# HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH #
# 2D Undrained Cyclic Direct Simple Shear Test Using One Element #
# University of Washington, Department of Civil and Environmental Eng #
# Geotechnical Eng Group, L. Chen, P. Arduino - Feb 2018 #
# Basic Units are m, kN and s unless otherwise specified #
# HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH #
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# ------------------------ #
# Test Specific parameters #
# ------------------------ #
# Initial Vertical Stress
set sigvo -101.3
# cyclic stress ratio
set CSR 0.16
# max number of cycles
set maxCycles 20
# strain increment
set strainIncr 5.0e-6
# K0
set K0 0.5
# set Poisson's ratio to match user specified K0 for applying initial confinement
set nu [expr $K0 / (1+$K0)]
# Cutoff shear strain
set devDisp 0.03
# Permeablity
set perm 1.0e-9
# ---------primary parameters-------------
set Dr 0.35
set G0 476.0
set hpo 0.53
set rho 1.42
# ---------secondary parameters-------------
set Patm 101.3
# all initial stress dependant parameters have negative default values
# 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
# ---------------------------------------------
# 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]
# HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
# HHHHHHHHHHHHHHHHHHHHHHHHHHHCreate ModelHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
# HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
# Create a 2D model with 3 Degrees of Freedom
model BasicBuilder -ndm 2 -ndf 3
# 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
# 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
# Create material
# 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
# Create element
element SSPquadUP 1 1 2 3 4 1 1.0 2.2e6 1.0 $perm $perm $eInit 1.0e-5
# 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
# 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
# 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 $vDisp
}"
# Close drainage valves
for {set x 1} {$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"
# 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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