20Node brick element

[liuxing08]

I want to use the 20 node brick element to simulate the pile. How can i deal with the stress of the element to get the shear force? e.g. Can i use the sigmaxz*Area=shear force?

[fmk]

why don't you get the element forces from the element directly instead?

[liuxing08]

fmk wrote:
> why don't you get the element forces from the element directly instead?

Thanks for your reply, Frank. I looked for the element recorder for the force. And I found this link http://opensees.berkeley.edu/OpenSees/m ... al/259.htm. I tried the command "recorder Element -file ele1local.out -time -ele 1 localForce" but there were not results recorded at all. My codes are as floowed:
model BasicBuilder -ndm 3 -ndf 3
#pile material
nDMaterial ElasticIsotropic3D 5 70000000 0.33 2.7
node 1 0 0 0
node 2 0.15 0 0
node 3 0.3 0 0
……
fix 1 1 1 1
fix 5 0 0 1
fix 6 0 0 1
fix 10 0 0 1
element 20NodeBrick 1 1 2 7 6 11 12 17 16 112 127 167 116 1212 1317 1717 1216 211 312 817 716 5 0 0 -27
element 20NodeBrick 2 2 3 8 7 12 13 18 17 123 138 178 127 1313 1418 1818 1317 312 413 918 817 5 0 0 -27
element 20NodeBrick 3 3 4 9 8 13 14 19 18 134 149 189 138 1414 1519 1919 1418 413 514 1019 918 5 0 0 -27
element 20NodeBrick 4 4 5 10 9 14 15 20 19 145 610 1010 149 1515 1620 2020 1519 514 615 1120 1019 5 0 0 -27
……
# ------------------------------------------------------------------------
# apply gravity load
# -------------------------------------------------------------------------

# Newmark parameters
set gamma 0.5
set beta 0.25

# analysis objects
constraints Penalty 1e18 1e18
test NormDispIncr 1e-6 50 0
algorithm KrylovNewton
numberer RCM
system ProfileSPD
set nw 1.5
integrator Newmark $nw [expr pow($nw+0.5, 2)/4]
analysis Transient

set startT [clock seconds]
analyze 10 5e1
puts "Finished with linear elastic gravity analysis..."
set endT [clock seconds]
puts "Execution time: [expr $endT-$startT] seconds."

wipeAnalysis
remove recorders
eval "recorder Element -eleRange 1 32 -time -file elelocal.out -dT 0.02 localForce"

pattern Plain 1 Constant {
load 81 2 0 0
load 85 2 0 0
load 86 2 0 0
load 90 2 0 0
}
integrator HHT 0.67
set massProportionalDamping 0.45 ;
set InitStiffnessProportionalDamping 0.05;
rayleigh $massProportionalDamping 0.0 $InitStiffnessProportionalDamping 0.0
constraints Penalty 1.e12 1.e12
test NormDispIncr 1.0e-3 50 0
algorithm KrylovNewton
system SparseSYM
numberer Plain
analysis VariableTransient

set dt 0.02
# set numSteps 1000
set numSteps 10
set startT [clock seconds]
analyze $numSteps $dt [expr $dt/64] $dt 15
set endT [clock seconds]
puts "Execution time: [expr $endT-$startT] seconds."

wipe

[fmk]

you want -force, not localForce (that option is for beam column elements only)