PM4Sand-Example 2

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2. 2D Undrained Cyclic 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 - Feb 2018 #
5. Basic Units are m, kN and s unless otherwise specified #
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1. ------------------------ #
2. Test Specific parameters #
3. ------------------------ #
4. Initial Vertical Stress

set sigvo -101.3

1. cyclic stress ratio

set CSR 0.16

1. max number of cycles

set maxCycles 20

1. strain increment

set strainIncr 5.0e-6

1. K0

set K0 0.5

1. set Poisson's ratio to match user specified K0 for applying initial confinement

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

1. Cutoff shear strain

set devDisp 0.03

1. Permeablity

set perm 1.0e-9

1. ---------primary parameters-------------

set Dr 0.35 set G0 476.0 set hpo 0.53 set rho 1.42

1. ---------secondary parameters-------------

set Patm 101.3

1. all initial stress dependant parameters have negative default values
2. and will be calculated during initialization

set h0 -1.0 set emax 0.8 set emin 0.5 set eInit [expr $emax - ($emax - $emin)*$Dr ] set nb 0.5 set nd 0.1 set Ado -1.0 set zmax -1.0 set cz 250.0 set ce -1.0 set phicv 33.0 set Cgd 2.0 set Cdr -1.0 set ckaf -1.0 set Q 10.0 set R 1.5 set m_m 0.01 set Fsed_min -1.0 set p_sedo -1.0

1. ---------------------------------------------
2. 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 $Patm $h0 $emax $emin $nb $nd $Ado $zmax $cz $ce $phicv $nu $Cgd $Cdr $ckaf $Q $R $m_m $Fsed_min $p_sedo

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 BandGeneral 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"

1. update Poisson's ratio for analysis

setParameter -value 0.3 -ele 1 poissonRatio 1 set controlDisp [expr 1.1 * $devDisp] set numCycle 0.25 while {$numCycle <= $maxCycles} { #impose 1/4 cycle set hDisp [nodeDisp 3 1] set currentTime [getTime] set steps [expr $controlDisp / $strainIncr] eval "timeSeries Path 2 -time {$currentTime [expr $currentTime + $steps] 1.0e10} -values {$hDisp $controlDisp $controlDisp} -factor 1" pattern Plain 3 2 { sp 3 1 1.0 } set b [eleResponse 1 stress] while {[lindex $b 2] < [expr $CSR * -1.0 * $sigvo]} { analyze 1 1.0 set b [eleResponse 1 stress] set hDisp [nodeDisp 3 1] if {$hDisp >= $devDisp} { exit } } set numCycle [expr $numCycle + 0.25] set hDisp [nodeDisp 3 1] set currentTime [getTime]

remove loadPattern 3 remove timeSeries 2 remove sp 3 1

#impose 1/2 cycle set steps [expr ($controlDisp + $hDisp)/ $strainIncr] eval "timeSeries Path 2 -time {$currentTime [expr $currentTime + $steps] 1.0e10} -values {$hDisp [expr -1.0 * $controlDisp] [expr -1.0 * $controlDisp]} -factor 1"

pattern Plain 3 2 { sp 3 1 1.0 }

while {[lindex $b 2] > [expr $CSR * $sigvo]} { analyze 1 1.0 set b [eleResponse 1 stress] set hDisp [nodeDisp 3 1] if {$hDisp <= [expr -1.0 * $devDisp]} { exit } } #impose 1/4 cycle set numCycle [expr $numCycle + 0.5] set hDisp [nodeDisp 3 1] set currentTime [getTime]

remove loadPattern 3 remove timeSeries 2 remove sp 3 1 set steps [expr ($controlDisp + $hDisp)/ $strainIncr] eval "timeSeries Path 2 -time {$currentTime [expr $currentTime + $steps] 1.0e10} -values {$hDisp $controlDisp $controlDisp} -factor 1"

pattern Plain 3 2 { sp 3 1 1.0 } while {[lindex $b 2] <= 0.0} { analyze 1 1.0 set b [eleResponse 1 stress] set hDisp [nodeDisp 3 1] if {$hDisp >= $devDisp} { exit } } set numCycle [expr $numCycle + 0.25] remove loadPattern 3 remove timeSeries 2 }

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