Pushover

[ftoledoj]

I recently download this example http://opensees.berkeley.edu/wiki/index ... _W-Section, I downloaded the fiber RC model and the push over, and it says it wont converge for certain points but completes te pushover, tis means heodelis wrong? i didnt chane anything .
Help Please

[fmk]

it's fine .. nonlinear analysis do not always converge .. most commercial codes high that fact and do stuff like cutting time step .. we don't .. in the script you have to try something different.

[ftoledoj]

Does the same applies to time history analysis where my model are fine cause i have checked them with static and modal analysis , but for some reason the analysis doesnt always converge, even when am using routines that are available in the wiki, i tried changing dampening the modes considered, the integrator and keep getting convergence problems.
thanks for the help

[fmk]

it is successfull if in the end you get as far as you want to go .. if you get errors along the way that is ok .. i

[yas]

hello every body
I,ve done a pushover analysis on a portal frame example but because of this message, it does,nt work
would you please help me to solve that?
I appreciate in advance.

my codes are:
wipe
model basic -ndm 2 -ndf 3;
#kips.ft
#############modeling
node 1 0 0
node 2 0 15
node 3 15 15
node 4 30 15
node 5 30 0
puts "ok"
fix 1 1 1 1
fix 5 1 1 1
#############material
#uniaxialMaterial Steel02 $matTag $Fy $E $b $R0 $cR2 $a1 $a2 $a3 $a4
uniaxialMaterial Steel02 1 7200 4176000 0.01 10 0.925 0.15
#############Geometric Transformation
geomTransf PDelta 1
#############section
section Fiber 1 { ;
patch quad 1 8 3 -0.041 0.0726 0.041 0.0726 0.041 0.08 -0.041 0.08
patch quad 1 3 8 -0.0025 -0.0726 0.0025 -0.0726 0.0025 0.0726 -0.0025 0.0726
patch quad 1 8 3 -0.041 -0.08 0.041 -0.08 0.041 -0.0726 -0.041 -0.0726 } ;
#############Element
#element nonlinearBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag
element nonlinearBeamColumn 1 1 2 5 1 1
element nonlinearBeamColumn 2 2 3 5 1 1
element nonlinearBeamColumn 3 3 4 5 1 1
element nonlinearBeamColumn 4 4 5 5 1 1
#################LOADING
set w 18.75
set b [expr 1.6*$w]
set d 25
set c [expr 1.2*$d]

pattern Plain 1 Constant {
load 3 0.0 -$c 0.0
}

pattern Plain 2 Linear {
load 2 $b 0.0 0.0
}

#################Recorder
#recorder Node <-file $fileName> <-xml $fileName> <-time> <-node ($node1 $node2)
recorder Node -file disp.out -time -node 2 -dof 1 disp

#recorder plot $fileName $windowTitle $xloc $yloc $xPixels $yPixels -columns $xCol0 $yCol0
recorder plot disp.out HorizentalDisp 0 0 500 500 -columns 2 1

##################Anaysis
constraints Plain
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-6 6
algorithm Newton
set peaks [ list 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 2.4 2.5 2.6 2.7 ]
for {set i 1} {$i <= 26} {incr i 1} {
set du [expr -1.0 * pow(-1.0,[expr $i-1])*[lindex $peaks[expr $i-1]]/100]
integrator DisplacementControl 2 1 $du
analysis Static
analyze 100
}
loadConst -time 0.0
puts "End Of Gravity Load Analyze"

####################display
recorder display DispShape 510 10 500 400
vup 0 1 0 #dirn defining up direction of view plane
vpn 0 0 1 #direction of outward normal to view plane
prp 2 1.5 10 #eye location in local coord sys defined by viewing system
display 1 5 1


and the warning is that:

missing operator at _@_
in expression "-1.0 * pow(-1.0,0)*0.2 _@_0.3 0.4 0.5 0.6 0.7 0...."
(parsing expression "-1.0 * pow(-1.0,0)*0.2...")
invoked from within
"expr -1.0 * pow(-1.0,[expr $i-1])*[lindex $peaks[expr $i-1]]/100"
("for" body line 2)
invoked from within
"for {set i 1} {$i <= 26} {incr i 1} {
set du [expr -1.0 * pow(-1.0,[expr $i-1])*[lindex $peaks[expr $i-1]]/100]
integrator DisplacementControl 2..."
(file "C:\Users\a\Desktop\example 1.tcl" line 57)

[Eli]

How can i draw pushover curve?
which recorders are need?

[fmk]

you want the force versus displacement. the applied force is the pseudoTime * $b
so all you need is a Node recoreder with the -time flag to get the pseudo time.

recorder Node -file res.out -time -node 2 -dof 1 disp