VELACS model-1 Modelling

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omidpaul
Posts: 2
Joined: Wed Jul 11, 2012 10:47 pm
Location: Sharif University of Technology

VELACS model-1 Modelling

Post by omidpaul » Sat Oct 20, 2012 3:21 am

Hello all,
I am trying to model VELACS 1, it is one of my first attempts to use OpenSees so I have a little bit of problems.
I have modeled the geometry of the problem, and in gravity loading (soil self weight) I have faced a problem and get errors while running the code.
I have distributed the soil weight forces to the nodes.
I hope somebody can help me with it,

here's the code:

# Units: m, sec, ton, kN

wipe all
set startT [clock seconds]

################################### Soil Properties ##########################################

set Gs 2.68 ;# Soil Grain mass density (Gs)
set nou 0.05 ;# Poisson's Ratio
set rhof 1.0 ;# Fluid mass density
set Phi 31.4 ;# Friction angle at peak shear strength, in degree
set Dr 40.0 ;# Relative Density
set e0 [expr 0.894-(0.894-0.516)*$Dr/100]
set poro0 [expr $e0/(1+$e0)]
set rhos [expr ((1.0-$poro0)*$Gs+$poro0)*$rhof] ;# Saturated Soil mass density

# Permeability (m/s)
set kx 2.1e-5
set ky 2.1e-5
set kz 2.1e-5

set gravX 0.0000
set gravY 0.0000
set gravZ -9.8100

################################### Define Number of Analysis steps ###########################

set NumIncr1 50 ; # Number of Steps in Static Analysis

################################### Define Soil Nodes ##########################################

model basic -ndm 2 -ndf 3

set xincr 2.54
set yincr 2.00

for {set i 1} {$i<=[expr int(22.86/$xincr)+1]} {incr i 1} {
for {set j 1} {$j<=[expr int(10.00/$yincr)+1]} {incr j 1} {
set xdim [expr ($i-1)*$xincr ]
set ydim [expr ($j-1)*$yincr ]
set NodeNum [expr $j+ (int(10.00/$yincr)+1)*($i-1)]
node $NodeNum $xdim $ydim
puts "$NodeNum $xdim $ydim"
}
}

########################## Define Constitutive Model for soil (Dafalias-Manzari) ###############

set Gr 7.5e4
set Br 2.0e5
set PeakShearStrain 0.1
set Pr 80
set pressDependCoe 0.5
set PTAng 27
set contrac 0.07
set dilat1 0.4
set dilat2 2
set liquefac1 10
set liquefac2 0.01
set liquefac3 1

nDMaterial PressureDependMultiYield 1 2 $rhos $Gr $Br $Phi $PeakShearStrain $Pr $pressDependCoe $PTAng $contrac $dilat1 $dilat2 $liquefac1 $liquefac2 $liquefac3

################################### Define Soil Elements #######################################

set m 1
for {set i 1} {$i <= [expr int(22.86/$xincr)]} {incr i 1} {
for {set j 1} {$j <= [expr int(10.00/$yincr)]} {incr j 1} {
set n1 [expr 6*$i-(6-$j)]
set n2 [expr 6*$i-(6-$j)+1]
set n3 [expr 6*$i+$j]
set n4 [expr 6*$i+$j+1]
set EleNum [expr ($m)]
element quadUP $EleNum $n1 $n2 $n3 $n4 1.0 1 [expr 2.2e6/$poro0] $rhof $kx $ky 0 -9.81 0
set m [expr ($m+1)]
puts "$EleNum $n1 $n2 $n3 $n4 $j"
}
}

### update material stage to zero for elastic behavior

updateMaterialStage -material 1 -stage 0

################################### Boundary Conditions #######################################

### Lateral Boundaries

fixX 0.0 1 0 0 -tol 1e-10
fixY 0.0 1 1 0 -tol 1e-10
fixX 22.86 1 0 0 -tol 1e-10

for {set m 1} {$m<=5} {incr m 1} {
equalDOF $m [expr $m+1] 2
equalDOF [expr $m+54] [expr $m+55] 2
}

### Surface Pore Pressure

for {set m 1} {$m<=10} {incr m 1} {
fix [expr 6*$m] 0 0 1
}

########################### Applying Gravity Loads to Nodes ###########################

set m 1
for {set i 1} {$i <= [expr int(22.86/$xincr)]} {incr i 1} {
for {set j 1} {$j <= [expr int(10.00/$yincr)]} {incr j 1} {
set n1 [expr 6*$i-(6-$j)]
set n2 [expr 6*$i-(6-$j)+1]
set n3 [expr 6*$i+$j]
set n4 [expr 6*$i+$j+1]
pattern Plain $m Linear {
load $n1 0 [expr $xincr*$yincr*9.81*($rhos-$rhof)/4] 0
load $n2 0 [expr $xincr*$yincr*9.81*($rhos-$rhof)/4] 0
load $n3 0 [expr $xincr*$yincr*9.81*($rhos-$rhof)/4] 0
load $n4 0 [expr $xincr*$yincr*9.81*($rhos-$rhof)/4] 0
set m [expr ($m+1)]
}
}
}
################################# Gravity Analysis #################################

system UmfPack
constraints Transformation
test NormDispIncr 0.01 50 1
algorithm Newton
numberer RCM
integrator LoadControl [expr 1.0/10]
analysis Static

analyze 10

updateMaterialStage -material 1 -stage 1

analyze 40

loadConst -time 0.0

TimCod
Posts: 2
Joined: Wed Nov 07, 2012 3:04 am

Re: VELACS model-1 Modelling

Post by TimCod » Wed Nov 07, 2012 3:06 am


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