How to define torsion stiffness with pre-integrated shell elements?

[Stasch]

Hi all!

I am using preintegrated shell element for the modeling of a complex sandwich structure. I have noticed that there is no option to assign the torsion stiffness of the cross section when pre-integrated elements are used. Consequently, when trying to validate the equivalency between modeling the complex structure and the simpler structure using pre-integrated shell elements, I have quite some error in the torsional moments mxy.

Does anyone know a way to assign torsion stiffness with this kind of formulation?

Thank you all in advance,

Stavroula Schoina.