Hi,

you can test ([0]) a new ElasticConstants class [1] that implements all possible conversion formulas for:

Young’s modulus Poisson’s ratio bulk modulus Lamé’s first parameter shear modulus = Lamé’s second parameter P-wave modulus = longitudinal wave modulus

Given any two constants, it can determine the remaining, see [2], [3]. Basically, at [2] there are all the formulas without the P-wave modulus, while at [3] there are all the constants, but not all the formulas (60 for six constants).

It uses sympy to some extent for the moment, but later we could just use the resulting relations converted to Python functions.

Let me know if it works for you or not.

thanks, r.

[0] http://github.com/rc/sfepy [1] http://docs.sfepy.org/doc-devel/src/sfepy/mechanics/matcoefs.html [2] http://www.efunda.com/formulae/solid_mechanics/mat_mechanics/calc_elastic_co... [3] http://en.wikipedia.org/wiki/Lam%C3%A9_parameters