a weird problem in modeling of 3d truss

[SadeghSalimian]

I tried to model a 3D truss structure by opensees. the model was simple and analysis method was linear. in fact the model was a 3D truss with linear behavior. unfortunately i faced with a unreasonable error message. I already modeled 2d trusses and was acquainted with truss modeling . but in this case I tried a lot to understand what was the problem and I found if I use an elastic beam element with insignificant flexural stiffness rather than truss element the analysis will be performed correctly . but as I used this model for optimization use of other element is inefficient in terms of performance. I really need your help to solve this problem and go on my project. it is worth mentioning that the if I model the truss as 2d Model it will be analyzed.


My Model


#=======================================================
# Model Name is: Kharpa2D.xlsx
wipe
#=======================================================
#=======================================================
# the Definition of the the Structure Model Dimension
model BasicBuilder -ndm 3 -ndf 6
#=======================================================
#=======================================================
# the Definition of the Nodes of the Structure Model
node 1 -450.000 0.000 0.000
fix 1 0 0 0 1 1 1
node 2 -150.000 0.000 0.000
fix 2 0 0 0 1 1 1
node 3 150.000 0.000 0.000
fix 3 0 0 0 1 1 1
node 4 450.000 0.000 0.000
fix 4 0 0 0 1 1 1
node 5 -300.000 0.000 300.000
fix 5 0 0 0 1 1 1
node 6 0.000 0.000 300.000
fix 6 0 0 0 1 1 1
node 7 300.000 0.000 300.000
fix 7 0 0 0 1 1 1
#=======================================================

#=======================================================
# the Definition of the Supports of the Structure Model
fix 1 1 1 1 0 0 0
fix 4 1 1 1 0 0 0
#=======================================================
#=======================================================
# The Material Defination
uniaxialMaterial Elastic 1 2000000.00
#=======================================================
# The Elements Defination
#=======================================================
element truss 1 1 2 33.175 1
element truss 2 2 3 33.175 1
element truss 3 3 4 33.175 1
element truss 4 5 6 33.175 1
element truss 5 6 7 33.175 1
element truss 6 1 5 33.175 1
element truss 7 2 6 33.175 1
element truss 8 3 7 33.175 1
element truss 9 2 5 33.175 1
element truss 10 3 6 33.175 1
element truss 11 4 7 33.175 1
#=======================================================
# the Definition of a linear Time Series
timeSeries Linear 1
#=======================================================
#=======================================================
# The DEAD Load Defination
pattern Plain 1 1 {
load 5 0.0000 0.0000 -4500.0000 0.0000 0.0000 0.0000
load 6 0.0000 0.0000 -9000.0000 0.0000 0.0000 0.0000
load 7 0.0000 0.0000 -4500.0000 0.0000 0.0000 0.0000
}
#=======================================================
recorder Node -file NodesDisplacement-DEAD.out -time -node 1 2 3 4 5 6 7 -dof 1 2 3 disp
recorder Element -file ElementAxialForce-DEAD.out -time -ele 1 2 3 4 5 6 7 8 9 10 11 axialForce
#=======================================================
# the Definition of the Analysis
# Type: Static
constraints Plain
numberer RCM
system BandGeneral
test NormDispIncr 1E-7 10
algorithm Linear
integrator LoadControl 1
analysis Static
analyze 1
#=======================================================
# Removing of the Analysis and recorders Objects
wipeAnalysis
remove recorders
setTime 0.0
remove loadPattern 1
#=======================================================
# The Live Load Defination
pattern Plain 2 1 {
load 5 0.0000 0.0000 -3000.0000 0.0000 0.0000 0.0000
load 6 0.0000 0.0000 -6000.0000 0.0000 0.0000 0.0000
load 7 0.0000 0.0000 -3000.0000 0.0000 0.0000 0.0000
}
#=======================================================
recorder Node -file NodesDisplacement-Live.out -time -node 1 2 3 4 5 6 7 -dof 1 2 3 disp
recorder Element -file ElementAxialForce-Live.out -time -ele 1 2 3 4 5 6 7 8 9 10 11 axialForce
#=======================================================
# the Definition of the Analysis
# Type: Static
constraints Plain
numberer RCM
system BandGeneral
test NormDispIncr 1E-7 10
algorithm Linear
integrator LoadControl 1
analysis Static
analyze 1
#=======================================================
# Removing of the Analysis and recorders Objects
wipeAnalysis
remove recorders
setTime 0.0
remove loadPattern 2
#=======================================================
# The Eq Load Defination
pattern Plain 3 1 {
load 5 3000.0000 0.0000 0.0000 0.0000 0.0000 0.0000
load 6 3000.0000 0.0000 0.0000 0.0000 0.0000 0.0000
load 7 3000.0000 0.0000 0.0000 0.0000 0.0000 0.0000
}
#=======================================================
recorder Node -file NodesDisplacement-Eq.out -time -node 1 2 3 4 5 6 7 -dof 1 2 3 disp
recorder Element -file ElementAxialForce-Eq.out -time -ele 1 2 3 4 5 6 7 8 9 10 11 axialForce
#=======================================================
# the Definition of the Analysis
# Type: Static
constraints Plain
numberer RCM
system BandGeneral
test NormDispIncr 1E-7 10
algorithm Linear
integrator LoadControl 1
analysis Static
analyze 1
#=======================================================
# Removing of the Analysis and recorders Objects
wipeAnalysis
remove recorders
setTime 0.0
remove loadPattern 3

[selimgunay]

Did you make sure that your truss is stable?