Prestressing

[AntoMarinelli]

Dear STKO team,
I'm trying to model a beam with prestressing, assigning the initial stress to the steel. I have a couple of questions about the comand.
- When I select the initial stress it requires the tag of material and the initial stress as the label tells but below in the explanetion box is written 'initial strain'. I attached the image. Is just a problem of label or not?

Supposing that is a label problem, the analysis does not run when I put the right value of the initial stress (999 MPa) but runs when I put low values. In particular, the warning error says: "WARNING: InitStressMaterial - could not find initStrain to within tol for material: 3 wanted sigInit: 999 using tStress: 0"

I attached also the model (it is a high performance fiber reinforced concrete).
Thanks in advance
Antonella

[marafini.f]

Dear Antonella,
in the model, you sent there is just the geometry.
Can you send me the correct one?
Francesca

[AntoMarinelli]

Oh, I'm sorry, it does not save the modifications.
I attached now

[marafini.f]

You defined a steel01 for your steel material to prestress with a 500 MPa maximum strength and then you try to apply higher stress, OpenSees it's just telling you that the steel is breaking. Normally steel cables for prestressing have a higher strength than 500. Either use a higher strength or an elastic material. Anyway check the constitutive behaviour of this kind of steel which is normally more brittle.

[AntoMarinelli]

Yes, I'm sorry for the dumb question!

Regards
Antonella

[marafini.f]

No problem!