# PM4Sand-Example 1

This example, provides an undrained confined direct simple shear test using one 4-node SSPQuadUP element and PM4Sand material model.

```tcl

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  2. 2D Undrained Direct Simple Shear Test Using One Element #
  3. University of Washington, Department of Civil and Environmental Eng #
  4. Geotechnical Eng Group, L. Chen, P. Arduino - Jan 2018 #
  5. Basic Units are m, kN and s unless otherwise specified #
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wipe

  1. ------------------------ #
  2. Test Specific parameters #
  3. ------------------------ #
  4. Initial Vertical Stress

set sigvo -101.3 set K0 0.5

  1. set Poisson's ratio to match user specified K0

set nu [expr $K0 / (1+$K0)]

  1. Deviatoric strain (Cyclic)

set devDisp 0.10

  1. Permeablity

set perm 1.0e-9

  1. Initial void ratio
  2. relative density

set Dr 0.35

  1. max and min void ratio

set emax 0.8 set emin 0.5 set eInit [expr $emax - ($emax - $emin)*$Dr ]

  1. other primary parameters

set G0 476.0 set hpo 0.53 set rho 1.42

  1. Rayleigh damping parameter

set damp 0.02 set omega1 0.2 set omega2 20.0 set a1 [expr 2.0*$damp/($omega1+$omega2)] set a0 [expr $a1*$omega1*$omega2]

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  1. Create a 2D model with 3 Degrees of Freedom

model BasicBuilder -ndm 2 -ndf 3

  1. Create nodes

node 1 0.0 0.0 node 2 1.0 0.0 node 3 1.0 1.0 node 4 0.0 1.0

  1. Create Fixities

fix 1 1 1 1 fix 2 1 1 1 fix 3 0 0 1 fix 4 0 0 1

equalDOF 3 4 1 2

  1. Create material
  2. PM4Sand tag Dr G0 hpo den Patm h0 emax emin nb nd Ado zmax cz ce phicv nu

nDMaterial PM4Sand 1 $Dr $G0 $hpo $rho 101.3 -1.00 $emax $emin 0.5 0.1 -1.0 -1.0 250.0 -1.00 33.0 $nu

  1. Create element

element SSPquadUP 1 1 2 3 4 1 1.0 2.2e6 1.0 $perm $perm $eInit 1.0e-5

  1. Create recorders

recorder Node -nodeRange 1 4 -time -file Cycdisp.out -dof 1 2 disp recorder Node -nodeRange 1 4 -time -file Cycpress.out -dof 3 vel recorder Element -ele 1 -time -file Cycstress.out stress recorder Element -ele 1 -time -file Cycstrain.out strain

  1. Create analysis

constraints Transformation test NormDispIncr 1.0e-5 35 1 algorithm Newton numberer RCM system SparseGeneral integrator Newmark [expr 5.0 / 6.0] [expr 4.0 / 9.0] rayleigh $a0 $a1 0.0 0.0 analysis Transient

  1. Apply consolidation pressure

set pNode [expr $sigvo / 2.0] pattern Plain 1 {Series -time {0 100 1e10} -values {0 1 1} -factor 1} { load 3 0.0 $pNode 0.0 load 4 0.0 $pNode 0.0 } updateMaterialStage -material 1 -stage 0

analyze 100 1 set vDisp [nodeDisp 3 2] set ts1 "{Series -time {100 80000 1.0e10} -values {1.0 1.0 1.0} -factor 1}" eval "pattern Plain 2 $ts1 { sp 3 2 $vDisp sp 4 2 $vDisp }"

  1. Close drainage valves

for {set x 1} {$x< 5} {incr x} { remove sp $x 3 }

analyze 25 1 puts "Removed drainage fixities."

updateMaterialStage -material 1 -stage 1 setParameter -value 0 -ele 1 FirstCall 1 analyze 25 1

puts "finished update fixties"

set ts2 "{Series -time {150 5150 1.0e10} -values {0.0 1.0 1.0} -factor 1}"

eval "pattern Plain 3 $ts2 { sp 3 1 $devDisp }"

  1. update Poisson's ratio for analysis

setParameter -value 0.3 -ele 1 poissonRatio 1 analyze 5000 1

wipe ```