restraint and non convergence

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majidkhan
Posts: 9
Joined: Wed Jul 08, 2015 12:57 am
Location: science and research university

restraint and non convergence

Post by majidkhan »

i am trying to perform pushover analysis on x direction . i define rigid diaphragms like this
#fix nodenumber fx fy fz mx my mz
fix 50 0 0 1 1 1 0

with this restraint results are good but when i restraint rotation,like this

fix 50 0 0 1 1 1 1
analysis is not converge

where is my wrong?
fmk
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Re: restraint and non convergence

Post by fmk »

neither are a rigid diaphragm constraint!
majidkhan
Posts: 9
Joined: Wed Jul 08, 2015 12:57 am
Location: science and research university

Re: restraint and non convergence

Post by majidkhan »

dear frank
thanks for your answering

I know that.
I don't write all of my code. i will send it to you if you want
node 50 is master node on rigid diaphragm command
rigidDiaphragm 3 50 2 9 16 23 30 37 44 100 107 114 121 128 135 142 292 299 306 313 320 327 334 341 348 355

first I define rigid diaphragm with rigidDiaphragm command and then i define restraint with fix
when i use fix 50 0 0 1 1 1 0 opensees and sap results are same but
when i restraint rotation (fix 50 0 0 1 1 1 1) opensees analysis is not converge and sap give me results why?
fmk
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Joined: Fri Jun 11, 2004 2:33 pm
Location: UC Berkeley
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Re: restraint and non convergence

Post by fmk »

the why is the model. the only difference between the 2 is that the second 3d model there is no rotation of the floor diaphragm .. if the constraint is causing problems it means the building wants to and some additional forces are getting imposed to enforce the constraint to stop the torsional motion .. what elements and constraint handler are you using?
majidkhan
Posts: 9
Joined: Wed Jul 08, 2015 12:57 am
Location: science and research university

Re: restraint and non convergence

Post by majidkhan »

dear frank
i try it for 2 models with nonlinear beamcolumn elements and transformation constraints
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