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EKOSCAN
EKOSCAN is a French manufacturer specialized in equipment for ultrasonic Non Destructive Testing: Probes,UT boards & Scanners tailored for your needs
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Career Discussions
Matt Harper
R & D
Instrumentation Group, United Kingdom, Joined May 2004, 3

Matt Harper

R & D
Instrumentation Group,
United Kingdom,
Joined May 2004
3
05:41 May-28-2004
Mode Conversion and elastic constants

I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?

Many thanks

Matt.



 
 Reply 
 
Godfrey Hands
Consultant,
PRI Nadcap, United Kingdom, Joined Nov 1998, 304

Godfrey Hands

Consultant,
PRI Nadcap,
United Kingdom,
Joined Nov 1998
304
09:08 May-31-2004
Re: Mode Conversion and elastic constants
Hi Matt,
I suggest you try and get hold of a copy of "Ultrasonic Testing of Materials" by Josef and Herbert Krautkramer. Published by Springer Verlag. There are two ISBN Numbers in my edition, I suspect one for the German Language and one for the English language editions. They are:
ISBN 3-540-07716-2 2nd edition and
ISBN 0-387-07716-2 2nd edition.
First edition should also help,
ISBN 3-540-04589-9 or
ISBN 0-387-04589-9.

This seems to have the information you need in it.

Regards,

Godfrey Hands
----------- Start Original Message -----------
: I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: Many thanks
: Matt.
------------ End Original Message ------------




 
 Reply 
 
Matt Harper
R & D
Instrumentation Group, United Kingdom, Joined May 2004, 3

Matt Harper

R & D
Instrumentation Group,
United Kingdom,
Joined May 2004
3
07:23 May-31-2004
Re: Mode Conversion and elastic constants
Many thanks, i'll go and look them up.

Matt.


----------- Start Original Message -----------
: Hi Matt,
: I suggest you try and get hold of a copy of "Ultrasonic Testing of Materials" by Josef and Herbert Krautkramer. Published by Springer Verlag. There are two ISBN Numbers in my edition, I suspect one for the German Language and one for the English language editions. They are:
: ISBN 3-540-07716-2 2nd edition and
: ISBN 0-387-07716-2 2nd edition.
: First edition should also help,
: ISBN 3-540-04589-9 or
: ISBN 0-387-04589-9.
: This seems to have the information you need in it.
: Regards,
: Godfrey Hands
: : I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: : Many thanks
: : Matt.
------------ End Original Message ------------




 
 Reply 
 
Ed Ginzel
R & D, -
Materials Research Institute, Canada, Joined Nov 1998, 1282

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1282
03:33 May-31-2004
Re: Mode Conversion and elastic constants
The equations for calculating the variation of reflection and transmission coeeficients of the compression and transverse modes are found in a few locations. Just a note, the Third edition of "Ultrasonic Testing of Materials" by Josef and Herbert Krautkramer had errors in the English version. (I think these were corrected in later English editions). Dale Ensminger in his book Ultrasonics- Fundamentals, Technology, Applications....has also provided the equations.

It is timely that you ask on this information as I believe it has been used in the development of the software provided by Philippe Rubbers in this month's NDT.net! When solved with the parameters input you will find that the pressure distributions of the wave modes are accounted for.

As for using elastic constants to predict mode conversion angles...I think getting acoustic velocities would be easier and more accurate.

Ed


Ed

----------- Start Original Message -----------
: Hi Matt,
: I suggest you try and get hold of a copy of "Ultrasonic Testing of Materials" by Josef and Herbert Krautkramer. Published by Springer Verlag. There are two ISBN Numbers in my edition, I suspect one for the German Language and one for the English language editions. They are:
: ISBN 3-540-07716-2 2nd edition and
: ISBN 0-387-07716-2 2nd edition.
: First edition should also help,
: ISBN 3-540-04589-9 or
: ISBN 0-387-04589-9.
: This seems to have the information you need in it.
: Regards,
: Godfrey Hands
: : I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: : Many thanks
: : Matt.
------------ End Original Message ------------




 
 Reply 
 
Neil Burleigh
Sales
Krautkramer Australia Pty Ltd, Australia, Joined Dec 2002, 158

Neil Burleigh

Sales
Krautkramer Australia Pty Ltd,
Australia,
Joined Dec 2002
158
01:16 Jun-01-2004
Re: Mode Conversion and elastic constants
----------- Start Original Message -----------
: I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: Many thanks
: Matt.
------------ End Original Message ------------


Hello Matt,
The first critical angle is where the longitudinal wave component of a mode converted sound wave is totally reflected at the interface. The second critical angle is where the transverse wave component is totally reflected at the interface. After the first critical angle you will not get a longitudinal sound wave propagating into the material.

We use Snell's law to calculate the first critical angle, the velocity of sound of the particular material is used in the formula of Snell's law. Elastic constants determine the velocity of sound within a material. So yes you could use the elastic constants to determine when mode conversion does or does not occur.

Happy Hunting

Regards

Neil Burleigh



 
 Reply 
 
Abdelmalek BOUHADJERA
Abdelmalek BOUHADJERA
05:45 Jun-01-2004
Re: Mode Conversion and elastic constants
Hello Matt

I have been involved for a long time now, designing measuring systems, which involve mode conversion of ultrasonic waves. My PhD thesis, "A Universal Ultrasonic Apparatus for Measuring Elastic Constants of Materials", Notts Uinv. 1988. Deals with the subject.
In Which I detailed a new technique based on prism shaped specimens.
I have recently proposed an improved version of the technique, and it is now called, the prism technique.

A more established technique, is called the rotating plate technique. It is based on a through transmission method, and measurements are carried out in a water tank.

Dr Abdelmalek BOUHADJERA
NDT Lab
Jijel University
Algeria

----------- Start Original Message -----------
: I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: Many thanks
: Matt.
------------ End Original Message ------------




 
 Reply 
 
Matt Harper
R & D
Instrumentation Group, United Kingdom, Joined May 2004, 3

Matt Harper

R & D
Instrumentation Group,
United Kingdom,
Joined May 2004
3
04:14 Jun-02-2004
Re: Mode Conversion and elastic constants
Thanks to all who pointed me in the right direction, i now have a lot of maths to get through.

For information the system i have developed here at Leeds is a through transmission system that can scan over injection made plaques and produce time of flight, amplitude and elastic modulus maps over the scanned area. Many of these plaques contain fibres and i'm looking at relationships between the orientation of these fibres in relation to the time of flight, aplitude and elastic modulus measurements to deduce mesostructoral properties.

again my thanks

Matt.

----------- Start Original Message -----------
: : I was trying to find information about ultrasonic wave propagation over water/sample interfaces to tidy up my PhD thesis, which is based upon a through transmision method, and it seems that there isn't ( or i can't find) much information about mode conversion? Can anyone point me in the right direcition, for example at a particular angle, the first critical angle, is where i beleive mode conversion occurs producing a longitudinal and a transverse wave depending on the symmetry, but is there any theory that predicts the reletive intensity of each of these two waves when you get them propagating within the sample at the same time ? as far as i understand the situation of both these waves propagating in the sample is possible. So how does mode conversion deal with this situation, as if it occurs at the first critical angle then there should be no longitudinal wave only transverse ? Also the incident angle at which mode conversion occurs should be predicted by the elastic constants of the sample, so knowing the elastic constants can we predict the angle at which mode conversion occurs ?
: : Many thanks
: : Matt.
:
: Hello Matt,
: The first critical angle is where the longitudinal wave component of a mode converted sound wave is totally reflected at the interface. The second critical angle is where the transverse wave component is totally reflected at the interface. After the first critical angle you will not get a longitudinal sound wave propagating into the material.
: We use Snell's law to calculate the first critical angle, the velocity of sound of the particular material is used in the formula of Snell's law. Elastic constants determine the velocity of sound within a material. So yes you could use the elastic constants to determine when mode conversion does or does not occur.
: Happy Hunting
: Regards
: Neil Burleigh
------------ End Original Message ------------




 
 Reply 
 

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