Talk:Lamé parameters

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The Elastic moduli template is not working properly. Its missing the introduction telling about possibility of choosing only two parameters. It is there (click view on the top right of the table), the linking just is not working. I don't know how to fix it. Dv3 20:41, 12 April 2007 (UTC)

The template has some extra text when you are viewing only the templated, that is not intended to be included when the template is transcluded into other pages. It is not common as far as I have seen to have much text in these templates, so I did not include it. But it should at least be explained in full detail in the Elastic moduli page. I encourage you to continue the discussion on the template's talk page: Template_talk:Elastic moduli --Berland 20:51, 12 April 2007 (UTC)

Um, lame parameters are ${\displaystyle \mu }$ and ${\displaystyle \lambda }$ of the hooke's equation of the form

${\displaystyle \sigma =2\mu \varepsilon +\lambda tr(\varepsilon )I}$

I think the above is enough about hooke's law on this page. It states that the material obeying hooke's law needs _only two_ parameters (e.g. lame parameters) even if the other components are tensors. After saying this I am changing the equation back to the one above.Dv3 19:44, 16 April 2007 (UTC)

All my references say e grave, not e acute. who is right? Greglocock 12:07, 16 May 2007 (UTC)

I am quite sure Lamé (acute e) is correct. The biographical article on Gabriel Lamé is authoritative for this article. --Berland 09:27, 18 May 2007 (UTC)
Ta Greglocock 11:02, 18 May 2007 (UTC)

Bulk modulus in 2d

I think it is misleading to say that there exists a 2D bulk modulus. In general, 2d models are based on certain hypothesis on the third dimension (ie plain stress or plain strain). But in any case the bulk modulus remains as a property that depends solely on the material (the one in 3D). The final shape of the equations may be different after these 2d hypothesis, but it does not mean the properties of the material have changed.

Pablo 147.83.143.248 (talk) 14:27, 28 March 2014 (UTC)

Incorrect formulas

From the French page, one can read the following formulas, which as far as I remember are correct:

${\displaystyle \lambda ={\frac {E\nu }{(1+\nu )(1-2\nu )}}}$
${\displaystyle \mu ={\frac {E}{2(1+\nu )}}}$

One can easily deduce from this that ${\displaystyle K=\lambda +2\mu }$, which contradicts the article as it is now (edit: see this diff). Another way to prove this is from the assumption that ${\displaystyle K}$, the bulk modulus, is such that isotropic strain ${\displaystyle \epsilon _{ij}=\epsilon _{0}\delta _{ij}}$ stores an energy ${\displaystyle E={\frac {K}{2}}\sum \epsilon _{ii}^{2}={\frac {3}{2}}K\epsilon _{0}^{2}}$.

Furthermore, "The first parameter λ is related to the bulk modulus and the shear modulus via..." before giving a relationship between the two parameters and the bulk modulus (without the shear modulus) seems to indicate that whoever wrote this got things mixed up.

I changed the article as a result, killing the reference to 2D and 3D bulk moduli on my way. Please indicate if I missed something. Tigraan (talk) 10:48, 24 November 2014 (UTC)