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 -

TWI
1035 views
Technical Discussions
x.chen
x.chen
03:37 Jul-06-2000
how can the shear wave transducers excite SH Wave?

As we know, the sh wave is usually excited by EMATs. But limited by the experiment equiments, I recently want to excite SH wave using shear wave transducers in a plate. Can I excite it? How can I do? where can i find some articles about shear wave transducers?


    
 
 Reply 
 
Uli Mletzko
R & D, Retired
Germany, Joined Nov 1998, 89

Uli Mletzko

R & D, Retired
Germany,
Joined Nov 1998
89
00:32 Jul-06-2000
Re: how can the shear wave transducers excite SH Wave?
: As we know, the sh wave is usually excited by EMATs. But limited by the experiment equiments, I recently want to excite SH wave using shear wave transducers in a plate. Can I excite it? How can I do? where can i find some articles about shear wave transducers?

It might be possible to use standard SV probes, coupled to the side of a plate. This could be equivalent to SH waves, excited at the surface of a plate by EMAT. But this is depending on your measuring or research task.

Regards
Uli Mletzko
NDT group, MPA
University of Stuttgart, Germany



    
 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1268

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1268
03:11 Jul-06-2000
Re: how can the shear wave transducers excite SH Wave?
Excitation of SH shear waves has been more popular
since the introduction of EMATs but prior to EMATs
SH Shear waves were also generated using piezo-electric
materials. A piezo ceramic can be polarised in several
ways, depending on the distortion you require when the
electric field is applied (dilational, extentional,
radial).

Most industrial applications use dilational mode and
shear waves are produced by mode conversion (these are
SV shear waves).

If the element is polarised to distort in the
extentional mode so dispacement is parallel to the test
surface, a direct shear action may occur in the test
piece (SH shear). The problem with using piezo elements
for this type of wave mode is the coupling efficiency.

Most liquids will not support a shear mode. To couple
(acoustically) the probe to the the test piece for SH
shear modes you require a non-Newtonian viscous fluid.
There are several commercially available such couplants
but I have found honey to be about as good as any.

The advantage of EMATs over piezo elements is their
ability to be moved over the test piece. Sliding a
probe through honey and maintaining constant quality
of coupling is impossible.
EMATs, however, produce an undamped signal so
resolution suffers. Piezo elements with 1 or 2 cycles
are ideal for signal analysis. This has been useful
for determining birefringence in anisotropic materials.

Ed

: As we know, the sh wave is usually excited by EMATs. But limited by the experiment equiments, I recently want to excite SH wave using shear wave transducers in a plate. Can I excite it? How can I do? where can i find some articles about shear wave transducers?




    
 
 Reply 
 
Harold Dunegan
Harold Dunegan
03:48 Aug-10-2000
Re: how can the shear wave transducers excite SH Wave?
You can excite Sh shear waves in a plate by using a
commercial shear transducer, placing it on the edge of
the plate with particle motion parallel to the plate.





    
 
 Reply 
 

Product Spotlight

Sci Aps Z-Series Portable Handheld Analysers

The world’s only handheld analyzer that measures carbon content in stainless (yes even L-grades),s
...
teels, and cast irons. Also accepted for low Si analysis for sulfidic corrosion analysis, and is widely used in the power industry for Cr analysis, for flow accelerated corrosion applications.
>

MUSE Mobile Ultrasonic Equipment

The MUSE, a portable ultrasonic imaging system, was developed for in-field inspections of light-weig
...
ht structures. The MUSE consists of a motor-driven manipulator, a water circulation system for the acoustic coupling and a portable ultrasonic flaw detector (USPC 3010). The MUSE provides images of internal defects (A-, B-,C- and D-scan).
>

Lyft™: Pulsed Eddy Current Reinvented

PEC Reinvented—CUI Programs Redefined Corrosion under insulation (CUI) is possibly the greatest u
...
nresolved asset integrity problem in the industry. Current methods for measuring wall thickness with liftoff, without removing insulation, all have severe limitations. Eddyfi introduces Lyft — a reinvented, high-performance pulsed eddy current (PEC) solution. The patent- pending system features a state-of-the-art portable instrument, real- time C-scan imaging, fast data acquisition with grid-mapping and dynamic scanning modes, and flexibility with long cables. It can also scan through thick metal and insulation, as well as aluminum, stainless steel, and galvanized steel weather jackets. Who else but Eddyfi to reinvent an eddy current technique and redefine CUI programs. Got Lyft?
>

Ultrasonic Testing Immersion Tanks with Unmatched Scanning Features

TecScan’s non-destructive testing Ultrasonic Immersion Tanks & scanners are designed for high pe
...
rformance and demanding NDT testing applications. Our Scan3D™ line of High Precision Immersion Tanks are specifically designed for automated ultrasonic testing of complex composites parts used in aerospace and 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