Megahertz-range longitudinal guided wave excitation by a flexible magnetostrictive sensor for steel strand inspection

2012 ◽  
Vol 2 (3) ◽  
pp. 217 ◽  
Author(s):  
Xiucheng Liu ◽  
Bin Wu ◽  
Cunfu He
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Yao Liu ◽  
Xiucheng Liu ◽  
Chehua Yang ◽  
Wenxin Guo ◽  
Bin Wu ◽  
...  

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.


Author(s):  
Ju Ding ◽  
Min Zhang ◽  
Shu-Hong Liu ◽  
Chen-huai Tang ◽  
Jie-Lu Wang ◽  
...  

Ultrasonic guided wave inspection technology has been widely for long distance pipeline inspection; however, the pipe elbow’s discontinuous structure and the dispersion of L-type wave are restricting the application of this technology. This paper proposes a method of L(0,2) mode guided wave excitation based on magnetostrictive effect and explores the optimization of the magnetization sensor arrangement. Test results shows that the proposed method can detect many types of defects in the pipe elbow. This paper encourages the use of L(0,2) mode guided wave excitation based on magnetostrictive effect in pipeline site inspections.


2006 ◽  
Vol 321-323 ◽  
pp. 780-783 ◽  
Author(s):  
Yong Moo Cheong ◽  
Hyun Kyu Jung ◽  
Young Suk Kim

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.


Author(s):  
Markus Rahammer ◽  
Igor Solodov ◽  
Wolfgang Bisle ◽  
Dieter Scherling ◽  
Marc Kreutzbruck
Keyword(s):  

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