# Determening shear modulus of glass fiber-epoxy compisite.

I'm trying to, experimentally, determin some material properties of a slab of glass fiber-epoxy compisite to use in a model of an airplane
wing. I'm after a first rough approximation only and as of now I only have access to relativly simple instruments. Does anyone have an idea of how to estimate the shear modulus? The dimensions of the slab are: 300*30*3 mm. I would be greateful for any help in this matter. //Alex
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I recall a short beam shear test. It's 3 point loading. Used to do it on 1/8 inch thick bars but I believe all you have to do is vary length. Frank
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you can make a traction test and measure the strain in the solicitation plane. this way, you obtain E1, Nu12=-eps2/eps1 and G12á/(2(1+nu12))
Good luck
Alexander von Essen wrote:

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make a 4-point bending test, measure the deflection and both orthogonal strains on a surface. Calculate E-modulus from deflection and ny from strains. Rest as before.
Peter
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There must be an ASTM or DIN standard test for this, best to stick with the standard if there is one, so other labs and scientists will have a common language with you.-Jitney
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There are databases of glass/epoxy composites in MIL-HDBK-17. Some of this may be on the internet. As far as testing, many of the US composites makers use ASTM D2344. Doug
snipped-for-privacy@kth.se (Alexander von Essen) wrote in message

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The way in which the composite was made and the fibre orientation will have a lot of effect. The laminate will be anisotropic.
--
Terry Harper
http://www.terry.harper.btinternet.co.uk /
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snipped-for-privacy@kth.se (Alexander von Essen) wrote in message

Alex, Which shear modulii are you looking for?
Call the 300mm direction x, the 30mm direction y, and 3mm direction z.
Do you want Gxy, Gyz, Gxz, what?
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