how to output stresses and strains in a element

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ouyang
Posts: 10
Joined: Thu Feb 10, 2005 8:58 pm

how to output stresses and strains in a element

Post by ouyang »

Hi everyone,

I am running the model: "Plastic Pressure Dependent Wet Inclined Dynamic" located at
http://cyclic.ucsd.edu/opensees/Plastic ... /index.htm
on opensees (1.7.3). Somehow, only node-related ouput, such as disp.out and acce.out, are generated by opensees with

recorder Node -file disp.out -time -node 1 2 3 4 -dof 1 2 -dT 0.01 disp
recorder Node -file acce.out -time -node 1 2 3 4 -dof 1 2 -dT 0.01 accel

And I got no ouput from the other element-related recorder command, such as

recorder Element 1 -time -file stress1.out material 1 stress -dT 0.01
recorder Element 1 -time -file strain1.out material 1 strain -dT 0.01
recorder Element 1 -time -file stress3.out material 3 stress -dT 0.01
recorder Element 1 -time -file strain3.out material 3 strain -dT 0.01
recorder Element 1 -time -file press1.out material 1 pressure -dT 0.01
recorder Element 1 -time -file press3.out material 3 pressure -dT 0.01

I have checked the opensees menu for a while and still have no clues.
Anybody knows what is going with this example?

Thanks a lot.

ouyang

For your reference, I put the whole tcl file for opensees here:
#######################################################################
#Created by Zhaohui Yang (zhyang@ucsd.edu)
#plastic pressure dependent material
#plane strain, single element, dynamic analysis (input motion: sinusoidal acceleration at base)
#SI units (m, s, KN, ton)
#
# 4 3
# -------
# | |
# | |
# | |
# 1-------2 (nodes 1 and 2 fixed)
# ^ ^
# <--> input motion: sinusoidal acceleration at base
wipe
#
#some user defined variables
#
set accMul 2 ;# acceleration multiplier
set massDen 2.0 ;# solid mass density
set fluidDen 1.0 ;# fluid mass density
set massProportionalDamping 0.0 ;
set stiffnessProportionalDamping 0.001 ;
set fangle 31.40 ;#friction angle
set ptangle 26.50 ;#phase transformation angle
set E 90000.0 ;#shear modulus
set poisson 0.40 ;
set G [expr $E/(2*(1+$poisson))] ;
set B [expr $E/(3*(1-2*$poisson))] ;
set press 0.0 ;# isotropic consolidation pressure on quad element(s)
set deltaT 0.010 ;# time step for analysis
set numSteps 2000 ;# Number of analysis steps
set gamma 0.600 ;# Newmark integration parameter
set period 1 ;# Period of applied sinusoidal load
set pi 3.1415926535 ;
set inclination 0 ;
set unitWeightX [expr ($massDen-$fluidDen)*9.81*sin($inclination/180.0*$pi)] ;# unit weight in X direction
set unitWeightY [expr -($massDen-$fluidDen)*9.81*cos($inclination/180.0*$pi)] ;# unit weight in Y direction
#############################################################

#############################################################

#create the ModelBuilder
model basic -ndm 2 -ndf 2

# define material and properties
nDMaterial PressureDependMultiYield 2 2 $massDen $G $B $fangle .1 80 0.5 \
$ptangle 0.17 0.4 10 10 0.015 1.0
nDMaterial FluidSolidPorous 1 2 2 2.2D+6

updateMaterialStage -material 1 -stage 0
updateMaterialStage -material 2 -stage 0

# define the nodes
node 1 0.0D0 0.0D0
node 2 1.0D0 0.0D0
node 3 1.0D0 1.0D0
node 4 0.0D0 1.0D0

# define the element thick material maTag press mDensity gravity
element quad 1 1 2 3 4 1.0 "PlaneStrain" 1 $press 0. $unitWeightX $unitWeightY

# fix the base
fix 1 1 1
fix 2 1 1

#tie nodes 3 and 4
equalDOF 3 4 1 2

#############################################################
# GRAVITY APPLICATION (elastic behavior)
# create the SOE, ConstraintHandler, Integrator, Algorithm and Numberer
system ProfileSPD
test NormDispIncr 1.D-12 25 0
constraints Transformation
integrator LoadControl 1 1 1 1
algorithm Newton
numberer RCM

# create the Analysis
analysis Static

#analyze
analyze 2

# switch the material to plastic
updateMaterialStage -material 1 -stage 1
updateMaterialStage -material 2 -stage 1
updateParameter -material 2 -refB [expr $G*2/3.];

#analyze
analyze 1

############################################################
# NOW APPLY LOADING SEQUENCE AND ANALYZE (plastic)

# rezero time
setTime 0.0
#loadConst -time 0.0D0
wipeAnalysis

pattern UniformExcitation 1 1 -accel "Sine 0 1000 $period -factor $accMul"

# create the Analysis
constraints Transformation;
test NormDispIncr 1.D-12 25 0
algorithm Newton
numberer RCM
system ProfileSPD
integrator Newmark $gamma [expr pow($gamma+0.5, 2)/4] \
$massProportionalDamping 0.0 $stiffnessProportionalDamping 0.0
analysis VariableTransient

recorder Node -file disp.out -time -node 1 2 3 4 -dof 1 2 -dT 0.01 disp
recorder Node -file acce.out -time -node 1 2 3 4 -dof 1 2 -dT 0.01 accel
recorder Element 1 -time -file stress1.out material 1 stress -dT 0.01
recorder Element 1 -time -file strain1.out material 1 strain -dT 0.01
recorder Element 1 -time -file stress3.out material 3 stress -dT 0.01
recorder Element 1 -time -file strain3.out material 3 strain -dT 0.01
recorder Element 1 -time -file press1.out material 1 pressure -dT 0.01
recorder Element 1 -time -file press3.out material 3 pressure -dT 0.01

#analyze
set startT [clock seconds]
analyze $numSteps $deltaT [expr $deltaT/100] $deltaT 10
set endT [clock seconds]
puts "Execution time: [expr $endT-$startT] seconds."

wipe #flush ouput stream
silvia
Posts: 3909
Joined: Tue Jan 11, 2005 7:44 am
Location: Degenkolb Engineers
Contact:

Post by silvia »

try to get in touch with the ucsd developers for that element/material.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104
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