# How to use SMSHookeToLame(E, v) when E is a tensor? (AceFem/Acegen Material properties)

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

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

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 :)

• Welcome to MSE. Please post code rather than an image. – Rohit Namjoshi Nov 7 '19 at 2:41
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• 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. – Pinti Nov 7 '19 at 8:30
• The Young's modulus is defined for isotropic materials and by nature is a scalar and cannot be a tensor. – KratosMath Nov 18 '19 at 10:21

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]