a small model

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im_pce
Posts: 27
Joined: Fri Feb 01, 2008 8:58 pm
Location: USA

a small model

Post by im_pce »

Hi,

I modeled a simple 2D structure. 7 elements are truss and 2 elements are column. I'm trying to do nonlinear time history analysis, but when I run the script, this error message appears;

WARNING BandGenLinLapackSolver::solve<> -LAPACK routine returned 3
WARNING NewtonRaphson::solveCurrentStep<> -the LinearSysOfEqn failed in solve<>
DirectIntegrationAnalysis::analyze<> - the Algorithm failed at time 0.01
OpenSees > analyze failed, returned: -3 error flag
-3

Here is my script. Would you please help me. Thank you very much.

# Units: Kgf,m,sec
wipe
model BasicBuilder -ndm 2 -ndf 3
# nodal coordinates:
node 1 -2 3
node 2 0 3
node 3 2 3
node 4 -1 5
node 5 1 5
node 6 -2 0
node 7 2 0
#-------------------------
fix 6 1 1 1
fix 7 1 1 1
#--------------------------------------------
# Define Node Mass #
#mass nodtag mx my mz
mass 1 10 0 0
mass 2 10 0 0
mass 3 10 0 0
mass 4 50 0 0
mass 5 50 0 0
mass 6 50 0 0
mass 7 50 0 0
#--------------------------------------------
# tag fy E b
uniaxialMaterial Steel01 1 2400E4 2E10 0.02
#------------------------------------------------
# tag node1 node2 A matID
element truss 1 1 2 5E-4 1
element truss 2 2 3 5E-4 1
element truss 3 4 5 5E-4 1
element truss 4 1 4 5E-4 1
element truss 5 2 5 5E-4 1
element truss 6 2 4 5E-4 1
element truss 7 3 5 5E-4 1
# ------------------ Column Member----------------------- #
geomTransf Linear 1
section Uniaxial 1 1 P
# tag I J numIntgrPts sec transf
element nonlinearBeamColumn 8 1 6 5 1 1
element nonlinearBeamColumn 9 3 7 5 1 1
#-------------------------------------------------------
rayleigh 0.31441 0 0.00281 0
# --------------------------------------------- #
# Time-history Load:
set accelSeries "Series -dt 0.02 -filePath north.acc -factor 9.81"; #Northridge Record
pattern UniformExcitation 2 1 -accel $accelSeries
# --------------------------------------------- #
recorder Node -file node5.out -node 5 -time -dof 1 2 3 disp
# --------------------------------------------- #
wipeAnalysis
constraints Transformation
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-8 30
algorithm Newton
integrator Newmark 0.5 0.25
analysis Transient
analyze 3998 0.01

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

Post by silvia »

please make sure you have enough constraints, and compare the analysis to those in the examples manual.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
im_pce
Posts: 27
Joined: Fri Feb 01, 2008 8:58 pm
Location: USA

Post by im_pce »

Dear Dr.silvia

I checked the model again, but opensees gives those messages. :(
If you look the model with OSP, you will observe that node 6 & node 7 constrained.
Would you please help me? :cry:
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

i don't use OSP and it may be outdated.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

okey, i looked it over.
interesting situation here.

when you have only truss elements at nodes when ndf=3, you have these dofs that are totally unrestrained.
i have never done this before, so this is interesting.
you can do one of the following:
1. keep one model builder for ease of everything, and constrain the rotational dof at nodes 2, 4, 5 (fix 2 0 0 1, etc)
2. use one model builder for the truss system, and another for the beam-column system.

i'd do 1.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
im_pce
Posts: 27
Joined: Fri Feb 01, 2008 8:58 pm
Location: USA

Post by im_pce »

Dear silvia,

First of all, thank you for your consideration, but below problems bring up:

1.why do you constrain only nodes 2,4,5 ?
2.when we constrain the rotational dof at only nodes 2, 4, 5, the support nodes (6,7) are unconstrained, so the all outputs(forces,displacements) are zero in dynamic analysis.
3.if we use one model builder for the truss system, and another for the beam-column system in one script,

model BasicBuilder -ndm 2 -ndf 3
model BasicBuilder -ndm 2 -ndf 2

opensees gives this message:
WARNING NDM=2 and NDF=2is imcompatible with available frame elements.
Is it possible that we use two model builder in one script? if so, how?

Dr.Silvia, would you please tell your opinions?

Thank you.
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

you also constrain the other nodes, of course.
for the frame elements you need to use ndf=3 for sure.
fist you use ndf=2 and define the trusses and nodes, then you use ndf=3 and define the frame elements and their nodes, then you connect the nodes.
as i said do the first option, constrain the frame dofs and ALSO contrain the extra dof where only trusses are connected.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
im_pce
Posts: 27
Joined: Fri Feb 01, 2008 8:58 pm
Location: USA

Post by im_pce »

OK, I put two nodes at the same location for participant nodes of truss and column (nodes 1,3)

node 1 -2 3
node 2 0 3
node 3 2 3
node 4 -1 5
node 5 1 5
node 6 -2 0
node 7 2 0
node 11 -2 3
node 33 2 3
#-------------------------
fix 1 0 0 1
fix 2 0 0 1
fix 3 0 0 1
fix 4 0 0 1
fix 5 0 0 1
fix 6 1 1 1
fix 7 1 1 1
fix 11 0 0 0
fix 33 0 0 0

after run opensees dosn't give error message :)

I think this was an interesting experience!
im_pce
Posts: 27
Joined: Fri Feb 01, 2008 8:58 pm
Location: USA

Post by im_pce »

Hi all

I modeled this structure (2D) with "nonlinearBeamColumn element" instead of "truss element" and I used equalDOF to release of the moments at the ends of elements with the exception of columns.
But when I run the script, this error message appears;

WARNING BandGenLinLapackSolver::solve() -LAPACK routine returned 1
WARNING NewtonRaphson::solveCurrentStep() -the LinearSysOfEqn failed in solve()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 0.01
OpenSees > analyze failed, returned: -3 error flag
-3
Here is my script;

# Units: Kgf,m,sec
wipe
model BasicBuilder -ndm 2 -ndf 3
# nodal coordinates:
node 1 -2 3
node 2 0 3
node 3 2 3
node 4 -1 5
node 5 1 5
node 6 -2 0
node 7 2 0
# --------------- Slave nodes -----------
#node 1:
node 11 -2 3
node 21 -2 3
#
#node 2:
node 12 0 3
node 22 0 3
node 32 0 3
#
#node 3:
node 13 2 3
node 23 2 3
#
#node 4:
node 14 -1 5
node 24 -1 5
#
#node 5:
node 15 1 5
node 25 1 5
#--------------------------
# release of the moments at the ends of elements
equalDOF 1 11 1 2
equalDOF 1 21 1 2
equalDOF 2 12 1 2
equalDOF 2 22 1 2
equalDOF 2 32 1 2
equalDOF 3 13 1 2
equalDOF 3 23 1 2
equalDOF 4 14 1 2
equalDOF 4 24 1 2
equalDOF 5 15 1 2
equalDOF 5 25 1 2
#----------------------------
fix 6 1 1 1
fix 7 1 1 1
#--------------------------------------------
# Define Node Mass #
#mass nodtag mx my mz
mass 1 10 10 10
mass 2 10 10 10
mass 3 10 10 10
mass 4 50 50 50
mass 5 50 50 50
mass 6 50 50 50
mass 7 50 50 50
#--------------------------------------------
# tag fy E b
uniaxialMaterial Steel01 1 2400E4 2E10 0.02
#------------------------------------------------
geomTransf Linear 1
section Uniaxial 2 1 P
# tag I J numIntgrPts sec transf
element nonlinearBeamColumn 1 21 2 5 2 1
element nonlinearBeamColumn 2 12 23 5 2 1
element nonlinearBeamColumn 3 4 5 5 2 1
element nonlinearBeamColumn 4 11 14 5 2 1
element nonlinearBeamColumn 5 22 5 5 2 1
element nonlinearBeamColumn 6 32 24 5 2 1
element nonlinearBeamColumn 7 13 15 5 2 1
element nonlinearBeamColumn 8 1 6 5 2 1
element nonlinearBeamColumn 9 3 7 5 2 1
#-------------------------------------------------------
rayleigh 0.31441 0 0.00281 0
# --------------------------------------------- #
# Time-history Load:
set accelSeries "Series -dt 0.02 -filePath north.acc -factor 9.81"; #Northridge Record
pattern UniformExcitation 2 1 -accel $accelSeries
# --------------------------------------------- #
recorder Node -file node1ttt.out -node 1 -time -dof 1 2 3 disp
# --------------------------------------------- #
wipeAnalysis
constraints Transformation
numberer RCM
system BandGeneral
test NormDispIncr 1.0e-8 30
algorithm Newton
integrator Newmark 0.5 0.25
analysis Transient
analyze 2000 0.01
#-------------------FINISH-------------------------------------------------

Would you please help me?
also, I modeled a 3D structure that used equalDOF to release of the moments at the ends of all elements with the exception of columns.when I run the script the same error message appears!
here is a part of my script:

node 1 3 0 0
node 101 3 0 0
.
.
.

# rNode cNode Dx Dy Dz
equalDOF 1 101 1 2 3
.
.
.
BUT WHEN I USED :
# rNode cNode Dx Dy Dz Rx Ry
equalDOF 1 101 1 2 3 4 5

THE ERROR MESSAGE DOES NOT appear! Is it correct that for release of the moments at the ends of elements Rx & Ry was constrained??


Thank you in advance for your time and consideration.
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

please look it over carefully, your system is not fully constrained.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
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