Technical Discussions: Re: alternative generation of ultrasound waves

[ Technical Discussions ]
[ Follow Ups ] [ Post Followup ] [ Help ]

Re: alternative generation of ultrasound waves
Posted by: Godfrey Hands (PID_83), E-mail: godfrey@ndt-consultants.co.uk, on August 20, 2005 at 10:26 :
In Reply to: Re: alternative generation of ultrasound waves posted by : Joel Vargas , E-mail: vargas.joel@gmail.com, on August 18, 2005 at 02:38 :
Dear Joel,
It is possible to produce and detect LRUT with magnetostrictive methods. The normal wave produced with the SwRI Guided Wave Ultrasonic system (from San Antonio, Texas) produces Torsional mode in Pipe and SH0 (Shear Horizontal) in plate.
Both of these waves are similar in propagation, and the velocities are constant for all frequencies unlike most of the other modes at lower frequencies. Also it will be almost entirely this mode of wave which is produced, so very little interference from other modes.
EMAT is somewhat different in mode of generation. With magnetostricive, you generate the particle movement on a strip of magnetostrictive material bonded to the metal, and with EMAT, you generate the wave on the surface of the material. This means you can generate EMAT under a thick coating, but not Magnetostrictive, unless you affix the magnetostrictive material under the coating (or rely on the natural magnetostrictive effect of the pipe).
Hope this helps.
Godfrey Hands
----------- Start Original Message -----------
: Dear Srs.
: Let me first introduce. I am Joel Vargas and I am working with LRUT for pipelines inspection and as you know it works with piezoelectric efect. So the point is if some body knows the diference betwen LRUT and Magnetostrictive wave generations methods..
: the second is that in LRUT I can use torsional mode and longitudinal mode. It is possible with Magnetostrictive method?
: By other hand EMAT transducer are the same of Magnetostrictive transducers or it is a diferent method of wave Generation?
: I hope some one of you can help me.
: PS:Sorry for my enghish.
: --- Start Original Message -----------
: : The use of piezoelectric transducers is well spread for the generation and receive of ultrasound waves. The use of microphones is also an existing technique for receiving acoustic and ultrasonic waves.
: : However what about microphone-speaker technology to generate and transmit ultrasound waves through solid material?
: : Is mechanical coupling (efficiency coef) a problem when generating waves by means of speakers?
: : This is an academic question that was brought about after using piezoelectric transducers.
------------ End Original Message ------------

Follow Ups:

Post a Followup:

Name:

E-Mail:

Subject:

Comments:
----------- Start Original Message ----------- : Dear Joel, : It is possible to produce and detect LRUT with magnetostrictive methods. The normal wave produced with the SwRI Guided Wave Ultrasonic system (from San Antonio, Texas) produces Torsional mode in Pipe and SH0 (Shear Horizontal) in plate. : Both of these waves are similar in propagation, and the velocities are constant for all frequencies unlike most of the other modes at lower frequencies. Also it will be almost entirely this mode of wave which is produced, so very little interference from other modes. : EMAT is somewhat different in mode of generation. With magnetostricive, you generate the particle movement on a strip of magnetostrictive material bonded to the metal, and with EMAT, you generate the wave on the surface of the material. This means you can generate EMAT under a thick coating, but not Magnetostrictive, unless you affix the magnetostrictive material under the coating (or rely on the natural magnetostrictive effect of the pipe). : Hope this helps. : Godfrey Hands : : Dear Srs. : : Let me first introduce. I am Joel Vargas and I am working with LRUT for pipelines inspection and as you know it works with piezoelectric efect. So the point is if some body knows the diference betwen LRUT and Magnetostrictive wave generations methods.. : : the second is that in LRUT I can use torsional mode and longitudinal mode. It is possible with Magnetostrictive method? : : By other hand EMAT transducer are the same of Magnetostrictive transducers or it is a diferent method of wave Generation? : : I hope some one of you can help me. : : PS:Sorry for my enghish. : : --- Start Original Message ----------- : : : The use of piezoelectric transducers is well spread for the generation and receive of ultrasound waves. The use of microphones is also an existing technique for receiving acoustic and ultrasonic waves. : : : However what about microphone-speaker technology to generate and transmit ultrasound waves through solid material? : : : Is mechanical coupling (efficiency coef) a problem when generating waves by means of speakers? : : : This is an academic question that was brought about after using piezoelectric transducers. ------------ End Original Message ------------

Optional Link URL: Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP

Link Title: is important! Information on my Home Page

Optional Image URL: http://www....gif

Attention! Please click the button only once. This may take a moment to process
[ Technical Discussions ] [ All Message Boards ] [ Help ]

Optional Link URL:	Example: "http://www....html". Alternative write "http://www.ndt.net/wshop/attach/filename.htm" if you transfered a filename.htm via FTP
Link Title: is important!	Information on my Home Page
Optional Image URL:	http://www....gif