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 -

712 views
Technical Discussions
Robert Oakley
Robert Oakley
09:39 Sep-16-2002
Probability of detection within a specific NDT method as a function of flaw size

I am a student engineer for a company called Miltec, and I am searching for information concerning the probability of detection by any and all methods of NDT as a function of flaw size. In addition I require figures on the probability of false detection by any and all NDT methods as a function of flaw size. Any help whatsoever as to references and sources for this material would be greatly appreciated.


    
 
 
Terry Oldberg
Engineering, Mechanical Electrical Nuclear Software
Consultant, USA, Joined Oct 1999, 42

Terry Oldberg

Engineering, Mechanical Electrical Nuclear Software
Consultant,
USA,
Joined Oct 1999
42
08:10 Oct-11-2002
Re: Probability of detection within a specific NDT method as a function of flaw size
Your requirements cannot be met, for past and current methods of flaw detection violate the axiom of probability theory that is known as Unit Measure. It follows that at least one of the two probabilities that you desire is not defined. (See my paper at http://www.ndt.net/article/v04n05/oldberg/oldberg.htm plus my postings in this forum on the topic of "Unit Measure violations" for details.)

By the way, when you say that you require a probability of false call as a function of flaw size, you seem to be making a mistake, for the statistical population underlying a probability of false call would be comprised of non-flaws.




    
 
 
David Forsyth
R & D
TRI/Austin, USA, Joined Nov 2001, 41

David Forsyth

R & D
TRI/Austin,
USA,
Joined Nov 2001
41
07:54 Oct-15-2002
Re: Probability of detection within a specific NDT method as a function of flaw size
>I am a student engineer for a company called Miltec, and I am searching for information concerning the probability of detection by any and all methods of NDT as a function of flaw size.

There are collections of POD curves publicly available from NTIAC (see http://www.ntiac.com), but these curves should only be used for qualitative purposes, unless you have exactly the same specimen, flaw type, and inspection equipment and procedure you can not use these quantitatively.

>In addition I require figures on the probability of false detection by any and all NDT methods as a function of flaw size. Any help whatsoever as to references and sources for this material would be greatly appreciated.
.

P(false call) is not related to flaw size, NTIAC document also shows P(false call) information. P(false call) is P(noise > threshold level). noise can be measured and threshold can be

Not everyone agrees with Oldberg or the conclusions in his paper.

Dave.


    
 
 
rodney fordham
Consultant
United Kingdom, Joined Feb 2002, 12

rodney fordham

Consultant
United Kingdom,
Joined Feb 2002
12
01:09 Oct-15-2002
Re: Probability of detection within a specific NDT method as a function of flaw size
: >I am a student engineer for a company called Miltec, and I am searching for information concerning the probability of detection by any and all methods of NDT as a function of flaw size.
.
: There are collections of POD curves publicly available from NTIAC (see http://www.ntiac.com), but these curves should only be used for qualitative purposes, unless you have exactly the same specimen, flaw type, and inspection equipment and procedure you can not use these quantitatively.
.
: >In addition I require figures on the probability of false detection by any and all NDT methods as a function of flaw size. Any help whatsoever as to references and sources for this material would be greatly appreciated.
: .
.
: P(false call) is not related to flaw size, NTIAC document also shows P(false call) information. P(false call) is P(noise > threshold level). noise can be measured and threshold can be
.
: Not everyone agrees with Oldberg or the conclusions in his paper.
.
: Dave.
.
but those who disagree owe it to all of us out here to explain in clear logical arguments exactly why they disagree.

In my experience, especially in the most important cases, Terry Oldberg is absolutely right.



    
 
 

Product Spotlight

ISONIC 3510

Very Powerful Superior Performance Extremely Portable Smart Phased Array Ultrasonic Flaw Detector an
...
d Recorder with 2 Conventional UT and TOFD Channels uniquely combines PA, single- and multi-channel conventional UT, and TOFD modalities providing 100% raw data recording and imaging. Suitable for all kinds of every-day ultrasonic inspections
>

Conformable wedge transducer

The conformability is obtained with a flexible membrane filled with water between the transducer and
...
the inspected component. The coupling between the membrane and the component requires a small quantity of water or couplant. The conformable wedge combines the acoustic performance of immersion technique with good coupling and low attenuation.
>

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.
>

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.
>

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