converge in static analyze

[engnomran]

Hello every body
I have a problem about converge in static analyze.
I model a isolator(Flat slider bearing) in opensees but static analyze not be converge.
What can I do for converge?
Please,You say several offer to me for converge in static analyze.
thanks

[fmk]

if you take out the isolator does it converge? depending on the isolator, you may need to fix the dof of the isolator and then remove the constraints after the gravity analysis to get some axial force into the isolator so it has some frictional resistance.

[engnomran]

I model a bridge with isolator.
I delete comments relate to isolator but not be converge.
I change comments in static analyze but but not be converge.

###############################################################################
# STATIC ANALYSIS #
###############################################################################
wipeAnalysis ; #
constraints Transformation ; #
numberer RCM ; #
system UmfPack
test NormDispIncr 1.0e-8 100
algorithm Newton #
integrator LoadControl 0.01 ; #
analysis Static ; #
analyze 100 ; #
###############################################################################
loadConst -time 0.0 ; #
###############################################################################


#============isolators================================================================================
uniaxialMaterial Elastic 10 434336528.49
uniaxialMaterial Elastic 20 0.0
frictionModel Coulomb 55 0.1
element flatSliderBearing 32 5 41 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 33 6 42 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 34 7 43 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 35 8 44 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 36 20 45 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 37 21 46 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 38 22 47 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0
element flatSliderBearing 39 23 48 55 4.2e6 -P 10 -T 20 -My 20 -Mz 20 -orient 1 0 0

[fmk]

if bridge does not converge without isolator and some fixed boundary conditions in their place your first problem lies with the bridge model

[engnomran]

thank you
I fix the dof of the isolator and then my model be converge.
2 question:
1)please, you more explain about be relate dof isolator and be converge.
2)But how am I remove the constraints after the gravity analysis?
Which one command with?
Is it correct?
All nodes of bottom isolators are fix.

Nodes of top isolators are be fix for model be converge.
Nodes of top isolators:
fix 41 1 1 1 1 1 1
fix 42 1 1 1 1 1 1
fix 43 1 1 1 1 1 1
fix 44 1 1 1 1 1 1
fix 45 1 1 1 1 1 1
fix 46 1 1 1 1 1 1
fix 47 1 1 1 1 1 1
fix 48 1 1 1 1 1 1
.
.
.
.
.
.
But after static analyze, I want remove x y z of isolators
remove sp 41 1
remove sp 41 2
remove sp 41 3

remove sp 42 1
remove sp 42 2
remove sp 42 3

remove sp 43 1
remove sp 43 2
remove sp 43 3

remove sp 44 1
remove sp 44 2
remove sp 44 3

remove sp 45 1
remove sp 45 2
remove sp 45 3

remove sp 46 1
remove sp 46 2
remove sp 46 3

remove sp 47 1
remove sp 47 2
remove sp 47 3

remove sp 48 1
remove sp 48 2
remove sp 48 3

But the program isnot correct

[Sunmin]

Im modeilng a cantilelver structure, a basement(by shell element), Leadrubber isolator.

I tried static analysis to put lateral load to the top of cantilever.

but ive got an error related to convergenceTest.

please check my tcl code and error

# Define model builder
# set up
wipe;
model basic -ndm 3 -ndf 6;
file mkdir Isolator;

# Define structure node
node 111 0. 0. 0.;
node 112 0. 0. [expr 36*$ft];

puts "node"

# Define nodal mass
mass 112 [expr 20*$kips] [expr 20*$kips] [expr 20*$kips] 0.0 0.0 0.0

puts "mass"


# Define fix command

fixZ [expr -10*$ft] 1 1 1 1 1 1;

puts "constraints"


# Define Geometric transformation
geomTransf Linear 1 0 1 0

puts "geometric Transfer"

# Define structure elements
set A1 [expr 25*$ft**2]
element elasticBeamColumn 50 111 112 $A1 $E $G $J [expr 52.083*$ft**4] [expr 52.083*$ft**4] 1

puts "structure element"

# Define basement node
node 1 [expr -10*$ft] [expr 10*$ft] [expr 0*$ft]
node 2 [expr 0*$ft] [expr 10*$ft] [expr 0*$ft]
node 3 [expr 10*$ft] [expr 10*$ft] [expr 0*$ft]
node 4 [expr -10*$ft] [expr 0*$ft] [expr 0*$ft]
node 5 [expr 0*$ft] [expr 0*$ft] [expr 0*$ft]
node 6 [expr 10*$ft] [expr 0*$ft] [expr 0*$ft]
node 7 [expr -10*$ft] [expr -10*$ft] [expr 0*$ft]
node 8 [expr 0*$ft] [expr -10*$ft] [expr 0*$ft]
node 9 [expr 10*$ft] [expr -10*$ft] [expr 0*$ft]

puts "basement"




# Redefine dimension and ndf
model basic -ndm 2 -ndf 3;

# Define section for basement shell element
# section Elastic $secTag $E $A $Iz <$Iy $G $J>
set A2 [expr 100*$ft**2]

section Elastic 101 $E $A2 [expr 833.33*$ft**4] [expr 52.083*$ft**4] $G $J

puts "section"


# Define basement element
# element ShellMITC4 $eleTag $iNode $jNode $kNode $lNode $secTag
element ShellMITC4 51 1 4 5 2 101
element ShellMITC4 52 2 5 6 3 101
element ShellMITC4 53 4 7 8 5 101
element ShellMITC4 54 5 8 9 6 101

puts "basement element"


# Combine Nodes
equalDOF 111 5 1 2 3 4 5 6

puts "equalDOF"


puts "recorder"

set g 9.810; # Acceleration due to gravity
set pi 3.14159; # Value of pi
set M [expr 2000*$kips]; # Mass of superstructure
#set G 0.450e+06; #Shear modulus of rubber obtained from testing of elastomeric bearings at large shear strains
set G1 0.870e+06; #This value was calculated from Kd=1080000 N/m as provided in the bearing
set K 2000e+06; #Bulk modulus of rubber
set ts 4.76e-03; #Thickness of steel shim plates
set tr 9.525e-03; # Thicness of a single rubber layer
set n 16; # Number of rubber layers
set D1 139.7e-03; #Internal diameter of lead rubber bearing
set D2 508e-03; #Outer diameter of lead rubber bearing
set tc 12.7e-03; #Bearing cover
set kc 20; #parameter for vertical cavitation
set PhiM 0.75; # Maximum damage index
set ac 1.0; # strength degradation parameter
set cd 128000; # viscous damping parameter
set sDratio 0.5; # shear distance ratio
set m 0.0; #mass of the bearing
#For heating effects in case of lead rubber bearings
set Fyl0 13.00e+06; #Yield stress of lead initially
set TL1 20; #Initial temperature in Fahrenheit
set qL 11200; #Density of lead in kg/m3
set cL 130; #Specific heat of lead in N-m/Kg oC
set kS 50; #thermal conductivity of steel m2/s
set aS 1.41e-05; #diffusitivity

#-------------------------------------------------------------------
#Derived Parameters
#-------------------------------------------------------------------

set A [expr ($pi/4)*(($D2)*($D2)-$D1*$D1)]; #Bonded area
set S [expr ($D2*$D2-$D1*$D1)/(4*$D2*$tr)]; #Shape factor
set Tr [expr $n*$tr]; #Total rubber thickness
set h [expr $Tr + ($n-1)*$ts]; #Total height of bearing
set r [expr $D2/$D1]; #outer to inner diameter ratio
set F [expr ($r*$r+1)/(($r-1)*($r-1)) + (1+$r)/((1-$r)*log($r))]; #diameter modification factor

#For horizontal motion
set uy_h 0.007; # Yield displacement of elastomeric bearing in horizontal direction
set Fy_h [expr $Fyl0*$pi*$D1*$D1/4]; # Yield strength of elastomeric bearing in horizontal direction
set k1 [expr $Fy_h/$uy_h]; #Elastic stiffness of bearing
set k2 [expr $G1*$A/$Tr]; #Post-yield stiffness of bearing
set Ccr [expr 2*sqrt(($k2)*$M)]; #Critical damping
set DampingRatio [expr $cd/$Ccr]; #Damping in the elastomeric bearing
#puts "Damping ratio is $DampingRatio"

#For vertical motion
set Ec [expr 1.0/((1.0/(6.0*$G1*$S*$S*$F))+(4.0/(3.0*$K)))]; #Compressive modulus of elastomeric bearing
set Ev [expr 3*$G1]; #Elastic modulus
set I [expr ($pi/64)*(($D2)**4-$D1**4)]; #Moment of inertia of bearing
set r [expr sqrt($I/$A)]; #Radius of gyration
set Kpre [expr $A*$Ec/$Tr ]; #Pre-cavitation stiffness in Tension
set Kpost [expr $A*$E/$Tr ]; #Post-cavitation stiffness in Tension
set Fc [expr 3*$G1*$A]; #Cavitation force
set uc [expr $Fc/$Kpre ]; #Cavitation displacement
set Er [expr $Ec/3]; #Rotation modulus of bearing
set As [expr $A*$h/$Tr]; #Adjusted shear area of bearing
set Is [expr $I*$h/$Tr]; #Adjusted moment of intertia of bearing
set Pe [expr $pi*$pi*$Er*$Is/($h*$h)]; #Euler buckling load of bearing
set Pcr [expr -sqrt($Pe*$G1*$As)]; #Critical buckling load in compression
set ucr [expr $Pcr/$Kpre]; #Critical displacement in compression


#print parameters
# puts " G: $G, K, $K, A : $A, Tr: $Tr, h: $h, S: $S, F: $F"
# puts " Horizontal motion: k1: $k1, k2: $k2, Fy_h: $Fy_h"
# puts " Vertical motion: Ec: $Ec, E: $E, r: $r, Kpre: $Kpre, Kpost: $Kpost, Fc: $Fc, uc: $uc, Pcr: $Pcr, ucr: $ucr"
#---------------------------------------------------------------------------------------------
#Start of model generation
#---------------------------------------------------------------------------------------------

# Elastomeric bearing is modeled as 2 node and 3 DOF element of height h
#Create Model Builder
model basic -ndm 3 -ndf 6

# Create nodes
node 1111 0 0 0
node 2222 0 -$h 0.0

# Define single point constraints (Constrain the isolator against rotation at both nodes)

fix 2222 1 1 1 1 1 1

#Define material and element for elastomeric bearings

#element elastomericBearing $eleTag $iNode $jNode $ke $fy $alpha -P $matTag -Mz $matTag <-orient $x1 $x2 $x3 $y1 $y2 $y3> <-mass $m>
#element elastomericBearing 1 1 2 $k1 $Fy_h [expr $k2/$k1] -P 3 -T 3 -My 3 -Mz 3
element LeadRubberX 101 1111 2222 $Fyl0 $uy_h $G1 $K $D1 $D2 $ts $tr $n 0 1 0 1 0 0 $kc $PhiM $ac $sDratio $m $cd $tc $qL $cL $kS $aS



puts "LR isolator"

equalDOF 111 1111 1 2 3 4 5 6


# Define RECODERS
recorder Node -file Isolator/DISP_Structure.out -time -node 112 -dof 1 2 3 disp;
recorder Node -file Isolator/DISP_Isolator1.out -time -node 1111 -dof 1 2 3 disp
recorder Node -file Isolator/DISP_Isolator2.out -time -node 2222 -dof 1 2 3 disp

recorder display "Displaced shape" 10 10 500 500 -file
prp 800. 500. 1;
vup 0 0 1;
vpn -1 1 -1;
display 1 5 40


# Define Load
timeSeries Linear 1
pattern Plain 1 1 {
load 1111 [expr 20*$kips] 0. 0. 0. 0. 0. ; # node#, FX FY MZ -- superstructure-weight
}

system BandSPD;
constraints Transformation;
numberer RCM;
test NormDispIncr 1.0e-15 10 3;
algorithm Newton;
integrator LoadControl 1 ;
analysis Static
analyze 1000 0.1;


========================================================================================

This is the error

WARNING: CTestNormDispIncr::test() - failed to converge
after: 6 iterations
NewtnRaphson::solveCurrentStep() -the ConvergenceTest object failed in test()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at
load factor 1
OpenSees > analyze failed, returned: -3 error flag


thanks

[kamehdikhani]

hello are u from International Institute of Earthquake Engineering and Seismology in tehrannnn? i will be glad to help u , i am from tehran too, this is my gmail : k.mehdikhani@gmail.com , i think i can help u , send an email to me.