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 -

LECOEUR ELECTRONIQUE
The Specialist of electronics for ultrasonic testing.

1067 views
Career Discussions
Jaeseok Park
Jaeseok Park
08:41 Jan-28-2004
about creeping wave and mode conversion

hi there,
Can anybody inform me about the theoretical background of creeping wave and mode conversion? please help me... T.T


    
 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1252

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1252
03:50 Jan-29-2004
Re: about creeping wave and mode conversion
Mr. Park:
The best work on the description of the so-called creeping wave is a paper entitled
"On the nature of the so-called subsurface Longitudinal wave and/or the surface Longitudinal Creeping wave" by K.J Langenberg, P. Fellinger, and R. Marklein, Research in Nondestructive Evaluation, Springer - Verlag, 1990 pp 61-81.
Regards
Ed


----------- Start Original Message -----------
: hi there,
: Can anybody inform me about the theoretical background of creeping wave and mode conversion? please help me... T.T
------------ End Original Message ------------




    
 
 
Hermann Wüstenberg
R & D
BAM Berlin, Germany, Joined Nov 1998, 26

Hermann Wüstenberg

R & D
BAM Berlin,
Germany,
Joined Nov 1998
26
03:06 Jan-29-2004
Re: about creeping wave and mode conversion
----------- Start Original Message -----------
: hi there,
: Can anybody inform me about the theoretical background of creeping wave and mode conversion? please help me... T.T
------------ End Original Message ------------
The name „creeping waves“ has been introduced around 1975 (if I am correctly informed at first in Germany) for a phenomenon observed at angle beam probes with a wedge angle close to the angle of total reflection of the longitudinal wave in steel (e.g. with a perspex wedge angle around 27°). The waves then generated in steel do have a complex structure. They do propagate into the halfspace as shear waves with a refraction angle around 33,2° and are linked to a remaining long-wave trace at the surface – a kind of longitudinal headwave, also known as lateral wave in the TOFD applications or as “creeping waves”, which is strongly attenuated with increasing distance from the probe due to the energy loss by the 33,2°-shear waves constantly irradiated from the surface into the half space. The term “creeping wave” is somehow misleading. It has been applied a lot earlier than 1975 for waves surrounding cylindrical reflectors hit by shear waves and producing small indications in A-scans of such reflectors which may be used for the determination of the reflector diameter. But once introduced into practical application, it has been impossible to correct this ambiguity.
Nowadays, the term “creeping wave” is linked to some important applications e.g. on stainless steel welds. The fast distance decay forces to use transmitter receiver probes. The family of transmitter-receiver probes for inclined longitudinal waves (TRL or SEL probes) is among others used with refraction angles around 70° (for the L-wave in steel!) eg. for the detection of sub-cladding cracks or with a wedge angle around 27° (producing more or less pure “creeping waves” ) for surface and near surface cracks. Since the always excited 33,2°-shear-wave may convert back into a longitudinal wave when hitting the opposite surface of a plate, one may use also this L-wave (which propagates nearly in parallel to the opposite surface) to detect cracks or other defects close to the opposite surface. The use of different interactions using different waves modes at one single probe is a typical multimode application producing quite complex patterns of A-scans which can only be evaluated with some success based on the context information of images like TD-, B-, or C-scans, that means it requires an automatic inspection.

Hermann Wuestenberg




    
 
 

Product Spotlight

NEW Wheel Type Phased Array Probe

DOPPLER NEW Wheel Type Phased Array Probe, more stable, new tyre makes lesser acoustic attenuation
...
, much lighter makes easier to handle, more slim size, magnetic and mechanical encoder optional etc...more
>

SONOAIR - air-coupled Phased Array Ultrasonic Inspection System

For highly attenuating materials, the performance of the system is critical. The ultrasonic sensors,
...
the scanning area and the system settings should be flexibly adapted to the test task and the material. These high expectations are met with the new and modular testing system SONOAIR. With the world’s first air-coupled phased-array UT inspection system SONOAIR we developed a technology that works with up to 4 transmitter and receiver channels with freely configurable square wave burst transmitters as wells as low noise receiving amplifiers.
>

IntraPhase Athena Phased Array System

The Athena Phased Array system, manufactured by WesDyne NDE Products & Technology, consists of a pha
...
sed array acquisition system and PC running IntraSpect software. A PC is used to perform acquisition, analysis and storage of the data. System hardware is capable of operating up to four data sets with any combination of phased array or conventional UT probes. NOW AVAILABLE IN 64-64 CONFIGURATION.
>

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.
>

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