Eigen Analysis

[schoolstru]

Dear All
i have problem with eigen analysis command; it does not work for manual example of opensees example;
i apply the eigen analysis in the " OpenSees Example 7. 3D Frame, 3-story 3-bayX 3-bayZ, Reinforced-Concrete Section & Steel W-Section " in the following the code is put
# --------------------------------------------------------------------------------------------------
# Example 7. 3D RC Frame
# Silvia Mazzoni & Frank McKenna, 2006
# nonlinearBeamColumn element, inelastic fiber section
#

# SET UP ----------------------------------------------------------------------------
wipe; # clear memory of all past model definitions
model BasicBuilder -ndm 3 -ndf 6; # Define the model builder, ndm=#dimension, ndf=#dofs
set dataDir Data; # set up name of data directory -- remove
file mkdir $dataDir; # create data directory
file mkdir Modes;
set GMdir "../GMfiles"; # ground-motion file directory
set ViewScale 0.25; # scaling factor for viewing deformed shape, it depends on the dimensions of the model
source LibUnits.tcl; # define units
source DisplayPlane.tcl; # procedure for displaying a plane in model
source DisplayModel3D.tcl; # procedure for displaying 3D perspectives of model
source BuildRCrectSection.tcl; # procedure for definining RC fiber section

# define GEOMETRY -------------------------------------------------------------
# define structure-geometry paramters
set LCol [expr 12*$ft]; # column height (parallel to Y axis)
set LBeam [expr 20*$ft]; # beam length (parallel to X axis)
set LGird [expr 20*$ft]; # girder length (parallel to Z axis)

# ------ frame configuration
set NStory 3; # number of stories above ground level
set NBay 1; # number of bays in X direction
set NBayZ 1; # number of bays in Z direction
set numModes 12
puts "Number of Stories in Y: $NStory; Number of bays in X: $NBay; Number of bays in Z: $NBayZ"

# define NODAL COORDINATES
# calculate locations of beam/column intersections:
set X1 0.;
set X2 [expr $X1 + $LBeam];
set Y1 0.;
set Y2 [expr $Y1 + $LCol];
set Y3 [expr $Y2 + $LCol];
set Y4 [expr $Y3 + $LCol];
set Z1 0.0;
set Z2 [expr $Z1 + $LGird];

node 111 $X1 $Y1 $Z1; # frame 1
node 112 $X2 $Y1 $Z1;
node 121 $X1 $Y2 $Z1;
node 122 $X2 $Y2 $Z1;
node 131 $X1 $Y3 $Z1;
node 132 $X2 $Y3 $Z1;
node 141 $X1 $Y4 $Z1;
node 142 $X2 $Y4 $Z1;
node 211 $X1 $Y1 $Z2; # frame 2
node 212 $X2 $Y1 $Z2;
node 221 $X1 $Y2 $Z2;
node 222 $X2 $Y2 $Z2;
node 231 $X1 $Y3 $Z2;
node 232 $X2 $Y3 $Z2;
node 241 $X1 $Y4 $Z2;
node 242 $X2 $Y4 $Z2;


# define Rigid Floor Diaphragm
set RigidDiaphragm ON ; # options: ON, OFF. specify this before the analysis parameters are set the constraints are handled differently.
set Xa [expr ($X2+$X1)/2]; # mid-span coordinate for rigid diaphragm
set Za [expr ($Z2+$Z1)/2];
# rigid-diaphragm nodes in center of each diaphram
set RigidDiaphragm ON ; # this communicates to the analysis parameters that I will be using rigid diaphragms
node 1121 $Xa $Y2 $Za; # master nodes for rigid diaphragm -- story 2, bay 1, frame 1-2
node 1131 $Xa $Y3 $Za; # master nodes for rigid diaphragm -- story 3, bay 1, frame 1-2
node 1141 $Xa $Y4 $Za; # master nodes for rigid diaphragm -- story 4, bay 1, frame 1-2
# Constraints for rigid diaphragm master nodes
fix 1121 0 1 0 1 0 1
fix 1131 0 1 0 1 0 1
fix 1141 0 1 0 1 0 1
# ------------------------define Rigid Diaphram, dof 2 is normal to floor
set perpDirn 2;
rigidDiaphragm $perpDirn 1121 121 122 221 222; # level 2
rigidDiaphragm $perpDirn 1131 131 132 231 232; # level 3
rigidDiaphragm $perpDirn 1141 141 142 241 242; # level 4

# determine support nodes where ground motions are input, for multiple-support excitation
set iSupportNode "111 112 211 212"

# BOUNDARY CONDITIONS
fixY 0 1 1 1 1 1 1; # pin all Y=0.0 nodes

# calculated MODEL PARAMETERS, particular to this model
# Set up parameters that are particular to the model for displacement control
set IDctrlNode 141; # node where displacement is read for displacement control
set IDctrlDOF 1; # degree of freedom of displacement read for displacement control
set LBuilding [expr $Y4]; # total building height

# Define SECTIONS -------------------------------------------------------------
set SectionType FiberSection ; # options: Elastic FiberSection
#set SectionType Elastic ; # options: Elastic FiberSection

# define section tags:
set ColSecTag 1
set BeamSecTag 2
set GirdSecTag 3
set ColSecTagFiber 4
set BeamSecTagFiber 5
set GirdSecTagFiber 6
set SecTagTorsion 70

# Section Properties:
set HCol [expr 28*$in]; # square-Column width
set BCol $HCol
set HBeam [expr 24*$in]; # Beam depth -- perpendicular to bending axis
set BBeam [expr 18*$in]; # Beam width -- parallel to bending axis
set HGird [expr 24*$in]; # Girder depth -- perpendicular to bending axis
set BGird [expr 18*$in]; # Girder width -- parallel to bending axis

if {$SectionType == "Elastic"} {
# material properties:
set fc 4000*$psi; # concrete nominal compressive strength
set Ec [expr 57*$ksi*pow($fc/$psi,0.5)]; # concrete Young's Modulus
set nu 0.2; # Poisson's ratio
set Gc [expr $Ec/2./[expr 1+$nu]]; # Torsional stiffness Modulus
set J $Ubig; # set large torsional stiffness
# column section properties:
set AgCol [expr $HCol*$BCol]; # rectuangular-Column cross-sectional area
set IzCol [expr 0.5*1./12*$BCol*pow($HCol,3)]; # about-local-z Rect-Column gross moment of inertial
set IyCol [expr 0.5*1./12*$HCol*pow($BCol,3)]; # about-local-z Rect-Column gross moment of inertial
# beam sections:
set AgBeam [expr $HBeam*$BBeam]; # rectuangular-Beam cross-sectional area
set IzBeam [expr 0.5*1./12*$BBeam*pow($HBeam,3)]; # about-local-z Rect-Beam cracked moment of inertial
set IyBeam [expr 0.5*1./12*$HBeam*pow($BBeam,3)]; # about-local-y Rect-Beam cracked moment of inertial
# girder sections:
set AgGird [expr $HGird*$BGird]; # rectuangular-Girder cross-sectional area
set IzGird [expr 0.5*1./12*$BGird*pow($HGird,3)]; # about-local-z Rect-Girder cracked moment of inertial
set IyGird [expr 0.5*1./12*$HGird*pow($BGird,3)]; # about-local-y Rect-Girder cracked moment of inertial

section Elastic $ColSecTag $Ec $AgCol $IzCol $IyCol $Gc $J
section Elastic $BeamSecTag $Ec $AgBeam $IzBeam $IyBeam $Gc $J
section Elastic $GirdSecTag $Ec $AgGird $IzGird $IyGird $Gc $J

set IDconcCore 1; # material numbers for recorder (this stressstrain recorder will be blank, as this is an elastic section)
set IDSteel 2; # material numbers for recorder (this stressstrain recorder will be blank, as this is an elastic section)

} elseif {$SectionType == "FiberSection"} {
# MATERIAL parameters
source LibMaterialsRC.tcl; # define library of Reinforced-concrete Materials

# FIBER SECTION properties
# Column section geometry:
set cover [expr 2.5*$in]; # rectangular-RC-Column cover
set numBarsTopCol 8; # number of longitudinal-reinforcement bars on top layer
set numBarsBotCol 8; # number of longitudinal-reinforcement bars on bottom layer
set numBarsIntCol 6; # TOTAL number of reinforcing bars on the intermediate layers
set barAreaTopCol [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaBotCol [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaIntCol [expr 1.*$in*$in]; # longitudinal-reinforcement bar area

set numBarsTopBeam 6; # number of longitudinal-reinforcement bars on top layer
set numBarsBotBeam 6; # number of longitudinal-reinforcement bars on bottom layer
set numBarsIntBeam 2; # TOTAL number of reinforcing bars on the intermediate layers
set barAreaTopBeam [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaBotBeam [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaIntBeam [expr 1.*$in*$in]; # longitudinal-reinforcement bar area

set numBarsTopGird 6; # number of longitudinal-reinforcement bars on top layer
set numBarsBotGird 6; # number of longitudinal-reinforcement bars on bottom layer
set numBarsIntGird 2; # TOTAL number of reinforcing bars on the intermediate layers
set barAreaTopGird [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaBotGird [expr 1.*$in*$in]; # longitudinal-reinforcement bar area
set barAreaIntGird [expr 1.*$in*$in]; # longitudinal-reinforcement bar area

set nfCoreY 20; # number of fibers in the core patch in the y direction
set nfCoreZ 20; # number of fibers in the core patch in the z direction
set nfCoverY 20; # number of fibers in the cover patches with long sides in the y direction
set nfCoverZ 20; # number of fibers in the cover patches with long sides in the z direction
# rectangular section with one layer of steel evenly distributed around the perimeter and a confined core.
BuildRCrectSection $ColSecTagFiber $HCol $BCol $cover $cover $IDconcCore $IDconcCover $IDSteel $numBarsTopCol $barAreaTopCol $numBarsBotCol $barAreaBotCol $numBarsIntCol $barAreaIntCol $nfCoreY $nfCoreZ $nfCoverY $nfCoverZ
BuildRCrectSection $BeamSecTagFiber $HBeam $BBeam $cover $cover $IDconcCore $IDconcCover $IDSteel $numBarsTopBeam $barAreaTopBeam $numBarsBotBeam $barAreaBotBeam $numBarsIntBeam $barAreaIntBeam $nfCoreY $nfCoreZ $nfCoverY $nfCoverZ
BuildRCrectSection $GirdSecTagFiber $HGird $BGird $cover $cover $IDconcCore $IDconcCover $IDSteel $numBarsTopGird $barAreaTopGird $numBarsBotGird $barAreaBotGird $numBarsIntGird $barAreaIntGird $nfCoreY $nfCoreZ $nfCoverY $nfCoverZ

# assign torsional Stiffness for 3D Model
uniaxialMaterial Elastic $SecTagTorsion $Ubig
section Aggregator $ColSecTag $SecTagTorsion T -section $ColSecTagFiber
section Aggregator $BeamSecTag $SecTagTorsion T -section $BeamSecTagFiber
section Aggregator $GirdSecTag $SecTagTorsion T -section $GirdSecTagFiber
} else {
puts "No section has been defined"
return -1
}
set GammaConcrete [expr 150*$pcf]; # Reinforced-Concrete weight density (weight per volume)
set QdlCol [expr $GammaConcrete*$HCol*$BCol]; # self weight of Column, weight per length
set QBeam [expr $GammaConcrete*$HBeam*$BBeam]; # self weight of Beam, weight per length
set QGird [expr $GammaConcrete*$HGird*$BGird]; # self weight of Gird, weight per length

# define ELEMENTS -------------------------------------------------------
# set up geometric transformations of element
# separate columns and beams, in case of P-Delta analysis for columns
# in 3D model, assign vector vecxz
set IDColTransf 1; # all columns
set IDBeamTransf 2; # all beams
set IDGirdTransf 3; # all girders
set ColTransfType Linear ; # options, Linear PDelta Corotational
geomTransf $ColTransfType $IDColTransf 0 0 1 ; # only columns can have PDelta effects (gravity effects)
geomTransf Linear $IDBeamTransf 0 0 1
geomTransf Linear $IDGirdTransf 1 0 0

# Define Beam-Column Elements
set np 5; # number of Gauss integration points for nonlinear curvature distribution

# Frame 1
# columns
element nonlinearBeamColumn 1111 111 121 $np $ColSecTag $IDColTransf; # level 1-2
element nonlinearBeamColumn 1112 112 122 $np $ColSecTag $IDColTransf
element nonlinearBeamColumn 1121 121 131 $np $ColSecTag $IDColTransf; # level 2-3
element nonlinearBeamColumn 1122 122 132 $np $ColSecTag $IDColTransf
element nonlinearBeamColumn 1131 131 141 $np $ColSecTag $IDColTransf; # level 3-4
element nonlinearBeamColumn 1132 132 142 $np $ColSecTag $IDColTransf
# beams
element nonlinearBeamColumn 1221 121 122 $np $BeamSecTag $IDBeamTransf; # level 2
element nonlinearBeamColumn 1231 131 132 $np $BeamSecTag $IDBeamTransf; # level 3
element nonlinearBeamColumn 1241 141 142 $np $BeamSecTag $IDBeamTransf; # level 4

# Frame 2
# columns
element nonlinearBeamColumn 2111 211 221 $np $ColSecTag $IDColTransf; # level 1-2
element nonlinearBeamColumn 2112 212 222 $np $ColSecTag $IDColTransf
element nonlinearBeamColumn 2121 221 231 $np $ColSecTag $IDColTransf; # level 2-3
element nonlinearBeamColumn 2122 222 232 $np $ColSecTag $IDColTransf
element nonlinearBeamColumn 2131 231 241 $np $ColSecTag $IDColTransf; # level 3-4
element nonlinearBeamColumn 2132 232 242 $np $ColSecTag $IDColTransf
# beams
element nonlinearBeamColumn 2221 221 222 $np $BeamSecTag $IDBeamTransf; # level 2
element nonlinearBeamColumn 2231 231 232 $np $BeamSecTag $IDBeamTransf; # level 3
element nonlinearBeamColumn 2241 241 242 $np $BeamSecTag $IDBeamTransf; # level 4

# girders connecting frames
# Frame 1-2
element nonlinearBeamColumn 1321 121 221 $np $GirdSecTag $IDGirdTransf; # level 2
element nonlinearBeamColumn 1322 122 222 $np $GirdSecTag $IDGirdTransf;
element nonlinearBeamColumn 1331 131 231 $np $GirdSecTag $IDGirdTransf; # level 3
element nonlinearBeamColumn 1332 132 232 $np $GirdSecTag $IDGirdTransf;
element nonlinearBeamColumn 1341 141 241 $np $GirdSecTag $IDGirdTransf; # level 4
element nonlinearBeamColumn 1342 142 242 $np $GirdSecTag $IDGirdTransf;


# --------------------------------------------------------------------------------------------------------------------------------
# Define GRAVITY LOADS, weight and masses
# calculate dead load of frame, assume this to be an internal frame (do LL in a similar manner)
# calculate distributed weight along the beam length
set Tslab [expr 6*$in]; # 6-inch slab
set Lslab [expr $LGird/2]; # slab extends a distance of $LGird/2 in/out of plane
set DLfactor 1.0; # scale dead load up a little
set Qslab [expr $GammaConcrete*$Tslab*$Lslab*$DLfactor];
set QdlBeam [expr $Qslab + $QBeam]; # dead load distributed along beam (one-way slab)
set QdlGird $QGird; # dead load distributed along girder
set WeightCol [expr $QdlCol*$LCol]; # total Column weight
set WeightBeam [expr $QdlBeam*$LBeam]; # total Beam weight
set WeightGird [expr $QdlGird*$LGird]; # total Beam weight

# assign masses to the nodes that the columns are connected to
# each connection takes the mass of 1/2 of each element framing into it (mass=weight/$g)
set Mmid [expr ($WeightCol/2 + $WeightCol/2 +$WeightBeam/2+$WeightGird/2)/$g];
set Mtop [expr ($WeightCol/2 + $WeightBeam/2+$WeightGird/2)/$g];

# frame 1
mass 121 $Mmid 0 $Mmid 0. 0. 0.; # level 2
mass 122 $Mmid 0 $Mmid 0. 0. 0.;
mass 131 $Mmid 0 $Mmid 0. 0. 0.; # level 3
mass 132 $Mmid 0 $Mmid 0. 0. 0.;
mass 141 $Mtop 0 $Mtop 0. 0. 0.; # level 4
mass 142 $Mtop 0 $Mtop 0. 0. 0.;

# frame 2
mass 221 $Mmid 0 $Mmid 0. 0. 0.; # level 2
mass 222 $Mmid 0 $Mmid 0. 0. 0.;
mass 231 $Mmid 0 $Mmid 0. 0. 0.; # level 3
mass 232 $Mmid 0 $Mmid 0. 0. 0.;
mass 241 $Mtop 0 $Mtop 0. 0. 0.; # level 4
mass 242 $Mtop 0 $Mtop 0. 0. 0.;

set FloorWeight2 [expr 4*$WeightCol + 2*$WeightGird + 2*$WeightBeam]
set FloorWeight3 [expr 4*$WeightCol + 2*$WeightGird + 2*$WeightBeam]
set FloorWeight4 [expr 2*$WeightCol + 2*$WeightGird + 2*$WeightBeam]
set WeightTotal [expr $FloorWeight2+$FloorWeight3+$FloorWeight4]; # total building weight
set MassTotal [expr $WeightTotal/$g]; # total building mass

# --------------------------------------------------------------------------------------------------------------------------------
# LATERAL-LOAD distribution for static pushover analysis
# calculate distribution of lateral load based on mass/weight distributions along building height
# Fj = WjHj/sum(WiHi) * Weight at each floor j
set sumWiHi [expr $FloorWeight2*$Y2+$FloorWeight3*$Y3+$FloorWeight4*$Y4]; # sum of storey weight times height, for lateral-load distribution
set WiHi2 [expr $FloorWeight2*$Y2]; # storey weight times height, for lateral-load distribution
set WiHi3 [expr $FloorWeight3*$Y3]; # storey weight times height, for lateral-load distribution
set WiHi4 [expr $FloorWeight4*$Y4]; # storey weight times height, for lateral-load distribution
set F2 [expr $WiHi2/$sumWiHi*$WeightTotal]; # lateral load at level
set F3 [expr $WiHi3/$sumWiHi*$WeightTotal]; # lateral load at level
set F4 [expr $WiHi4/$sumWiHi*$WeightTotal]; # lateral load at level

puts "before Recorder";
# Define RECORDERS -------------------------------------------------------------
recorder Node -file $dataDir/DFree.out -time -node 141 -dof 1 2 3 disp; # displacements of free node
recorder Node -file $dataDir/DBase.out -time -node 111 112 211 212 -dof 1 2 3 disp; # displacements of support nodes
recorder Node -file $dataDir/RBase.out -time -node 111 112 211 212 -dof 1 2 3 reaction; # support reaction
recorder Drift -file $dataDir/DrNode.out -time -iNode 111 -jNode 141 -dof 1 -perpDirn 2; # lateral drift
recorder Element -file $dataDir/Fel1.out -time -ele 1111 localForce; # element forces in local coordinates
recorder Element -xml $dataDir/PlasticRotation1.out -time -ele 1111 plasticRotation; # element forces in local coordinates
recorder Element -file $dataDir/ForceEle1sec1.out -time -ele 1111 section 1 force; # section forces, axial and moment, node i
recorder Element -file $dataDir/DefoEle1sec1.out -time -ele 11111 section 1 deformation; # section deformations, axial and curvature, node i
recorder Element -file $dataDir/ForceEle1sec$np.out -time -ele 111 section $np force; # section forces, axial and moment, node j
recorder Element -file $dataDir/DefoEle1sec$np.out -time -ele 1111 section $np deformation; # section deformations, axial and curvature, node j
set yFiber [expr $HCol/2-$cover]; # fiber location for stress-strain recorder, local coords
set zFiber [expr $BCol/2-$cover]; # fiber location for stress-strain recorder, local coords
recorder Element -file $dataDir/SSconcEle1sec1.out -time -ele 1111 section $np fiber $yFiber $zFiber $IDconcCore stressStrain; # steel fiber stress-strain, node i
recorder Element -file $dataDir/SSreinfEle1sec1.out -time -ele 1111 section $np fiber $yFiber $zFiber $IDSteel stressStrain; # steel fiber stress-strain, node i
puts "Before Display";
# Define DISPLAY -------------------------------------------------------------
#set xPixels 1200; # height of graphical window in pixels
#set yPixels 800; # height of graphical window in pixels
#set xLoc1 10; # horizontal location of graphical window (0=upper left-most corner)
#set yLoc1 10; # vertical location of graphical window (0=upper left-most corner)
#set dAmp 2; # scaling factor for viewing deformed shape, it depends on the dimensions of the model
#DisplayModel3D NodeNumbers $dAmp $xLoc1 $yLoc1 $xPixels $yPixels;
#puts "After Display"
#
# define GRAVITY -------------------------------------------------------------
# GRAVITY LOADS # define gravity load applied to beams and columns -- eleLoad applies loads in local coordinate axis
pattern Plain 101 Linear {
# Frame 1
# columns
eleLoad -ele 1111 -type -beamUniform 0. 0. -$QdlCol; # level 1-2
eleLoad -ele 1112 -type -beamUniform 0. 0. -$QdlCol
eleLoad -ele 1121 -type -beamUniform 0. 0. -$QdlCol; # level 2-3
eleLoad -ele 1122 -type -beamUniform 0. 0. -$QdlCol
eleLoad -ele 1131 -type -beamUniform 0. 0. -$QdlCol; # level 3-4
eleLoad -ele 1132 -type -beamUniform 0. 0. -$QdlCol
# beams
eleLoad -ele 1221 -type -beamUniform -$QdlBeam 0.; # level 2
eleLoad -ele 1231 -type -beamUniform -$QdlBeam 0.; # level 3
eleLoad -ele 1241 -type -beamUniform -$QdlBeam 0.; # level 4

# Frame 2
# columns
eleLoad -ele 2111 -type -beamUniform 0. 0. -$QdlCol; # level 1-2
eleLoad -ele 2112 -type -beamUniform 0. 0. -$QdlCol
eleLoad -ele 2121 -type -beamUniform 0. 0. -$QdlCol; # level 2-3
eleLoad -ele 2122 -type -beamUniform 0. 0. -$QdlCol
eleLoad -ele 2131 -type -beamUniform 0. 0. -$QdlCol; # level 3-4
eleLoad -ele 2132 -type -beamUniform 0. 0. -$QdlCol
# beams
eleLoad -ele 2221 -type -beamUniform -$QdlBeam 0.; # level 2
eleLoad -ele 2231 -type -beamUniform -$QdlBeam 0.; # level 3
eleLoad -ele 2241 -type -beamUniform -$QdlBeam 0.; # level 4

# girders connecting frames
# Frame 1-2
eleLoad -ele 1321 -type -beamUniform -$QdlGird 0.; # level 2
eleLoad -ele 1322 -type -beamUniform -$QdlGird 0.;
eleLoad -ele 1331 -type -beamUniform -$QdlGird 0.; # level 3
eleLoad -ele 1332 -type -beamUniform -$QdlGird 0.;
eleLoad -ele 1341 -type -beamUniform -$QdlGird 0.; # level 4
eleLoad -ele 1342 -type -beamUniform -$QdlGird 0.;
}
puts "Before Analysis";
# Gravity-analysis parameters -- load-controlled static analysis
set Tol 1.0e-8; # convergence tolerance for test
variable constraintsTypeGravity Plain; # default;
if { [info exists RigidDiaphragm] == 1} {
if {$RigidDiaphragm=="ON"} {
variable constraintsTypeGravity Lagrange; # large model: try Transformation
}; # if rigid diaphragm is on
}; # if rigid diaphragm exists
constraints $constraintsTypeGravity ; # how it handles boundary conditions
numberer RCM; # renumber dof's to minimize band-width (optimization), if you want to
system BandGeneral ; # how to store and solve the system of equations in the analysis (large model: try UmfPack)
test EnergyIncr $Tol 6 ; # determine if convergence has been achieved at the end of an iteration step
algorithm Newton; # use Newton's solution algorithm: updates tangent stiffness at every iteration
set NstepGravity 10; # apply gravity in 2000 steps
set DGravity [expr 1./$NstepGravity]; # first load increment;
#integrator LoadControl $DGravity; # determine the next time step for an analysis
#analysis Static; # define type of analysis static or transient
#analyze $NstepGravity; # apply gravity
#
#
# ------------------------------------------------- maintain constant gravity loads and reset time to zero
#loadConst -time 0.0
set Tol 1.0e-6; # reduce tolerance after gravity loads
puts "Model Built"
# record eigenvectors
#----------------------
#for { set k 1 } { $k <= $numModes } { incr k } {
# recorder Node -file [format "modes/mode%i.out" $k] -nodeRange 121 122 221 222 131 132 231 232 141 142 241 242 -dof 1 2 3 4 5 6 "eigen $k"
#}
#
# perform eigen analysis
#-----------------------------
set lambda [eigen -genBandArpack $numModes];

# calculate frequencies and periods of the structure
#---------------------------------------------------
set omega {}
set f {}
set T {}
set pi 3.141593

foreach lam $lambda {
lappend omega [expr sqrt($lam)]
lappend f [expr sqrt($lam)/(2*$pi)]
lappend T [expr (2*$pi)/sqrt($lam)]
}

puts "periods are $T"

i could not figure out why it did not work?

[seiche]

From the command manual: The default eigensolver is able to solve only for N-1 eigenvalues, where N is the number of inertial DOFs. When running into this limitation the -fullGenLapack solver can be used instead of the default Arpack solver.

Try changing the solver from -genBandArpack to -fullGenLapack or reducing the number of eigenvalues you're extracting from 12 to 11, and see if it works.

[schoolstru]

thanks for your answer seiche
i applied the points you told, it does not still work and this message is displayed
"WARNING
.
.
.
WARNING lagrange MP_FE ::getM-Force - not yet implemented"
i thought it means that it is necessary to apply a load to run eigen analysis but i apply the lateral load and it does not still work.
i do not know why this happened.

[fmk]

that warning means the necessary method has not been implemented for the constraint handler you have chosen .. choose another handler

[schoolstru]

thanks for your answers
there are some points and problem i should express and i would like to ask you all to shed some light on them
1- when i change the place of "eigen command" it works and it did not need change the solver from -genBandArpack to -fullGenLapack, in the proceeding program i put the eigen command after loading and gravity analysis suprisingly when i put the eigen analysis command before gravity analysis it worked and i do not figure out why this happened, in addition that the structure does not go to inelastic state because i did not choose Fibersection switch and i set it to Elasticsection, so it is excepted that the eigen analysis should not differ before and after gravity analysis
2- Another problem is that when i set the eigen analysis to 1 [eigen 1], it gave the period 3.777e161 which is not rational and acceptalbe for three story building with such configuration, and as soon as i set it to number greater then 1 it works properly and calculate the periods "0.40269 0.40269 ..." which are acceptable
i should say and repeat that i run eigen analysis for that 3-Storey 3-D example model in opensees wiki examples with out any changes because i want to know how eigen analysis command works in 3-D model

[schoolstru]

I would be thankful if anyone answer

[fmk]

1) the eigen command uses whatever analysis objects have already been constructuted, e.g. constraint handler, system of eqn, .... when none of these have been constructed we create some defaults, e.g. PlainHandler, ProfileSPD and Arpack eigen solver. the defaults were working for your problem, the ones you subsequenly constructed in the analysis were not.

2) the iterative Arpack solver does not handle duplicate eigenvalues well, the direct eigen solver (e.g, lapack can)