PushOver Converge Problem

[spinasA]

Dear all,
I did pushover analysis for 5-storied RC moment-frame.my model has different diagonal strut pattern ( for modeling infill of frame , strut=brace) that replace in compression diameter. I pushed bare frame and Did not have a problem. But When I pushed my model with different strut pattern in some pattern it converge very well but in some pattern with same frame and same analysis command Does not converge.
I tried different algorithm and tolerance and it not work.........

important part of model is:


#units N,m,sec


file mkdir 5Story-3Bay-Model5

model basic -ndm 2 -ndf 3

node 1 0. 0.
node 2 0. 3.5
node 3 0. 6.5
node 4 0. 9.5
node 5 0. 12.5
node 6 0. 15.5

node 7 5.5 0.
node 8 5.5 3.5
node 9 5.5 6.5
node 10 5.5 9.5
node 11 5.5 12.5
node 12 5.5 15.5

node 13 11. 0.
node 14 11. 3.5
node 15 11. 6.5
node 16 11. 9.5
node 17 11. 12.5
node 18 11. 15.5

node 19 16.5 0.
node 20 16.5 3.5
node 21 16.5 6.5
node 22 16.5 9.5
node 23 16.5 12.5
node 24 16.5 15.5

#############################

fix 1 1 1 1
fix 7 1 1 1
fix 13 1 1 1
fix 19 1 1 1


#equalDOF $rNodeTag $cNodeTag $dof1
equalDOF 2 8 1
equalDOF 2 14 1
equalDOF 2 20 1
equalDOF 3 9 1
equalDOF 3 15 1
equalDOF 3 21 1
equalDOF 4 10 1
equalDOF 4 16 1
equalDOF 4 22 1
equalDOF 5 11 1
equalDOF 5 17 1
equalDOF 5 23 1
equalDOF 6 12 1
equalDOF 6 18 1
equalDOF 6 24 1

###########################
uniaxialMaterial Concrete01 $Ccover -24.e6 -0.002 -4.8e6 -0.005
uniaxialMaterial Concrete01 $Ccore -28.e6 -0.0024 -5.6e6 -0.015

uniaxialMaterial Steel02 $Rein 400e6 2.038e11 0.01 15 .925 .15

## Material For 23cm strut
uniaxialMaterial Concrete01 $Mkoloft -4.e6 -0.0014 -0.8e6 -0.0028 ;

##################################################

set np 7; # number of Gauss integration points for nonlinear curvature distribution

# $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag
element nonlinearBeamColumn 1 1 2 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 2 2 3 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 3 3 4 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 4 4 5 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 5 5 6 $np $ColumnSect $transftag ;#-mass .00001
element nonlinearBeamColumn 6 7 8 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 7 8 9 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 8 9 10 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 9 10 11 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 10 11 12 $np $ColumnSect $transftag ;#-mass .00001
element nonlinearBeamColumn 11 13 14 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 12 14 15 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 13 15 16 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 14 16 17 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 15 17 18 $np $ColumnSect $transftag ;#-mass .00001
element nonlinearBeamColumn 16 19 20 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 17 20 21 $np $ColumnSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 18 21 22 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 19 22 23 $np $ColumnSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 20 23 24 $np $ColumnSect $transftag ;#-mass .00001


element nonlinearBeamColumn 21 2 8 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 22 3 9 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 23 4 10 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 24 5 11 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 25 6 12 $np $BeamSect $transftag ;#-mass .00001
element nonlinearBeamColumn 26 8 14 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 27 9 15 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 28 10 16 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 29 11 17 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 30 12 18 $np $BeamSect $transftag ;#-mass .00001
element nonlinearBeamColumn 31 14 20 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 32 15 21 $np $BeamSecf $transftag ;#-mass .00001
element nonlinearBeamColumn 33 16 22 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 34 17 23 $np $BeamSecs $transftag ;#-mass .00001
element nonlinearBeamColumn 35 18 24 $np $BeamSect $transftag ;#-mass .00001




#element corotTruss 36 2 7 $MSec
element corotTruss 37 3 8 $MSec
element corotTruss 38 4 9 $MSec
element corotTruss 39 5 10 $MSec
element corotTruss 40 6 11 $MSec

#################
#element corotTruss 41 8 13 $MSec
#element corotTruss 42 9 14 $MSec
#element corotTruss 43 10 15 $MSec
#element corotTruss 44 11 16 $MSec
#element corotTruss 45 12 17 $MSec
#
#############
#element corotTruss 46 14 19 $MSec
element corotTruss 47 15 20 $MSec
element corotTruss 48 16 21 $MSec
element corotTruss 49 17 22 $MSec
element corotTruss 50 18 23 $MSec

**********************************************
set IDctrlNode 6
set IDctrlDOF 1
set Dmax 0.65
set Dincr .001

pattern Plain 2 Linear {
load 2 3409.4 0. 0.
load 3 6329.2 0. 0.
load 4 9257.7 0. 0.
load 5 12177.5 0. 0.
load 6 12147.2 0. 0.

}


########################################3
#Push


onstraints Plain
numberer RCM
system BandGeneral
set Tol 1.e-6
set maxNumIter 100
set printFlag 0
set TestType NormDispIncr
test $TestType $Tol $maxNumIter $printFlag
set algorithmType KrylovNewton
algorithm $algorithmType
integrator DisplacementControl $IDctrlNode $IDctrlDOF $Dincr
analysis Static

set Nsteps [expr int($Dmax/$Dincr)]; # number of pushover analysis steps
set ok [analyze $Nsteps];

*************************************************
*************************************************
--------------------------------------------------
WARNING - ForceBeamColumn2d:update - failed to get compatible element forces & deformations for element: 2<dw:<< 374192>
WARNING - ForceBeamColumn2d:update - failed to get compatible element forces & deformations for element: 3<dw:<<0.00546918>
WARNING - ForceBeamColumn2d:update - failed to get compatible element forces & deformations for element: 6<dw:<< 90932.8>
WARNING - ForceBeamColumn2d:update - failed to get compatible element forces & deformations for element: 20<dw:<< -1.411509e-005>
WARNING - ForceBeamColumn2d:update - failed to get compatible element forces & deformations for element: 31<dw:<< 675675>
Domain :: update - domain failed in update
DisplacementControl::update - model failed to update for new du
WARNING AccelerationNewton::solveCurrentStep<> - the integrator failed in update<>

StaticAnalysis::Analyze <> - the algorithm failed at iteration:0 with domain at load factor 224.336
Opensees > analyze failed , returned :-3 error flag
--------------------------------------------------



I really appreciate if anybody could help me to solve this.
Thank you very much!

[fmk]

i suggest you replace this
set ok [analyze $Nsteps];

with a bunch of lines that try differnt options if the analysis fails. nonlinear analysis does not always converge. if it fails try other things.
i suuggest you look at the last 1/3 of this presentation.

http://opensees.berkeley.edu/OpenSees/w ... alysis.pdf

[meopensees]

Hi.I have the same problem.I have a 7-story concrete frame(2D) and i want to do pushover analysis but whatever i do i face convergence problems . i've tested different analysis parameters and i have changed # of steps and it hasn't worked yet.and i have used FBE and DBE elements and both have convergence problems.Could you please help me with this one?

[fmk]

no. but i suggest you look at your section and material definitions. models with well-bahaved sections do not typically fail.