Beam column connection model not Convergent

[lkang6]

Hi Vesna,
I did static analysis on a beam column connection model using some springs and rigid link to connect the beam/column to the shear panel. The vertical analysis is successful, but the lateral force failes for convergency problem. Could you please take a look and check my model? Thank you so much!!

#create the ModelBuilder object
model BasicBuilder -ndm 2 -ndf 3
set dataDir Data_s2s3r1; # set up name of data directory
file mkdir $dataDir; # create data directory

#dimension set, in SI unit::m,kg,second
#column
set lcol 1.050; #the length of the column
set bc 0.120 ; #the width of the column
set dc 0.120 ; #the depth of the column
set tf 0.00346 ; #the thickness of the column flange
set tw 0.00346; #the thickness of the column web
puts "set column finished"
#beam
set lbeam 1.500; #the length of the beam
set db 0.160; #the depth of the H-beam
set bf 0.080; #the width of the flange
set tbf 0.00353; #the thickness of the H-beam flange
set tbw 0.00353; #the thickness of the H-beam web
set density 7800 ; #the density of the beam
set gravity [expr ($db*$bf-($bf-$tbw)*($db-2*$tbf))*$lbeam*$density*9.8/2] ;
puts "set beam finished"
#shear panel zone
set hz $db;
set bz $dc;

#nodes
node 1 [expr -$lbeam/2] 0
node 2 [expr -$lbeam/4] 0
node 3 [expr -$bz/2] 0
node 4 [expr $bz/2] 0
node 5 [expr $lbeam/4] 0
node 6 [expr $lbeam/2] 0
node 7 0 [expr -$lcol/2]
node 8 0 [expr -$hz/2]
node 9 0 [expr $hz/2]
node 10 0 [expr $lcol/2]
node 101 [expr -$bz/2] [expr -$hz/2]
node 102 [expr -$bz/2] [expr -$hz/2]
node 103 [expr -$bz/2] [expr $hz/2]
node 104 [expr -$bz/2] [expr $hz/2]
node 105 [expr -$bz/2] [expr $hz/2]
node 106 [expr -$bz/2] [expr $hz/2]
node 107 [expr $bz/2] [expr $hz/2]
node 108 [expr $bz/2] [expr $hz/2]
node 109 [expr $bz/2] [expr $hz/2]
node 110 [expr $bz/2] [expr $hz/2]
node 111 [expr $bz/2] [expr -$hz/2]
node 112 [expr $bz/2] [expr -$hz/2]
node 113 [expr $bz/2] [expr -$hz/2]
node 114 [expr $bz/2] [expr -$hz/2]
node 115 [expr -$bz/2] [expr -$hz/2]
node 116 [expr -$bz/2] [expr -$hz/2]
node 117 [expr -$bz/2] 0
node 118 0 [expr $hz/2]
node 119 [expr $bz/2] 0
node 120 0 [expr -$hz/2]

#element
#beam
geomTransf Linear 1
element elasticBeamColumn 1 1 2 1 1.0e9 1.0e10 1
element elasticBeamColumn 2 2 3 1 1.0e9 1.0e10 1
element elasticBeamColumn 3 4 5 1 1.0e9 1.0e10 1
element elasticBeamColumn 4 5 6 1 1.0e9 1.0e10 1
#column
geomTransf Linear 2
element elasticBeamColumn 5 7 8 1 2.0e9 2.0e10 2
element elasticBeamColumn 6 9 10 1 2.0e9 2.0e10 2
#rigid link in the connection
geomTransf Linear 3
element elasticBeamColumn 101 101 3 1 1.0e11 1.0e12 3
element elasticBeamColumn 102 102 117 1 1.0e11 1.0e12 3
element elasticBeamColumn 103 103 3 1 1.0e11 1.0e12 3
element elasticBeamColumn 104 104 117 1 1.0e11 1.0e12 3
element elasticBeamColumn 105 105 9 1 1.0e11 1.0e12 3
element elasticBeamColumn 106 106 118 1 1.0e11 1.0e12 3
element elasticBeamColumn 107 107 9 1 1.0e11 1.0e12 3
element elasticBeamColumn 108 108 118 1 1.0e11 1.0e12 3
element elasticBeamColumn 109 109 4 1 1.0e11 1.0e12 3
element elasticBeamColumn 110 110 119 1 1.0e11 1.0e12 3
element elasticBeamColumn 111 111 4 1 1.0e11 1.0e12 3
element elasticBeamColumn 112 112 119 1 1.0e11 1.0e12 3
element elasticBeamColumn 113 113 8 1 1.0e11 1.0e12 3
element elasticBeamColumn 114 114 120 1 1.0e11 1.0e12 3
element elasticBeamColumn 115 115 8 1 1.0e11 1.0e12 3
element elasticBeamColumn 116 116 120 1 1.0e11 1.0e12 3
#spring
#set Es200 1.0e12;
#set epsP200 0.5;
#set epsN200 0.5;
#uniaxialMaterial ElasticPP 200 $Es200 $epsP200 $epsN200
uniaxialMaterial Elastic 200 7.19e8
element zeroLength 201 101 102 -mat 200 -dir 1
element zeroLength 202 3 117 -mat 200 -dir 2
element zeroLength 203 103 104 -mat 200 -dir 1
element zeroLength 205 105 106 -mat 200 -dir 2
element zeroLength 206 9 118 -mat 200 -dir 1
element zeroLength 207 107 108 -mat 200 -dir 2
element zeroLength 209 109 110 -mat 200 -dir 1
element zeroLength 210 4 119 -mat 200 -dir 2
element zeroLength 211 111 112 -mat 200 -dir 1
element zeroLength 213 113 114 -mat 200 -dir 2
element zeroLength 214 8 120 -mat 200 -dir 1
element zeroLength 215 115 116 -mat 200 -dir 2
equalDOF 101 102 2
equalDOF 3 117 1
equalDOF 103 104 2
equalDOF 105 106 1
equalDOF 9 118 2
equalDOF 107 108 1
equalDOF 109 110 2
equalDOF 4 119 1
equalDOF 111 112 2
equalDOF 113 114 1
equalDOF 8 120 2
equalDOF 115 116 1

#shear panel
element zeroLength 300 108 110 -mat 200 -dir 6
equalDOF 102 116 1 2
equalDOF 104 106 1 2
equalDOF 108 110 1 2
equalDOF 112 114 1 2

#boundary conditions
fix 1 0 1 0
fix 6 0 1 0
fix 7 1 1 0

recorder Element -file $dataDir/GF.out -time -ele 1 2 3 4 5 6 globalForce;
recorder Element -file $dataDir/E300F.out -time -ele 300 force;
recorder Element -file $dataDir/E300D.out -time -ele 300 deformation;
recorder Element -file $dataDir/E201F.out -time -ele 201 force;
recorder Element -file $dataDir/E201D.out -time -ele 201 deformation;
recorder Node -file $dataDir/N7.out -time -node 7 -dof 1 2 3 reaction;

#load condition
pattern Plain 1 Linear {
load 2 0.0 -1.0e3 0.0
load 5 0.0 -1.0e3 0.0
#load 10 0.0 -2000 0.0
}

system BandGeneral
#constraints Plain # Plain constraints can not be used if there is MP constraint in the model
constraints Transformation
integrator LoadControl 0.1
test NormDispIncr 1e-5 5
algorithm Newton
numberer RCM
analysis Static
analyze 10
loadConst -time 0.0
puts "Vertical force done"

#lateral load
pattern Plain 2 Linear {
load 10 1.0 0.0 0.0
}
#integrator DisplacementControl 10 1 0.01
#analyze 5


set maxU 15.0; set dU 0.1
constraints Transformation
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-6 6 2
algorithm Newton
integrator DisplacementControl 10 1 $dU
analysis Static
set ok 0
set currentDisp 0.0
while {$ok == 0 && $currentDisp < $maxU} {
set ok [analyze 1]
if {$ok != 0} {
test NormDispIncr 1.0e-6 1000 1
algorithm ModifiedNewton –initial
set ok [analyze 1]
test NormDispIncr 1.0e-6 6 2
algorithm Newton
}
set currentDisp [nodeDisp 10 1]
}
puts "Lateral load done"

[lkang6]

Hi Vesna,
I found the problem. I should not use "equalDOF" between the two nodes that make a spring.

But, there is another problem:
if I the constraint is:
fix 1 0 1 0
fix 6 0 1 0
fix 7 1 1 1
It can work, and the results are right.
But if the constraint is:
fix 1 0 1 0
fix 6 0 1 0
fix 7 1 1 0
In lateral forca case, it can not converge.

Could you please take a look at my model and tell me why? Thank you!!

[vesna]

Would you send me (vesna AT berkeley DOT edu) a sketch of your model with all nodes and elements marked? Would you also post the version of the file that works for you?

[lkang6]

Hi Vesna,
Thank you for your reply!!
I found my problem. I should not use equalDOF between the two nodes that form a zerolength translational spring.

The model can work with beam and column as nonlinearbeamcolumn element type. If I use elastic element for spring, with displacement control, it can work and the result is right. While I use Bilin material for spring, it can work and gave all the results, but the displacement result at the control node is larger than what i defined.

The only difference between the two file is the material of the sping, which I think cause the problem. But I can not understand it and I don't know how to corrct the material.I sent the file to your Email. Could you please take a look and tell me why?