element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

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chicken
Posts: 9
Joined: Thu Jul 16, 2020 7:25 pm

element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by chicken » Fri Apr 09, 2021 12:00 am

This is my code
proc MomentCurvature {secTag axialLoad maxK {numIncr 100} } {
# Define two nodes at (0,0)
node 1 0.0 0.0
node 2 0.0 0.0

# Fix all degrees of freedom except axial and bending
fix 1 1 1 1
fix 2 0 1 0

# Define element
# tag ndI ndJ secTag
element zeroLengthSection 1 1 2 $secTag

# Create recorder
recorder Node -file section$secTag.out -time -node 2 -dof 3 disp
recorder Element -file Element1.out -time -ele 1 2 section 1 fiber 5.68 4.8 stressStrain


# Define constant axial load
pattern Plain 1 "Constant" {
load 2 $axialLoad 0.0 0.0
}

# Define analysis parameters
integrator LoadControl 0.0
system SparseGeneral -piv; # Overkill, but may need the pivoting!
test NormUnbalance 1.0e-2 10
numberer Plain
constraints Plain
algorithm Newton
analysis Static

# Do one analysis for constant axial load
analyze 1

# Define reference moment
pattern Plain 2 "Linear" {
load 2 0.0 0.0 1.0
}

# Compute curvature increment
set dK [expr $maxK/$numIncr]

# Use displacement control at node 2 for section analysis
integrator DisplacementControl 2 3 $dK 1 $dK $dK

# Do the section analysis
analyze $numIncr
}


# Define model builder
# --------------------
model basic -ndm 2 -ndf 3

# Define materials for nonlinear columns
# ------------------------------------------
uniaxialMaterial Concrete02 1 -37597.5 -0.0055 -7519.5 -0.0161 0.1 3759.7 1319350
uniaxialMaterial Concrete02 2 -37597.5 -0.0055 -7519.5 -0.0137 0.1 3759.7 1319350

uniaxialMaterial Steel02 3 335000 200000000 0.01 18 0.925 0.15


puts "section"
section Fiber 1 {
patch rect 1 15 1 -6.5 4.8 6.5 6
patch rect 1 15 1 -6.5 -6 6.5 -4.8
patch rect 1 1 8 -6.5 -4.8 -5.6 4.8
patch rect 1 1 8 -0.3 -4.8 0.3 4.8
patch rect 1 1 8 5.6 -4.8 6.5 4.8
layer straight 3 132 0.000615 -6.45 5.95 6.45 5.95
layer straight 3 132 0.000615 -6.45 4.85 6.45 4.85
layer straight 3 132 0.000615 -6.45 -4.85 6.45 -4.85
layer straight 3 132 0.000615 -6.45 -5.95 6.45 -5.95
layer straight 3 120 0.000615 -6.45 5.95 -6.45 -5.95
layer straight 3 120 0.000615 -5.65 5.95 -5.65 -5.95
layer straight 3 120 0.000615 -0.25 5.95 -0.25 -5.95
layer straight 3 120 0.000615 0.25 5.95 0.25 -5.95
layer straight 3 120 0.000615 5.65 5.95 5.65 -5.95
layer straight 3 120 0.000615 6.45 5.95 6.45 -5.95
}


# Estimate yield curvature
# (Assuming no axial load and only top and bottom steel)
set d 12.975
set epsy 0.001675
set Ky 1.8442058904486650151390035783099e-4

# Print estimate to standard output
puts "Estimated yield curvature: $Ky"

# Set axial load
set P -450000

set mu 8; # Target ductility for analysis
set numIncr 100; # Number of analysis increments

# Call the section analysis procedure
MomentCurvature 1 $P [expr $Ky*$mu] $numIncr

This output command:
recorder Element -file Element1.out -time -ele 1 2 section 1 fiber 5.68 4.8 stressStrain
Unable to output the specified fiber stress and strain
Ask everybody to help see be what reason :roll: :roll: :roll: :roll: :roll: :roll:

mhscott
Posts: 582
Joined: Tue Jul 06, 2004 3:38 pm
Location: Corvallis, Oregon USA
Contact:

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by mhscott » Fri Apr 09, 2021 6:16 am

Why do you have the 2 in '-ele 1 2 section...'?

chicken
Posts: 9
Joined: Thu Jul 16, 2020 7:25 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by chicken » Fri Apr 09, 2021 5:12 pm

Thank you for your reply,I don't know what you mean, the one at the bottom is not my command stream,I only have one in '-ele 1 2 section...

chicken
Posts: 9
Joined: Thu Jul 16, 2020 7:25 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by chicken » Fri Apr 09, 2021 5:14 pm

mhscott wrote:
Fri Apr 09, 2021 6:16 am
Why do you have the 2 in '-ele 1 2 section...'?
Thank you for your reply,I don't know what you mean, the one at the bottom is not my command stream,I only have one in '-ele 1 2 section...

chicken
Posts: 9
Joined: Thu Jul 16, 2020 7:25 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by chicken » Fri Apr 09, 2021 5:25 pm

mhscott wrote:
Fri Apr 09, 2021 6:16 am
Why do you have the 2 in '-ele 1 2 section...'?
I think I know what you mean,Are you saying this should be the case,
recorder Element -file Element1.out -time -ele 1 Section 1 fiber 5.6 4.8 strainstress
I tried again, Element1.out still got the bending moment Rather than strainstress
Can you help me see why I can't output the stress strain :roll: :roll: :roll: :roll: :roll:

section1.out got the Bending curvature Element1.out got the bending moment

section1.out
0 5.85311e-021
249900 1.47536e-005
498028 2.95073e-005
744360 4.42609e-005
988873 5.90146e-005
1.23154e+006 7.37682e-005
1.4661e+006 8.85219e-005
1.70399e+006 0.000103276
1.94091e+006 0.000118029
2.17477e+006 0.000132783
2.32598e+006 0.000147536
2.45079e+006 0.00016229
2.567e+006 0.000177044
2.6658e+006 0.000191797
2.76236e+006 0.000206551
2.84771e+006 0.000221305
2.92844e+006 0.000236058
3.00806e+006 0.000250812
3.07986e+006 0.000265566
3.14816e+006 0.000280319
3.21333e+006 0.000295073
3.27355e+006 0.000309827
3.3241e+006 0.00032458
3.36479e+006 0.000339334
3.39915e+006 0.000354088
3.42869e+006 0.000368841
3.45499e+006 0.000383595
3.47913e+006 0.000398348
3.49889e+006 0.000413102
3.51421e+006 0.000427856
3.5271e+006 0.000442609
3.54098e+006 0.000457363
3.55401e+006 0.000472117
3.56628e+006 0.00048687
3.58959e+006 0.000501624
3.61589e+006 0.000516378
3.64156e+006 0.000531131
3.66087e+006 0.000545885
3.67413e+006 0.000560639
3.68689e+006 0.000575392
3.69919e+006 0.000590146
3.71068e+006 0.0006049
3.72379e+006 0.000619653
3.7373e+006 0.000634407
3.75047e+006 0.00064916
3.76331e+006 0.000663914
3.77584e+006 0.000678668
3.78941e+006 0.000693421
3.8032e+006 0.000708175
3.81672e+006 0.000722929
3.82731e+006 0.000737682
3.83732e+006 0.000752436
3.8471e+006 0.00076719
3.85677e+006 0.000781943
3.86758e+006 0.000796697
3.8781e+006 0.000811451
3.88831e+006 0.000826204
3.89816e+006 0.000840958
3.90757e+006 0.000855712
3.91649e+006 0.000870465
3.92474e+006 0.000885219
3.93169e+006 0.000899972
3.93908e+006 0.000914726
3.94699e+006 0.00092948
3.95445e+006 0.000944233
3.96148e+006 0.000958987
3.9681e+006 0.000973741
3.9743e+006 0.000988494
3.98007e+006 0.00100325
3.9854e+006 0.001018
3.99031e+006 0.00103276
3.99464e+006 0.00104751
3.99623e+006 0.00106226
3.9976e+006 0.00107702
3.99966e+006 0.00109177

Element1.out

0
249900
498028
744360
988873
1.23154e+006
1.4661e+006
1.70399e+006
1.94091e+006
2.17477e+006
2.32598e+006
2.45079e+006
2.567e+006
2.6658e+006
2.76236e+006
2.84771e+006
2.92844e+006
3.00806e+006
3.07986e+006
3.14816e+006
3.21333e+006
3.27355e+006
3.3241e+006
3.36479e+006
3.39915e+006
3.42869e+006
3.45499e+006
3.47913e+006
3.49889e+006
3.51421e+006
3.5271e+006
3.54098e+006
3.55401e+006
3.56628e+006
3.58959e+006
3.61589e+006
3.64156e+006
3.66087e+006
3.67413e+006
3.68689e+006
3.69919e+006
3.71068e+006
3.72379e+006
3.7373e+006
3.75047e+006
3.76331e+006
3.77584e+006
3.78941e+006
3.8032e+006
3.81672e+006
3.82731e+006
3.83732e+006
3.8471e+006
3.85677e+006
3.86758e+006
3.8781e+006
3.88831e+006
3.89816e+006
3.90757e+006
3.91649e+006
3.92474e+006
3.93169e+006
3.93908e+006
3.94699e+006
3.95445e+006
3.96148e+006
3.9681e+006
3.9743e+006
3.98007e+006
3.9854e+006
3.99031e+006
3.99464e+006
3.99623e+006
3.9976e+006
3.99966e+006
4.0015e+006
4.00317e+006
4.00471e+006
4.00613e+006
4.00745e+006
4.00868e+006
4.00983e+006
4.01091e+006
4.01192e+006
4.01285e+006
4.01373e+006
4.01454e+006
4.01529e+006
4.01774e+006
4.02099e+006
4.02414e+006
4.02722e+006
4.02984e+006
4.03235e+006
4.0348e+006
4.03718e+006
4.0395e+006
4.04214e+006
4.0447e+006
4.04718e+006
4.04958e+006

abira
Posts: 26
Joined: Mon Feb 03, 2020 10:26 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by abira » Mon Apr 12, 2021 8:41 am

The output you are getting is not bending moment but it is the pseudotime. There must be something wrong with your code due to which it is unable to record the stress and strain and you are only getting pseudotime as an output.

chicken
Posts: 9
Joined: Thu Jul 16, 2020 7:25 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by chicken » Tue Apr 13, 2021 1:16 am

abira wrote:
Mon Apr 12, 2021 8:41 am
The output you are getting is not bending moment but it is the pseudotime. There must be something wrong with your code due to which it is unable to record the stress and strain and you are only getting pseudotime as an output.
Thank you for your reply. Could you please help me to see how to modify the output stress and strain :cry: :cry: :cry: :cry: :cry:

selimgunay
Posts: 879
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by selimgunay » Tue Apr 13, 2021 2:28 pm

You can find the stress-strain recorder command at the very bottom of this link:

https://opensees.berkeley.edu/wiki/inde ... t_Recorder

abira
Posts: 26
Joined: Mon Feb 03, 2020 10:26 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by abira » Tue Apr 13, 2021 8:09 pm

chicken wrote:
Tue Apr 13, 2021 1:16 am
abira wrote:
Mon Apr 12, 2021 8:41 am
The output you are getting is not bending moment but it is the pseudotime. There must be something wrong with your code due to which it is unable to record the stress and strain and you are only getting pseudotime as an output.
Thank you for your reply. Could you please help me to see how to modify the output stress and strain :cry: :cry: :cry: :cry: :cry:
why don't you begin with just a simple rectangular cross-section with one layer of steel and see if you are able to get the results.

abira
Posts: 26
Joined: Mon Feb 03, 2020 10:26 pm

Re: element zeroLengthSection-The moment curvature analysis cannot output the stress and strain of the fiber

Post by abira » Thu Apr 15, 2021 12:47 am

chicken wrote:
Tue Apr 13, 2021 1:16 am
abira wrote:
Mon Apr 12, 2021 8:41 am
The output you are getting is not bending moment but it is the pseudotime. There must be something wrong with your code due to which it is unable to record the stress and strain and you are only getting pseudotime as an output.
Thank you for your reply. Could you please help me to see how to modify the output stress and strain :cry: :cry: :cry: :cry: :cry:
You don't have to specify the section number in case of zero length section. Just .... section fiber ....

reference: (check the bottom of the page)
https://opensees.berkeley.edu/OpenSees/ ... al/645.htm

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