help! Analysis error

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Feliciasatriya
Posts: 4
Joined: Mon Feb 24, 2020 5:23 pm

help! Analysis error

Post by Feliciasatriya » Wed Feb 26, 2020 11:39 pm

I really need some help. I tried to run my model and it does not work.

The input model
model basic -ndm 2 -ndf 3
file mkdir Kurumakaeri/Result;

# DEFINING PROPERTIES, UNIT & CONSTANTS
# All units are in SI units
set k 1000; # Kilo...
set M 1000000; # Mega...
set g 9.8; # Gravitational acceleration (m/s2)
set Pi 3.14; # Phi value


# NODES --------------------------------------------------------------------------------------------
# Nodes properties
set l 10.96; # Horizontal node spacing (m)

# Define node --> node $tag $X $Y
node 1 [expr $l*0] 0
node 2 [expr $l*5] 0

node 3 [expr $l*0] 0
node 4 [expr $l*1] 0
node 5 [expr $l*2] 0
node 6 [expr $l*3] 0
node 7 [expr $l*4] 0
node 8 [expr $l*5] 0

# Fix supports/nodes --> fix $nodetag $ValueX $ValueY $ValueRotation
fix 1 1 1 1
fix 2 1 1 1

# Add in nodal mass
mass 3 11951.43283 0 0
mass 4 23902.86566 0 0
mass 5 23902.86566 0 0
mass 6 23902.86566 0 0
mass 7 23902.86566 0 0
mass 8 11951.43283 0 0

# GIRDER --------------------------------------------------------------------------------------------
# Girder steel properties
set Fy [expr 365*10**4]; # Steel yield strength (N/m2)
set E0 [expr 210*10**9]; # Initial young's modulus (Pa)
set b 0.01; # Strain hardening ratio

# Define material
uniaxialMaterial SteelMP 1 $Fy $E0 $b

# Define cross section
section Fiber 1 {
# patch rect $matTag $numSubdivY $numSubdivZ $yI $zI $yJ $zJ
# Girder top span (R1)
patch rect 1 3 3 0.000 1.812 12.000 1.800

# Left box of the girder (R2,R3,R6)
patch rect 1 3 3 2.900 1.800 2.912 0.000
patch rect 1 3 3 4.888 1.800 4.900 0.000
patch rect 1 3 3 2.912 0.000 4.888 0.012

# Right box of the girder (R4,R5,R7)
patch rect 1 3 3 8.300 1.800 8.312 0.000
patch rect 1 3 3 10.288 1.800 10.300 0.000
patch rect 1 3 3 8.312 0.000 10.288 0.012
}

# Define girder transformation
geomTransf Linear 1

# Define girder full length
# element forceBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag
element forceBeamColumn 1 3 4 10 1 1
element forceBeamColumn 2 4 5 10 1 1
element forceBeamColumn 3 5 6 10 1 1
element forceBeamColumn 4 6 7 10 1 1
element forceBeamColumn 5 7 8 10 1 1


# RUBBER BEARING --------------------------------------------------------------------------------------
# Rubber bearing properties
set E [expr 1.8667*$M]; # Stiffness tangent (N/m)
set epsy 1.0; # Yield strain (m)

# Defining material
uniaxialMaterial Elastic 2 $E

# Creating element
# element zeroLength $eleTag $iNode $jNode -mat $matTag -dir $dir
element zeroLength 6 1 3 -mat 2 -dir 1
element zeroLength 7 2 8 -mat 2 -dir 1


# RECORDER -----------------------------------------------------------------------------------------------------
recorder Node -file Kurumakaeri/Result/DispN4.out -time -node 4 -dof 1 2 3 disp; # Displacements of node 4
recorder Element -file Kurumakaeri/Result/ForceEle2.out -time -ele 2 force; # Force of element 2
recorder Element -file Kurumakaeri/Result/DeformSpr1.out -time -ele 6 -dof 1 deformation; # Deformation of spring 1
recorder Element -file Kurumakaeri/Result/DeformSpr2.out -time -ele 7 -dof 1 deformation; # Deformation of spring 2


# SEISMIC LOADING ------------------------------------------------------------------------------------------------
# Define Acceleration
timeSeries Trig 1 0 1 $Pi;
# Tag DOF Accel
pattern UniformExcitation 2 1 -accel 1 ;


# ANALYSIS ---------------------------------------------------------------------------------------------------------
wipeAnalysis ;
constraints Transformation ;
numberer RCM ;
system BandGeneral ;
test EnergyIncr 1e-7 25 0 ;
algorithm Newton ;
integrator Newmark 0.5 0.25 ;
analysis Transient ;
analyze 3140 0.01;

And the output I receive after running it
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 17
WARNING NewtonRaphson::solveCurrentStep() -the LinearSysOfEqn failed in solve()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 0.01

What can I do to solve the error ?
Any help is very much appreciated

zhangtian
Posts: 2
Joined: Wed Oct 14, 2020 12:03 am

Re: help! Analysis error

Post by zhangtian » Sun Oct 18, 2020 7:31 pm

hello,could you tell me how you solved this problem?

mhscott
Posts: 586
Joined: Tue Jul 06, 2004 3:38 pm
Location: Corvallis, Oregon USA
Contact:

Re: help! Analysis error

Post by mhscott » Sun Oct 18, 2020 8:25 pm

Probably was missing equalDOF commands between nodes (1 and 3) and (2 and 8 ). Without those, you'd get a singular stiffness matrix.

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