plastic curvature of dispBeamColumn element

[niloufar]

Dear Vesna
I want to calculate the plastic rotation of dispBeamColumn element during nonlinear timehistory analyses, I used the below command:

recorder Element -file Curvature.out -time -ele 1 section 1 deformation

The above recorder gave me the total curvatue of section (icluding the elastic and plastic rotation of the section), but I want to obtain just the plastic curvature.
how can I subtract the elastic rotation of the total rotation?
whould you please give me an example recorder?

I need your guidance
Sincerely yours

[niloufar]

Dear Vesna
I really need your guidance

[taneryilmaz]

I'm not sure if I understood your question correct, but your plastic curvature depends on your criteria about when your section is yielded. For example, if you have a reinforced concrete section and if you make a sectional analysis, find the moment-curvature behavior under a certain axial load, you will get a nonlinear curve. If you apply Priestley's recommendation on equivalent bilinear curve, you may assume that the ill curvaturture is your yield curvature. The critical point is that you have to consider the effect of axial load and the distance between contra-flexure and fixity points.

[niloufar]

Thank you dear Taneryilmaz
I have used fiber elements to model the steel beams and columns, and I could obtain the curvature of the elements at both ends of them (including plastic and yielding curvature).
But the problem is that, I can't obtain the plastic curvature apart from the yielding curvature.

[niloufar]

Dear Vesna
would you please help me?
I need your guidance

[taneryilmaz]

You can get the rotations along your element (if you use sufficient number of nodes), and then obtain an approximate result for the total curvature by using the rotations. Then you can get the plastic curvature by subtracting the yield curvature (found explicitly) from the total curvature. A quite long method, but this is what comes to my mind.

[niloufar]

Thanks dear Taneryilmaz
but my question is : how can I obtain yield curvature?
How can I found it explicitly? would you give me an example?

[niloufar]

Dear Vesna
would you please consider my question? I'm in need of calculating elastic rotations of dipsBeamColumn elements.
Thank you very much