strands. Scalea et al (2003) integrated the acoustoelastic equations and the guided wave relations for thin rods to derive an expression for the acoustoelastic factor in terms of loaded and unloaded group velocities.…”

Section: Acoustical Guided Waves In Seven-strand Cablesmentioning

confidence: 99%

“…9.6 Notch frequency and other waveguide effects Kwun and Bartels (1998) first investigated the presence of a load-dependent notch frequency, which in laboratory settings has been used successfully to ascertain cable load. In addition to this notch frequency increasing with load, large dispersion was observed on both sides of a notch in a manner similar to the behavior near a cutoff frequency.…”

Section: Acoustical Guided Waves In Seven-strand Cablesmentioning

confidence: 99%

Assessing Corrosion Damage and Corrosion Progression in Multistrand Anchor Systems in Use at Corps Projects

Ebeling¹,

Strom²,

Hite³

et al. 2013

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Stressed steel tendons have been used to strengthen hydraulic structures and to improve their serviceability and stability. Over the past three decades, the US Army Corps of Engineers has worked to upgrade its projects by installing high-capacity, post-tensioned foundation anchors. The goal has been to achieve structural stability for Corps hydraulic concrete structures and/or to remediate cracked concrete monoliths. Substantial improvements to protect multistrand anchor systems from corrosion have been made since they were first used at Corps projects more the 50 years ago. Corrosion of older multistrand units is of concern.Researchers at the US Army Engineer Research and Development Center (ERDC) are looking to develop engineering procedures to estimate the current state of load-carrying capacity of the ground anchorage, to estimate remaining life of the tendon, and to establish the deterioration of anchorage capacity (with time) so costly replacement of ground anchorage can be delayed until absolutely needed. Analytical, laboratory, and field-testing efforts will be used to develop a methodology and analytical models. Probabilistic procedures will be used to quantify uncertainties for the primary variables and will be carried into the analytical model. Procedures to extend the life of deteriorating multistrand tendons also will be investigated.A review of Corps projects using multistrand anchors and a literature review of corrosion of the anchors are summarized in this report. Also included are the history and performance of the multistrand anchors at the John Day Navigation Lock (Columbia River, Portland District), along with postinstallation lift-off test results. A summary of a review of nondestructive testing (NDT) to identify defects in the anchors is part of this report, too.

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“…The reverse phenomenon, in which the magnetic induction of the material changes when the material is mechanically deformed, is called the inverse magnetostrictive effect. Based on these phenomena, Kwun and Bartels [83] invented a type of magnetostrictive sensor (MsS) which could generate and detect guided waves in the ferromagnetic materials under testing without direct physical contact to the material surface. Khazem et al [84] utilized MsS to inspect suspender ropes on the George Washington Bridge in New York.…”

Section: Magnetostrictive Sensorsmentioning

confidence: 99%

Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

Sun

Staszewski

Swamy

2010

Advances in Civil Engineering

114

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Structural Health Monitoring (SHM) aims to develop automated systems for the continuous monitoring, inspection, and damage detection of structures with minimum labour involvement. The first step to set up a SHM system is to incorporate a level of structural sensing capability that is reliable and possesses long term stability. Smart sensing technologies including the applications of fibre optic sensors, piezoelectric sensors, magnetostrictive sensors and self-diagnosing fibre reinforced composites, possess very important capabilities of monitoring various physical or chemical parameters related to the health and therefore, durable service life of structures. In particular, piezoelectric sensors and magnetorestrictive sensors can serve as both sensors and actuators, which make SHM to be an active monitoring system. Thus, smart sensing technologies are now currently available, and can be utilized to the SHM of civil engineering structures. In this paper, the application of smart materials/sensors for the SHM of civil engineering structures is critically reviewed. The major focus is on the evaluations of laboratory and field studies of smart materials/sensors in civil engineering structures.

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Magnetostrictive sensor technology and its applications

Cited by 200 publications

References 3 publications

Reflection of torsional T(0,1) guided waves from defects in pipe bends

Reflection of torsional T(0,1) guided waves from defects in pipe bends

Assessing Corrosion Damage and Corrosion Progression in Multistrand Anchor Systems in Use at Corps Projects

Smart Sensing Technologies for Structural Health Monitoring of Civil Engineering Structures

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