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 -

GRANPECT COMPANY Ltd
GRANPECT bends to the industrialization of high-tech research achievements and specializes in research and development of various X-ray radiation imag ...
423 views
Technical Discussions
Lirin Philip
,
VALDEL , India, Joined Sep 2019, 9

Lirin Philip

,
VALDEL ,
India,
Joined Sep 2019
9
06:01 Sep-10-2019
UT TESTING -VELOCITY OF MATERIAL

As know material velocity is property of material its depend on density and Poisson ratio,so its should be same for all the probes,e,g we using CFRP composite material velocity is 2800 m/sec,
we doing thickness calibration of laminate e.g 3 mm plate ,with 5MHz ,getting velocity 2800 m/sec,when we try with 2.25MHz for same thickness velocity found 2400 m/sec,its varring with probes frequency as we know velocity of material ,should be constant for all probes.

    
 
 Reply 
 
Edward Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1266

Edward Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1266
14:02 Sep-10-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Lirin Philip at 06:01 Sep-10-2019 (Opening).

Lirin, although 400m/s seems to be a rather high difference if the samples were tested in the same orientations, indeed some materials can be dispersive. By this we mean that the phase velocity is dependent on frequency. (See https://en.wikipedia.org/wiki/Acoustic_dispersion
and the reference #2 in that URL to the paper by Ping for how it is measured).
Your CFRP materials add to the complexities by their anisotropic characteristics.

Was there a question in your posting?

    
 
 Reply 
 
Wieslaw Bicz
Engineering,
PBP Optel sp. z o.o., Poland, Joined Feb 2009, 256

Wieslaw Bicz

Engineering,
PBP Optel sp. z o.o.,
Poland,
Joined Feb 2009
256
15:44 Sep-10-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Lirin Philip at 06:01 Sep-10-2019 (Opening).

Ed can be correct with the assumption, but there could be another reason: The method, how the signal is evaluated to get the information about the time of flight and - as result - about the thickness. We are delivering since many years systems, that measures - among other parameters - material thickness and sound speed in different materials. Based on huge experience with very different applications and conditions I would assume, that the method of measuring time of flight can be the reason. If you calibrate with one frequency and measure with other this can be the main reason. I do not know, what device you are using, and how it is working, but I would assume, that this is a very realistic reason.

    
 
 Reply 
 
Lirin Philip
,
VALDEL , India, Joined Sep 2019, 9

Lirin Philip

,
VALDEL ,
India,
Joined Sep 2019
9
06:01 Sep-11-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Wieslaw Bicz at 15:44 Sep-10-2019 .

Sir, we are using Omni scan SX 16:64 by olympus. We are using Pulse echo method.

    
 
 Reply 
 
Anmol Birring
Consultant,
Birring NDE Center, Inc., USA, Joined Aug 2011, 738

Anmol Birring

Consultant,
Birring NDE Center, Inc.,
USA,
Joined Aug 2011
738
19:20 Sep-11-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Lirin Philip at 06:01 Sep-11-2019 .


You need to use external UT pulser with oscilloscope to take velocity measurement.

    
 
 Reply 
 
Wieslaw Bicz
Engineering,
PBP Optel sp. z o.o., Poland, Joined Feb 2009, 256

Wieslaw Bicz

Engineering,
PBP Optel sp. z o.o.,
Poland,
Joined Feb 2009
256
15:18 Sep-12-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Lirin Philip at 06:01 Sep-11-2019 .

I have not enough experience with it to be able to tell, how you device is processing data. Measuring sound speed (time of flight)or thickness requires in all cases where accuracy is important some signal analysis. Ultrasonic signal is namely never a Dirac delta, but always much more complicated. To determine, when the signal arrived (what was the time of flight) requires some assumptions, especially in the case, if the signal is changing its form due to attenuation (higher frequencies are attenuated stronger than lower). It is naturally possible to solve the problems connected with such measurements, but it requires sometimes some relatively sophisticated procedures. I assume, that in your case the material is relatively strongly attenuating, but without experience with your case and equipment I am not able to tell more.

    
 
 Reply 
 
Joe Buckley
Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT, United Kingdom, Joined Oct 1999, 521

Joe Buckley

Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT,
United Kingdom,
Joined Oct 1999
521
16:21 Sep-12-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Lirin Philip at 06:01 Sep-10-2019 (Opening).

What procedure are you using to measure the velocity?

3mm CFRP is only 2-3 wavelengths thick at 2.2MHz, It can be very difficult to get an accurate measurement on materials this thin in relation to the wavelength unless you are very careful about measurement points. most calibration routines are set up assuming a much longer path.

A good check would be to measure the velocity for a piece of steel - around 6-8mm thick (so about the same transit time.) and confirm you get consistent velocity at the two frequencies.

    
 
 Reply 
 
Wieslaw Bicz
Engineering,
PBP Optel sp. z o.o., Poland, Joined Feb 2009, 256

Wieslaw Bicz

Engineering,
PBP Optel sp. z o.o.,
Poland,
Joined Feb 2009
256
13:42 Sep-13-2019
Re: UT TESTING -VELOCITY OF MATERIAL
In Reply to Joe Buckley at 16:21 Sep-12-2019 .

If the thickness will be 3 mm, frequency 2.25 MHz and sound speed 2800 m/s the distance must be counted double and in wave lengths it will be around 5 (the thickness must be counted double). Using transducer with short signal such thickness can be quite easily calculated with relatively simple procedures.

    
 
 Reply 
 

Product Spotlight

Lyft™: Pulsed Eddy Current Reinvented

PEC Reinvented—CUI Programs Redefined Corrosion under insulation (CUI) is possibly the greatest u
...
nresolved asset integrity problem in the industry. Current methods for measuring wall thickness with liftoff, without removing insulation, all have severe limitations. Eddyfi introduces Lyft — a reinvented, high-performance pulsed eddy current (PEC) solution. The patent- pending system features a state-of-the-art portable instrument, real- time C-scan imaging, fast data acquisition with grid-mapping and dynamic scanning modes, and flexibility with long cables. It can also scan through thick metal and insulation, as well as aluminum, stainless steel, and galvanized steel weather jackets. Who else but Eddyfi to reinvent an eddy current technique and redefine CUI programs. Got Lyft?
>

Teletest Focus+

Teletest Focus+ electronics have superior capabilities than rivals on the market. Beyond the usual
...
test features, Focus+ has 24 transmit channels and 24 receive channels, with an additional on-board switching capabilities. The instrument's frequency range is 10–300 kHz.
>

AIS229 - Multipurpose Real Time System

Latest standard & automatic real time system developed by Balteau. The AIS229 has been designed to
...
do series inspection in a wide variety of industry. Composed of a shielded cabinet, 5 axis manipulator, x-ray generator and tubehead from 160kV to 225kV, a fl at panel & much more, the AIS229 is most certainly one of the most multipurpose RTR system available on the market.
>

High-performance Linear Phased Array Probes

Available to order from stock in a range of 5MHz – 7.5MHz and from 16 to 64 elements. Designed w
...
ith piezo-composite elements, Phoenix phased array probes provide high-resolution imaging to maximise sensitivity; accurate ultrasonic detection and sizing of defects in welds; and effective corrosion mapping. Housed in a rugged stainless steel case for on-site industrial NDT applications.
>

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