Magnetostrictive Acoustic Transducer Based Torsional Wave Generation in Pipes Using Magnetic Tapes
28 Mar 2007-Vol. 894, Iss: 1, pp 934-941
TL;DR: In this article, a long range torsional guided wave generation in pipes using magnetostrictive sensor (MsS), made of video magnetic tape material, that has a potential application in nondestructive pipe line testing in oil and gas industry is reported.
Abstract: Long range torsional guided wave generation in pipes using magnetostrictive sensor (MsS), made of video magnetic tape material, that has a potential application in nondestructive pipe line testing in oil and gas industry is reported in this paper. Generally, magnetic metal strips of Nickel or amorphous Cobalt alloys are used as magnetostricitive strips in these types of sensors. Though in principle, the technique is an established one, there is still scope for improving its sensitivity by getting rid of eddy current losses in these metallic strips. And also corrosion and oxidation will pose a problem in the long run resulting in signal degradation. To avoid such problems, a magnetic oxide based Ms strip material is a good choice. Further, a field enhancer strip in between the coil and Ms strip can also be added to increase the magnetic field on the Ms strips thus reducing the power to drive the coils. The present sensor is designed to have a video magnetic tape as the magnetostrictive strip, and permalloy strip as field enhancer. Results obtained from a systematic study to assess the quality of the torsional wave generated by this sensor in terms of the amplitude and its frequency dependence with two different orientations of magnetostrictive strips and also the defect sensitivity of the sensor to radial notch and drill hole are reported in this paper.
Citations
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TL;DR: In this paper, the magnetic and structural properties of Gd5Si2.7Ge1.3 have been investigated and it has been shown that the film undergoes a first order magnetostructural transition and as a consequence exhibits large magnetocaloric effect.
Abstract: Magnetic refrigeration based on the magnetocaloric effect is one of the best alternatives to compete with vapor-compression technology. Despite being already in its technology transfer stage, there is still room for optimization, namely, on the magnetic responses of the magnetocaloric material. In parallel, the demand for different magnetostrictive materials has been greatly enhanced due to the wide and innovative range of technologies that emerged in the last years (from structural evaluation to straintronics fields). In particular, the Gd5(SixGe1−x)4 compounds are a family of well-known alloys that present both giant magnetocaloric and colossal magnetostriction effects. Despite their remarkable properties, very few reports have been dedicated to the nanostructuring of these materials: here, we report a ∼800 nm Gd5Si2.7Ge1.3 thin film. The magnetic and structural investigation revealed that the film undergoes a first order magnetostructural transition and as a consequence exhibits large magnetocaloric ef...
26 citations
TL;DR: In this paper, the relationship between the amplitude of crack reversed echo and the size of crack which detection by the T(0,1) modal is studied by the method of simulation.
Abstract: Based on the theory of elastodynamics , the relationship between the amplitude of crack reversed echo and the size of crack which detection by the T(0,1) modal is studied by the method of simulation. Based on the simulation result, T(0,1) modal sensitive to a radial crack which length below the perimeter of pipe and the reflection ratio increase as the length of crack raised are got. The T(0,1) modal is insensitivity to a permeate axial crack which length between 20% to 45% of wavelength. The reflectance became minimum when the length arrive at 50% of wavelength, it get maximum when size reach 90% of wavelength, then it has a small decrease till 100%.
References
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Patent•
22 Mar 2001TL;DR: In this paper, a magnetostrictive sensor is used to generate guided waves in a pipe or tube, which waves travel therethrough in a direction parallel to the longitudinal axis of the pipe.
Abstract: A method and apparatus is shown for implementing magnetostrictive sensor techniques for the nondestructive evaluation of pipes or tubes. A magnetostrictive sensor generates guided waves in a pipe or tube, which waves travel therethrough in a direction parallel to the longitudinal axis of the pipe or tube. This is achieved by using a magnetized ferromagnetic strip being pressed circumferentially against the pipe or tube. The guided waves are generated in the strip and coupled to the pipe or tube and propagate along the length of said pipe or tube. For detection, the guided waves in said pipe or tube are coupled to the thin ferromagnetic strip and are detected by receiving MsS coils. Reflected guided waves may represent defects in the pipe or tube.
95 citations