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FI Test- und Messtechnik GmbH

651 views
07:22 Jun-02-1999

Anatol Krozer

R & D, project manager
Imego Institute,
Sweden,
Joined Oct 1999
2
wave propagation at liquid7solid interface

Dear everybody
I have 3 requests:
1. Please advise on references regarding frequency dependence of the attenation length for (penetration depth of) acoustic (shear) waves incident from solids onto a solid/liquid interface.
2. Acoustic wave propagating in a solid, e.g. pipe. What are the reflection conditions at an inner surface of the pipe with/without liquid
3. Advise on a broadband flat response sensor to be operated in liquids.
Look forward to many suggestions
Anatol
Anatol Krozer, assoc. prof.
project manager
The IMEGO Institute, Aschebergsgatan 46, bd.11
SE-411 33 Göteborg
tel. +46 (0)31 750 18 06; mobile: +46 (0)709 15 18 06
e-mail: anatol.krozer@imego.com



 
03:36 Jun-03-1999
Wieslaw Bicz
Re: wave propagation at liquid7solid interface

: Dear everybody
: I have 3 requests:
: 1. Please advise on references regarding frequency dependence of the attenation length for (penetration depth of) acoustic (shear) waves incident from solids onto a solid/liquid interface.
: 2. Acoustic wave propagating in a solid, e.g. pipe. What are the reflection conditions at an inner surface of the pipe with/without liquid
: 3. Advise on a broadband flat response sensor to be operated in liquids.
: Look forward to many suggestions
: Anatol
: Anatol Krozer, assoc. prof.
: project manager
: The IMEGO Institute, Aschebergsgatan 46, bd.11
: SE-411 33 Göteborg
: tel. +46 (0)31 750 18 06; mobile: +46 (0)709 15 18 06
: e-mail: anatol.krozer@imego.com

1. In many books you can find the information, that the shear wave can propagate in the liquid only about 1 wavelength. Frequency dependance is probably not important.

2. You can find in many books concerning ultrasound formulas describing the reflections conditions.
They work very good, but only, if your incidence angles are not narrow to the critical or 90 degrees.
And I don´t know any good formula that can give you real good worth for the phase. We have made a program, that works in many cases.
If you are interested in this problems - plese contact us.

3. I think, we can offer you such transducer. Please see on the following page: http://www.optel.com.pl/manual/english/transd.htm



 
05:26 Jun-04-1999

Richard Freemantle

NDT Inspector, Consultant, R&D
Wavelength NDT Limited,
United Kingdom,
Joined Nov 1998
15
Re: wave propagation at liquid7solid interface : 2. You can find in many books concerning ultrasound formulas describing the reflections conditions.
: They work very good, but only, if your incidence angles are not narrow to the critical or 90 degrees.
: And I don´t know any good formula that can give you real good worth for the phase. We have made a program, that works in many cases.
: If you are interested in this problems - plese contact us.

A more general solution lies with matrix methods - the equations are more involved but will deal with the issues of critical incidence
angles and evenescent waves.

I have used solutions based on the work of Knopoff.

ref: L. Knopoff (1964) A matrix method for elastic wave problems. Bull. Seism. Soc. Am., Bol. 54, 431-438

The formulations allow the calculation of the compression and shear wave transmission and relfection coefficients for single or multiple interfaces for both compression
and shear wave incidence. These can be calculated as functions of incidence angle and frequency. Forexample, Fourier Analysis will give you the time domain impulse
response of the system.

The formulations are usually derived in the complex frequency domain and will yield the amplitude and phase of the transmission and reflection
coefficients. Depending on what formulation you use, they will give accurate results in situations where the incidence angle is high
leading to complex refraction angles. The formulations generally assume complex wave propagation which will allow you to calculate the effects
of loss in the system (eg frequency dependent attenuation and phase velocity)

A good review of these technqiues can be found in:

MATRIX TECHNIQUES FOR MODELING ULTRASONIC-WAVES IN MULTILAYERED MEDIA
LOWE_MJS
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, 1995, Vol.42, No.4, pp.525-542

Hope this info helps,

Best regards

Richard Freemantle

=====================
Dr. R.J. Freemantle

NDT Solutions Ltd
Suite 3.2
Keele University Science Park
Keele
Staffordshire
ST5 5SP
UK

Tel +44 (0)1782 584306
Fax +44 (0)1782 711093

Email r.j.freemantle@ndtsolutions.com
http://www.ndtsolutions.com



 


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