Hi Dear all
I have a question. is it correct that if we have a frame with nonlinearBeamColumn element we can not use equalDOF command for defining rigid diaphragm in 2D model? is this related to materials or not? I mean for steel frame and concrete frame?
Regards
equalDOF command
Moderators: silvia, selimgunay, Moderators
Re: equalDOF command
Hi
i have used it in 2D RC model for verifying experimental test and results was good.....i think there is not any problem.
use nonlinearBeamColumn (Displacement-based Beam-Column).
i have used it in 2D RC model for verifying experimental test and results was good.....i think there is not any problem.
use nonlinearBeamColumn (Displacement-based Beam-Column).
Last edited by hnaderi on Mon Aug 12, 2013 12:06 am, edited 1 time in total.
Re: equalDOF command
hnaderi wrote:
> Hi
> i have used it in 2D RC model for verifying experimental test and results
> was good.....i think there is not any problem.
what did you use for the beams?? forceBeamColumn or dispBeamColumn element?
please look at http://opensees.berkeley.edu/community/ ... =2&t=60480, fmk wrote "if you do use equaldDOF make sure you are not using the nonlinearBEamColumn (forceBeamColumn) for the beams in the model as the axial forces will end up being unrealistic because of the constraint"
> Hi
> i have used it in 2D RC model for verifying experimental test and results
> was good.....i think there is not any problem.
what did you use for the beams?? forceBeamColumn or dispBeamColumn element?
please look at http://opensees.berkeley.edu/community/ ... =2&t=60480, fmk wrote "if you do use equaldDOF make sure you are not using the nonlinearBEamColumn (forceBeamColumn) for the beams in the model as the axial forces will end up being unrealistic because of the constraint"
Re: equalDOF command
Hi Mohammadf and civil
Sorry if my description was vague. Mohammadf 's question was general.
I have nonlinearBeamColumn (Displacement-Based Beam-Column) for beams in my model.
As fmk wrote in that topic, it depends on the structural system.
when you have axial force in one element and your solution method is exact equilibrium between element and section forces (Force-Based Element), you can not define axial constraint between two end of it.
With equalDOF, relative displacement between node i and node j is zero AND there is not axial strain in element, therefore equilibrium is changed.
I hope my description is clear.
You can control Beam's local forces in your model with and without equalDOF and with nonlinearBeamColumn (force Beam-Column) element for beams.
Results will vary.
I think you can not define rigid diaphragm only in this special case :
2D model.... Moment Resistant Frame with nonlinearBeamColumn (Force Beam-column) element for beams.
Use Beam With hinges Element or nonlinearBeamColumn (Displacement Beam-column).
Displacement-based element has its own problems. we need to know the advantages and disadvantages of these elements and how to use them.
there is a good description about force-based and disp-based elements in below link. It helps.
http://opensees.berkeley.edu/wiki/index ... _final.pdf
Sorry if my description was vague. Mohammadf 's question was general.
I have nonlinearBeamColumn (Displacement-Based Beam-Column) for beams in my model.
As fmk wrote in that topic, it depends on the structural system.
when you have axial force in one element and your solution method is exact equilibrium between element and section forces (Force-Based Element), you can not define axial constraint between two end of it.
With equalDOF, relative displacement between node i and node j is zero AND there is not axial strain in element, therefore equilibrium is changed.
I hope my description is clear.
You can control Beam's local forces in your model with and without equalDOF and with nonlinearBeamColumn (force Beam-Column) element for beams.
Results will vary.
I think you can not define rigid diaphragm only in this special case :
2D model.... Moment Resistant Frame with nonlinearBeamColumn (Force Beam-column) element for beams.
Use Beam With hinges Element or nonlinearBeamColumn (Displacement Beam-column).
Displacement-based element has its own problems. we need to know the advantages and disadvantages of these elements and how to use them.
there is a good description about force-based and disp-based elements in below link. It helps.
http://opensees.berkeley.edu/wiki/index ... _final.pdf