I'm using a constitive model for an FEA analysis that is outlined as follows: enter image description here

In which Young's Modulus is an structure strain invariant defined by the following tensor: enter image description here

And I need to use the SMSHookeToLame function in order to compensate for poisson's ratio (v) and E, however, I'm not really sure how to go about it due to the tensorial nature E.

I apologize if this is a stupid question but I am just learning to use AceFem.

Thank you and have a great day :)

  • 1
    $\begingroup$ Welcome to MSE. Please post code rather than an image. $\endgroup$ Nov 7, 2019 at 2:41
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    – Pinti
    Nov 7, 2019 at 8:16
  • $\begingroup$ Are you sure about tensorial nature of Young's modulus in your equation? You seem to define it as a trace (Tr) of something and that should return a scalar. $\endgroup$
    – Pinti
    Nov 7, 2019 at 8:30
  • $\begingroup$ The Young's modulus is defined for isotropic materials and by nature is a scalar and cannot be a tensor. $\endgroup$
    – KratosMath
    Nov 18, 2019 at 10:21

1 Answer 1


SMSHookeToLame is a small utility function which converts Young's modulus and Poisson ratio to Lame's constants. They are more suitable for direct use in constitutive equations.

{λ, g} = SMSHookeToLame[e, ν]

{(e ν)/((1 - 2 ν) (1 + ν)), e/(2 (1 + ν))}

You can also enter Young's modulus as a tensor (3 x 3 matrix), but I am not sure if that is physically correct approach.


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