where expertise comes together - since 1996 -

The Largest Open Access Portal of Nondestructive Testing (NDT)

Conference Proceedings, Articles, News, Exhibition, Forum, Network and more

where expertise comes together
- since 1996 -
724 views
Technical Discussions
Doug Mendes
NDT Inspector, R & D
Imetrix Inc., USA, Joined Oct 1999, 7

Doug Mendes

NDT Inspector, R & D
Imetrix Inc.,
USA,
Joined Oct 1999
7
05:45 Nov-16-1999
Resonance Testing

I'm considering the application of resonance testing for immersion thickness gauging on steel for corrosion, but i'm unsure as to how the frequency of the transducer is selected. I know the instrumentation is tuneable but how do the two relate? Does the thickness of the test speciman govern the frequency? Is there a table that gives a starting point for thinkness vs. frequency selection? Any information would be most helpful and greatly appreciated.
Regards
Doug



 
 Reply 
 
Paul A. Meyer
R & D,
GE Inspection Technologies, USA, Joined Nov 1998, 47

Paul A. Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
05:58 Nov-16-1999
Re: Resonance Testing
Hi Doug,
One method uses broadband ultrasonic pulses and looks at the frequency content of the entire signal reflected from the layer. If you have the same liquid (for example water) on both sides of the layer, then the reflection factor is zero at frequencies for which the layer is a multiple of one-half wavelength thick. If the frequency spectrum of the probe is in this range you will see a depression or notch in the reflection because those frequencies are totally transmitted. You select the probe so that its center frequency will be close to one-half wavelength in the layer.
You can achieve the same effect using tone-burst excitation and sweeping the frequency of the source. Using this method you generate the same spectrum one component at a time.
I hope this helps.
Regards,
Paul

: I'm considering the application of resonance testing for immersion thickness gauging on steel for corrosion, but i'm unsure as to how the frequency of the transducer is selected. I know the instrumentationis tuneable but how do the two relate? Does the thickness of the test speciman govern the frequency? Is there a table that gives a starting point for thinkness vs. frequency selection? Any information would be most helpful and greatly appreciated.
: Regards
: Doug




 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 304

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
304
09:18 Nov-17-1999
Re: Resonance Testing
: I'm considering the application of resonance testing for immersion thickness gauging on steel for corrosion, but i'm unsure as to how the frequency of the transducer is selected. I know the instrumentation is tuneable but how do the two relate? Does the thickness of the test speciman govern the frequency? Is there a table that gives a starting point for thinkness vs. frequency selection? Any information would be most helpful and greatly appreciated.
: Regards
: Doug

Dear Doug,
The reply from Krautkramer suggested two techniques, one a broad band excitation and one a swept frequency excitation.
We market the Quasar International Resonant Inspection instrument here in Europe. This may provide a solution.
It could also possibly be used in contact mode, and does not need a couplant.
e-mail me if you need more information.

Godfrey Hands
Godfrey Hands Ltd.
Godfrey@hands-ndt.co.uk


 
 Reply 
 

Product Spotlight

Research and Applications Development For NDT

The Research and Applications Development (RAD) group is a newly formed team within Acuren dedicat
...
ed to tackling challenging inspection problems. Our focus is the development of novel, field deployable, advanced inspection techniques for use in cases where standard NDT methods are ineffective. We don't wait for new innovations, we engineer them. From concept to commissioning.
>

Robotic laser shearography enables 100% inspection of complex, flight-critical composite structures

An article in “Composites World Magazine” showcases Non Destructive Testing of aero-structures
...
with Laser Shearography. Over the years Dantec Dynamics has supplied many solutions for the aerospace industry. Referring to specific customer projects several of these cases are examined to outline the advantages of using Laser Shearography for automated defect detection.
>

TraiNDE UT

TraiNDE UT is a virtual tool associated with a signal database which simulates real inspection con
...
ditions for numerous applications (Type A/V1 block, DAC block, welds and plates).
>

OmniScan™ X3 flaw detector

The OmniScan X3 flaw detector is a complete phased array toolbox. Powerful tools, like total focus
...
ing method (TFM) images and advanced visualization capabilities, enable you to complete your inspection with greater confidence.
>

Share...
We use technical and analytics cookies to ensure that we will give you the best experience of our website - More Info
Accept
top
this is debug window