Discussion Forum

Hi everyone, I am using the Structural Mechanics module. My aim is to consider the stress field and I was wondering if I understood properly how the results are shown in Comsol. In my model, I plot the result in map view of my 2Axisymmetric model. In the menu option for the result, I selected the first, second, principal stresses (solid.sp3,solid.sp2,solid.sp1)

1) What is not clear is if by default the model is considering some kind of small gravity effect or if, to have that, do I need to add the gravity node in the structural mechanics? Otherwise the result is gravity-free? And the result is the total stress or a deviatoric stress? Here, I noticed that in the menu option for the plot there is also "deviatoric stress tensor" option, so the principal stress (solid.sp3,solid.sp2,solid.sp1) should not include deviatoric stress? 2) My model include a viscoelastic rheology. I was plotting the “initial stress tensor” and my plot gives 0 MPa as a result. After, I noticed another option ”Viscoelastic stress tensor”. My question is if there is a real difference between the two or if the name is only indicating to plot the result in case of an elastic model (initial stress tensor) or viscoelastic model (Viscoelastic stress tensor). Is there a real difference or is just a name thing and I choose one or another based on my model?

If some of you can help me to clarify these things and/or recommend some documentation, it would be perfect. I coudn't find a good explanation about this topic searching in the manual. If you have suggestion, I will gadly accept them.

Best, Chiara