Modeling foam material with /MAT/LAW70
Overview
The attached example illustrates the compression test of foam material.
For the foam material the law /MAT/LAW70 is used.
This law describes the visco-elastic foam tabulated material. This material law can be used only with solid elements.
In the model there are two foam blocks. Each with dimensions (WxDxH) = 50.x50.x25.mm^3.
And the blocks are compressed by the top and bottom rigid surfaces to the limit of 0.85 strain.
Both blocks use the same stress_strain curve for the material loading behavior in compression.
However,
for "Part_1" material uses the Iflag=4 option.
With that the unloading behavior of material is defined using the HYS and SHAPE parameters.
And for the "Part_2" the material is set with Iflag=0.
With this option an unloading curve need to be defined.
Image below from HyperGraph, depicts the FEA results of stress vs strain of the foam blocks.
In this example, one curve for loading or unloading is defined, but the material model is formulate to accept loading curves related to different strain rates.
More information about the material setting can be found in the help documentation
https://2021.help.altair.com/2021.2/hwsolvers/rad/topics/solvers/rad/mat_law70_foam_tab_starter_r.htm?zoom_highlight=%2Fmat%2Flaw70
Please, let us know if this example is helpful for your application.
Pre-Requisite
Model was created in set to run on Radioss version 2021.2 or newer.
Usage/Installation Instructions
No additional requirement
Post-Requisite
Use hyperGraph and HyperView for post processing
Comments
-
Hi,
this is very useful at least to get the model working. I don't know why, but when my material is loaded, there is a strange signal distortion. Can you help me?
Thank you!
0 -
Community Guest said:
Hi,
this is very useful at least to get the model working. I don't know why, but when my material is loaded, there is a strange signal distortion. Can you help me?
Thank you!
Here is material data:
/MAT/LAW70/4
Foam_LAW70_krivky
5.628E-11
7. 400. 0
10. 1 6 6 0
2 0. 1.
3 0.12744 1.
4 0.63653 1.
5 1.2766 1.
6 2.5263 1.0025
6 2.6 1.00255
7 0. 0.999
8 0.12744 0.999
9 0.63653 0.9999
10 1.2766 0.9999
11 2.5263 1.00249
11 2.6 1.00254
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/FUNCT/2
FoamLoad_2
0. -2.70117E-6
0.003928876 0.0002839011
0.008289264 0.0005738915
0.0126505 0.0008422769
0.01705864 0.001095774
0.0214313 0.001335176
0.02582346 0.001558813
0.03027485 0.001767384
0.03470929 0.00196196
0.03911108 0.00213673
0.04350878 0.002301618
0.04787424 0.002452065
0.05225693 0.002589483
0.05661048 0.002723581
0.06095241 0.002840644
0.06527906 0.002962328
0.06957513 0.003063471
0.07387557 0.003170185
0.08254014 0.003356488
0.09128291 0.003541805
0.100041 0.003712641
0.1087836 0.003875029
0.1174894 0.004031954
0.1261569 0.004186381
0.1348217 0.004340509
0.1434374 0.004493739
0.1519428 0.004641399
0.1604176 0.004793368
0.1689648 0.004944876
0.1774828 0.005103826
0.1861625 0.005264523
0.1948796 0.005427901
0.2036793 0.0055941
0.2123596 0.005750424
0.2209864 0.005913621
0.2295177 0.006081799
0.2379729 0.006244679
0.2468147 0.006418595
0.2554984 0.006586299
0.2640792 0.006766299
0.2727266 0.006944797
0.2814289 0.007126566
0.2902021 0.007314843
0.298813 0.00750171
0.3032427 0.007607469
0.3077206 0.00770947
0.3165562 0.007918589
/FUNCT/3
FoamLoad_3
2.151492E-5 8.874334E-7
0.00366582 0.0002371266
0.007858419 0.0005116919
0.01205265 0.0007762242
0.01629815 0.00102741
0.02054189 0.001265
0.02479451 0.001487778
0.02906146 0.001697792
0.03337216 0.001901786
0.03765406 0.002086216
0.04193208 0.00225207
0.04618266 0.002408853
0.05045172 0.002553297
0.05468762 0.002691854
0.05891796 0.002815071
0.06314239 0.002934034
0.067327 0.00304191
0.07150977 0.00315281
0.0799129 0.003344272
0.08838218 0.003529961
0.09692193 0.003708531
0.1054446 0.003872924
0.1139174 0.004029368
0.1223908 0.004186396
0.1308399 0.004339632
0.1392579 0.00448416
0.1475862 0.00463618
0.1558449 0.004785658
0.1641127 0.004932128
0.1723666 0.005082034
0.1806575 0.005241284
0.18905 0.005393642
0.1975025 0.005554244
0.2060622 0.005710315
0.2144981 0.005875384
0.2228663 0.006044219
0.2311444 0.006196467
0.2393456 0.006361226
0.2478727 0.006529602
0.2563527 0.006705262
0.2647421 0.006884198
0.2730846 0.007058211
0.2814752 0.007240504
0.2899751 0.007434821
0.2983002 0.007628246
0.3026293 0.007735114
0.3070422 0.007843625
0.3155641 0.008057937
/FUNCT/4
FoamLoad_4
0.0007500391 6.409296E-6
0.006242721 0.0003144679
0.009554695 0.0004665913
0.01351436 0.000749578
0.01728083 0.0009778842
0.02113504 0.001143696
0.0248738 0.001400191
0.02894875 0.001604142
0.03267924 0.00177638
0.03664545 0.001991769
0.04060211 0.002125474
0.04434953 0.002292573
0.04838133 0.002449457
0.052213 0.002579602
0.0560744 0.002719866
0.05999546 0.002842287
0.06378348 0.002948196
0.06764953 0.003065851
0.07528687 0.003266533
0.0791575 0.003371544
0.08683792 0.003544159
0.09461015 0.003722806
0.1024254 0.003891791
0.110192 0.004046377
0.1179894 0.004207459
0.1257664 0.004356662
0.1334954 0.004502865
0.141238 0.00465552
0.148897 0.004804338
0.156477 0.004949705
0.1640325 0.005096798
0.1716256 0.005245118
0.1792178 0.005402229
0.1867952 0.005549386
0.1944866 0.005705582
0.202252 0.005863397
0.210009 0.006027693
0.217719 0.006188844
0.2253513 0.006349525
0.232978 0.006510339
0.2404689 0.006675313
0.2482362 0.006848481
0.2559568 0.00703018
0.2636391 0.007200319
0.2713042 0.007378839
0.2789402 0.007569494
0.2865764 0.007757983
0.2943423 0.007959943
0.2981967 0.008060824
0.3020188 0.008163935
0.3059194 0.008272437
0.3098126 0.008380218
0.3174951 0.008569168
/FUNCT/5
FoamLoad_5
0.0004726525 1.254642E-5
0.005288342 0.0001014074
0.008770336 0.0003681256
0.01166925 0.0006294094
0.01483664 0.0007778676
0.01872069 0.0009418809
0.02277637 0.001187198
0.02660322 0.001468716
0.03040506 0.001702666
0.03440744 0.001851419
0.03844307 0.001975945
0.04227861 0.002124292
0.04602004 0.00230889
0.04995495 0.002504597
0.05410226 0.002671136
0.05818757 0.002783205
0.06571876 0.002992987
0.06958963 0.003137388
0.07364062 0.003267077
0.08146233 0.003415083
0.0890575 0.003610712
0.09310493 0.003724864
0.1010845 0.003892003
0.1088441 0.004040808
0.1128231 0.004142097
0.1207802 0.00431543
0.1286108 0.00445351
0.1364699 0.004624432
0.1443465 0.004767891
0.1520479 0.004920261
0.1597993 0.005092447
0.1675147 0.005241628
0.1751765 0.005393067
0.1828641 0.005546262
0.1905711 0.005707393
0.1983894 0.00588535
0.2063137 0.006055574
0.2141846 0.006220172
0.2219722 0.006381692
0.229752 0.006559711
0.2375351 0.00673885
0.2452572 0.006913601
0.2530377 0.007098428
0.2608557 0.007280358
0.2686429 0.00747219
0.2725438 0.007573204
0.2764295 0.007679245
0.2842205 0.007875669
0.2919842 0.008079134
0.295885 0.008191163
0.2997764 0.008293666
0.3036663 0.008406606
0.3075816 0.008521845
0.3115221 0.008637112
0.3182576 0.008741948
/FUNCT/6
FoamLoad_6
0.0006616645 3.101893E-5
0.01186346 0.0002985273
0.0162679 0.0007315103
0.0202031 0.001122789
0.02424582 0.001383933
0.02892497 0.001546599
0.03424715 0.00170379
0.03981753 0.00193411
0.04525716 0.002224009
0.05046962 0.002534628
0.05564095 0.002807494
0.06098637 0.003003462
0.06650878 0.003111596
0.0773538 0.003260728
0.08245367 0.003367015
0.08745737 0.003495213
0.09256243 0.003646754
0.09788937 0.003817554
0.1034238 0.003985791
0.1090504 0.004137535
0.1146234 0.00425721
0.1253482 0.004444762
0.1358097 0.004655982
0.1411472 0.004785558
0.1465845 0.004909165
0.1520417 0.005028605
0.1627038 0.00519958
0.1730013 0.005376641
0.1781558 0.00549113
0.1833793 0.005617484
0.1886779 0.00575518
0.1940321 0.005893775
0.1994265 0.006027982
0.2048282 0.006149283
0.2102037 0.006253586
0.21554 0.006359729
0.2208423 0.006469278
0.2261394 0.006591681
0.2314455 0.006723921
0.236763 0.006858318
0.24209 0.006994118
0.2474138 0.007119343
0.2527166 0.007240905
0.2579944 0.007356776
0.2632574 0.00747794
0.2685385 0.007616899
0.2738497 0.007763473
0.2791793 0.007921205
0.2845105 0.008082789
0.2898339 0.008232416
0.2951489 0.008369704
0.3004553 0.008513733
0.3057545 0.008666352
0.3182386 0.008875803
/FUNCT/7
FoamUnload_7
0.002160585 7.124342E-5
0.006502037 0.0002516515
0.01082776 0.0004371919
0.01518874 0.0006164205
0.01954358 0.0007951747
0.02388805 0.0009614148
0.02828189 0.001119835
0.03269527 0.00127228
0.03707513 0.001408009
0.0414729 0.00153935
0.04582463 0.001661841
0.05019975 0.001778003
0.05455702 0.001886402
0.06323912 0.002085051
0.07182351 0.002260113
0.08043817 0.002427697
0.08912556 0.002590072
0.09786944 0.002743264
0.1066522 0.002895973
0.1154033 0.003047372
0.1241585 0.003193741
0.1329192 0.003342041
0.1416784 0.003497679
0.1503194 0.003642897
0.1589504 0.003794593
0.1675329 0.003942316
0.1760624 0.004102634
0.1846605 0.004252095
0.193429 0.004414632
0.2022398 0.004584228
0.2109639 0.004753869
0.2196404 0.004928754
0.2283227 0.005118088
0.2369866 0.005307949
0.2456165 0.005501159
0.2499633 0.005609753
0.2543318 0.005716871
0.2586756 0.005825093
0.2629906 0.005936733
0.267332 0.006053015
0.2716722 0.006170362
0.2759742 0.006290856
0.2803108 0.006414498
0.2846491 0.006550867
0.288984 0.006687321
0.2933244 0.006829343
0.2976755 0.006981538
0.3019808 0.007140255
0.3063324 0.007316322
0.3106387 0.007503186
0.3149381 0.0077099
0.3187562 0.007963246
/FUNCT/8
FoamUnload_8
0.002986567 8.778616E-5
0.007220252 0.0002565039
0.01145099 0.0004325855
0.01571077 0.0006102894
0.01995062 0.0007883795
0.02421229 0.0009544549
0.02849427 0.001107043
0.03279564 0.001259518
0.03707 0.00139953
0.04134285 0.0015263
0.04558976 0.001655144
0.04985906 0.001774509
0.05409808 0.001881016
0.05832717 0.001985124
0.06673867 0.002176116
0.07510232 0.0023476
0.08352716 0.002513993
0.09203365 0.002672144
0.1005648 0.002820583
0.1091075 0.002969092
0.1176426 0.003122782
0.1261543 0.003269486
0.1346698 0.003412504
0.1431271 0.003561492
0.151505 0.003711058
0.1598914 0.00385962
0.1682189 0.004005239
0.176493 0.004153479
0.1848357 0.004308424
0.1933736 0.004468038
0.2019096 0.004632817
0.2103748 0.004805582
0.2188099 0.004981869
0.2272281 0.005164539
0.2356017 0.005349004
0.2398062 0.005450412
0.2481556 0.005644955
0.2523599 0.005751634
0.2565758 0.005861579
0.2607628 0.005978002
0.2649532 0.006087069
0.2691558 0.006200907
0.2733197 0.006316803
0.2774967 0.006447993
0.2816799 0.00657469
0.2858722 0.006704146
0.2900457 0.006848087
0.2942578 0.006991528
0.2984241 0.007146271
0.302579 0.007305503
0.3067991 0.007484567
0.310927 0.00766684
0.3150492 0.007874511
0.3184958 0.008113298
/FUNCT/9
FoamUnload_9
0.001583451 1.865917E-5
0.004968643 7.07945E-5
0.008905503 0.0001983038
0.01281817 0.0003466521
0.01673402 0.0005073247
0.02068313 0.0006664617
0.02461528 0.0008226568
0.0285569 0.0009767062
0.0324944 0.001128127
0.03643857 0.001264065
0.0403478 0.001396826
0.04427145 0.001517351
0.04817079 0.0016361
0.0520709 0.001751569
0.05594275 0.001860289
0.06365623 0.002055096
0.07134249 0.002237883
0.07904001 0.002402441
0.08685887 0.002559734
0.09468002 0.002719068
0.1024902 0.00286291
0.1102973 0.003019071
0.1180976 0.003162626
0.1258628 0.003308085
0.1336128 0.003450454
0.1413151 0.003593912
0.1489585 0.00374156
0.1565614 0.003882795
0.1642233 0.004022162
0.1717805 0.004174294
0.1793786 0.004318662
0.1870568 0.00447735
0.1948042 0.004633062
0.2025847 0.004798276
0.2103303 0.004976352
0.2179895 0.005136567
0.2256579 0.005319988
0.2332703 0.00550853
0.2408633 0.005695986
0.2446928 0.005797678
0.2484976 0.005899246
0.2523471 0.00600028
0.2561882 0.006112697
0.2599721 0.006213397
0.2638402 0.006326379
0.2675951 0.006447748
0.271372 0.006552693
0.2753095 0.006685038
0.2828456 0.006913292
0.2867037 0.007079663
0.2903831 0.007199828
0.2943545 0.007345878
0.2980864 0.007539655
0.3017952 0.007640068
0.3056379 0.007816626
0.3095 0.008027165
0.3127442 0.00816488
0.3159589 0.008430224
0.3180544 0.008561036
/FUNCT/10
FoamUnload_10
0.001749665 2.509283E-5
0.007569847 9.530082E-5
0.01155255 0.0002159446
0.01553353 0.0003658387
0.019519 0.0005256634
0.02350747 0.0006828291
0.02750666 0.0008439406
0.03150403 0.001001159
0.03548362 0.001148095
0.03944469 0.001282424
0.04340765 0.001412599
0.04736437 0.001543834
0.05131221 0.001667675
0.05523719 0.001783479
0.05913106 0.001889169
0.06692205 0.002082255
0.07474008 0.002264654
0.08262371 0.002435573
0.09056016 0.002609863
0.0984769 0.002773679
0.1063678 0.002922453
0.1142529 0.003075804
0.1221424 0.003221788
0.1300009 0.003385483
0.1377879 0.003538226
0.1455092 0.003674944
0.1531885 0.00382511
0.1609064 0.003965025
0.1686527 0.004130815
0.1763318 0.004290056
0.1841294 0.004432703
0.1919747 0.004617144
0.1997922 0.004771672
0.2076886 0.00494758
0.2115916 0.005055436
0.2192654 0.005225922
0.2270615 0.005397346
0.2309901 0.005512095
0.2385835 0.005726789
0.2463662 0.005880289
0.2503358 0.006005944
0.2542114 0.006148101
0.2579865 0.006266244
0.2657288 0.006437943
0.2697284 0.006586299
0.2736266 0.006755611
0.2773636 0.00690538
0.2849778 0.007093507
0.2889452 0.007203266
0.2928118 0.007363997
0.2966069 0.007582532
0.3004926 0.007772586
0.3042877 0.007885454
0.3075491 0.008000798
0.3104885 0.008213818
0.3137944 0.008484727
0.3185483 0.008742632
/FUNCT/11
FoamUnload_11
0.003314895 6.203787E-5
0.01356938 0.0002195922
0.01897907 0.0004052804
0.02439453 0.000604703
0.0298223 0.0008093485
0.03525797 0.001018924
0.0406903 0.001221626
0.04610275 0.001415997
0.0514754 0.001602487
0.05679751 0.001762354
0.06208051 0.001906929
0.06736128 0.002035706
0.07268279 0.002152753
0.07806276 0.002271265
0.08349296 0.002398874
0.08893202 0.002522612
0.09434428 0.002646904
0.09971289 0.002766794
0.1103546 0.002963535
0.121057 0.003159856
0.1264726 0.003263004
0.1318828 0.003387134
0.1372344 0.003518194
0.1425083 0.003648277
0.1528554 0.003861723
0.1632241 0.004016908
0.1738756 0.004191829
0.1792541 0.004317078
0.1846083 0.004454547
0.1898926 0.004576901
0.1951489 0.004683982
0.2057955 0.00487921
0.211208 0.005004054
0.2166497 0.005169978
0.222065 0.005355248
0.2273638 0.005523876
0.2324966 0.00567535
0.2375267 0.005809767
0.2425973 0.005915169
0.2532545 0.006092221
0.2587528 0.006193999
0.2641363 0.006349129
0.2693003 0.006577139
0.2743585 0.006853013
0.2795557 0.00710205
0.2849546 0.007274551
0.2950127 0.007468473
0.299152 0.007663948
0.3030723 0.007979841
0.307307 0.008348214
0.3119342 0.008675003
0.3183164 0.0088847650