The models with rigid zones

Forum for OpenSees users to post questions, comments, etc. on the use of the OpenSees interpreter, OpenSees.exe

Moderators: silvia, selimgunay, Moderators

Post Reply
Rocky
Posts: 38
Joined: Tue May 17, 2005 7:57 pm
Location: IEM

The models with rigid zones

Post by Rocky »

I recently built two frame models with concentrated plasticity represented by one zeroLengthSection element at each end. The rigid zone are simulated by several elastic elements with a common joint. One model is one story, it runs ok! However, when the model is extended to 2 stories, something strange happen. Because no explicit reason is given, I cannot locate the problem. I would appreciate if anyone could give me any instruction.

Listed below are source codes of the two models:
Model 1 (One story successful!)
-----------------------------------------------------------
model BasicBuilder -ndm 2 -ndf 3
node 1 0.0 0.0
node 101 0.0 0.0
node 2 2250.0 0.0
node 201 2250.0 0.0
node 3 0.0 1000.0
node 31 0.0 950.0
node 311 0.0 950.0
node 33 50.0 1000.0
node 4 2250.0 1000.0
node 41 2250.0 950.0
node 411 2250.0 950.0
node 43 2200.0 1000.0

fix 1 1 1 1
fix 101 1 1 0
fix 2 1 1 1
fix 201 1 1 0

equalDOF 31 311 1 2
equalDOF 41 411 1 2

uniaxialMaterial Steel01 1 1.0e5 1.0e13 1.0e-11
section Uniaxial 1 1 Mz

geomTransf Corotational 1

element elasticBeamColumn 1 101 311 373.76 2.05e5 212614.6 1
element elasticBeamColumn 2 201 411 373.76 2.05e5 212614.6 1

element elasticBeamColumn 11 31 3 373.76 2.05e5 212614.6 1
element elasticBeamColumn 12 41 4 373.76 2.05e5 212614.6 1

element elasticBeamColumn 21 33 43 3156.0 2.05e5 667724.0 1

element elasticBeamColumn 31 3 33 3156.0 2.05e5 667724.0 1
element elasticBeamColumn 32 43 4 3156.0 2.05e5 667724.0 1

element zeroLengthSection 51 1 101 1
element zeroLengthSection 52 2 201 1
element zeroLengthSection 53 311 31 1
element zeroLengthSection 54 411 41 1

pattern Plain 1 "Linear" {
load 3 0.0 -3750.0 0.0
load 4 0.0 -3750.0 0.0
}

mass 3 1.0 1.0 0.0
mass 4 1.0 1.0 0.0

set a [eigen 1]
puts "Period = [expr 2*3.1415926/sqrt([lindex $a 0])]"

recorder display PlanerFrames 480 0 960 640 -wipe
prp 360000 200000 3000000
vup 0 1 0
display 1 -1 10

system SparseGeneral -piv
numberer RCM
constraints Transformation
integrator LoadControl 0.1
test EnergyIncr 1.0e-8 1000
algorithm Newton
analysis Static
analyze 10
puts "Gravity load analysis completed"
loadConst -time 0.0

pattern Plain 2 "Linear" {
load 3 1.0 0.0 0.0
}

integrator DisplacementControl 3 1 0.01

recorder Node -file node3v.txt -time -node 3 4 -dof 2 disp
recorder Node -file node3h.txt -time -node 3 6 -dof 1 disp
recorder plot node3h.txt "Response" 0 0 480 400 -columns 2 1

analyze 1000
-----------------------------------------------------------
Model 2 (Two story failed)
-----------------------------------------------------------
model BasicBuilder -ndm 2 -ndf 3
node 1 0.0 0.0
node 101 0.0 0.0
node 2 2250.0 0.0
node 201 2250.0 0.0
node 3 0.0 1000.0
node 31 0.0 950.0
node 311 0.0 950.0
node 32 0.0 1050.0
node 321 0.0 1050.0
node 33 50.0 1000.0
node 4 2250.0 1000.0
node 41 2250.0 950.0
node 411 2250.0 950.0
node 42 2250.0 1050.0
node 421 2250.0 1050.0
node 43 2200.0 1000.0
node 5 0.0 2000.0
node 51 0.0 1950.0
node 511 0.0 1950.0
node 53 50.0 2000.0
node 6 2250.0 2000.0
node 61 2250.0 1950.0
node 611 2250.0 1950.0
node 63 2200.0 2000.0

fix 1 1 1 1
fix 101 1 1 0
fix 2 1 1 1
fix 201 1 1 0

equalDOF 31 311 1 2
equalDOF 41 411 1 2
equalDOF 32 321 1 2
equalDOF 42 421 1 2
equalDOF 51 511 1 2
equalDOF 61 611 1 2

uniaxialMaterial Steel01 1 1.0e5 1.0e13 1.0e-11
section Uniaxial 1 1 Mz

geomTransf Corotational 1

element elasticBeamColumn 1 101 311 373.76 2.05e5 212614.6 1
element elasticBeamColumn 2 201 411 373.76 2.05e5 212614.6 1
element elasticBeamColumn 3 321 511 373.76 2.05e5 212614.6 1
element elasticBeamColumn 4 421 611 373.76 2.05e5 212614.6 1

element elasticBeamColumn 11 31 3 373.76 2.05e5 212614.6 1
element elasticBeamColumn 12 41 4 373.76 2.05e5 212614.6 1
element elasticBeamColumn 13 3 32 373.76 2.05e5 212614.6 1
element elasticBeamColumn 14 4 42 373.76 2.05e5 212614.6 1
element elasticBeamColumn 15 51 5 373.76 2.05e5 212614.6 1
element elasticBeamColumn 16 61 6 373.76 2.05e5 212614.6 1

element elasticBeamColumn 21 33 43 3156.0 2.05e5 667724.0 1
element elasticBeamColumn 22 53 63 3156.0 2.05e5 667724.0 1

element elasticBeamColumn 31 3 33 3156.0 2.05e5 667724.0 1
element elasticBeamColumn 32 43 4 3156.0 2.05e5 667724.0 1
element elasticBeamColumn 33 5 53 3156.0 2.05e5 667724.0 1
element elasticBeamColumn 34 63 6 3156.0 2.05e5 667724.0 1

element zeroLengthSection 51 1 101 1
element zeroLengthSection 52 2 201 1
element zeroLengthSection 53 311 31 1
element zeroLengthSection 54 411 41 1
element zeroLengthSection 55 32 321 1
element zeroLengthSection 56 42 421 1
element zeroLengthSection 57 511 51 1
element zeroLengthSection 58 611 61 1

pattern Plain 1 "Linear" {
load 3 0.0 -3750.0 0.0
load 4 0.0 -3750.0 0.0
load 5 0.0 -3750.0 0.0
load 6 0.0 -3750.0 0.0
}

mass 3 1.0 1.0 0.0
mass 4 1.0 1.0 0.0
mass 5 1.0 1.0 0.0
mass 6 1.0 1.0 0.0

set a [eigen 1]
puts "Period = [expr 2*3.1415926/sqrt([lindex $a 0])]"

recorder display PlanerFrames 480 0 480 320 -wipe
prp 360000 200000 3000000
vup 0 1 0
display 1 -1 10

system SparseGeneral -piv
numberer RCM
constraints Transformation
integrator LoadControl 0.1
test EnergyIncr 1.0e-8 1000
algorithm Newton
analysis Static
analyze 10
puts "Gravity load analysis completed"
loadConst -time 0.0

pattern Plain 2 "Linear" {
load 3 1.0 0.0 0.0
load 5 1.0 0.0 0.0
}

integrator DisplacementControl 3 1 0.01

recorder Node -file node3h.txt -time -node 3 6 -dof 1 disp
recorder Node -file node3v.txt -time -node 3 4 -dof 2 disp
recorder plot node3h.txt "Response" 0 0 480 400 -columns 2 1

analyze 1000
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

you should use the rigid links in the geometric transformation.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
Post Reply