Talk:Shear modulus

Relation to Poisson's ratio and Young's modulus
Where the hell does this relationship come from. Surely its not an empirical formula! a derivation should be provided somewhere or at least an explination.

-It comes from analysis of the tensor representing the transferance of force onto the tensor representing the material.Jgreeter (talk) 21:29, 3 May 2011 (UTC)jgreeter

the formula

$$G = \frac {E} {2(1 + \nu)}$$ should be added, here $$E$$ is young's modulus, $$\nu$$ is poisson ratio which is usually 0.33.

This formula is the regular formula for G and can't be excluded in the article


 * I have just added this formula back. I see that it was removed, because it is present in a hidden table below the article. You have to click show to see this table. I'm convinced, that this formula should be in the main body of this article. And that hidden table is only for a reference - having all the formulas listed together. Janek Kozicki 14:07, 28 April 2007 (UTC)
 * The template for the relationsships has changed (Template:Elastic moduli) since the formulas were removed from this page. The template should be modified somewhat so that only the big table of formulas is hidden, not all of the templates content. When that happens, I think repeating a subset of the relevant formulas in this page is superflous. --Berland 21:13, 29 April 2007 (UTC)

swapnil k — Preceding unsigned comment added by 114.143.182.194 (talk) 12:06, 27 September 2016 (UTC)

Poisson's Ratio
Although the value of Poisson's Ratio is sometimes 0.33, it is in no way usually 0.33. It may be the case for a few materials, however, by no means is it the case in general. y?

For ordinary materials the Poisson's ratio is between zero and one-half. —Preceding unsigned comment added by 64.126.190.120 (talk) 22:07, 20 October 2008 (UTC)

Is the shear modulus for a fluid always exactly zero or just very close? Fornadan (t) 23:38, 5 November 2006 (UTC)

its zero for a hypothetical 'newtonian fluid' only, otherwise close to zero but it gets higher the more jelly like the fluid. Maybe this is worth a mention in the article?

Consistent shear modulus for rubber?
I was wondering if the specified shear modulus for rubber is correct? According to the wiki page on the elasticity modulus, E for rubber is typically between 0.01 and 0.1 GPa, which with Poisson's ratio = 0.5 would give G between ca 0.003 and 0.03 GPa? —The preceding unsigned comment was added by 62.247.4.34 (talk) 11:08, 28 March 2007 (UTC).

For rubber, the elasticity modulus, E, is typically between 0.1-0.6 ksi (0.0007-0.004 GPa). This puts the shear modulus, G, at 0.03-0.2 ksi (0.0002-0.001 GPa). Poisson's ratio for rubber is between 0.45-0.50. —Preceding unsigned comment added by 64.126.190.120 (talk) 22:15, 20 October 2008 (UTC)

Strength or stiffness ?
In the "Explanation" it says that "The shear modulus is one of several quantities for measuring the strength of materials ..." but surely the word "strength" there should be replaced by "stiffness"? Fathead99 (talk) 14:14, 20 November 2007 (UTC)

Relation to torsion modulus ?
there has to be a simple mathematical relation between shear modulus and torsion modulus, but I don't seem to be able to find one off hand, if there is it should be included here, and should also be noted in the page for tension modulus and everywhere else the big conversion table "from any two moduli to any other two moduli" appears or is replicated. And even though torsion modulus may not be a purely material property (it may also be geometric, related to the square(?), or cube(?) of the diameter of the torsion rod) I still find it disagreeable to not be able to find torsion modulus anywhere in wikipedia. Peterl95124 (talk) 07:13, 27 February 2009 (UTC)peterl95124
 * The shear modulus is sometimes also called torsion modulus. This is because torsion to a simple (e.g. round) rod gives pure shear at small loads.--Ulrich67 (talk) 17:53, 11 May 2012 (UTC)

shear Modulus of Liquids
The classical picture is to have zero shear modulus in a liquid. This is even one way to define a liquid as opposed to a solid. The viscoelastic picture uses a kind of sear modulus for liquids too, however his is a dynamic modulus at higher frequencies or a short time scale. The long time or low frequency limit is zero even in viscoelastic liquids. We may have a separate section on the sear modulus in liquids, but this is a rather complicated part, not easy for everybody. The table should not mix dynamic values for liquids with the normal modulus values. The given Ref. even states that the give value for water is not valid (e.g. outside the scope of there instrument). Without an extra notation of the time scale or frequency dynamic moduli are not useful anyway.--Ulrich67 (talk) 08:02, 16 February 2013 (UTC)
 * yes you are right this is the shear relaxation modulus you mention. Biggerj1 (talk) 11:10, 17 November 2019 (UTC)

Misleading information about diamond
This article mentions nothing about the shear modulus of diamond varying with orientation. It says the shear modulus of diamond is 478 GPa but I read that it was 535 GPa. Is that the shear modulus of polycrystal diamond? This article should at least mention the shear modulus of diamond with respect to a cleavage plain and that with respect to a plane paralell to a face of its cubic unit cell. Blackbombchu (talk) 02:42, 17 June 2013 (UTC)