Multilinear Elastic Material

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mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Multilinear Elastic Material

Post by mnazari »

Hi,
I have a question regarding this OS command:
"uniaxialMaterial ElasticMultiLinear $matTag -strain $strainPoints -stress $stressPoints"
I wrote a MATLAB code to read stress and strain data from a file (Experimental data after exciting the structure by EQ), but it does not work in OS.
Is there any limitations in using this "uniaxialMaterial ElasticMultiLinear" command. About number of points, or positive and negative values?
I really appreciate your prompt reply.

Thanks
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: Multilinear Elastic Material

Post by vesna »

The only constrain is the following: the number of provided strain points needs to be equal to the number of provided stress points.
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

Number of strain and stress points are the same but OS stops working...
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: Multilinear Elastic Material

Post by vesna »

Do you get any message?
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

No, Just stops working and I should quit. I was thinking it is due to the large number of points we have during earthquake.
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: Multilinear Elastic Material

Post by vesna »

How do you know that it stops working? Does it look like the analysis "hangs" at the certain time step?
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

When I run it, it hangs and do not work, since I close the program
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: Multilinear Elastic Material

Post by vesna »

There are most probably some issues with your model.

At what time step does it stop?
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

While I start running, it hangs and does not go on. When I delete half of points, it starts running but cannot still finish the analysis. That's why I was thinking there should be a limit on the number of points in "uniaxialMaterial ElasticMultiLinear".
vesna
Posts: 3033
Joined: Tue May 23, 2006 11:23 am
Location: UC Berkeley

Re: Multilinear Elastic Material

Post by vesna »

I talked with the developer of that material and he confirmed that there is no limit on the number of points. There is something else in your model that creates that problem.
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

Dear Vesna,
When I define a multilinear elastic spring at the base of the specimen, for a linear system I expect to get the same force-displacement behavior curve from OS result. But it is not happening. Is it possible that I mail you some results to find out the problem?
Many Thanks
fmk
Site Admin
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Joined: Fri Jun 11, 2004 2:33 pm
Location: UC Berkeley
Contact:

Re: Multilinear Elastic Material

Post by fmk »

just send the command you used and the recorded material stress-strain values.
mnazari
Posts: 29
Joined: Wed Aug 15, 2012 11:28 am
Location: ISU

Re: Multilinear Elastic Material

Post by mnazari »

Sure; Thanks,
Here is the command:

node 1 0.0 0; # node#, X Y
node 2 0.0 0;
node 3 0.0 168;

fix 1 1 1 1 ; # node DX DY RZ
equalDOF 1 2 1 2 ;

uniaxialMaterial ElasticMultiLinear 1 -strain -0.03 -0.02 -0.01 -0.0075 -0.0050 -0.0025 -0.0015 -0.0010 -0.000057 0 0.000057 0.0010 0.0015 0.0025 0.0050 0.0075 0.01 0.02 0.03 -stress -6220.473 -4958.83 -3697.316 -3382.45 -3068.41 -2675.91 -2538.94 -2477.39 -937.77 0 937.77 2477.39 2538.94 2675.91 3068.41 3382.45 3697.316 4958.83 6220.473

# Define the material
element zeroLength 1 1 2 -mat 1 -dir 6 -doRayleigh 1
element elasticBeamColumn 2 2 3 375 5285.96 175781 1; # element elasticBeamColumn $eleTag $iNode $jNode $A $E $Iz $transfTag

and here is the results for base-shear vs top relative displacement:

-1.40E-03 -0.409057
-1.35E-03 -0.393789
1.31E-04 0.0384243
-1.65E-03 -0.48241
-5.94E-04 -0.173862
-9.39E-04 -0.274873
1.47E-04 0.0430897
-1.63E-04 -0.0478106
-1.46E-05 -0.00426555
-8.05E-04 -0.235705
-1.72E-04 -0.0502076
-2.81E-06 -0.000823183
6.32E-04 0.185009
3.05E-04 0.089167
4.41E-04 0.129147
5.62E-04 0.164393
6.73E-04 0.197079
7.58E-04 0.221744
1.75E-03 0.511306
8.18E-04 0.239404
8.10E-04 0.237224
1.25E-03 0.366453
7.20E-04 0.21084
1.11E-03 0.32453
5.31E-04 0.155299
8.81E-04 0.257879
2.70E-04 0.0790097
1.27E-04 0.0370277
-1.75E-05 -0.00511571
3.09E-04 0.0905558
1.59E-04 0.0464525
-4.53E-04 -0.132676
-1.05E-03 -0.308358
-2.24E-04 -0.0656959
-3.15E-04 -0.0921138
-8.71E-04 -0.25491
-9.39E-04 -0.274754
-9.71E-04 -0.284227
-9.71E-04 -0.284314
-9.53E-04 -0.279062
-4.49E-04 -0.131347
-8.67E-04 -0.25374
-3.21E-04 -0.0938758
-7.10E-04 -0.207793
-1.34E-04 -0.0391546
-5.04E-04 -0.147584
-3.88E-04 -0.113694
-2.65E-04 -0.0777021
3.12E-04 0.0913018
-2.71E-05 -0.00791932
9.99E-04 0.292443
1.56E-04 0.0457212
2.37E-04 0.0692433
3.08E-04 0.090197
3.71E-04 0.108628
4.23E-04 0.123832
4.63E-04 0.135457
2.95E-05 0.00862269
5.19E-04 0.152008
5.38E-04 0.157466
1.00E-03 0.293592
5.00E-04 0.146396
9.24E-04 0.270567
3.88E-04 0.113579
1.24E-03 0.362872
1.98E-04 0.057889
5.48E-04 0.160259
8.90E-04 0.260469
7.31E-04 0.213853
1.03E-03 0.301531
3.66E-04 0.10714
1.10E-03 0.32293
4.03E-04 0.117817
6.36E-04 0.186212
8.53E-04 0.249692
1.12E-04 0.0326848
3.15E-04 0.0921944
5.07E-04 0.14839
6.90E-04 0.201973
3.87E-04 0.11313
5.44E-04 0.159333
2.24E-04 0.06544
-1.03E-03 -0.301561
-2.24E-03 -0.656954
-2.91E-03 -0.851426
-3.49E-03 -1.02287
-4.44E-03 -1.30018
-5.28E-03 -1.54479
-5.95E-03 -1.74013
-7.39E-03 -2.16422
-8.63E-03 -2.52542
-8.69E-03 -2.54439
-9.95E-03 -2.9119
-9.53E-03 -2.78832
-8.89E-03 -2.60093
-8.48E-03 -2.48241
-7.89E-03 -2.30799
-7.11E-03 -2.08129
-5.70E-03 -1.66912
-5.57E-03 -1.62987
-5.32E-03 -1.55682
-4.96E-03 -1.45259
-4.49E-03 -1.31446
-3.94E-03 -1.15279
-3.79E-03 -1.11002
-4.49E-03 -1.31383
-5.10E-03 -1.49344
-5.59E-03 -1.63686
-6.90E-03 -2.01853
-7.58E-03 -2.21755
-9.00E-03 -2.6348
-1.02E-02 -2.99267
-1.03E-02 -3.00678
-1.01E-02 -2.95056
-9.68E-03 -2.83206
-8.12E-03 -2.37672
-7.35E-03 -2.15254
-5.97E-03 -1.74865
-4.51E-03 -1.31862
-2.06E-03 -0.602219
3.63E-04 0.106313
3.66E-03 1.07117
6.75E-03 1.9771
9.60E-03 2.80951
1.21E-02 3.54666
1.52E-02 4.43916
1.54E-02 4.51459
1.66E-02 4.87033
1.50E-02 4.40457
1.30E-02 3.81813
1.12E-02 3.26414
7.12E-03 2.08519
2.92E-03 0.855727
-3.19E-03 -0.933275
-9.17E-03 -2.68335
-1.58E-02 -4.62252
-2.43E-02 -6.57134
-3.41E-02 -5.73972
-4.57E-02 -6.81483
-5.84E-02 -7.61022
-7.23E-02 -8.37565
-8.92E-02 -9.27195
-1.07E-01 -10.212
-1.27E-01 -11.2483
-1.47E-01 -12.3249
-1.71E-01 -13.5626
-1.95E-01 -14.8038
-2.21E-01 -14.899
-2.48E-01 -15.0083
-2.77E-01 -15.1266
-3.08E-01 -15.257
-3.39E-01 -15.4081
-3.69E-01 -15.5521
-3.99E-01 -15.6979
-4.28E-01 -15.8344
-4.51E-01 -15.946
-4.72E-01 -16.0471
-4.88E-01 -16.145
-5.00E-01 -16.2125
-5.08E-01 -16.2579
-5.13E-01 -16.2868
-5.17E-01 -16.3097
-5.19E-01 -16.3242
-5.20E-01 -16.328
-5.21E-01 -16.3339
-5.21E-01 -16.3369
-5.24E-01 -16.35
-5.27E-01 -16.3705
-5.32E-01 -16.3985
-5.41E-01 -16.4444
-5.48E-01 -16.4848
-5.55E-01 -16.5248
-5.60E-01 -16.5491
-5.61E-01 -16.5575
-5.60E-01 -16.5476
-5.55E-01 -16.522
-5.45E-01 -16.4651
-5.30E-01 -16.3874
-5.11E-01 -16.2813
-4.82E-01 -16.1209
-4.45E-01 -15.9145
-3.97E-01 -15.6643
-3.40E-01 -15.3962
-2.72E-01 -15.0753
-1.94E-01 -14.7303
-1.05E-01 -13.698
-8.69E-03 -5.99415
9.29E-02 11.1537
1.97E-01 21.2038
3.00E-01 20.3093
4.02E-01 19.2863
5.02E-01 18.708
6.03E-01 18.4835
7.03E-01 18.4993
8.05E-01 18.6927
9.04E-01 18.9862
1.00E+00 19.2785
1.10E+00 19.5888
1.20E+00 19.9344
1.30E+00 20.305
1.40E+00 20.7044
1.50E+00 21.1204
1.60E+00 21.5529
1.71E+00 21.9993
1.81E+00 22.4572
1.92E+00 22.9278
2.03E+00 23.4016
2.14E+00 23.8855
2.25E+00 24.3747
2.36E+00 24.8707
2.48E+00 25.3753
2.59E+00 25.8816
2.70E+00 26.3896
2.82E+00 26.8926
2.93E+00 27.3991
3.05E+00 27.8984
3.16E+00 28.3879
3.26E+00 28.8589
3.36E+00 29.3135
3.46E+00 29.7284
3.54E+00 30.114
3.63E+00 30.4744
3.70E+00 30.7927
3.76E+00 31.0772
3.82E+00 31.3236
3.86E+00 31.5319
3.90E+00 31.7063
3.93E+00 31.8383
3.95E+00 31.9322
3.97E+00 31.988
3.97E+00 32.0037
3.97E+00 31.9792
3.95E+00 31.9085
3.92E+00 31.7978
3.89E+00 31.6389
3.84E+00 31.4278
3.78E+00 31.1709
3.71E+00 30.8663
3.63E+00 30.5099
3.54E+00 30.104
3.44E+00 29.6596
3.33E+00 29.1725
3.21E+00 28.6368
3.09E+00 28.0758
2.95E+00 27.473
2.81E+00 26.8413
2.66E+00 26.183
2.50E+00 25.4923
2.34E+00 24.7799
2.18E+00 24.0398
2.01E+00 23.2892
1.83E+00 22.5138
1.65E+00 21.7285
1.47E+00 20.9241
1.29E+00 20.1091
1.11E+00 19.2992
9.20E-01 18.4818
7.39E-01 17.6583
5.62E-01 16.7463
3.89E-01 15.7419
2.25E-01 14.8643
6.87E-02 13.2462
-7.90E-02 2.55912
-2.15E-01 -12.4306
-3.39E-01 -17.8329
-4.53E-01 -17.6582
-5.55E-01 -17.6587
-6.47E-01 -17.8106
-7.31E-01 -18.0247
-8.05E-01 -18.2648
-8.73E-01 -18.5242
-9.34E-01 -18.7287
-9.87E-01 -18.9106
-1.04E+00 -19.0874
-1.08E+00 -19.246
-1.11E+00 -19.3875
-1.15E+00 -19.5117
-1.17E+00 -19.6128
-1.19E+00 -19.7
-1.21E+00 -19.7586
-1.21E+00 -19.7912
-1.22E+00 -19.8123
-1.22E+00 -19.8112
-1.22E+00 -19.7958
-1.21E+00 -19.7705
-1.21E+00 -19.7413
-1.20E+00 -19.6997
-1.19E+00 -19.6543
-1.17E+00 -19.6028
-1.16E+00 -19.5536
-1.15E+00 -19.5027
-1.14E+00 -19.4541
-1.13E+00 -19.4161
-1.13E+00 -19.3931
-1.12E+00 -19.3829
-1.13E+00 -19.398
-1.14E+00 -19.4322
-1.15E+00 -19.4937
-1.17E+00 -19.5825
-1.20E+00 -19.7027
-1.23E+00 -19.8418
-1.27E+00 -20.01
-1.31E+00 -20.2053
-1.36E+00 -20.4197
-1.41E+00 -20.6567
-1.47E+00 -20.9059
-1.53E+00 -21.167
-1.59E+00 -21.438
-1.65E+00 -21.7061
-1.71E+00 -21.9818
-1.77E+00 -22.2501
-1.83E+00 -22.5179
-1.89E+00 -22.7761
-1.94E+00 -23.0164
-2.00E+00 -23.2553
-2.05E+00 -23.4739
-2.10E+00 -23.6869
-2.14E+00 -23.8836
-2.18E+00 -24.0621
-2.22E+00 -24.2243
-2.25E+00 -24.366
-2.28E+00 -24.4872
-2.30E+00 -24.5878
-2.32E+00 -24.6637
-2.33E+00 -24.7212
-2.34E+00 -24.7602
-2.34E+00 -24.7893
-2.35E+00 -24.8146
-2.35E+00 -24.8237
-2.35E+00 -24.8223
-2.35E+00 -24.8169
-2.35E+00 -24.812
-2.35E+00 -24.7992
-2.34E+00 -24.7871
-2.34E+00 -24.7712
-2.34E+00 -24.7602
-2.33E+00 -24.7351
-2.32E+00 -24.7023
-2.31E+00 -24.6514
-2.30E+00 -24.5784
-2.28E+00 -24.4852
-2.25E+00 -24.368
-2.22E+00 -24.2183
-2.17E+00 -24.0343
-2.13E+00 -23.8202
-2.07E+00 -23.5678
-2.00E+00 -23.2752
-1.93E+00 -22.9469
-1.85E+00 -22.5786
-1.76E+00 -22.1812
-1.66E+00 -21.7465
-1.55E+00 -21.2813
-1.44E+00 -20.782
-1.32E+00 -20.2543
-1.20E+00 -19.6988
-1.06E+00 -19.1081
-9.24E-01 -18.4972
-7.78E-01 -17.8384
-6.27E-01 -17.0256
-4.70E-01 -16.1248
-3.09E-01 -15.2291
-1.41E-01 -13.9777
2.82E-02 -2.61925
2.00E-01 12.6246
3.71E-01 17.3459
5.43E-01 17.6235
7.14E-01 18.1711
8.86E-01 18.8732
1.06E+00 19.5292
1.23E+00 20.157
1.40E+00 20.8161
1.57E+00 21.4988
1.73E+00 22.1975
1.90E+00 22.9016
2.07E+00 23.6095
2.23E+00 24.3088
2.38E+00 24.9912
2.54E+00 25.6678
2.69E+00 26.3161
2.83E+00 26.9482
2.96E+00 27.5464
3.09E+00 28.1143
3.21E+00 28.6537
3.33E+00 29.162
3.44E+00 29.637
3.54E+00 30.0722
3.63E+00 30.4715
3.71E+00 30.8348
3.78E+00 31.1556
3.84E+00 31.4319
3.90E+00 31.6718
3.94E+00 31.8629
3.97E+00 31.9924
3.99E+00 32.0877
4.00E+00 32.1342
4.00E+00 32.136
3.99E+00 32.0869
3.97E+00 31.985
3.93E+00 31.8388
3.89E+00 31.6421
3.83E+00 31.397
3.77E+00 31.1123
3.70E+00 30.786
3.61E+00 30.4203
3.52E+00 30.0219
3.43E+00 29.5845
3.32E+00 29.1084
3.20E+00 28.6046
3.08E+00 28.0689
2.96E+00 27.4995
2.82E+00 26.9009
2.68E+00 26.2732
2.53E+00 25.6129
2.38E+00 24.9264
2.21E+00 24.2098
2.05E+00 23.4656
1.87E+00 22.6856
1.69E+00 21.8872
1.50E+00 21.063
1.31E+00 20.205
1.11E+00 19.332
9.09E-01 18.4311
7.04E-01 17.4965
4.95E-01 16.3836
2.84E-01 15.176
7.08E-02 13.1552
-1.42E-01 -0.123174
-3.53E-01 -17.2426
-5.62E-01 -22.0534
-7.70E-01 -21.4688
-9.74E-01 -21.3894
-1.18E+00 -21.559
-1.38E+00 -21.8777
-1.57E+00 -22.3338
-1.76E+00 -22.8909
-1.94E+00 -23.5094
-2.12E+00 -24.1655
-2.30E+00 -24.827
-2.46E+00 -25.4859
-2.62E+00 -26.121
-2.76E+00 -26.7407
-2.90E+00 -27.3259
-3.03E+00 -27.8691
-3.14E+00 -28.3681
-3.25E+00 -28.8149
-3.34E+00 -29.2042
-3.41E+00 -29.5392
-3.47E+00 -29.8069
-3.52E+00 -30.0152
-3.55E+00 -30.1574
-3.57E+00 -30.2357
-3.57E+00 -30.2393
-3.56E+00 -30.1851
-3.54E+00 -30.0751
-3.50E+00 -29.9074
-3.45E+00 -29.6965
-3.39E+00 -29.4365
-3.32E+00 -29.1337
-3.25E+00 -28.7925
-3.16E+00 -28.4172
-3.07E+00 -28.0143
-2.97E+00 -27.5819
-2.87E+00 -27.1243
-2.76E+00 -26.6377
-2.65E+00 -26.1243
-2.53E+00 -25.5908
-2.40E+00 -25.033
-2.27E+00 -24.4618
-2.14E+00 -23.8649
-2.00E+00 -23.2613
-1.86E+00 -22.6326
-1.72E+00 -22.004
-1.57E+00 -21.3682
-1.43E+00 -20.721
-1.28E+00 -20.0728
-1.13E+00 -19.4203
-9.85E-01 -18.7663
-8.37E-01 -18.1066
-6.86E-01 -17.3207
-5.35E-01 -16.4628
-3.82E-01 -15.6105
-2.30E-01 -14.8301
-7.90E-02 -13.3287
7.06E-02 -2.77136
2.16E-01 12.5408
3.59E-01 18.3


and here is the expected values, which is pretty similar to experimental results:
-4.92 -37.92971475
-3.28 -30.23676857
-1.64 -22.54460804
-1.23 -20.62469057
-0.82 -18.70979745
-0.41 -16.31650204
-0.246 -15.48134552
-0.164 -15.10604653
-0.009269012 -5.718125953
0 0
0.009269012 5.718125953
0.164 15.10604653
0.246 15.48134552
0.41 16.31650204
0.82 18.70979745
1.23 20.62469057
1.64 22.54460804
3.28 30.23676857
4.92 37.92971475

These are the same values used as input to define "multilinear elastic material"; but force-displacement points instead of moment-rotation;
As you can see force values exceeded suddenly (while changing stiffness), which is not correct. I really appreciate it if you help me with that. Thanks
fmk
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Posts: 5884
Joined: Fri Jun 11, 2004 2:33 pm
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Re: Multilinear Elastic Material

Post by fmk »

sorry for the delay .. can you provide the results for the moment versus rotation in the truss (or the stress-strain response in the truss material itself)
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