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Hi all,

I want to use nDMaterial PM4Sand.
Although the material is in the source code and there are two examples on the website, I'm getting a warning saying "could not create nDMaterial: PM4Sand".
Any ideas?

I just want to control the displacement so I wouldn't get huge displacements resulting in convergence problems.

Hi,

Suppose I have a zerolength element with Elastic Perfectly Plastic (EPP) or Steel01 (with a minuscule hardening ratio).
If I load my material, after I'd reach the yielding force, I'd get huge displacements due to plasticity.
Is there any possible way that I can limit these displacements?
Or alternatively, have an interlocking effect?

An update:

I tested a couple of scripts and the conclusions are as follow:
The zerolengthContact act as a zeroLength element with an ENT material in the direction normal to the frictional plane.
If both the elements are used, they act parallel. Under the same load, the stiffness doubles and the normal displacement halves.

Hi,

What are the correct element recorder tags for zerolengthContact3D material?
I have used 'force', 'forces', 'globalForce' and these just record bunch of zeros (while there is a force in the element, I've checked this by using a simple zeroLength element).
I used 'deformation', 'stiff' and 'stiffness' and all these three don't record anything even zeros.

How about the recorders of the element (zeroLengthContact3D )?
I cannot record the forces!

Hi All,

I want to define the interface between soil and shallow foundation.
Suppose the followings are my soil and foundation nodes. Both nodes have 3 DOFs.

Foundation: node 1 0.0 0.0 10.0
Soil: node 2 0.0 0.0 10.0

I want to have frictional behaviour in lateral DOFs (X- and Y-direction) and elastic with no tension in vertical DOF (Z-direction) so it can transfer compression but no tension.
For lateral interface, I want to use zerolengthContact3D and for the vertical one, zeroLength with ENT (elastic with no tension material).
The definition of zerolengthContact3D is:
element zeroLengthContact3D $eleTag $sNode $mNode $Kn $Kt $mu $c $dir
My understanding is the direction of the material should be normal to the directions I want the material to act frictional. In my case this would the 3rd DOF. So I used:

element zeroLengthContact3D 1 2 1 3e10 3e13 0.163 0 3

In addition, for my vertical behaviour I used:

uniaxialMaterial ENT 2 3e7
element zeroLength 2 642 727 -mat 2 -dir 3

Do you think these elements work for as I want in the above-mentioned format?
Also, what are the valid ElemenRecorders for zerolengthRecorder? I've used 'force', 'forces' and 'globalForce' but I only got a bunch of zeros (there is a horizontal shear in the model on the foundation so it shouldn't be zero).

Cheers,
Arman

You're right Frank. There was a problem with their compilation and they've fixed it now.

Hi,

I have a large model and I'm using OpenSees on an HPC platform.
My analysis script consists of two phases: static and transient analyses.
Since my model is large I cannot use any system solver other than Mumps or the analysis would crash.
If I use Mumps in both phases, the transient analysis doesn't work.
What're the possible solutions to this?

Cheers,
Arman

I would appreciate if somebody can answer to this, is it do to Mumps?

Hi,

I want to run my script on an HPC (NeSI Pan cluster).
When I run my script on Pan cluster with more than 1 cpu, I confront an error saying:

"Input Error: Incorrect ncuts.
DomainPartitioner::partition - too few elements for model to be partitioned
WARNING before analysis; partition failed - too few elements
Process Terminating 1
Process Terminating"

However, I can run a similar model with around 30,000 DOFs on my office computer using parallel processing and 4cpus (the larger model contains almost 800,000 DOFs).
Any idea on this? Is it possible it's due to the NeSI OpenSeesSP compilation (they're using MPI)?

Kindest regards,
Arman

Hi,

I want to model a 3D retaining wall while having pore pressure.
Since there is retaining wall in addition to soil, all 6dofs are needed.
Considering the fact that modelling pore pressure requires an additional dof, can this model be built?
Any recommendations and guides are truly appreciated.

Hi,

I want to know if the Gauss point location is dependent and same is numbering order of quad element nodes or Gauss point 1 will always be on bottom left corner, 2 on bottom right, 3 on top right and 4 on top left?

I don't know whom I should ask this question and I have emailed code developers but got no answers so far.

Hi,

I have modeled a simple medium sand soil column with PDMY material using four 1x1m quad elements which is fixed at based and constrained at 1st Dof (horizontally) at both sides.
A series of loading/unloading vertical load is applied on upper surface nodes. This is like compression test (Oedometer) and the loading phase of vertical stress-strain is expected but the unloading phase is so close to loading case which is so unexpected. The vertical load/unload is with 50KN increment increasing from 0 to 1000MN and then decreasing to 0 again.
The ideal curve and the obtained curve are as follows respectively:
https://i.imgsafe.org/d3b702703a.jpg

https://i.imgsafe.org/d45d09aa66.jpg

Also you can find the loading/unloading file if needed here:
http://www.fileconvoy.com/dfl.php?id=gf ... 02b213218b


And the script is copied here:
-------------------------------------------------------------------------------------------------------------------------------------------------
wipeAnalysis

model BasicBuilder -ndm 2 -ndf 2

node 1 0.0 0.0
node 2 1.0 0.0
node 3 0.0 1.0
node 4 1.0 1.0
node 5 0.0 2.0
node 6 1.0 2.0
node 7 0.0 3.0
node 8 1.0 3.0
node 9 0.0 4.0
node 10 1.0 4.0

fix 1 1 1
fix 2 1 1
fix 3 1 0
fix 4 1 0
fix 5 1 0
fix 6 1 0
fix 7 1 0
fix 8 1 0
fix 9 1 0
fix 10 1 0

set dt 5.0
set gamma 0.5

#---MATERIAL PROPERTIES
# soil mass density (Mg/m^3)
set rho [expr 18/9.81]
# soil shear velocity
set Vs 200.0
# soil elastic modulus
set Es 40000
# poisson's ratio of soil
set nu 0.3
# soil shear modulus
set Gmax [expr $Es/(2*(1+$nu))]
# soil bulk modulus
set bulk [expr $Es/(3*(1-2*$nu))]
# soil friction angle
set phi 35.0
# soil cohesion
set coh 0.0
# peak shear strain
set gammaPeak 0.1
# reference pressure
set refPress 80.0
# pressure dependency coefficient
set pressDependCoe 0.5
# phase transformation angle
set PTAng 27
# rate of shear-induced volume decrease (contraction) or pore pressure buildup
set contrac 0.07
# the rate of shear-induced volume increase (dilation)
set dilat1 0.4
set dilat2 2.0
# parameters controlling the mechanism of cyclic mobility (Kpa)
set liquefac1 10
set liquefac2 0.01
set liquefac3 1


nDMaterial PressureDependMultiYield 10 2 $rho $Gmax $bulk $phi $gammaPeak $refPress $pressDependCoe $PTAng $contrac $dilat1 $dilat2 $liquefac1 $liquefac2 $liquefac3
nDMaterial InitialStateAnalysisWrapper 1 10 2

set wgtX 0.0
set wgtY [expr -9.81*$rho]
element quad 1 1 2 4 3 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 2 3 4 6 5 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 3 5 6 8 7 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY
element quad 4 7 8 10 9 1.0 "PlaneStrain" 1 0.0 0.0 $wgtX $wgtY

recorder Node -file ESoilDispDir1.out -time -nodeRange 1 10 -dof 1 disp
recorder Node -file ESoilDispDir2.out -time -nodeRange 1 10 -dof 2 disp

recorder Node -file ESoilForceDir1.out -time -nodeRange 1 10 -dof 1 reaction
recorder Node -file ESoilForceDir2.out -time -nodeRange 1 10 -dof 2 reaction

recorder Element -file Estress1.out -time -dT $dt -eleRange 1 4 material 1 stress
recorder Element -file Estress2.out -time -dT $dt -eleRange 1 4 material 2 stress
recorder Element -file Estress3.out -time -dT $dt -eleRange 1 4 material 3 stress
recorder Element -file Estress4.out -time -dT $dt -eleRange 1 4 material 4 stress

recorder Element -file Estrain1.out -time -dT $dt -eleRange 1 4 material 1 strain
recorder Element -file Estrain2.out -time -dT $dt -eleRange 1 4 material 2 strain
recorder Element -file Estrain3.out -time -dT $dt -eleRange 1 4 material 3 strain
recorder Element -file Estrain4.out -time -dT $dt -eleRange 1 4 material 4 strain


constraints Transformation
test NormDispIncr 1.e-5 15 1
algorithm Newton
numberer RCM
system SparseGeneral
integrator LoadControl 1
analysis Static

InitialStateAnalysis on
updateMaterialStage -material 1 -stage 0

analyze 4

updateMaterialStage -material 1 -stage 1

analyze 2

InitialStateAnalysis off

setTime 0.0
wipeAnalysis

set Vloading Vloading.out
timeSeries Path 2 -dt $dt -filePath $Vloading -factor 0.5

pattern Plain 1 2 {
load 9 0.0 -1.0
load 10 0.0 -1.0
}

#---RAYLEIGH DAMPING PARAMETERS
set pi 3.141592654
# damping ratio
set damp 0.02
# lower frequency
set omega1 [expr 2*$pi*0.2]
# upper frequency
set omega2 [expr 2*$pi*20]
# damping coefficients
set a0 [expr 2*$damp*$omega1*$omega2/($omega1 + $omega2)]
set a1 [expr 2*$damp/($omega1 + $omega2)]
puts "damping coefficients: a_0 = $a0; a_1 = $a1"

recorder Node -file SoilDispDir1.out -time -nodeRange 1 10 -dof 1 disp
recorder Node -file SoilDispDir2.out -time -nodeRange 1 10 -dof 2 disp
recorder Node -file SoilSettlement.out -time -nodeRange 9 10 -dof 2 disp

recorder Node -file SoilForceDir1.out -time -nodeRange 1 10 -dof 1 reaction
recorder Node -file SoilForceDir2.out -time -nodeRange 1 10 -dof 2 reaction

recorder Element -file stress1.out -time -dT $dt -eleRange 1 4 material 1 stress
recorder Element -file stress2.out -time -dT $dt -eleRange 1 4 material 2 stress
recorder Element -file stress3.out -time -dT $dt -eleRange 1 4 material 3 stress
recorder Element -file stress4.out -time -dT $dt -eleRange 1 4 material 4 stress
recorder Element -file stressBase.out -time -dT $dt -eleRange 1 1 material 1 stress


recorder Element -file strain1.out -time -dT $dt -eleRange 1 4 material 1 strain
recorder Element -file strain2.out -time -dT $dt -eleRange 1 4 material 2 strain
recorder Element -file strain3.out -time -dT $dt -eleRange 1 4 material 3 strain
recorder Element -file strain4.out -time -dT $dt -eleRange 1 4 material 4 strain

constraints Penalty 1.e16 1.e16
test NormDispIncr 1.e-5 35 1
algorithm KrylovNewton
numberer RCM
system ProfileSPD
integrator Newmark $gamma [expr pow($gamma+0.5, 2.)/4.]
rayleigh $a0 $a1 0.0 0.0
analysis Transient
analyze 40010 $dt