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1395 views
01:06 Oct-18-2001
Chris Coughlin
Dry-coupled UT transducers

Hi All;

TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.

Thanks!
Chris



 
06:23 Nov-02-2001

Kelly Phelps

Consultant, IT Manager/Marketing Manager
NDT Engineering Corporation,
USA,
Joined Oct 2001
6
Re: Dry-coupled UT transducers : Hi All;
.
: TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.
.
: Thanks!
: Chris
.

Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.


 
06:55 Nov-02-2001
Chris Coughlin
Re: Dry-coupled UT transducers : : Hi All;
: .
: : TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.
: .
: : Thanks!
: : Chris
: .
.
: Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.
.


Yes, we're mainly interested in dry-coupled roller probes, but we haven't been able to find any yet that will support shear wave modes.


 
07:16 Nov-02-2001

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1185
Re: Dry-coupled UT transducers : : : Hi All;
: : .
: : : TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.
: : .
: : : Thanks!
: : : Chris
: : .
: .
: : Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.
: .
.
:
: Yes, we're mainly interested in dry-coupled roller probes, but we haven't been able to find any yet that will support shear wave modes.
.
Do you REALLY mean that the dry-coupled roller must support Shear mode, as in SH shear wave inspection?
To accomplish this as a "coupling medium" you would still need a nonNewtonian viscous fluid to then couple the SH mode from the roller into the workpiece if using a piezo-element. Even with good SH shear coupling materials (like honey) you are likely to struggle to maintain a constant quality of coupling. It is hard enough to do this in a static condition let alone trying to do so on a dynamic scan.
I would think that most shear wave applications would use SV shear so you would rely on mode conversion from compression waves and the reverse (SV to compression) just as is done when using standard plastic refracting wedges.

Otherwise, if it is SH mode you require perhaps EMATs might be the only option.

Ed



 
07:52 Nov-02-2001

Kelly Phelps

Consultant, IT Manager/Marketing Manager
NDT Engineering Corporation,
USA,
Joined Oct 2001
6
Re: Dry-coupled UT transducers : : : : Hi All;
: : : .
: : : : TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.
: : : .
: : : : Thanks!
: : : : Chris
: : : .
: : .
: : : Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.
: : .
: .
: :
: : Yes, we're mainly interested in dry-coupled roller probes, but we haven't been able to find any yet that will support shear wave modes.

The problem is that at a shear wave angle, both the thickness of the roller material and the dead air space that might be encountered at the point that the roller curves up off the surface of the part being inspected, would provide too much attenuation. However, a tractor wheel design that keeps the shear wave flat to the surface would work, provided that the rubber tracks are thin enough to transmit sound.


 
08:17 Nov-02-2001
Chris Coughlin
Re: Dry-coupled UT transducers : : : : : Hi All;
: : : : .
: : : : : TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or transducers (e.g. EMATs) at this stage.
: : : : .
: : : : : Thanks!
: : : : : Chris
: : : : .
: : : .
: : : : Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.
: : : .
: : .
: : :
: : : Yes, we're mainly interested in dry-coupled roller probes, but we haven't been able to find any yet that will support shear wave modes.
.
: The problem is that at a shear wave angle, both the thickness of the roller material and the dead air space that might be encountered at the point that the roller curves up off the surface of the part being inspected, would provide too much attenuation. However, a tractor wheel design that keeps the shear wave flat to the surface would work, provided that the rubber tracks are thin enough to transmit sound.
.


Right, that's pretty much the same conclusion we had come to for the transducers. We're hoping to find some COTS transducers, rather than (pun intended) reinvent the wheel.


 
08:36 Nov-02-2001

Kelly Phelps

Consultant, IT Manager/Marketing Manager
NDT Engineering Corporation,
USA,
Joined Oct 2001
6
Re: Dry-coupled UT transducers : Right, that's pretty much the same conclusion we had come to for the transducers. We're hoping to find some COTS transducers, rather than (pun intended) reinvent the wheel.


It really wouldn't be hard to design since we already make several types of roller probes. The question is what you would use for the rubber track.



 
00:39 Nov-02-2001

Ken Camplin

,
Joined

Re: Dry-coupled UT transducers : : : : Hi All;
: : : .
: : : : TRI/Austin is looking for "dry coupled" ultrasonic transducers in the 1-5 MHz range that generate shear waves. Our application is a pretty tight fit, and ideally we're looking for fluid-filled wheels or similar configurations. Any and all help is appreciated; more info on the RFI is available from http://www.ntiac.com/rfi.html. Please note we're not interested in alternative NDE techniques or
transducers (e.g. EMATs) at this stage.
: : : .
: : : : Thanks!
: : : : Chris

: : : .
: : .
: : : Are you looking for dry-coupled roller probes? By what you describe this is what I am guessing.
: : .
: .
: :
: : Yes, we're mainly interested in dry-coupled roller probes, but we haven't been able to find any yet that will support shear wave modes.
: .
: Do you REALLY mean that the dry-coupled roller must support Shear mode, as in SH shear wave inspection?
: To accomplish this as a "coupling medium" you would still need a nonNewtonian viscous fluid to then couple the SH mode from the roller into the workpiece if using a piezo-element. Even with good SH shear coupling materials (like honey) you are likely to struggle to maintain a constant quality of coupling. It is hard enough to do this in a static condition let alone trying to do so on a dynamic scan.
: I would think that most shear wave applications would use SV shear so you would rely on mode conversion from compression waves and the reverse (SV to compression) just as is done when using standard plastic refracting wedges.
.
: Otherwise, if it is SH mode you require perhaps EMATs might be the only option.
.
: Ed
.
Hello Chris:

I know you orinally said you were not looking at EMATs, but I am sure you know that EMATs are particularly well suited for generating shear waves, especially SH waves. EMATs have come along way lately and have been fielded in very harsh enviroments and in automated fashion. If you would like to know more about our EMAT systems, please visit us at www.innerspec.com.


 


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