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Technical Discussions
Don
Don
00:51 Sep-26-2005
Near surface creeping (Head) wave signals

I am testing steel for small surface breaking cracks (probe side)using 20MHz immersion probes angled at slightly less than the 1st critical angle to produce head waves in the material. The problem is that I only seem to get signals from the crack tips, and not from the surface breaking corner as I would expect. Is this normal for head waves or have I got somthing wrong?


 
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John Turner
John Turner
03:29 Sep-26-2005
Re: Near surface creeping (Head) wave signals
You have problems with setting up creeping waves this way. The major one is the attenuation of the head wave at 20MHz. It also concerns me that you are using an immersion probe - how are you setting up the beam angle with this?

For further information, please contact Phoenix Inspection Systems.

Regards

John Turner

----------- Start Original Message -----------
: I am testing steel for small surface breaking cracks (probe side)using 20MHz immersion probes angled at slightly less than the 1st critical angle to produce head waves in the material. The problem is that I only seem to get signals from the crack tips, and not from the surface breaking corner as I would expect. Is this normal for head waves or have I got somthing wrong?
------------ End Original Message ------------




 
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