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 -

834 views
Technical Discussions
General
General
02:27 Nov-12-2004
Square vs Round Transducers

Why does AWS D1.1 specify to use a square transducer and does not allow round transducers for doing shear wave inspections. CSA W59, the Canadian equivilent does not stipulate that sqaure transducers have to be used.

Why do AWS specify square?


 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1304

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1304
06:05 Nov-13-2004
Re: Square vs Round Transducers
----------- Start Original Message -----------
: Why does AWS D1.1 specify to use a square transducer and does not allow round transducers for doing shear wave inspections. CSA W59, the Canadian equivilent does not stipulate that sqaure transducers have to be used.
: Why do AWS specify square?
------------ End Original Message ------------

I cannot state with authority as to WHY AWS imposes this rule, but perhaps it is just part of the "tradition" of the document being carried forward for nearly 50 years. In a correspondence with a committee member I was told that this was because square or rectangular elements have a "more uniform sound field". This is not true when you plot echo responses off ideal targets such as a FBH. Mechanical clamping in the corners of a rectangular probe is not the same as the clamping along the sides. The effect is that lobes occur. This is often seen on the ends of cylindrically focused immersion probes. The mechanical clamping on a round element is generally of better uniformity thereby providing a more uniform sound field than the square probes.

There are several issues with the old AWS D1 code that make it "different" from all the rest. One in particular is the way they treat amplitude correction with the strange formula for compensation of soundpath (the same rate of compensation is applied for all angles!). Other Codes tend to use a method of DAC compensation that allow for angle variations in echo-transmittance.
But AWS has finally updated itself in the 2004 edition. Annex K allows other options and even describes the more familiar DAC construction. But this is apparently so radical that it requires the approval of the engineer.
Ed


 
 Reply 
 

Product Spotlight

VOGT Ultrasonics awarded innovation champion

Let go of the old and try something new. VOGT convinced the jury in the 27th round of the TOP 100
...
innovation competition. Our team is very pleased to officially belong to the TOP 100 in Germany!
>

On Demand Webinar: Using Eddy Current Array for Large Areas in Place of Magnetic Particle and Liquid Penetrant Testing

New on-demand webinar on the use of eddy current array (ECA) technology in lieu of liquid penetrant
...
testing (PT) and magnetic particle testing (MT) for large area screenings. The webinar includes an introduction to the technologies with advantages and disadvantages of each. Side by side examples are discussed including aircraft stringers, engine blades, forgings, weld plates & more. View it today.
>

NDT.net launches mobile-friendly design

NDT.net has revamped its website providing a mobile-friendly design.The front page received a comp
...
letely new design and all other sections are now reacting responsively on mobile devices. This has been a major step to make our website more user- friendly.
>

Portable Ground Penetrating Radar - Proceq GP8000

The Proceq GP8000 portable ground penetrating radar instrument is the beginning of a new era in ND
...
T. The outstanding, patented ultra- wideband technology combined with a compact wireless probe delivers unmatched industry performance. Proceq GP8000 is the world’s first large-scale inspection solution that utilizes Augmented Reality in industrial applications.
>

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