Plastic rotation of fiber elements

[nparsaeifard]

Dear all
I have modeled a steel moment resisting building using fiber elements (Displacement-Based Beam-Column Element)
I need to calculate the plastic rotation of elements to evaluate the performance level of elements.
Would you please let me know the exact formulation to find the plastic rotation of elements?
Can you give me the corresponding recorder command?
Looking forward to your answer
Thank you

[mhscott]

recorder .... element 1 plasticDeformation

[nparsaeifard]

Dear professor Michael H. Scott
I appreciate your guidance
I used the aforementioned recorder, but it gives small plastic rotation values.
What should I do to obtain the correct plastic rotation values?
Looking forward to your help
Thank you very much

[mhscott]

How do you know what's correct?

That recorder gives three values ... you should look at the last two, not the first, which is plastic axial deformation

[nparsaeifard]

Dear professor Michael H. Scott
Thank you very much for your quick and very useful response. you helped solve my problem, I appreciate your help
I used the recorder commend you had proposed, yes it works,and I could get the rotations.
I just want to know if they are just plastic rotations or I must subtract the elastic rotations to obtain plastic rotations? and is there any command to obtain elastic rotations?
Again I thank you
Looking forward to your guidance

[mhscott]

The plasticDeformation recorder gives you the plastic rotations (with elastic part subtracted) theta^p = theta - theta^e

Take a look at Figure 1 of this paper: http://dx.doi.org/10.1061/(ASCE)0733-9445(2007)133:9(1341)

[nparsaeifard]

Dear professor Michael H. Scott
Thank you very much, I'm trying to get the recommended article, It seems very helpful to my research
By the way is there a command in opensees to get the elastic rotations?
I thank you again
Sincerely yours

[nparsaeifard]

Dear professor Michael H. Scott
Can I use these plastic rotations to evaluate the performance of structural members?
(I evaluate performance of the structure based on FEMA provisions, using the plastic rotations limit states presented in FEMA).
Looking forward to your guidance
Sincerely yours

[Tas]

A related older post is given below, maybe it will help you.
http://opensees.berkeley.edu/community/ ... =2&t=55855

[nparsaeifard]

Thank you very much for your guidance