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Defning Ogden material at Abaqus UMAT

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Posts: 6
Topic starter
Active Member
Joined: 9 years ago

Hi all,

Im writting an subroutine to define the Ogden constitutive laws, and I reach the following procedure:

1) calculate the isochoric left cauchy-green tensor [B]b[/B]

2) perform the spectral decomposition of [B]b[/B]

3) get the principal stretches

4) calculate the derivatives of the strain-energy in order to the principal stretches

5) calculte the principal cauchy stresses and the derivatives in order to the principal stretches

6)calculate the spatial elasticity tensor

This is the normal procedure for Ogden material?It is computationally expensive....

Instead of the spectral decomposition, it is better to get the close form of the derivatives in order to the invariants?

Any suggestion for alternartive procedures?

best regards,

1 Reply
Posts: 3998
Joined: 5 years ago

That is the way. What problem are you working on where speed is such an issue?


1 Reply