Problem with rigid diaphragm

Forum for OpenSees users to post questions, comments, etc. on the use of the OpenSees interpreter, OpenSees.exe

Moderators: silvia, selimgunay, Moderators

Post Reply
hosiensg
Posts: 22
Joined: Sat Feb 22, 2014 10:00 am
Location: shiraz

Problem with rigid diaphragm

Post by hosiensg »

hi
my 3d model is 3 stories, 6 bays in x direction, 4 bays in y direction and have chevron brace in 3 bays in 2 direction
when i introduce rigid diaphragm (like :http://opensees.berkeley.edu/wiki/image ... d.Wsec.tcl) my model has this error in timehistory analysis:
WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element
i don't know my brace elements have problem or rigid diaphragm, because by removing one of them my analysis do perfectly.
fmk
Site Admin
Posts: 5884
Joined: Fri Jun 11, 2004 2:33 pm
Location: UC Berkeley
Contact:

Re: Problem with rigid diaphragm

Post by fmk »

is the element that is failing a beam or a brace? if a beam change try changing your constraint handler to Penalty as the force beam elements cannot handle a rigid axial constraint (i.e. 0 axial displacement) very well if in bending and section response not symmetric.
hosiensg
Posts: 22
Joined: Sat Feb 22, 2014 10:00 am
Location: shiraz

Re: Problem with rigid diaphragm

Post by hosiensg »

failing is related to the columns. what i should do?
if i want use from penalty , how i can determine alpha coefficient.
hosiensg
Posts: 22
Joined: Sat Feb 22, 2014 10:00 am
Location: shiraz

Re: Problem with rigid diaphragm

Post by hosiensg »

dear fmk
I try all type of element for Beam, Brace and column
but my problem don't solve
after using penalty get compatible error is in many beam, brace and column
fmk
Site Admin
Posts: 5884
Joined: Fri Jun 11, 2004 2:33 pm
Location: UC Berkeley
Contact:

Re: Problem with rigid diaphragm

Post by fmk »

if the column is failing it is not due to high axial forces in the beams that the transformation method can introduce with rigid diaphragms.

you could try substituting 1 force based element for 4 or 5 disp based elements for the columns or tweaking the material properties in the col sections.
Post Reply