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07:39 Jan-03-2005
comparison of young's modulus measured by tensile tests and ultrasounds

Dear All,
I am looking for references on the comparison of the values of the young's modulus obtained by tensile test, flexural methods and so on, versus ultrasonic echography.
For the moment, I got a 5 and 10% disperancy between my ultrasonic measurements and classic mechanical data on 6061t6 and ag3 aluminium alloys?????

04:20 Jan-04-2005
Re: comparison of young's modulus measured by tensile tests and ultrasounds

Hi,
Tensile tests will let you determine the Youngs Modulus of a sample in a condition of plastic deformation.
Sound Velocity based techniques (Flexural and Ultrasonic) will determine the elastic constants under elastic deformation, which is closer to the real life situation.

Quasar International in the USA (+1 505 247 9660, contact Kim Johnson) manufactures and markets an instrument (called the RU-Spec) which determines the elastic constants of solids with a claimed accuracy of better than 0.1%.

NDT Consultants markets this same instrument for Quasar in the United Kingdom and large parts of Europe.
Contact us for more information. (+44 2476 511 151 or email to Godfrey@ndt-consultants.co.uk).

Regards,

Godfrey Hands

09:23 Jan-04-2005
Re: comparison of young's modulus measured by tensile tests and ultrasounds

That's not really the case, is it? If you don't load
the material past its yeild stress then - it's elastic.
The real challenge is to measure the (very small)
elastic deformation as you load it. To get over that
you might try flexure tests to get large deflections
for small strains.

Robert Paynter

Oxford UK

00:09 Jan-04-2005
Re: comparison of young's modulus measured by tensile tests and ultrasounds

For a well made sample lacking any physical defects, extraordinarily accurate results are obtained - sometimes to better than 0.1% if one is inclined to make the near perfect test sample. Half a percent is usually adequate and is easily obtained for most all common crystaline structures. (Metals are generally treated as isotropic for samples greater than a few mm on a side.)

It is usually the dynamic modulus that people wish to use in making calculations. If you need to measure this, and wish more details, please see http://www.quasarintl.com/ruspec/ruspec.html.

M. Kim Johnson
Quasar International, Inc.
5550 Midway Park NE
Albuquerque, NM 87109

505 247-9660
kim@quasarintl.com

----------- Start Original Message -----------
: : Godfrey Hands wrote:
: > Tensile tests will let you determine the Youngs Modulus of a sample in a condition of plastic deformation.
: That's not really the case, is it? If you don't load
: the material past its yeild stress then - it's elastic.
: The real challenge is to measure the (very small)
: elastic deformation as you load it. To get over that
: you might try flexure tests to get large deflections
: for small strains.
: Robert Paynter
: Oxford UK
------------ End Original Message ------------