Long-range guided wave inspection of pipe using magnetostrictive sensor technology: the feasibility of defect characterization

1998 ◽  
Author(s):  
Hegeon Kwun ◽  
Chris P. Dynes
Keyword(s):  
Long Range ◽  
Guided Wave ◽  
Sensor Technology ◽  
Defect Characterization ◽  
Magnetostrictive Sensor

Magnetostrictive Sensor Long-Range Guided-Wave Technology for Long-Term Monitoring of Piping and Vessels

2007 ◽  
Author(s):  
Hegeon Kwun ◽  
Sang Y. Kim ◽  
Glenn M. Light
Keyword(s):  
Long Range ◽  
Pressure Vessels ◽  
Guided Wave ◽  
Long Distance ◽  
Inspection Method ◽  
Wave Technology ◽  
Long Term Monitoring ◽  
Magnetostrictive Sensor ◽  
Term Monitoring

Long-range guided-wave technology is a recently developed inspection method for surveying large areas of structures and is widely used as a screening tool for corrosion defects in piping. Because of its ability to examine a structure over a long distance, this technology with permanently installed probes is ideal for on-line long-term structural health monitoring of pressure vessels or piping for improved safety, operation, and maintenance. The magnetostrictive sensor (MsS) technology is a guided-wave technology developed at authors’ institution. It uses a probe that consists of thin ferromagnetic strip and coil for guided-wave generation and detection. The MsS probe is inexpensive and can be used on components up to 300°C. Applications of the MsS for long-term monitoring of pressure vessels and piping are presented, including the configuration of MsS probes, types of guided-wave mode used, defect types detectable with guided waves, and example data.

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.

Subwavelength Defect Characterization Using Guided Wave Scattering Matrix

2013 ◽  
Vol 330 ◽  
pp. 504-509
Author(s):  
Yang Zheng ◽  
Jin Jie Zhou ◽  
Hui Zheng
Keyword(s):  
Wave Scattering ◽  
Scattering Matrix ◽  
Guided Wave ◽  
Defect Characterization ◽  
Challenging Problem ◽  
Recognition Method ◽  
Quantitative Characterization ◽  
S Matrix ◽  
Imaging Algorithms

Although many imaging algorithms such as ellipse and hyperbola algorithm can roughly locate defects in large plate-like structures with sparse guided wave arrays, quantitative characterization of them is still a challenging problem, especially for those small defects known as subwavelength defects. Scattering signals of defects contain abundant information so that can be used to evaluate defects. A defects recognition method using the S-matrix (scattering matrix) was presented. S-matrices of hole and crack with S0 mode incident were experimentally measured. The results show that defects can be recognized from the morphology of 2D S-matrix chart. This method has great potential to achieve more specific parameters of small defects with sparse guided wave arrays.

Comparison of an Array of EMATs Technique and a Magnetostrictive Sensor Technique for a Guided Wave Inspection of a Pipe

2006 ◽  
Vol 321-323 ◽  
pp. 780-783 ◽  
Author(s):  
Yong Moo Cheong ◽  
Hyun Kyu Jung ◽  
Young Suk Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Ultrasonic Method ◽  
Wave Structure ◽  
Guided Wave ◽  
Point Of View ◽  
Torsional Mode ◽  
Ultrasonic Methods ◽  
Sensor Technique ◽  
Magnetostrictive Sensor

The leakage of a pipe in nuclear power plants is a significant concern from the point of view of nuclear safety. Because of the geometrical complexity of a pipe and an inaccessibility due to a high radiation, it is difficult to inspect it by the conventional ultrasonic methods. The guided ultrasonic method can be useful for the inspection of a pipe in those harsh environments. Based on the analysis of the dispersion curves for a pipe, a torsional vibration mode, T(0,1) was selected for the detection of cracks. The T(0,1) mode has many advantages, such as a higher sensitivity for a crack from the viewpoint of its non-dispersion characteristics and its wave structure. The torsional mode can be generated by using either an array of electromagnetic acoustic transducers (EMATs) technique or a magnetostrictive sensor technique. The detectability of the cracks was estimated through a series of experiments with artificial notches on a pipe.

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