A flexural mode guided wave transducer for pipes based on magnetostrictive effect

2020 ◽  
Vol 64 (1-4) ◽  
pp. 335-342
Author(s):  
Yun Sun ◽  
Jiang Xu ◽  
Chaoyue Hu ◽  
Guang Chen ◽  
Yunfei Li
Keyword(s):  
Magnetic Field ◽  
Guided Waves ◽  
Permanent Magnets ◽  
Wave Structure ◽  
Guided Wave ◽  
Circumferential Direction ◽  
Bias Magnetic Field ◽  
Flexural Mode ◽  
Axial Crack ◽  
Wave Transducer

The flexural mode guided waves of pipes which are sensitive the axial crack and suitable for wave focused gain more attention recently. In this paper, a non-contact flexural mode guided wave transducer based on magnetostrictive effect is provided for pipes. Based on the magnetostrictive transduction principle and the wave structure of the flexural mode guided wave, the sensing method for generating and receiving the flexural mode guided waves based on magnetostrictive effect is obtained. According to the theoretical analysis, a non-contact magnetostrictive transducer for F (3, m) mode guided waves is given. Six permanent magnets which are evenly distributed in the circumferential direction of the pipe and arranged in opposite polarities are employed to provide the bias magnetic field in the circumferential direction. A solenoid coil is employed to induce the axial alternating magnetic field. The bias magnetic field distribution of the flexural mode guided wave in the pipeline is analyzed by the finite element simulation. The mode of the transduction guided wave in the pipe is verified by experiments based on the dispersion curves.

scholarly journals Experimental Study of the Guided Wave Directivity Patterns of Thin Removable Magnetostrictive Patches

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7189
Author(s):  
Akram Zitoun ◽  
Steven Dixon ◽  
Graham Edwards ◽  
David Hutchins
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Guided Waves ◽  
Permanent Magnets ◽  
Guided Wave ◽  
Metallic Plate ◽  
Static Magnetic Fields ◽  
Directivity Patterns ◽  
Spiral Coils ◽  
Dynamic Magnetic Field

The characteristics of removable magnetostrictive thin patches are investigated for the generation of guided waves in plates. The directivity patterns of SH, S0 and A0 modes have been measured in a thin metallic plate for different combinations of static and dynamic magnetic field directions. This used different coil geometries such as racetrack and spiral coils to generate the dynamic magnetic field, as well as separate biasing static magnetic fields from permanent magnets. This arrangement generated signals via both Lorentz and magnetostrictive forces, and the resultant emitted guided waves were studied for different dynamic and static magnetic field directions and magnitudes. It is demonstrated that different guided wave modes can be produced by controlling these parameters.

New Magnetostrictive Transducers and Applications for SHM of Pipes and Vessels

2019 ◽  
Author(s):  
Sergey Vinogradov ◽  
Jay L. Fisher
Keyword(s):  
Magnetic Field ◽  
Guided Waves ◽  
Permanent Magnets ◽  
Elevated Temperatures ◽  
Service Industry ◽  
Guided Wave ◽  
Transverse Motion ◽  
Time Varying ◽  
Transducer Design ◽  
Magnetostrictive Transducer

Abstract The use of guided waves for long-range inspection of components is a rapidly growing area of the nondestructive evaluation service industry. Magnetostrictive sensors utilizing ferromagnetic strip material for the transduction effect have proven to be very effective for guided wave testing (GWT) on a variety of components. There is still a demand for enhanced sensor characterization and sensors with specific characteristics. The most challenging area is structural health monitoring (SHM) of components operating at elevated temperatures of at least 200°C. A new configuration of a sensor for generating and receiving transverse-motion guided waves swaps the biasing and time-varying magnetic field directions. This alternative design is a reversed Wiedemann effect magnetostrictive transducer. These transducers exhibit a number of unique features compared with the more conventional Wiedemann sensor, including: (1) the use of smaller rare earth permanent magnets to achieve large, uniform, and self-sustained bias fields; (2) the use of more efficient electric coil arrangements to induce a stronger time-varying magnetic field for a given coil impedance; (3) the ability to generate both transverse and longitudinal waves; (4) they can be used on pipes ranging from a few millimeters to several meters in diameter. In this paper, the new transducer design will be described and its performance will be analyzed in application to SHM of pressurized pipe operating at 200°C and automated omnidirectional scan of large storage tank walls.

Guided Wave Focusing Mechanics in Pipe

2003 ◽  
Author(s):  
Takahiro Hayashi ◽  
Koichiro Kawashima ◽  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Guided Waves ◽  
Wave Structure ◽  
Guided Wave ◽  
Pipe Inspection ◽  
Specific Point ◽  
Wave Focusing ◽  
Beam Focusing ◽  
Subsequent Time

Guided waves can be used in pipe inspection over long distances. Presented in this paper is a beam focusing technique to improve the S/N ratio of the reflection from a tiny defect. Focusing is accomplished by using non-axisymmetric waveforms and subsequent time delayed superposition at a specific point in a pipe. A semi-analytical finite element method is used to present wave structure in the pipe. Focusing potential is also studied with various modes and frequencies.

scholarly journals Numerical and Experimental Investigation of Guided Wave Propagation in a Multi-Wire Cable

2019 ◽  
Vol 9 (5) ◽  
pp. 1028 ◽  
Author(s):  
Pengfei Zhang ◽  
Zhifeng Tang ◽  
Fuzai Lv ◽  
Keji Yang
Keyword(s):  
Wave Energy ◽  
Guided Waves ◽  
Wave Structure ◽  
Excitation Power ◽  
Dispersion Analysis ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Mechanical Coupling ◽  
Guided Wave Propagation ◽  
Contact Acoustic Nonlinearity

Ultrasonic guided waves (UGWs) have attracted attention in the nondestructive testing and structural health monitoring (SHM) of multi-wire cables. They offer such advantages as a single measurement, wide coverage of the acoustic field, and long-range propagation ability. However, the mechanical coupling of multi-wire structures complicates the propagation behaviors of guided waves and signal interpretation. In this paper, UGW propagation in these waveguides is investigated theoretically, numerically, and experimentally from the perspective of dispersion and wave structure, contact acoustic nonlinearity (CAN), and wave energy transfer. Although the performance of all possible propagating wave modes in a multi-wire cable at different frequencies could be obtained by dispersion analysis, it is ineffective to analyze the frequency behaviors of the wave signals of a certain mode, which could be analyzed using the CAN effect. The CAN phenomenon of two mechanically coupled wires in contact was observed, which was demonstrated by numerical guided wave simulation and experiments. Additionally, the measured guided wave energy of wires located in different layers of an aluminum conductor steel-reinforced cable accords with the theoretical prediction. The model of wave energy distribution in different layers of a cable also could be used to optimize the excitation power of transducers and determine the effective monitoring range of SHM.

High efficiency guided-wave magnetooptic Bragg cell modulator using nonuniform bias magnetic field

1997 ◽  
Vol 71 (25) ◽  
pp. 3715-3717 ◽  
Author(s):  
C. S. Tsai ◽  
Y. S. Lin ◽  
J. Su ◽  
S. R. Calciu
Keyword(s):  
Magnetic Field ◽  
High Efficiency ◽  
Guided Wave ◽  
Bias Magnetic Field

scholarly journals Effect of Tensile Force on Magnetostrictive Sensors for Generating and Receiving Longitudinal Mode Guided Waves in Steel Wires

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jiang Xu ◽  
Yong Li ◽  
Guang Chen
Keyword(s):  
Magnetic Field ◽  
Coupling Coefficient ◽  
Guided Waves ◽  
Steel Wire ◽  
Tensile Force ◽  
Longitudinal Mode ◽  
Effective Field ◽  
Bias Magnetic Field ◽  
Magnetostrictive Sensor ◽  
The Relationship

When the longitudinal mode guided waves based on magnetostrictive effect were employed to inspect the bridge cables, we found that there was a large difference in the signal’s amplitude of the same specification cable under different tensile force. This difference would affect the test results and the identification of defects. It is necessary to study the effect of tensile force on the signal for the reliability of detection. Firstly, the effective field theory is employed to take the force as an additional bias magnetic field. Then, the effect of the tensile force on generating and receiving longitudinal mode guided waves based on magnetostrictive effect is obtained by the relationship between the bias magnetic field and the magnetostrictive coupling coefficient. Finally, the experiment of the magnetostrictive sensor is carried out on a Φ5 mm steel wire under different force. The experimental results are in good agreement with the theoretical results. The results show that the existence of the tensile force would change the operation point for generating and receiving the longitudinal mode guided waves based on magnetostrictive effect, which associated with the coupling coefficient. In order to obtain the optimal conversion efficiency for the force state wire and cable, the applied bias magnetic field should be set smaller than the bias magnetic field for the force-free state.

Guided Wave Focusing Mechanics in Pipe

2005 ◽  
Vol 127 (3) ◽  
pp. 317-321 ◽  
Author(s):  
Takahiro Hayashi ◽  
Koichiro Kawashima ◽  
Zongqi Sun ◽  
Joseph L. Rose
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Guided Waves ◽  
Wave Structure ◽  
Guided Wave ◽  
Pipe Inspection ◽  
Specific Point ◽  
Wave Focusing ◽  
Beam Focusing ◽  
Subsequent Time

Guided waves can be used in pipe inspection over long distances. Presented in this paper is a beam focusing technique to improve the S∕N ratio of the reflection from a tiny defect. Focusing is accomplished by using nonaxisymmetric waveforms and subsequent time delayed superposition at a specific point in a pipe. A semianalytical finite element method is used to present wave structure in the pipe. Focusing potential is also studied with various modes and frequencies.

Defect Detection in Seven-Wire Steel Strands Using Single Magnetostrictive Transducer with Two-Layer Coil

2010 ◽  
Vol 34-35 ◽  
pp. 456-461 ◽  
Author(s):  
Zeng Hua Liu ◽  
Ji Chen Zhao ◽  
Bin Wu ◽  
Cun Fu He
Keyword(s):  
Guided Waves ◽  
Permanent Magnets ◽  
Signal To Noise Ratio ◽  
Wave Mode ◽  
Guided Wave ◽  
High Signal ◽  
Helical Surface ◽  
Artificial Defect ◽  
Wire Steel ◽  
Magnetostrictive Transducer

In order to achieve active health monitoring of seven-wire steel strands, single magnetostrictive transducer with two-layer coil is developed and applied for the excitation and reception of ultrasonic longitudinal guided waves simultaneously. The transducer can be conveniently fixed at any single one position on the helical surface of these structures. The inner and outer layers of its coil are used for excitation and reception respectively with the help of same axisymmetric permanent magnets. Experimental results show that chosen ultrasonic longitudinal guided wave mode, L(0,1) at 140kHz, can be excited and received with high signal-to-noise ratio in steel strands by using the developed magnetostrictive transducer. Furthermore, to identify the performance of the transducer, the detection of an artificial defect is also conducted.

A Computational Tool for Defect Analysis in Rail with Ultrasonic Guided Waves

2006 ◽  
Vol 321-323 ◽  
pp. 784-787
Author(s):  
Chong Myoung Lee ◽  
Joseph L. Rose ◽  
Wei Luo ◽  
Youn Ho Cho
Keyword(s):  
Guided Waves ◽  
Wave Structure ◽  
Propagation Characteristic ◽  
Guided Wave ◽  
Bulk Wave ◽  
Transverse Cracks ◽  
Wave Technique ◽  
Multiple Defect ◽  
Important Means ◽  
Nondestructive Testing Methods

Rail represents one of the most important means of transportation. Many nondestructive testing methods have been used to find defects in rail. The guided wave technique is the most efficient because of its long propagation characteristic along the rail. Potential for detecting transverse cracks exists whereas standard bulk wave technique could miss the cracks. The wave structure of the rail cross-section for a particular loading condition of modes and frequencies is an important feature. In this paper, the propagation and scattering patterns of guided waves in a rail are studied using finite element methods. The wave structures are also examined. Various multiple defect situations and rail boundary conditions can also be studied.

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