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1003 views
02:01 Jul-03-2007
Rich Riley
shear wave compatability

I am looking for a good, practical way of performing shear wave compatibility of a calibration standard to the part being inspected.
Is the any practical way to determine compatibility using shear waves? There is only one way that I know of and that is to compare corners of the cal std to the part under inspection. This seems to be a very poor way to determine compatability since corner traps make very poor reflectors. If you should know of any way to perform a compatability check using shear waves, please let me know. Right now I am stumped. Would appreaciate any help.

thanks

Rich Riley


 
03:06 Jul-03-2007
chris s
Re: shear wave compatability ----------- Start Original Message -----------
: I am looking for a good, practical way of performing shear wave compatibility of a calibration standard to the part being inspected.
: Is the any practical way to determine compatibility using shear waves? There is only one way that I know of and that is to compare corners of the cal std to the part under inspection. This seems to be a very poor way to determine compatability since corner traps make very poor reflectors. If you should know of any way to perform a compatability check using shear waves, please let me know. Right now I am stumped. Would appreaciate any help.
: thanks
: Rich Riley
------------ End Original Message ------------

what exactly is ment by "compatability"


 
05:47 Jul-04-2007

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1208
Re: shear wave compatability Rich:
This sounds like you are trying to determine the "transfer value" betweeen the cal block and tested article. For weld inspection we typically start off making a DAC (preferrably with a 45° probe) on your A scan display.
Then, change from the pulse-echo mode to through transmission and connect an identical 45° probe to the receiver terminal. Place the probes on the cal block test surface facing each other and get a maximised signal from the Vee path and set the signal amplitude to the DAC and note the gain setting. Now move to the test piece and again maximise the response from the Vee path. Adjust the gain to bring the signal to the DAC again. If no gain was added the transfer value is zero. If you need to add gain because the test piece is more attenuative, the extra gain (transfer value) is added to the scanning level over reference.
This is a reasonable approximation when the cal block and part tested have parallel surfaces to effect the Vee path. The fact that the DAC is used allows for some difference in thickness between the cal block and test piece.
Generally a condition indicating that the test piece is not as attenuative as the cal block (i.e. negative transfer value) is treated as a zero dB transfer value. If the transfer value is large (e.g. 6dB or more), you may need to reconsider the suitability of the cal block you are using.

----------- Start Original Message -----------
: I am looking for a good, practical way of performing shear wave compatibility of a calibration standard to the part being inspected.
: Is the any practical way to determine compatibility using shear waves? There is only one way that I know of and that is to compare corners of the cal std to the part under inspection. This seems to be a very poor way to determine compatability since corner traps make very poor reflectors. If you should know of any way to perform a compatability check using shear waves, please let me know. Right now I am stumped. Would appreaciate any help.
: thanks
: Rich Riley
------------ End Original Message ------------




 
04:00 Jul-05-2007

Dent McIntyre

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
247
Re: shear wave compatability If you can stamp a notch on your part and a like notch on your cal block you can compare these and determine the transfer value.
Sometimes you cannot stamp on your part, so Ed's through transmission method is all you can do.


----------- Start Original Message -----------
: I am looking for a good, practical way of performing shear wave compatibility of a calibration standard to the part being inspected.
: Is the any practical way to determine compatibility using shear waves? There is only one way that I know of and that is to compare corners of the cal std to the part under inspection. This seems to be a very poor way to determine compatability since corner traps make very poor reflectors. If you should know of any way to perform a compatability check using shear waves, please let me know. Right now I am stumped. Would appreaciate any help.
: thanks
: Rich Riley
------------ End Original Message ------------




 


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