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 -

GB Inspection Systems Ltd.
A leading UK manufacturer of Ultrasonic Probes, Accessories, Supplier of NDT Equipment and more.
735 views
Technical Discussions
Graham Stephen
Graham Stephen
09:02 Sep-21-1998
Fault detection

I am curious to know if anyone has been involved
in detecting flaws before phiysical damage is shown
(ie. "pre-crack" fault detection in steel).



 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 305

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
305
08:40 Sep-22-1998
Re: Fault detection

: I am curious to know if anyone has been involved
: in detecting flaws before phiysical damage is shown
: (ie. "pre-crack" fault detection in steel).


I assume here that Graham is talking about condition monitoring structures or components.
I have been involved now for some years with Resonant Inspection. This technique analyses the component's or structure's Eigen modes, and these are affected by dimensions and material properties.
Material properties is a very general term, and includes things like microstructure, alloying elements and RESIDUAL STRESS, which I assume is responsible for the onset of cracking.
This means that by monitoring the resonances of a component or structure, we should be able to detect changes in residual stress, perhaps before cracking is evident.
Resonanat Inspection, as we are applying it, is very new, and I myself have no experiences with monitoring Residual Stress. Perhaps you can get more information from Quasar International in New Mexico, USA.
E-Mail info@quasarintl.co

Another technique that is used to monitor Residual Stress is Barkhausen noise, but I have no experiences there.


 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1292

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1292
03:44 Sep-22-1998
Re: Fault detection
: I am curious to know if anyone has been involved
: in detecting flaws before phiysical damage is shown
: (ie. "pre-crack" fault detection in steel).

Graham:
Could you please be a bit more detailed about the application
the question is based on. Nearly all NDT is based on the
principle that the test is to locate areas of "potential"
failure. This is normally dealt with as acceptance criteria
and examples of how they are derived are seen in many Codes
such as ASME Boiler and Pressure Vessels, CSA Z662 and
API 1104 (plus many more). Fracture mechanics will
indicate that not all flaws are reason for concern
and you will need to know several things about the
product, such as, material properties, dimensions,
service conditions (stress direction and magnitude),
is loading static or cyclic, etc, etc, etc.
Fracture mechanics equations then usually want some
sort of input on the flaw. Mostly flaw size perpendicular
to the direction of stress and where the flaw is with
respect to the surface.

One then has to assess how reliable the NDT test is and
the probability that the most critical flaw conditions
have been detected. E.g. did you select the best test
for detecting the most likely flaws and does the test
provide you with a useful means of sizing it for fracture
mechanics.

Therefore, simply "detecting flaws before physical
damage is shown (ie. "pre-crack" fault detection in steel)"
is not sufficient information.




 
 Reply 
 

Product Spotlight

NOVO Armor 15 & NOVO Armor 22

The Armor Kit Contains the NOVO Armor, which provides additional mechanical protection to the NOVO 1
...
5WN & NOVO 22WN Detectors, the Armor Stand and a traveling soft cover. - Newest shock absorbent technology case - Water resistant design - Supports wired & wireless communication - Multiple positioning options - Tripod connection using the Built-in 1/4” threads - Simple Detector battery replacement
>

HARDNESS TESTER TKM-459CE combi

TKM-459CE combi applies 2 methods of hardness control: UCI and Leeb. It provides high-accuracy tes
...
ting of metals and alloys as well as items of different sizes and configurations, their hardened layers and galvanic coatings. Device represents results in HB, HRC, HV and others. Shock-, dust- and water-proof housing with intuitive software make this gauge easy to use in all working conditions.
>

IRIS 9000Plus - Introducing the next generation of heat exchanger inspection.

Representing the seventh generation of the IRIS system, the IRIS 9000 Plus has nearly 200 years of c
...
ombined field inspection experience incorporated in its design. This experience combined with a strong commitment to quality and a history of innovation has made Iris Inspection Services® the undisputed leader in IRIS technology.
>

NDT Master Lecturer

In the program both university professors and practitioners will give lectures, which guarantees the
...
oretical depth and practical inside. Academic Director: Prof. Dr. Christian Boller
The following lecturers are not complete: Prof. Tadeusz Stepinski, Prof. Wieslaw Staszewski, Prof. Frank Walther, Prof. Giovanni Bruno, Prof. Gerd Dobmann, Prof. Philippe Guy
>

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