Unbonded prestressing condition

[AntoMarinelli]

Dear STKO,
I have to model an unbonded cable. My idea is to constrais the inital point of the bar to the concrete body by means of an "node to element" interaction and a "edof" constrains, but the analysis doesn't run because it says that the matrix is singural. I have also to precise that the bar is composed by a part that is bonded (for that I used an embedded condition) and a part unbonded, represented by a wire which each part has differents proprieties (in particular different different areas to simulate the ancorage lenght). How can I give the unbonded condition?

Thanks for the support
Antonella

[marafini.f]

Could you attach your model?

[AntoMarinelli]

Yes, sure!

Thanks in advance
Antonella

[marafini.f]

Dear Antonella,
the singularity occurs because you are using a truss element and discretize it. The node of the bar that is created by the mesh and are not on the extremities are free, so your model is singular. You can try using a beam element, if you accept that something other then axial force is transmitted in such cable, otherwise you should discretize it as one single element and you analysis will run.
Francesca

[AntoMarinelli]

[quote=marafini.f post_id=4551 time=1636551631 user_id=2956]
Dear Antonella,
the singularity occurs because you are using a truss element and discretize it. The node of the bar that is created by the mesh and are not on the extremities are free, so your model is singular.



You can try using a beam element, if you accept that something other then axial force is transmitted in such cable, otherwise you should discretize it as one single element and you analysis will run.
Francesca
[what do you mean with a sigle element?]

[marafini.f]

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