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 -

1230 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, 528

Joe Buckley, Sonatest Plc

Consultant, ASNT L-III, Honorary Secretary of BINDT
Level X NDT, BINDT,
United Kingdom,
Joined Oct 1999
528
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

Wireless TOFD scanner

Quick, accurate and highly reproducible welds testing. The System operates wirelessly and is compat
...
ible with any type of Windows based Laptop, Desktop or Tablet.
>

OmniScan™ X3 flaw detector

The OmniScan X3 flaw detector is a complete phased array toolbox. Powerful tools, like total focus
...
ing method (TFM) images and advanced visualization capabilities, enable you to complete your inspection with greater confidence.
>

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
>

NEW - TD Focus-ScanRX

The NEW Next Generation Advanced UT platform, TD Focus ScanRX - Also available as a card stack solut
...
ion. Key Improvements 1. Data acquisition is significantly faster than current design 2. Better aesthetic – closely aligns with HandyScan RX 3. Improved IP rating (Target IP66) 4. Ruggedized housing 5. Connectors are protected from impact and ingress 6. Integrated stand and separate retractable handle easy to keep clean) 7. Touchscreen with ruggedized display glass 8. 3-Axis encoder input
>

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