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Cauchy Stress

hi
I´m modeling a plate. In the results branch I configurated a 2D plot to show "the Second Piola-Kirchhoff stress, xx component" using the expresion "plate.Sxx".
I want to know if it's possible to configurate a Cauchy stress component in the 2D plot.

Regards.

2 Replies Last Post Jan 14, 2013, 2:42 AM EST
Posted: 5 years ago Jan 12, 2013, 3:28 PM EST
Hi

The Cauchy stress is the stress in the Eulerian representation check for the "spatial stress tensor"
The second Piola-Kirchhoff (or material) stress is in the Lagrangian representation, these are dissociated, in particular for "geometric non-linearity enabled"

Check carefully the doc and use the right Frame for your integrations (see the doc ;)

--
Good luck
Ivar
Hi The Cauchy stress is the stress in the Eulerian representation check for the "spatial stress tensor" The second Piola-Kirchhoff (or material) stress is in the Lagrangian representation, these are dissociated, in particular for "geometric non-linearity enabled" Check carefully the doc and use the right Frame for your integrations (see the doc ;) -- Good luck Ivar

Henrik Sönnerlind COMSOL Employee
Posted: 5 years ago Jan 14, 2013, 2:42 AM EST
As long as the analysis is geometrically linear, 2nd P-K and Cauchy stresses are the same.

If you have a geometrically nonlinear problem, the interpretation of a Cauchy stress would still be problematic, since it has fixed directions in space, and there would thus be stress components not aligned with the deformed plate.

Regards,
Henrik
As long as the analysis is geometrically linear, 2nd P-K and Cauchy stresses are the same. If you have a geometrically nonlinear problem, the interpretation of a Cauchy stress would still be problematic, since it has fixed directions in space, and there would thus be stress components not aligned with the deformed plate. Regards, Henrik

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