I am new to OpenSEES and trying to model soil using Gazeta's springs and dampers. Right now I have written a small code to verify if the 2D soil model I am using is correct.

I defined two uniaxial materials, one elastic (for spring) and another viscous (for damper). Then I defined another uniaxial parallel material made of elastic and viscous material.

I define two uniaxial sections, one for axial for deformation, and one for torsion. (Axial force deformation for X & Y direction and torsion for rotation along Z direction).

Then I defined three zero length elements representing spring and dampers in each direction.

The code I wrote is inline, any suggestions would be highly appreciated. I have just assumed some spring and damper coefficients.

- Code: Select all
`wipe;`

wipeAnalysis;

model basic -ndm 2 -ndf 3;

set u 0.0000000001;

node 1 0. 0. -mass $u $u $u;

node 2 0. 0. -mass $u $u $u;

node 3 0. 10. -mass 1000. $u $u;

fix 1 1 1 1;

fix 2 0 0 1;

fix 3 0 0 0;

geomTransf Linear 1;

uniaxialMaterial Elastic 1 30000.;

uniaxialMaterial Viscous 2 20000. 1.;

uniaxialMaterial Parallel 3 1 2;

section Uniaxial 1 3 P;

section Uniaxial 2 3 T;

element zeroLengthSection 1 1 2 1 -orient 0 1 0 0 0 1; # Vertical Spring-Damper

element zeroLengthSection 2 1 2 1 -orient 1 0 0 0 1 0; # Horizontal Spring-Damper

element zeroLengthSection 3 1 2 2 -orient 0 0 1 0 1 0; # Rotational Spring-Damper

element elasticBeamColumn 4 2 3 100. 1000. 10000. 1;

pattern Plain 1 Linear {

load 3 100. 0. 100.

}

constraints Transformation

numberer RCM

system BandGeneral

test NormDispIncr 1.0e-5 60

algorithm Newton

integrator DisplacementControl 3 1 0.1

analysis Static

analyze 10

#Earthquake Analysis

source ReadSMDFile.tcl;

ReadSMDFile BM68elc.th BM68elc.acc dt;

set accelSeries "Series -dt $dt -filePath BM68elc.acc -factor 1";

pattern UniformExcitation 2 1 -accel $accelSeries;

#rayleigh 0. 0. 0. [expr 2*0.02/pow([eigen 1],0.5)];

constraints Plain;

numberer RCM;

system BandGeneral;

test NormDispIncr 1.0e-8 10;

algorithm Newton;

integrator Newmark 0.5 0.25;

analysis Transient;

analyze 500 0.02;

Thanks.