Simple SDOF problem with TwoNodeLink element and prescribed displacement doesn't work

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pablourzua
Posts: 2
Joined: Thu Jan 12, 2023 5:41 pm

Simple SDOF problem with TwoNodeLink element and prescribed displacement doesn't work

Post by pablourzua » Thu Jan 12, 2023 6:06 pm

Hello, I'm new in OpenSees and trying to run a model defined by two nodes connected by a TwoNodeLink element. The load only consists of a prescribed displacement of 0.02 m at the node 2 in x direction. The problem is, when I run the code, the console just closes with the following message "On entry to DGBSV parameter number 9 had an illegal value". Is it because I'm prescribing the only DOF of the model? I'm trying to generate the force/displacement curve of my bilinear material. Thanks in advance.

wipe all;

model BasicBuilder -ndm 2 -ndf 3

# Nodos
node 1 0.0 0.0
node 2 0.0 1

# Apoyos
fix 1 1 1 1
fix 2 0 1 1

# 2c. Propiedades curva bilineal para material Steel01
set ke 39.478; # rigidez inicial kN/m
set b 0.05; # razon de rigidez
set kh [expr $b*$ke]; # kN/m
set fy 1.525;

# se define un material bilineal
uniaxialMaterial Steel01 1 $fy $ke $b

# Elementos
# element twoNodeLink $eleTag $iNode $jNode -mat $matTags -dir $dirs
element twoNodeLink 1 1 2 -mat 1 -dir 2

recorder Node -file run2_u.out -time -node 2 -dof 1 disp;
recorder Node -file run2_v.out -node 2 -dof 1 reaction;

timeSeries Linear 1;
pattern Plain 1 1 {
# load 2 0.5 0.0 0.0;
sp 2 1 0.02
}

system BandGeneral;
numberer RCM;
constraints Transformation

set Tol 1e-8;
set iter 100;
test NormDispIncr $Tol $iter;
algorithm Newton;

integrator LoadControl 0.1;
analysis Static
analyze 10

puts "Analisis Finalizado"
puts " "
wipe


pablourzua
Posts: 2
Joined: Thu Jan 12, 2023 5:41 pm

Re: Simple SDOF problem with TwoNodeLink element and prescribed displacement doesn't work

Post by pablourzua » Sun Jan 15, 2023 12:40 pm

mhscott wrote:
Fri Jan 13, 2023 8:46 am
Yes. Try using UmfPack.
https://portwooddigital.com/2020/08/27/ ... -marplots/
Thank you!

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