Two Single Degree of freedom system

[myasanwai]

Hello all,

I tried to analyse Two single degree of freedom mass connected with damper and spring in parallel using zerolength element in 2Dimensional plane. Two masses are in vertical direction and applied seismic excitation.
I have the problem I cannot finish transient analysis. Error has occurred as follows:

WARNING BandGenLinLapackSolver::solve() -LAPACK routine returned 1
WARNING Linear::solveCurrentStep() -the LinearSOE failed in solve()
DirectIntegrationAnalysis::analyze() - the Algorithm failed at time 0.005
OpenSees > analyze failed, returned: -3 error flag -3

For 1 Dimension plane, two masses connected in horizontal dir, the script is working. But 2D Plane, it has the problem.


I have attached my script as follows:

Please give me suggestion how should I do for the transient analysis if you have idea.

Thanks.


wipe

# Build model
model basicBuilder -ndm 2 -ndf 3

# Define Parameters
set Hs 96.0; #m
set b 7.36 ; #m
set d 8.504 ; #m

# Rectangle Section 7360x8504 mm2,

set A 62.589; # cross-sectional area m2
set Iz 2.83E2; # moment of inertia m4
# set Iy 3.77E2; # moment of inertia m4
# set J 4.814E2; # torsional stiffness m4

# set E [expr 2*10E11]; # Young's modulus of elasticity

#Define nodes

node 1 0 0; # fixed base
node 2 0 0; # Structure
node 3 0 0; # TMD


#Base system (Structure)

set ks 83625.75; #Spring (N/m)
set cs 0.; #Damper
set ms 5020.7; #mass (kg)


# TMD system with mass ratio : 0.2

set kt 11613.7584 ; #Spring (N/m)
set ct 2376.8958; #Damper (N-Sec/m)
set mt 1004.14; #mass (kg)



# Structure
uniaxialMaterial Elastic 1 $ks
uniaxialMaterial Viscous 2 $cs 1.
uniaxialMaterial Parallel 3 1 2
element zeroLength 1 1 2 -mat 3 -dir 2

# Damper system
uniaxialMaterial Elastic 4 $kt
uniaxialMaterial Viscous 5 $ct 1.
uniaxialMaterial Parallel 6 4 5
element zeroLength 2 2 3 -mat 6 -dir 2


# Define masses
mass 2 $ms 0 ; # Structure
mass 3 $mt 0 ; # TMD


# Boundary Conditions
fix 1 0 0


# Define Time Series
timeSeries Path 1 -dt 0.02 -filePath elc1940_ew.dat -factor 9.81

# Define Load
pattern Plain 1 1 {

load 1 [expr $mt*(1.0)] 0.0

}


# Analysis

integrator Newmark 0.5 [expr 1./4.]
test EnergyIncr 1.0e-12 50 1
algorithm Linear
numberer Plain
constraints Plain
system BandGeneral
analysis Transient


# Output Specification

recorder Node -file wTMD_d_Node21.out -time -node 2 -dof 1 disp; # Fdn Dis
recorder Node -file wTMD_d_Node22.out -node 2 -dof 1 disp; # Fdn Dis


# Run the analysis
analyze 3200 0.005

[Jhno]

Your model is ill defined.
you have three node, yet you did not prescript any fix condition. You used the fix command for node 1 but you told the node should be free in both dir 1 and 2.

[myasanwai]

Thanks Jhno for your comment and suggestion. Although I tried to fix the node in one or two direction, it has still same problem.

[selimgunay]

You should fix the bottom node completely and nodes 2 and 3 in vertical and rotational degrees of freedom.

fix 1 1 1 1
fix 2 0 1 1
fix 3 0 1 1

[myasanwai]

Thanks selimgunay. I follow as your suggestion and my script is now working.