Hi all,
I want to simulate a monotonic, consolidated and undrained triaxial compression (CU) test. I am using a single BrickUP element (8-node) and PressureDependentMultiyield02 material. The specimen is a cylinder with the diamter of 50mm and height of 100mm. To make use of the axisymmetry of the specimen, I am just modeling 1/8 of the specimen with the cell pressure of 50kPa and strain control rate of 10%/min. The simulation turns out to be wrong since the generated pore water pressure can reach an extremely high value(about 1.8e5 kPa) at the end of the loading.
Actually, I have a few doubts with this model. First, how should the confining pressure be applied to the element, uniform load or equivalent nodal load? Second, since I am modeling 1/8 of the specimen, should the target displacement be a half of the recorded displacement at the end of the test according to symmetry? If yes, it seems to be contradictory with the fact that the bottom of the specimen is fixed in the experiment. Third, the pore water pressure of the OpenSees model is actually always negative and keeps decreasing since the valve is closed. This is inconsistent with the observation in the experiment, which shows that the pore water pressure first increases, and then drops down, finally reaches a nearly stable negative value, meaning that the dense soil specimen exhibits a strong dilatancy.
Could anybody look at my script as posted below and figure out the problem with it? Any advice or ideas will be appreciated.
##----------------------------#
wipe
## ------------------------ #
## Test Specific parameters #
## ------------------------ #
# Confinement Stress
set pConf [expr -50]
set npConf [expr -50]
# Deviatoric strain
set devDisp [expr (-0.01536/2)]
# Permeablity
set perm [expr 8.5e-5/(9.81*1)]
# Initial void ratio
set vR 0.603
## Rayleigh damping parameter
set damp 0.03
set pi 3.141592654
set omega1 [expr 2*$pi*0.2]
set omega2 [expr 2*$pi*20]
set a1 [expr 2.0*$damp/($omega1+$omega2)]
set a0 [expr $a1*$omega1*$omega2]
# Create a 3D model with 4 Degrees of Freedom
model BasicBuilder -ndm 3 -ndf 4
# Create nodes
node 1 0.025 0.0 0.0
node 2 0.025 0.025 0.0
node 3 0.0 0.025 0.0
node 4 0.0 0.0 0.0
node 5 0.025 0.0 0.05
node 6 0.025 0.025 0.05
node 7 0.0 0.025 0.05
node 8 0.0 0.0 0.05
# Create Fixities
fix 1 0 1 1 1
fix 2 0 0 1 1
fix 3 1 0 1 1
fix 4 1 1 1 1
fix 5 0 1 0 1
fix 6 0 0 0 1
fix 7 1 0 0 1
fix 8 1 1 0 1
set Gref 2.82e4
set niu 0.3
set Bref [expr 2*$Gref*(1+$niu)/(3*(1-2*$niu))]
set fAngle 35.5
set PTAngle 26
set c 18
set PDCoef 0.5
# Create material
nDMaterial PressureDependMultiYield02 1 3 2.63 $Gref $Bref $fAngle 0.1 \
101.0 $PDCoef $PTAngle 0.028 0.05 0.1 0.05 \
20 5.0 3.0 1.0 \
0.0 $vR 0.9 0.02 0.7 101.0 $c
set fBulk [expr 2.2e6*(1+$vR)/$vR]
element brickUP 1 1 2 3 4 5 6 7 8 1 $fBulk 1.0 $perm $perm $perm 0.0 0.0 0.0
# Create recorders
recorder Node -file disp1.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press1.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress1.out -time material 1 stress
recorder Element -file strain1.out -time material 1 strain
updateMaterialStage -material 1 -stage 0
# Create analysis
constraints Penalty 1.0e18 1.0e18
test NormDispIncr 1.0e-5 500 1
algorithm Newton
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
# Apply confinement pressure
set pNode [expr $pConf / 4.0]
set npNode [expr $npConf / 4.0]
pattern Plain 1 {Series -time {0 25000 1e10} -values {0 1 1} -factor 1} {
load 1 $npNode 0.0 0.0 0.0
load 2 $npNode $npNode 0.0 0.0
load 3 0.0 $npNode 0.0 0.0
load 4 0.0 0.0 0.0 0.0
load 5 $npNode 0.0 $pNode 0.0
load 6 $npNode $npNode $pNode 0.0
load 7 0.0 $npNode $pNode 0.0
load 8 0.0 0.0 $pNode 0.0
}
analyze 100 100
puts "Done Elastic"
updateMaterialStage -material 1 -stage 1
analyze 100 100
analyze 50 100
puts "Done Plastic"
puts "Gravity Done!"
# Close drainage valves
for {set x 1} {$x<9} {incr x} {
remove sp $x 4
}
constraints Transformation
test EnergyIncr 1.0e-3 500 1
algorithm NewtonLineSearch
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
analyze 50 100
puts "Drainage of upper surface closed!"
wipeAnalysis
remove recorders
recorder Node -file disp2.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press2.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress2.out -time material 1 stress
recorder Element -file strain2.out -time material 1 strain
# Read vertical displacement of top plane
set vertDisp [nodeDisp 5 3]
# Apply deviatoric strain
set lValues [list 1 [expr 1+$devDisp/$vertDisp] [expr 1+$devDisp/$vertDisp]]
set ts "{Series -time {30000 130000 1030000} -values {$lValues} -factor 1}"
eval "pattern Plain 2 $ts {
sp 5 3 $vertDisp
sp 6 3 $vertDisp
sp 7 3 $vertDisp
sp 8 3 $vertDisp
}"
constraints Transformation
test NormDispIncr 1.0e-05 500 1
integrator DisplacementControl 5 3 [expr 0.01536/(2*939)] 50 [expr 0.01536/(2*939)] [expr 0.01536/(2*939)]
rayleigh $a0 0. $a1 0.0
algorithm NewtonLineSearch
numberer RCM
system UmfPack
analysis VariableTransient
set dT 100
set numStep 10000
set startT [clock seconds]
while {[expr abs([nodeDisp 5 3])]< [expr -1*($devDisp+$vertDisp)] && [getTime]<1.03e6} {
analyze 1 $dT [expr $dT/100] $dT 20
puts "time = [getTime] sec"
}
puts "analysis done"
wipe
monotonic triaxial test simulation
Moderators: silvia, selimgunay, Moderators
-
skamalzare
- Posts: 112
- Joined: Thu Jun 27, 2013 11:45 am
- Location: Seattle, WA
Re: monotonic triaxial test simulation
Hello Sanjianke,
I ran your code and noticed you are applying to much load on your sample. If you look at your stresses after gravity analyses, you have sigma_r = 40 MPa and sigma_a = 80 MPa. Too much! The model is working right because you are applying 50 kN load on top, and have area = 0.025*0.025 m2, which results 80 MPa stress (Load/area). This probably is the reason why you are seeing too much PWP.
I am very suspicious if PDMY02 can give you any realistic values under 80 MPa stress (or anything above 1 MPa).
I am not sure if you can apply distributed load on top of brick elements. I usually apply nodal loads and ensure the stresses are what I wanted.
If you turn off the OpenSees analysis reports, you can see that right before shearing stage, you receive an error that Transient analyses did not recognize the integrator. This might be because transient analyses don't work with DisplacementControl integrator (maybe Frank can explain this better). The program then proceeds with default Newmark <0.5,0.25>. I think a better way to simulate shearing part can be to apply deviatoric loads instead of displacements and use the transient analyses to capture the response (like what you did in consolidation stage).
The default value for c parameter of PDMY02 is 0.1 and you are using 18. Moreover, you are inputting rho = 2.63 Mg/m3 (too much for soils). You might want to double check these!
Bests,
Soheil
I ran your code and noticed you are applying to much load on your sample. If you look at your stresses after gravity analyses, you have sigma_r = 40 MPa and sigma_a = 80 MPa. Too much! The model is working right because you are applying 50 kN load on top, and have area = 0.025*0.025 m2, which results 80 MPa stress (Load/area). This probably is the reason why you are seeing too much PWP.
I am very suspicious if PDMY02 can give you any realistic values under 80 MPa stress (or anything above 1 MPa).
I am not sure if you can apply distributed load on top of brick elements. I usually apply nodal loads and ensure the stresses are what I wanted.
If you turn off the OpenSees analysis reports, you can see that right before shearing stage, you receive an error that Transient analyses did not recognize the integrator. This might be because transient analyses don't work with DisplacementControl integrator (maybe Frank can explain this better). The program then proceeds with default Newmark <0.5,0.25>. I think a better way to simulate shearing part can be to apply deviatoric loads instead of displacements and use the transient analyses to capture the response (like what you did in consolidation stage).
The default value for c parameter of PDMY02 is 0.1 and you are using 18. Moreover, you are inputting rho = 2.63 Mg/m3 (too much for soils). You might want to double check these!
Bests,
Soheil
---
PhD, EIT, Geotechnical Engineer
Condon-Johnson & Associates INC
PhD, EIT, Geotechnical Engineer
Condon-Johnson & Associates INC
Re: monotonic triaxial test simulation
Hi, skamalzare,
So glad to see your reply. It is very insightful. I have modified my script as you suggested. It seems the pore water pressure might be ok at the consolidation stage. But the analysis results of the shearing stage still makes no sense if I apply the deviatoric loading as shown below at the top of the element. It looks like the loading is not actually applied on the element. And I don't know why...Could you please have a look at my revised script below when you are free? Thank you very much in advance.
time(sec) deviatoric load (kN)
0.1 0
0.2 0
0.3 0.021574973
0.4 0.045111307
0.5 0.058840836
0.6 0.068647641
0.7 0.076493086
0.8 0.084338531
0.9 0.088261253
1 0.094145337
1.1 0.096106698
1.2 0.101990782
1.3 0.101990782
1.4 0.107874865
1.5 0.109836226
1.6 0.113758949
1.7 0.11572031
1.8 0.117681671
1.9 0.119643032
2 0.125527116
2.1 0.127488477
2.2 0.129449838
2.3 0.131411199
2.4 0.133372561
2.5 0.137295283
2.6 0.139256644
2.7 0.141218005
2.8 0.145140728
2.9 0.147102089
3 0.14906345
3.1 0.152986172
3.2 0.154947534
3.3 0.158870256
3.4 0.160831617
3.5 0.160831617
3.6 0.16475434
3.7 0.168677062
3.8 0.172599784
3.9 0.172599784
4 0.178483868
4.1 0.180445229
4.2 0.184367951
4.3 0.188290674
4.4 0.192213396
4.5 0.192213396
4.6 0.196136118
4.7 0.200058841
4.8 0.203981563
4.9 0.205942924
5 0.209865647
5.1 0.213788369
5.2 0.217711091
5.3 0.221633814
5.4 0.225556536
5.5 0.229479259
5.6 0.23144062
5.7 0.235363342
5.8 0.241247426
5.9 0.243208787
6 0.247131509
6.1 0.251054232
6.2 0.256938315
6.3 0.258899676
6.4 0.26478376
6.5 0.268706482
6.6 0.272629205
6.7 0.276551927
6.8 0.282436011
6.9 0.286358733
7 0.290281455
7.1 0.296165539
7.2 0.300088261
7.3 0.304010984
7.4 0.309895067
7.5 0.31381779
7.6 0.317740512
7.7 0.321663234
7.8 0.327547318
7.9 0.333431401
8 0.339315485
8.1 0.343238207
8.2 0.34716093
8.3 0.353045013
8.4 0.360890458
8.5 0.362851819
8.6 0.368735903
8.7 0.374619986
8.8 0.38050407
8.9 0.386388153
9 0.392272237
9.1 0.39815632
9.2 0.402079043
9.3 0.407963126
9.4 0.415808571
9.5 0.419731294
9.6 0.425615377
9.7 0.431499461
9.8 0.439344905
9.9 0.443267628
10 0.451113072
10.1 0.458958517
10.2 0.46288124
10.3 0.470726684
10.4 0.476610768
10.5 0.482494851
10.6 0.490340296
10.7 0.498185741
10.8 0.504069824
10.9 0.511915269
11 0.517799353
11.1 0.525644797
11.2 0.531528881
11.3 0.539374326
11.4 0.547219771
11.5 0.553103854
11.6 0.560949299
11.7 0.568794744
11.8 0.576640188
11.9 0.582524272
12 0.592331078
12.1 0.598215161
12.2 0.608021967
12.3 0.613906051
12.4 0.621751496
12.5 0.631558301
12.6 0.639403746
12.7 0.649210552
12.8 0.655094636
12.9 0.66294008
13 0.672746886
13.1 0.680592331
13.2 0.690399137
13.3 0.700205943
13.4 0.708051388
13.5 0.717858194
13.6 0.725703638
13.7 0.735510444
13.8 0.743355889
13.9 0.753162695
14 0.76100814
14.1 0.772776307
14.2 0.780621751
14.3 0.788467196
14.4 0.800235363
14.5 0.808080808
14.6 0.817887614
14.7 0.82769442
14.8 0.837501226
14.9 0.847308032
15 0.857114838
15.1 0.868883005
15.2 0.878689811
15.3 0.888496617
15.4 0.898303423
15.5 0.908110228
15.6 0.919878396
15.7 0.929685202
15.8 0.939492007
15.9 0.953221536
16 0.963028342
16.1 0.972835148
16.2 0.984603315
16.3 0.996371482
16.4 1.004216927
16.5 1.017946455
16.6 1.027753261
16.7 1.039521428
16.8 1.051289595
16.9 1.063057762
17 1.074825929
17.1 1.086594096
17.2 1.098362263
17.3 1.112091792
17.4 1.12582132
17.5 1.135628126
17.6 1.149357654
17.7 1.161125821
17.8 1.170932627
17.9 1.184662156
18 1.196430323
18.1 1.20819849
18.2 1.221928018
18.3 1.235657546
18.4 1.249387075
18.5 1.263116603
18.6 1.272923409
18.7 1.286652937
18.8 1.300382465
18.9 1.312150633
19 1.325880161
19.1 1.34157105
19.2 1.353339217
19.3 1.369030107
19.4 1.380798274
19.5 1.396489163
19.6 1.408257331
19.7 1.421986859
19.8 1.43963911
19.9 1.453368638
20 1.465136805
20.1 1.480827694
20.2 1.494557223
20.3 1.510248112
20.4 1.52397764
20.5 1.53966853
20.6 1.553398058
20.7 1.567127587
20.8 1.582818476
20.9 1.598509365
21 1.612238894
21.1 1.627929783
21.2 1.643620673
21.3 1.659311562
21.4 1.673041091
21.5 1.68873198
21.6 1.706384231
21.7 1.72207512
21.8 1.735804648
21.9 1.753456899
22 1.769147789
22.1 1.784838678
22.2 1.800529568
22.3 1.816220457
22.4 1.833872708
22.5 1.849563597
22.6 1.867215848
22.7 1.882906737
22.8 1.898597627
22.9 1.914288516
23 1.933902128
23.1 1.949593018
23.2 1.965283907
23.3 1.982936158
23.4 2.00254977
23.5 2.018240659
23.6 2.033931548
23.7 2.049622438
23.8 2.06923605
23.9 2.0868883
24 2.10257919
24.1 2.122192802
24.2 2.141806414
24.3 2.157497303
24.4 2.175149554
24.5 2.192801804
24.6 2.212415416
24.7 2.230067667
24.8 2.247719918
24.9 2.269294891
25 2.283024419
25.1 2.30067667
25.2 2.320290281
25.3 2.337942532
25.4 2.353633422
25.5 2.375208395
25.6 2.392860645
25.7 2.410512896
25.8 2.428165147
25.9 2.447778758
26 2.465431009
26.1 2.48308326
26.2 2.502696872
26.3 2.520349122
26.4 2.538001373
26.5 2.553692262
26.6 2.573305874
26.7 2.588996764
26.8 2.608610376
26.9 2.624301265
27 2.643914877
27.1 2.659605766
27.2 2.673335295
27.3 2.690987545
27.4 2.706678435
27.5 2.722369324
27.6 2.736098853
27.7 2.753751103
27.8 2.767480632
27.9 2.777287437
28 2.791016966
28.1 2.800823772
28.2 2.812591939
28.3 2.824360106
28.4 2.836128273
28.5 2.845935079
28.6 2.849857801
28.7 2.859664607
28.8 2.867510052
28.9 2.875355497
29 2.879278219
29.1 2.885162303
29.2 2.891046386
29.3 2.894969109
29.4 2.898891831
29.5 2.902814553
29.6 2.906737276
29.7 2.910659998
29.8 2.916544082
29.9 2.920466804
30 2.922428165
30.1 2.922428165
30.2 2.926350888
30.3 2.926350888
30.4 2.926350888
30.5 2.93027361
30.6 2.934196332
30.7 2.934196332
30.8 2.934196332
30.9 2.938119055
31 2.938119055
31.1 2.940080416
31.2 2.940080416
31.3 2.944003138
31.4 2.944003138
31.5 2.945964499
31.6 2.945964499
31.7 2.947925861
31.8 2.947925861
31.9 2.947925861
32 2.949887222
32.1 2.951848583
32.2 2.951848583
32.3 2.953809944
32.4 2.953809944
32.5 2.955771305
32.6 2.955771305
32.7 2.957732666
32.8 2.957732666
32.9 2.957732666
33 2.957732666
33.1 2.955771305
33.2 2.959694028
33.3 2.957732666
33.4 2.961655389
33.5 2.961655389
33.6 2.961655389
33.7 2.96361675
33.8 2.96361675
33.9 2.96361675
34 2.961655389
34.1 2.961655389
34.2 2.965578111
34.3 2.965578111
34.4 2.96361675
34.5 2.965578111
34.6 2.965578111
34.7 2.967539472
34.8 2.969500834
34.9 2.969500834
35 2.969500834
35.1 2.967539472
35.2 2.969500834
35.3 2.971462195
35.4 2.973423556
35.5 2.973423556
35.6 2.975384917
35.7 2.973423556
35.8 2.971462195
35.9 2.973423556
36 2.975384917
36.1 2.975384917
36.2 2.973423556
36.3 2.975384917
36.4 2.977346278
36.5 2.977346278
36.6 2.975384917
36.7 2.977346278
36.8 2.97930764
36.9 2.97930764
37 2.981269001
37.1 2.981269001
37.2 2.977346278
37.3 2.977346278
37.4 2.97930764
37.5 2.97930764
37.6 2.981269001
37.7 2.983230362
37.8 2.985191723
37.9 2.983230362
38 2.981269001
38.1 2.981269001
38.2 2.983230362
38.3 2.983230362
38.4 2.985191723
38.5 2.985191723
38.6 2.989114445
38.7 2.985191723
38.8 2.989114445
38.9 2.987153084
39 2.989114445
39.1 2.989114445
39.2 2.993037168
39.3 2.993037168
39.4 2.991075807
39.5 2.991075807
39.6 2.991075807
39.7 2.993037168
39.8 2.993037168
39.9 2.994998529
40 2.994998529
40.1 2.99695989
40.2 2.994998529
40.3 2.994998529
40.4 2.994998529
40.5 2.994998529
40.6 2.993037168
40.7 2.994998529
40.8 2.994998529
40.9 2.99695989
41 2.99695989
41.1 2.998921251
41.2 2.998921251
41.3 3.000882613
41.4 3.000882613
41.5 2.998921251
41.6 2.998921251
41.7 3.000882613
41.8 2.998921251
41.9 2.998921251
42 3.000882613
42.1 3.002843974
42.2 3.002843974
42.3 3.000882613
42.4 3.000882613
42.5 3.000882613
42.6 3.000882613
42.7 3.000882613
42.8 3.004805335
42.9 3.006766696
43 3.002843974
43.1 3.002843974
43.2 3.004805335
43.3 3.002843974
43.4 3.002843974
43.5 3.004805335
43.6 3.008728057
43.7 3.006766696
43.8 3.004805335
43.9 3.006766696
44 3.006766696
44.1 3.006766696
44.2 3.008728057
44.3 3.008728057
44.4 3.010689418
44.5 3.010689418
44.6 3.01265078
44.7 3.010689418
44.8 3.010689418
44.9 3.010689418
45 3.010689418
45.1 3.010689418
45.2 3.010689418
45.3 3.008728057
45.4 3.010689418
45.5 3.01265078
45.6 3.016573502
45.7 3.014612141
45.8 3.016573502
45.9 3.014612141
46 3.01265078
46.1 3.014612141
46.2 3.01265078
46.3 3.014612141
46.4 3.016573502
46.5 3.016573502
46.6 3.014612141
46.7 3.014612141
46.8 3.016573502
46.9 3.020496224
47 3.020496224
47.1 3.022457586
47.2 3.020496224
47.3 3.020496224
47.4 3.020496224
47.5 3.016573502
47.6 3.022457586
47.7 3.020496224
47.8 3.022457586
47.9 3.022457586
48 3.020496224
48.1 3.020496224
48.2 3.022457586
48.3 3.024418947
48.4 3.022457586
48.5 3.024418947
48.6 3.024418947
48.7 3.024418947
48.8 3.024418947
48.9 3.026380308
49 3.028341669
49.1 3.024418947
49.2 3.024418947
49.3 3.026380308
49.4 3.028341669
49.5 3.028341669
49.6 3.026380308
49.7 3.024418947
49.8 3.026380308
49.9 3.028341669
50 3.028341669
50.1 3.03030303
50.2 3.028341669
50.3 3.03030303
50.4 3.026380308
50.5 3.028341669
50.6 3.028341669
50.7 3.03030303
50.8 3.03030303
50.9 3.028341669
51 3.024418947
51.1 3.03030303
51.2 3.03030303
51.3 3.028341669
51.4 3.028341669
51.5 3.032264391
51.6 3.03030303
51.7 3.032264391
51.8 3.03030303
51.9 3.032264391
52 3.03030303
52.1 3.032264391
52.2 3.032264391
52.3 3.032264391
52.4 3.028341669
52.5 3.03030303
52.6 3.03030303
52.7 3.028341669
52.8 3.032264391
52.9 3.028341669
53 3.03030303
53.1 3.028341669
53.2 3.03030303
53.3 3.032264391
53.4 3.028341669
53.5 3.032264391
53.6 3.032264391
53.7 3.034225753
53.8 3.032264391
53.9 3.03030303
54 3.036187114
54.1 3.036187114
54.2 3.032264391
54.3 3.034225753
54.4 3.036187114
54.5 3.036187114
54.6 3.032264391
54.7 3.034225753
54.8 3.032264391
54.9 3.03030303
55 3.034225753
55.1 3.034225753
55.2 3.032264391
55.3 3.03030303
55.4 3.032264391
55.5 3.034225753
55.6 3.034225753
55.7 3.034225753
55.8 3.036187114
55.9 3.036187114
56 3.032264391
56.1 3.034225753
56.2 3.036187114
56.3 3.034225753
56.4 3.036187114
56.5 3.038148475
56.6 3.036187114
56.7 3.034225753
56.8 3.036187114
56.9 3.034225753
57 3.036187114
57.1 3.036187114
57.2 3.038148475
57.3 3.040109836
57.4 3.038148475
57.5 3.038148475
57.6 3.038148475
57.7 3.038148475
57.8 3.038148475
57.9 3.040109836
58 3.044032559
58.1 3.040109836
58.2 3.038148475
58.3 3.040109836
58.4 3.036187114
58.5 3.036187114
58.6 3.038148475
58.7 3.038148475
58.8 3.036187114
58.9 3.038148475
59 3.040109836
59.1 3.038148475
59.2 3.036187114
59.3 3.040109836
59.4 3.040109836
59.5 3.038148475
59.6 3.038148475
59.7 3.036187114
59.8 3.036187114
59.9 3.036187114
60 3.034225753
60.1 3.038148475
60.2 3.036187114
60.3 3.034225753
60.4 3.036187114
60.5 3.038148475
60.6 3.040109836
60.7 3.040109836
60.8 3.040109836
60.9 3.040109836
61 3.038148475
61.1 3.040109836
61.2 3.038148475
61.3 3.038148475
61.4 3.038148475
61.5 3.040109836
61.6 3.040109836
61.7 3.038148475
61.8 3.036187114
61.9 3.038148475
62 3.040109836
62.1 3.040109836
62.2 3.044032559
62.3 3.042071197
62.4 3.040109836
62.5 3.040109836
62.6 3.040109836
62.7 3.040109836
62.8 3.038148475
62.9 3.042071197
63 3.040109836
63.1 3.038148475
63.2 3.038148475
63.3 3.038148475
63.4 3.040109836
63.5 3.040109836
63.6 3.042071197
63.7 3.038148475
63.8 3.040109836
63.9 3.040109836
64 3.040109836
64.1 3.042071197
64.2 3.044032559
64.3 3.044032559
64.4 3.044032559
64.5 3.042071197
64.6 3.040109836
64.7 3.042071197
64.8 3.042071197
64.9 3.040109836
65 3.038148475
65.1 3.044032559
65.2 3.040109836
65.3 3.040109836
65.4 3.040109836
65.5 3.040109836
65.6 3.042071197
65.7 3.040109836
65.8 3.042071197
65.9 3.044032559
66 3.038148475
66.1 3.040109836
66.2 3.042071197
66.3 3.040109836
66.4 3.040109836
66.5 3.040109836
66.6 3.042071197
66.7 3.042071197
66.8 3.036187114
66.9 3.038148475
67 3.040109836
67.1 3.040109836
67.2 3.040109836
67.3 3.042071197
67.4 3.044032559
67.5 3.040109836
67.6 3.040109836
67.7 3.044032559
67.8 3.042071197
67.9 3.042071197
68 3.044032559
68.1 3.040109836
68.2 3.040109836
68.3 3.044032559
68.4 3.044032559
68.5 3.044032559
68.6 3.040109836
68.7 3.042071197
68.8 3.040109836
68.9 3.042071197
69 3.040109836
69.1 3.040109836
69.2 3.040109836
69.3 3.036187114
69.4 3.038148475
69.5 3.044032559
69.6 3.042071197
69.7 3.042071197
69.8 3.040109836
69.9 3.038148475
70 3.040109836
70.1 3.040109836
70.2 3.040109836
70.3 3.038148475
70.4 3.040109836
70.5 3.042071197
70.6 3.042071197
70.7 3.042071197
70.8 3.040109836
70.9 3.044032559
71 3.044032559
71.1 3.040109836
71.2 3.038148475
71.3 3.042071197
71.4 3.040109836
71.5 3.040109836
71.6 3.040109836
71.7 3.040109836
71.8 3.040109836
71.9 3.040109836
72 3.040109836
72.1 3.044032559
72.2 3.042071197
72.3 3.040109836
72.4 3.040109836
72.5 3.038148475
72.6 3.034225753
72.7 3.038148475
72.8 3.036187114
72.9 3.038148475
73 3.040109836
73.1 3.040109836
73.2 3.040109836
73.3 3.038148475
73.4 3.042071197
73.5 3.042071197
73.6 3.040109836
73.7 3.040109836
73.8 3.040109836
73.9 3.040109836
74 3.036187114
74.1 3.040109836
74.2 3.044032559
74.3 3.040109836
74.4 3.040109836
74.5 3.040109836
74.6 3.038148475
74.7 3.036187114
74.8 3.036187114
74.9 3.040109836
75 3.038148475
75.1 3.038148475
75.2 3.040109836
75.3 3.040109836
75.4 3.040109836
75.5 3.038148475
75.6 3.038148475
75.7 3.036187114
75.8 3.038148475
75.9 3.040109836
76 3.042071197
76.1 3.040109836
76.2 3.040109836
76.3 3.040109836
76.4 3.036187114
76.5 3.036187114
76.6 3.040109836
76.7 3.040109836
76.8 3.038148475
76.9 3.032264391
77 3.036187114
77.1 3.038148475
77.2 3.036187114
77.3 3.038148475
77.4 3.036187114
77.5 3.036187114
77.6 3.034225753
77.7 3.036187114
77.8 3.036187114
77.9 3.036187114
78 3.036187114
78.1 3.038148475
78.2 3.034225753
78.3 3.032264391
78.4 3.032264391
78.5 3.038148475
78.6 3.040109836
78.7 3.040109836
78.8 3.040109836
78.9 3.042071197
79 3.040109836
79.1 3.036187114
79.2 3.038148475
79.3 3.040109836
79.4 3.038148475
79.5 3.042071197
79.6 3.044032559
79.7 3.040109836
79.8 3.036187114
79.9 3.036187114
80 3.040109836
80.1 3.038148475
80.2 3.036187114
80.3 3.038148475
80.4 3.038148475
80.5 3.040109836
80.6 3.040109836
80.7 3.040109836
80.8 3.040109836
80.9 3.042071197
81 3.044032559
81.1 3.042071197
81.2 3.040109836
81.3 3.040109836
81.4 3.042071197
81.5 3.036187114
81.6 3.042071197
81.7 3.038148475
81.8 3.038148475
81.9 3.038148475
82 3.040109836
82.1 3.040109836
82.2 3.040109836
82.3 3.040109836
82.4 3.040109836
82.5 3.040109836
82.6 3.036187114
82.7 3.036187114
82.8 3.036187114
82.9 3.038148475
83 3.038148475
83.1 3.040109836
83.2 3.040109836
83.3 3.036187114
83.4 3.036187114
83.5 3.036187114
83.6 3.036187114
83.7 3.036187114
83.8 3.038148475
83.9 3.038148475
84 3.036187114
84.1 3.034225753
84.2 3.038148475
84.3 3.034225753
84.4 3.038148475
84.5 3.036187114
84.6 3.040109836
84.7 3.042071197
84.8 3.042071197
84.9 3.040109836
85 3.040109836
85.1 3.036187114
85.2 3.042071197
85.3 3.042071197
85.4 3.040109836
85.5 3.038148475
85.6 3.040109836
85.7 3.040109836
85.8 3.040109836
85.9 3.042071197
86 3.042071197
86.1 3.040109836
86.2 3.036187114
86.3 3.040109836
86.4 3.040109836
86.5 3.038148475
86.6 3.036187114
86.7 3.038148475
86.8 3.040109836
86.9 3.034225753
87 3.032264391
87.1 3.034225753
87.2 3.036187114
87.3 3.032264391
87.4 3.036187114
87.5 3.036187114
87.6 3.036187114
87.7 3.036187114
87.8 3.036187114
87.9 3.036187114
88 3.034225753
88.1 3.034225753
88.2 3.038148475
88.3 3.036187114
88.4 3.034225753
88.5 3.032264391
88.6 3.036187114
88.7 3.036187114
88.8 3.036187114
88.9 3.036187114
89 3.036187114
89.1 3.034225753
89.2 3.036187114
89.3 3.034225753
89.4 3.036187114
89.5 3.036187114
89.6 3.034225753
89.7 3.034225753
89.8 3.034225753
89.9 3.034225753
90 3.032264391
90.1 3.032264391
90.2 3.032264391
90.3 3.036187114
90.4 3.038148475
90.5 3.034225753
90.6 3.032264391
90.7 3.036187114
90.8 3.034225753
90.9 3.036187114
91 3.036187114
91.1 3.036187114
91.2 3.036187114
91.3 3.034225753
91.4 3.034225753
91.5 3.032264391
91.6 3.034225753
91.7 3.036187114
91.8 3.040109836
91.9 3.032264391
92 3.032264391
92.1 3.03030303
92.2 3.03030303
92.3 3.028341669
92.4 3.03030303
92.5 3.032264391
92.6 3.03030303
92.7 3.032264391
92.8 3.032264391
92.9 3.032264391
93 3.03030303
93.1 3.03030303
93.2 3.03030303
93.3 3.03030303
93.4 3.028341669
93.5 3.024418947
93.6 3.024418947
93.7 3.028341669
93.8 3.028341669
93.9 3.028341669
##----------------------------#
wipe
## ------------------------ #
## Test Specific parameters #
## ------------------------ #
# Confinement Stress
set pConf [expr -50.0*0.025*0.025]
set npConf [expr -50.0*0.025*0.05]
# Deviatoric strain
set devDisp [expr (-0.01536/2)]
# Permeablity
set perm [expr 8.5e-5/(9.81*1)]
# Initial void ratio
set vR 0.603
## Rayleigh damping parameter
set damp 0.03
set pi 3.141592654
set omega1 [expr 2*$pi*0.2]
set omega2 [expr 2*$pi*20]
set a1 [expr 2.0*$damp/($omega1+$omega2)]
set a0 [expr $a1*$omega1*$omega2]
# Create a 3D model with 4 Degrees of Freedom
model BasicBuilder -ndm 3 -ndf 4
# Create nodes
node 1 0.025 0.0 0.0
node 2 0.025 0.025 0.0
node 3 0.0 0.025 0.0
node 4 0.0 0.0 0.0
node 5 0.025 0.0 0.05
node 6 0.025 0.025 0.05
node 7 0.0 0.025 0.05
node 8 0.0 0.0 0.05
# Create Fixities
fix 1 0 1 1 1
fix 2 0 0 1 1
fix 3 1 0 1 1
fix 4 1 1 1 1
fix 5 0 1 0 1
fix 6 0 0 0 1
fix 7 1 0 0 1
fix 8 1 1 0 1
set Gref 2.82e4
set niu 0.3
set Bref [expr 2*$Gref*(1+$niu)/(3*(1-2*$niu))]
set fAngle 35.5
set PTAngle 26
set c 0.1
set PDCoef 0.5
# Create material
nDMaterial PressureDependMultiYield02 1 3 2.06 $Gref $Bref $fAngle 0.1 \
101.0 $PDCoef $PTAngle 0.028 0.05 0.1 0.05 \
20 5.0 3.0 1.0 \
0.0 $vR 0.9 0.02 0.7 101.0 $c
set fBulk [expr 2.2e6*(1+$vR)/$vR]
element brickUP 1 1 2 3 4 5 6 7 8 1 $fBulk 1.0 $perm $perm $perm 0.0 0.0 0.0
# Create recorders
recorder Node -file disp1.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press1.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress1.out -time material 1 stress
recorder Element -file strain1.out -time material 1 strain
updateMaterialStage -material 1 -stage 0
# Create analysis
constraints Penalty 1.0e18 1.0e18
test NormDispIncr 1.0e-5 500 1
algorithm Newton
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
# Apply confinement pressure
set pNode [expr $pConf / 4.0]
set npNode [expr $npConf / 4.0]
pattern Plain 1 {Series -time {0 25000 1e10} -values {0 1 1} -factor 1} {
load 1 $npNode 0.0 0.0 0.0
load 2 $npNode $npNode 0.0 0.0
load 3 0.0 $npNode 0.0 0.0
load 4 0.0 0.0 0.0 0.0
load 5 $npNode 0.0 $pNode 0.0
load 6 $npNode $npNode $pNode 0.0
load 7 0.0 $npNode $pNode 0.0
load 8 0.0 0.0 $pNode 0.0
}
analyze 100 100
puts "Done Elastic"
updateMaterialStage -material 1 -stage 1
analyze 100 100
analyze 50 100
puts "Done Plastic"
puts "Gravity Done!"
# Close drainage valves
for {set x 1} {$x<9} {incr x} {
remove sp $x 4
}
constraints Transformation
test EnergyIncr 1.0e-3 500 1
algorithm NewtonLineSearch
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
analyze 50 100
puts "Drainage of upper surface closed!"
wipeAnalysis
remove recorders
recorder Node -file disp2.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press2.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress2.out -time material 1 stress
recorder Element -file strain2.out -time material 1 strain
timeSeries Path 2 -fileTime time.txt -filePath load.txt -factor 1.0
pattern Plain 2 2 -fact 0.25 {
load 5 0 0 -1 0
load 6 0 0 -1 0
load 7 0 0 -1 0
load 8 0 0 -1 0
}
constraints Penalty 1.0e18 1.0e18
test NormDispIncr 1.0e-05 500 1
integrator DisplacementControl 5 3 [expr 0.01536/(2*939)] 50 [expr 0.01536/(2*939)] [expr 0.01536/(2*939)]
rayleigh $a0 0. $a1 0.0
algorithm NewtonLineSearch
numberer RCM
system UmfPack
analysis Transient
set dT 0.01
set numStep 939
set startT [clock seconds]
analyze $numStep $dT
set endT [clock seconds]
puts "analysis done"
puts "loading analysis execution time: [expr $endT-$startT] seconds."
wipe
skamalzare wrote:
> Hello Sanjianke,
>
> I ran your code and noticed you are applying to much load on your sample. If you look
> at your stresses after gravity analyses, you have sigma_r = 40 MPa and sigma_a = 80
> MPa. Too much! The model is working right because you are applying 50 kN load on top,
> and have area = 0.025*0.025 m2, which results 80 MPa stress (Load/area). This
> probably is the reason why you are seeing too much PWP.
>
> I am very suspicious if PDMY02 can give you any realistic values under 80 MPa stress
> (or anything above 1 MPa).
>
> I am not sure if you can apply distributed load on top of brick elements. I usually
> apply nodal loads and ensure the stresses are what I wanted.
>
> If you turn off the OpenSees analysis reports, you can see that right before shearing
> stage, you receive an error that Transient analyses did not recognize the integrator.
> This might be because transient analyses don't work with DisplacementControl
> integrator (maybe Frank can explain this better). The program then proceeds with
> default Newmark <0.5,0.25>. I think a better way to simulate shearing part can
> be to apply deviatoric loads instead of displacements and use the transient analyses
> to capture the response (like what you did in consolidation stage).
>
> The default value for c parameter of PDMY02 is 0.1 and you are using 18. Moreover,
> you are inputting rho = 2.63 Mg/m3 (too much for soils). You might want to double
> check these!
>
> Bests,
> Soheil
So glad to see your reply. It is very insightful. I have modified my script as you suggested. It seems the pore water pressure might be ok at the consolidation stage. But the analysis results of the shearing stage still makes no sense if I apply the deviatoric loading as shown below at the top of the element. It looks like the loading is not actually applied on the element. And I don't know why...Could you please have a look at my revised script below when you are free? Thank you very much in advance.
time(sec) deviatoric load (kN)
0.1 0
0.2 0
0.3 0.021574973
0.4 0.045111307
0.5 0.058840836
0.6 0.068647641
0.7 0.076493086
0.8 0.084338531
0.9 0.088261253
1 0.094145337
1.1 0.096106698
1.2 0.101990782
1.3 0.101990782
1.4 0.107874865
1.5 0.109836226
1.6 0.113758949
1.7 0.11572031
1.8 0.117681671
1.9 0.119643032
2 0.125527116
2.1 0.127488477
2.2 0.129449838
2.3 0.131411199
2.4 0.133372561
2.5 0.137295283
2.6 0.139256644
2.7 0.141218005
2.8 0.145140728
2.9 0.147102089
3 0.14906345
3.1 0.152986172
3.2 0.154947534
3.3 0.158870256
3.4 0.160831617
3.5 0.160831617
3.6 0.16475434
3.7 0.168677062
3.8 0.172599784
3.9 0.172599784
4 0.178483868
4.1 0.180445229
4.2 0.184367951
4.3 0.188290674
4.4 0.192213396
4.5 0.192213396
4.6 0.196136118
4.7 0.200058841
4.8 0.203981563
4.9 0.205942924
5 0.209865647
5.1 0.213788369
5.2 0.217711091
5.3 0.221633814
5.4 0.225556536
5.5 0.229479259
5.6 0.23144062
5.7 0.235363342
5.8 0.241247426
5.9 0.243208787
6 0.247131509
6.1 0.251054232
6.2 0.256938315
6.3 0.258899676
6.4 0.26478376
6.5 0.268706482
6.6 0.272629205
6.7 0.276551927
6.8 0.282436011
6.9 0.286358733
7 0.290281455
7.1 0.296165539
7.2 0.300088261
7.3 0.304010984
7.4 0.309895067
7.5 0.31381779
7.6 0.317740512
7.7 0.321663234
7.8 0.327547318
7.9 0.333431401
8 0.339315485
8.1 0.343238207
8.2 0.34716093
8.3 0.353045013
8.4 0.360890458
8.5 0.362851819
8.6 0.368735903
8.7 0.374619986
8.8 0.38050407
8.9 0.386388153
9 0.392272237
9.1 0.39815632
9.2 0.402079043
9.3 0.407963126
9.4 0.415808571
9.5 0.419731294
9.6 0.425615377
9.7 0.431499461
9.8 0.439344905
9.9 0.443267628
10 0.451113072
10.1 0.458958517
10.2 0.46288124
10.3 0.470726684
10.4 0.476610768
10.5 0.482494851
10.6 0.490340296
10.7 0.498185741
10.8 0.504069824
10.9 0.511915269
11 0.517799353
11.1 0.525644797
11.2 0.531528881
11.3 0.539374326
11.4 0.547219771
11.5 0.553103854
11.6 0.560949299
11.7 0.568794744
11.8 0.576640188
11.9 0.582524272
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89 3.036187114
89.1 3.034225753
89.2 3.036187114
89.3 3.034225753
89.4 3.036187114
89.5 3.036187114
89.6 3.034225753
89.7 3.034225753
89.8 3.034225753
89.9 3.034225753
90 3.032264391
90.1 3.032264391
90.2 3.032264391
90.3 3.036187114
90.4 3.038148475
90.5 3.034225753
90.6 3.032264391
90.7 3.036187114
90.8 3.034225753
90.9 3.036187114
91 3.036187114
91.1 3.036187114
91.2 3.036187114
91.3 3.034225753
91.4 3.034225753
91.5 3.032264391
91.6 3.034225753
91.7 3.036187114
91.8 3.040109836
91.9 3.032264391
92 3.032264391
92.1 3.03030303
92.2 3.03030303
92.3 3.028341669
92.4 3.03030303
92.5 3.032264391
92.6 3.03030303
92.7 3.032264391
92.8 3.032264391
92.9 3.032264391
93 3.03030303
93.1 3.03030303
93.2 3.03030303
93.3 3.03030303
93.4 3.028341669
93.5 3.024418947
93.6 3.024418947
93.7 3.028341669
93.8 3.028341669
93.9 3.028341669
##----------------------------#
wipe
## ------------------------ #
## Test Specific parameters #
## ------------------------ #
# Confinement Stress
set pConf [expr -50.0*0.025*0.025]
set npConf [expr -50.0*0.025*0.05]
# Deviatoric strain
set devDisp [expr (-0.01536/2)]
# Permeablity
set perm [expr 8.5e-5/(9.81*1)]
# Initial void ratio
set vR 0.603
## Rayleigh damping parameter
set damp 0.03
set pi 3.141592654
set omega1 [expr 2*$pi*0.2]
set omega2 [expr 2*$pi*20]
set a1 [expr 2.0*$damp/($omega1+$omega2)]
set a0 [expr $a1*$omega1*$omega2]
# Create a 3D model with 4 Degrees of Freedom
model BasicBuilder -ndm 3 -ndf 4
# Create nodes
node 1 0.025 0.0 0.0
node 2 0.025 0.025 0.0
node 3 0.0 0.025 0.0
node 4 0.0 0.0 0.0
node 5 0.025 0.0 0.05
node 6 0.025 0.025 0.05
node 7 0.0 0.025 0.05
node 8 0.0 0.0 0.05
# Create Fixities
fix 1 0 1 1 1
fix 2 0 0 1 1
fix 3 1 0 1 1
fix 4 1 1 1 1
fix 5 0 1 0 1
fix 6 0 0 0 1
fix 7 1 0 0 1
fix 8 1 1 0 1
set Gref 2.82e4
set niu 0.3
set Bref [expr 2*$Gref*(1+$niu)/(3*(1-2*$niu))]
set fAngle 35.5
set PTAngle 26
set c 0.1
set PDCoef 0.5
# Create material
nDMaterial PressureDependMultiYield02 1 3 2.06 $Gref $Bref $fAngle 0.1 \
101.0 $PDCoef $PTAngle 0.028 0.05 0.1 0.05 \
20 5.0 3.0 1.0 \
0.0 $vR 0.9 0.02 0.7 101.0 $c
set fBulk [expr 2.2e6*(1+$vR)/$vR]
element brickUP 1 1 2 3 4 5 6 7 8 1 $fBulk 1.0 $perm $perm $perm 0.0 0.0 0.0
# Create recorders
recorder Node -file disp1.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press1.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress1.out -time material 1 stress
recorder Element -file strain1.out -time material 1 strain
updateMaterialStage -material 1 -stage 0
# Create analysis
constraints Penalty 1.0e18 1.0e18
test NormDispIncr 1.0e-5 500 1
algorithm Newton
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
# Apply confinement pressure
set pNode [expr $pConf / 4.0]
set npNode [expr $npConf / 4.0]
pattern Plain 1 {Series -time {0 25000 1e10} -values {0 1 1} -factor 1} {
load 1 $npNode 0.0 0.0 0.0
load 2 $npNode $npNode 0.0 0.0
load 3 0.0 $npNode 0.0 0.0
load 4 0.0 0.0 0.0 0.0
load 5 $npNode 0.0 $pNode 0.0
load 6 $npNode $npNode $pNode 0.0
load 7 0.0 $npNode $pNode 0.0
load 8 0.0 0.0 $pNode 0.0
}
analyze 100 100
puts "Done Elastic"
updateMaterialStage -material 1 -stage 1
analyze 100 100
analyze 50 100
puts "Done Plastic"
puts "Gravity Done!"
# Close drainage valves
for {set x 1} {$x<9} {incr x} {
remove sp $x 4
}
constraints Transformation
test EnergyIncr 1.0e-3 500 1
algorithm NewtonLineSearch
numberer RCM
system BandGeneral
set gama 1.5;
set betta [expr pow($gama+0.5, 2)/4];
integrator Newmark $gama $betta;
rayleigh $a0 0. $a1 0.0
analysis Transient
analyze 50 100
puts "Drainage of upper surface closed!"
wipeAnalysis
remove recorders
recorder Node -file disp2.out -time -nodeRange 1 8 -dof 1 2 3 disp
recorder Node -file press2.out -time -nodeRange 1 8 -dof 4 vel
recorder Element -file stress2.out -time material 1 stress
recorder Element -file strain2.out -time material 1 strain
timeSeries Path 2 -fileTime time.txt -filePath load.txt -factor 1.0
pattern Plain 2 2 -fact 0.25 {
load 5 0 0 -1 0
load 6 0 0 -1 0
load 7 0 0 -1 0
load 8 0 0 -1 0
}
constraints Penalty 1.0e18 1.0e18
test NormDispIncr 1.0e-05 500 1
integrator DisplacementControl 5 3 [expr 0.01536/(2*939)] 50 [expr 0.01536/(2*939)] [expr 0.01536/(2*939)]
rayleigh $a0 0. $a1 0.0
algorithm NewtonLineSearch
numberer RCM
system UmfPack
analysis Transient
set dT 0.01
set numStep 939
set startT [clock seconds]
analyze $numStep $dT
set endT [clock seconds]
puts "analysis done"
puts "loading analysis execution time: [expr $endT-$startT] seconds."
wipe
skamalzare wrote:
> Hello Sanjianke,
>
> I ran your code and noticed you are applying to much load on your sample. If you look
> at your stresses after gravity analyses, you have sigma_r = 40 MPa and sigma_a = 80
> MPa. Too much! The model is working right because you are applying 50 kN load on top,
> and have area = 0.025*0.025 m2, which results 80 MPa stress (Load/area). This
> probably is the reason why you are seeing too much PWP.
>
> I am very suspicious if PDMY02 can give you any realistic values under 80 MPa stress
> (or anything above 1 MPa).
>
> I am not sure if you can apply distributed load on top of brick elements. I usually
> apply nodal loads and ensure the stresses are what I wanted.
>
> If you turn off the OpenSees analysis reports, you can see that right before shearing
> stage, you receive an error that Transient analyses did not recognize the integrator.
> This might be because transient analyses don't work with DisplacementControl
> integrator (maybe Frank can explain this better). The program then proceeds with
> default Newmark <0.5,0.25>. I think a better way to simulate shearing part can
> be to apply deviatoric loads instead of displacements and use the transient analyses
> to capture the response (like what you did in consolidation stage).
>
> The default value for c parameter of PDMY02 is 0.1 and you are using 18. Moreover,
> you are inputting rho = 2.63 Mg/m3 (too much for soils). You might want to double
> check these!
>
> Bests,
> Soheil
-
skamalzare
- Posts: 112
- Joined: Thu Jun 27, 2013 11:45 am
- Location: Seattle, WA
Re: monotonic triaxial test simulation
Sanjianke,
A couple of points:
1) You're applying too much load. You built 50 kPa confining pressure and then apply around 6000 kPa deviatoric stress. The loads you are applying will work on an area of 0.025*0.025 m2, this is why you see large values of PWP.
* I mentioned this in my first message about your consolidation stage and you fixed it correctly. You need to do the same for shearing stage.
2) Change the last values after "test" commands to 0. This will stop OpenSees from showing iteration results. You will see, the displacementcontrol integrator in shearing stage is not working. OpenSees prints a message that, it will use Newmark method with default values. Just to inform you, how the model integrates!
3) You have assigned transient analysis dt = 0.01 sec with 939 steps. This will consider your loads till time = 9.39 sec, and not to the end of your time series with time = 93.9 sec. You need to either change your dt to 0.1 sec or use 9390 steps.
Bests,
Soheil
A couple of points:
1) You're applying too much load. You built 50 kPa confining pressure and then apply around 6000 kPa deviatoric stress. The loads you are applying will work on an area of 0.025*0.025 m2, this is why you see large values of PWP.
* I mentioned this in my first message about your consolidation stage and you fixed it correctly. You need to do the same for shearing stage.
2) Change the last values after "test" commands to 0. This will stop OpenSees from showing iteration results. You will see, the displacementcontrol integrator in shearing stage is not working. OpenSees prints a message that, it will use Newmark method with default values. Just to inform you, how the model integrates!
3) You have assigned transient analysis dt = 0.01 sec with 939 steps. This will consider your loads till time = 9.39 sec, and not to the end of your time series with time = 93.9 sec. You need to either change your dt to 0.1 sec or use 9390 steps.
Bests,
Soheil
---
PhD, EIT, Geotechnical Engineer
Condon-Johnson & Associates INC
PhD, EIT, Geotechnical Engineer
Condon-Johnson & Associates INC
Re: monotonic triaxial test simulation
Hi, skamalzare,
I fixed the issues of shear loading and the time steps. But the model still cannot give me good results. Do you think it is because of the failure of displacementcontrol integrator? If so, how could I make this integrator work? Thanks.
I fixed the issues of shear loading and the time steps. But the model still cannot give me good results. Do you think it is because of the failure of displacementcontrol integrator? If so, how could I make this integrator work? Thanks.
Re: monotonic triaxial test simulation
Hi All.
Is it possible to perform dynamic simulation for an elastic material under undrained condition (using FluidPorousMaterial)?
Is it possible to perform dynamic simulation for an elastic material under undrained condition (using FluidPorousMaterial)?
-
sadeghihabib
- Posts: 5
- Joined: Tue Jan 30, 2018 1:24 am
- Contact:
Re: monotonic triaxial test simulation
Hi sanjianke
Could you finally model triaxial test successfully?
I wish you could post your Tcl script here for us, please.
Could you finally model triaxial test successfully?
I wish you could post your Tcl script here for us, please.
Habibollah Sadeghi
MSc Student of Geotechnical Engineering
Sharif University of technology
Tehran, Iran
MSc Student of Geotechnical Engineering
Sharif University of technology
Tehran, Iran
Re: monotonic triaxial test simulation
Hi everyone,
Could you please post the final code please? I have been fighting against programming for my very first time and it's really difficult, that code would be helpful.
Could you please post the final code please? I have been fighting against programming for my very first time and it's really difficult, that code would be helpful.