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Technical Discussions
Jaeseok Park
Jaeseok Park
07:36 Aug-09-2018
UT physics - SV wave

Deaer UT professionals,

1) What is the speed of SH mode surface wave, which is named as Love wave in some text?
2) Is "Love wave" simply 90 degree refracted bulk SH wave? Just like creeping wave to longitudinal wave?

Thank you

 
 Reply 
 
Marius S Purcell
Engineering,
Sasol (Pty) Ltd., South Africa, Joined Jul 2018, 10

Marius S Purcell

Engineering,
Sasol (Pty) Ltd.,
South Africa,
Joined Jul 2018
10
09:32 Aug-09-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 07:36 Aug-09-2018 (Opening).

Greetings Jaeseok Park,

It depends on the thickness of the material and the frequency used. Now, saying that: Shear Horizontal has different components to it which is Phase or Group velocities. You normally have SH0, SH1 etc. which describes these phases. It depends which band you want to focus on. Matlab will generally modulate this in a better perspective. Look at dispersion curves.

If I can refer you to literature, read Ultrasonic Guided Waves in Solid Media by
Joseph L. Rose. It is too technical at some stage but you will get the basics down in the first tow chapters. Remember this book is written based on Matlab modulations which will in all likely hood not hold any relevance to certain aspects of our question hear.

Hope this helps.

 
 Reply 
 
Rolf Diederichs
Director,
NDT.net, Germany, Joined Nov 1998, 609

Rolf Diederichs

Director,
NDT.net,
Germany,
Joined Nov 1998
609
09:52 Aug-09-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 07:36 Aug-09-2018 (Opening).

In our Open Access Database you can find 25 articles from Joseph L. Rose https://www.ndt.net/search/docs.php3?AuthorID=2995

Amog 28 articles from Peter Cawley you can find also a lot about guided waves:
https://www.ndt.net/search/docs.php3?AuthorID=544
Here one video of a presentation:
https://www.ndt.net/search/docs.php3?id=12499&content=1

By database search - guided waves - and restrict to keywords and sort by relevance you find 405 articles:
https://www.ndt.net/search/docs.php3?SearchDocs=guided+waves&restrict=keywords&searchmode=AND&OrderBy=relevance

Good luck!

Rolf

 
 Reply 
 
Jaeseok Park
R & D,
DOOSAN, South Korea, Joined Jun 2009, 10

Jaeseok Park

R & D,
DOOSAN,
South Korea,
Joined Jun 2009
10
15:07 Aug-09-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 07:36 Aug-09-2018 (Opening).

Thank you gentlmen,
Yes, its true that speed of guided wave is decribed by despersion curves;
However I need to clarify my question. Sorry for confusion.

It is known that there are several types of "surface wave"; Rayleigh, leaky Rayleig, Stonely (or Scholte), Love, and Sezawa. The characteristics of Rayleigh wave is well known and decribed in text book very well. My question is about properties of SH move surface wave, so called Love wave.

(1) Propergation speed; same with bulk SH wave or not.
(2) Particle motion; elliptical or sinusolidal.
(3) Enegy concentration near surface, in other words does it progagate long?

Thank you.

 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1287

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1287
15:37 Aug-09-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 15:07 Aug-09-2018 .

Jaeseok, there seems to be very little information on Love waves in our ultrasonic applications. Perhaps the literature on seismic studies is more appropriate. There is a Wikipedia article on Love waves at https://en.wikipedia.org/wiki/Love_wave
In that article it states; "Love waves travel with a lower velocity than P- or S- waves, but faster than Rayleigh waves. These waves are observed only when there is a low velocity layer overlying a high velocity layer/ sub–layers."
If Rayleigh waves travel at about 90% of the shear velocity then Love waves would be slightly higher than that.

 
 Reply 
 
John Norman
Consultant, owner of business
NTS Ultrasonics Pty Ltd, Australia, Joined Oct 2012, 116

John Norman

Consultant, owner of business
NTS Ultrasonics Pty Ltd,
Australia,
Joined Oct 2012
116
02:40 Aug-10-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 15:07 Aug-09-2018 .

Hi Jaesek.

If you are up for a bit of mathematics and physics, you can find discussions on Love waves in "Ultrasonic Waves in Solid Media" by Joseph L. Rose, and also in "Wave Motion in Elastic Solids" by Karl F. Graff. The second book might be hard to find, but I think the ASNT bookstore sells the first book.

The book by Rose derives some equations for Love waves and presents some dispersion curves. However, neither book explicitly discusses particle motion.

A Love wave propagates along the interface as explained by Ed in his answer. At longer wavelengths the velocity approaches that of the half space (i.e. the lower velocity layer). The energy distribution concentrates closer to the interface.

That is about all I can get from the books. These days I don't speak "physics" as well as I used to many years ago.

John Norman

 
 Reply 
 
Jaeseok Park
R & D,
DOOSAN, South Korea, Joined Jun 2009, 10

Jaeseok Park

R & D,
DOOSAN,
South Korea,
Joined Jun 2009
10
07:47 Aug-10-2018
Re: UT physics - SV wave
In Reply to Jaeseok Park at 07:36 Aug-09-2018 (Opening).

Thank you all your advises,
Information abvove is enough for me.

(1) The speed is somewhere between shear and Rayleigh,
(2) and it propagate long.
Particle motion is sinusoidal. I found at a seismology blog.

Thank you

 
 Reply 
 

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