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436 views
03:01 May-12-2000

David Hermanutz

Consultant,
Hbndt.com,
China,
Joined Jul 2012
85
Excitation energy effect on shear wave transducers.

Is there any effect on beam angle when changing the Excitation pulse from 100v to 400v as found on the Epoch3?

How would a typical sound pulse react to this increase in energy? Could different lobes be produced resulting in odd echo patterns from a known defect?


 
05:24 May-12-2000

Tom Nelligan

Engineering,
retired,
USA,
Joined Nov 1998
390
Re: Excitation energy effect on shear wave transducers. : Is there any effect on beam angle when changing the Excitation pulse from 100v to 400v as found on the Epoch3?

: How would a typical sound pulse react to this increase in energy? Could different lobes be produced resulting in odd echo patterns from a known defect?

There is no effect on beam angle. Increasing the excitation voltage will increase pulse amplitude, but it doesn't change the refracted angle from the wedge, which is based on the Snell's Law relationship between the sound velocities of the wedge insert material and the metal you're testing.

As for the shape of the pulse, it will get bigger, but generally won't change significantly in shape if you're using common transducers designed for angle beam inspection. We normally recommend using the highest excitation voltage (400v) for best signal-to-noise ration in most applications. The 100v setting is most useful when working with high frequency delay line transducers rather than wedges.

Damping changes, on the other hand, MAY alter the shape and phase of the waveform, so you should always do your initial calibration at whatever damping setting you're going to use in your actual inspection.

--Tom Nelligan
Panametrics, Inc.



 


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