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 -

AT-Automation Technology GmbH
AT -Automation Technology is a systems house for industrial image processing. AT offers thermographic ndt systems as well as high-speed 3D sensors.
1158 views
Technical Discussions
Tony Martland
, Joined ,
03:09 Sep-24-2002
Calculation of particle velocity....please help !!!!

Hello

Can anybody help me ? I am trying to find out how to calculate the particle velocity of a longitudinal wave in a solid. I am applying the wave by means of a transducer, into mild steel, and I know the wavespeed in the mild steel (5900 m/s) but how do I calculate the actual particle velocity.

ANY help would be much appreciated.

Thanks

Tony


 
 Reply 
 
Paul A. Meyer
R & D,
GE Inspection Technologies, USA, Joined Nov 1998, 47

Paul A. Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
06:15 Sep-24-2002
Re: Calculation of particle velocity....please help !!!!
Hi Tony,
The particle velocity is proportional to the ratio of the sound pressure to the acoustic impedance. You know the acoustic impedance but the sound pressure is a function of the transducer design, the driving pulse, and the coupling conditions, making it very difficult to determine. If you have access to a KLM transducer model, you can perhaps estimate the sound pressure in the steel.
Paul
: Hello
.
: Can anybody help me ? I am trying to find out how to calculate the particle velocity of a longitudinal wave in a solid. I am applying the wave by means of a transducer, into mild steel, and I know the wavespeed in the mild steel (5900 m/s) but how do I calculate the actual particle velocity.
.
: ANY help would be much appreciated.
.
: Thanks
.
: Tony
.



 
 Reply 
 
luis marques
refinery inspector
petrogal, Portugal, Joined Jul 2002, 5

luis marques

refinery inspector
petrogal,
Portugal,
Joined Jul 2002
5
06:50 Sep-24-2002
Re: Calculation of particle velocity....please help !!!!
It depends on what kind of apparatus you are using. Simple digital ultrasonic equipment such as a Krautkramer DM4 will do what you want. With this equipment if you do not know the sound velocity in the medium you are scanning, you just need a calibration block of a known thickness and same material, you want to scan. In these calibration conditions the equipment will display automatically the sound velocity.

Regards

Luis


 
 Reply 
 
Joe Buckley, Sonatest Plc
Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT, United Kingdom, Joined Oct 1999, 523

Joe Buckley, Sonatest Plc

Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT,
United Kingdom,
Joined Oct 1999
523
07:21 Sep-24-2002
Re: Calculation of particle velocity....please help !!!!
This is one that could 'get extremely silly'
remember that:

1. The net value of the particle velocity is zero - They dont move, just oscillate about a fixed point (thats why its solid)

2. The bulk properties of the material (Youngs modulus etc) are not necessarily appropriate things to use when you get to the atomic level.

3. You cant necessarily assume a sine wave or anything like that, so building up a theoretical model will be quite complex -

May be worth asking exactly what is it you 'really' want to know?

Joe

: Hi Tony,
: The particle velocity is proportional to the ratio of the sound pressure to the acoustic impedance. You know the acoustic impedance but the sound pressure is a function of the transducer design, the driving pulse, and the coupling conditions, making it very difficult to determine. If you have access to a KLM transducer model, you can perhaps estimate the sound pressure in the steel.
: Paul
: : Hello
: .
: : Can anybody help me ? I am trying to find out how to calculate the particle velocity of a longitudinal wave in a solid. I am applying the wave by means of a transducer, into mild steel, and I know the wavespeed in the mild steel (5900 m/s) but how do I calculate the actual particle velocity.
: .
: : ANY help would be much appreciated.
: .
: : Thanks
: .
: : Tony
: .
.



 
 Reply 
 
Pierre Marty
R & D
Saab Aeronautic, Sweden, Joined Jul 2002, 5

Pierre Marty

R & D
Saab Aeronautic,
Sweden,
Joined Jul 2002
5
04:02 Sep-26-2002
Re: Calculation of particle velocity....please help !!!!
HI Tony

A possible way is to use a dynamic Finite Element Model. It is not so difficult to estimate the profile of the sound pressure at the interface betrween the transducer and the sample, so that you can model the system with a good accuracy.
If you have any mean (laser probe ?9 to measure the displacement at the outer surface of the transducer and if you assume a good coupling between the transducer and the sample than the FE method will give you a fair estimation of the particle displacement in the bulk of the steel sample. The limits of such aproach are those of the FE method and of your own assumptions in term of displacement profile and magnitude at the surface of the transducer.

I beleive commercial FE programs such as ANSYS, PZFLEX can do that. IF you need contact me for more info on that subject. I did some similar models myself with another FE code.

Pierre


: Hello
.
: Can anybody help me ? I am trying to find out how to calculate the particle velocity of a longitudinal wave in a solid. I am applying the wave by means of a transducer, into mild steel, and I know the wavespeed in the mild steel (5900 m/s) but how do I calculate the actual particle velocity.
.
: ANY help would be much appreciated.
.
: Thanks
.
: Tony
.



 
 Reply 
 

Product Spotlight

NDTkit RT

NDTkit RT, TESTIA's Digital Radiography software The NDTkit product line software for X-ray analysi
...
s. NDTkit RT is a software benefiting from the Ultis kernel which is dedicated to radiographic image analysis. It offers a set of tools and filtering processes to assist RT operators in finding relevant flaws.
>

NEW! The PragmaPro Instrument Platform

The PragmaPro is based on a modular cartridge technology and supports various NDT instrument modal
...
ities such as UT, PAUT, ECT and many more. This new platform is based on a machined, powder-coated aluminum frame for shock-proofness, best sealing qualities and maximum heat dissipation. This is practical to extend the outdoor temperature range and/or to extend the power injected in the transducers. The PragmaPro is aiming at a very wide range of applications, such as weld scanning, corrosion mapping and composite testing.
>

Surf-X® Array Probe

Introducing the Surf-X family of flexible Eddy Current Array (ECA) probes. Featuring unique multiple
...
coil sets and proprietary X-PROBE technology, Surf-X array probes can quickly and accurately handle a range of inspection applications, from inspecting corrosion or cracking in pipes, pressure vessels, or tanks, to assessing and sizing cracks in raised welds and friction stir welds.
>

YXLON Cougar EVO

Scalable small footprint X-ray inspection systems for assembly and laboratory applications. The
...
YXLON Cougar EVO series was designed to provide the "best-in- class" inspection solutions for SMT, semiconductor, and laboratory assembly applications, while maintaining a small system footprint for maximum convenience. With optimized software and hardware, these systems produce higher quality and more consistent results than other electronics inspection systems currently on the market.
>

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