In this post we will have a look at a simple linear modal analysis.
This case is taken from a publicy available example on the internet, but the original source is probably this one, for all due credit.
To read this article one will need some knowledge both in Nastran and in Code_Aster.
The translation between Nastran and Code_Aster can be made by using the following correspondances :
Nastran keyword | Code_Aster keyword |
---|---|
BEGIN | DEBUT |
SOL 103 + SUBCASE(METHOD=1) | ASSEMBLAGE + CALC_MODES(SOLVEUR_MODAL =_F(METHODE=’TRI_DIAG’),) |
TIME 600 | See “prob19.export” file, line “A tpmax 600“ |
EIGRL | CALC_MODES(OPTION=’PLUS_PETITE’,CALC_FREQ=_F(NMAX_FREQ=5),) |
PSHELL | AFFE_MODELE(MODELISATION=’DKT‘), AFFE_CARA_ELEM(COQUE_F(EPAIS)) + AFFE_MATERIAU |
CQUAD4 | See “prob19.mail” file: QUAD4 + AFFE_CARA_ELEM(COQUE=_F(GROUPMA)) |
MAT1 | DEFI_MATERIAU(ELAS) |
GRID | See “prob19.mail” file: COOR_3D |
SPC1 | AFFE_CHAR_MECA(DDL_IMPO) |
ENDDATA | FIN |
After the calculation we can find the frequencies for the first five modes and compare them with the Nastran results :
Here is the corresponding mode from Code_Aster results :
Here is a table of comparison between Nastran and Code_Aster results for this case (Nastran values are taken from the pdf file above) :
Mode | Nastran Frequency | Code_Aster Frequency | Diff % |
---|---|---|---|
1 | 133.6996 | 133.75689075 | 0.04% |
2 | 689.7916 | 698.719757183 | 1.29% |
3 | 843.8915 | 837.469216421 | 0.76% |
4 | 2212.03 | 2220.53352351 | 0.75% |
5 | 2379.052 | 2361.13583993 | 0.75% |
First of all, let’s see the Nastran code (file “prob19.dat”) for this exemple :
ID SEMINAR, PROB19 SOL 103 TIME 600 CEND TITLE = NORMAL MODES EXAMPLE ECHO = UNSORTED SUBCASE 1 SUBTITLE= USING LANCZOS METHOD = 1 SPC = 1 $VECTOR=ALL BEGIN BULK PARAM,COUPMASS,1 PARAM,WTMASS,.00259 EIGRL,1,5, PSHELL,1,1,.1,1,,1 CQUAD4,1,1,1,2,13,12 =,*1,=,*1,*1,*1,*1 =8 CQUAD4,11,1,12,13,24,23 =,*1,=,*1,*1,*1,*1 =8 CQUAD4,21,1,23,24,35,34 =,*1,=,*1,*1,*1,*1 =8 CQUAD4,31,1,34,35,46,45 =,*1,=,*1,*1,*1,*1 =8 MAT1,1,3.+7,.3,,.282 GRID,1,,0.,0.,0. =,*1,=,*0.5,=,= =9 GRID,12,,0.,.5,0. =,*1,=,*0.5,=,= =9 GRID,23,,0.,1.,0. =,*1,=,*0.5,=,= =9 GRID,34,,0.,1.5,0. =,*1,=,*0.5,=,= =9 GRID,45,,0.,2.,0. =,*1,=,*0.5,=,= =9 SPC1,1,12345,1,12,23,34,45 ENDDATA
In Code_Aster, you will need to create distinct files for the mesh and the commands. Let’s start with the main mesh file (file “prob19.mail”) :
TITRE prob19 NORMAL MODES EXAMPLE FINSF COOR_3D N1 0.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N2 5.0000000000e-01 0.0000000000e+00 0.0000000000e+00 N13 5.0000000000e-01 5.0000000000e-01 0.0000000000e+00 N12 0.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N3 1.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N14 1.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N10 4.5000000000e+00 0.0000000000e+00 0.0000000000e+00 N11 5.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N22 5.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N21 4.5000000000e+00 5.0000000000e-01 0.0000000000e+00 N9 4.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N20 4.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N8 3.5000000000e+00 0.0000000000e+00 0.0000000000e+00 N19 3.5000000000e+00 5.0000000000e-01 0.0000000000e+00 N7 3.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N18 3.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N6 2.5000000000e+00 0.0000000000e+00 0.0000000000e+00 N17 2.5000000000e+00 5.0000000000e-01 0.0000000000e+00 N5 2.0000000000e+00 0.0000000000e+00 0.0000000000e+00 N16 2.0000000000e+00 5.0000000000e-01 0.0000000000e+00 N4 1.5000000000e+00 0.0000000000e+00 0.0000000000e+00 N15 1.5000000000e+00 5.0000000000e-01 0.0000000000e+00 N24 5.0000000000e-01 1.0000000000e+00 0.0000000000e+00 N23 0.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N25 1.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N33 5.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N32 4.5000000000e+00 1.0000000000e+00 0.0000000000e+00 N31 4.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N30 3.5000000000e+00 1.0000000000e+00 0.0000000000e+00 N29 3.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N28 2.5000000000e+00 1.0000000000e+00 0.0000000000e+00 N27 2.0000000000e+00 1.0000000000e+00 0.0000000000e+00 N26 1.5000000000e+00 1.0000000000e+00 0.0000000000e+00 N35 5.0000000000e-01 1.5000000000e+00 0.0000000000e+00 N34 0.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N36 1.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N44 5.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N43 4.5000000000e+00 1.5000000000e+00 0.0000000000e+00 N42 4.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N41 3.5000000000e+00 1.5000000000e+00 0.0000000000e+00 N40 3.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N39 2.5000000000e+00 1.5000000000e+00 0.0000000000e+00 N38 2.0000000000e+00 1.5000000000e+00 0.0000000000e+00 N37 1.5000000000e+00 1.5000000000e+00 0.0000000000e+00 N46 5.0000000000e-01 2.0000000000e+00 0.0000000000e+00 N45 0.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N47 1.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N55 5.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N54 4.5000000000e+00 2.0000000000e+00 0.0000000000e+00 N53 4.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N52 3.5000000000e+00 2.0000000000e+00 0.0000000000e+00 N51 3.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N50 2.5000000000e+00 2.0000000000e+00 0.0000000000e+00 N49 2.0000000000e+00 2.0000000000e+00 0.0000000000e+00 N48 1.5000000000e+00 2.0000000000e+00 0.0000000000e+00 FINSF QUAD4 E1 N1 N2 N13 N12 E2 N2 N3 N14 N13 E10 N10 N11 N22 N21 E9 N9 N10 N21 N20 E8 N8 N9 N20 N19 E7 N7 N8 N19 N18 E6 N6 N7 N18 N17 E5 N5 N6 N17 N16 E4 N4 N5 N16 N15 E3 N3 N4 N15 N14 E11 N12 N13 N24 N23 E12 N13 N14 N25 N24 E20 N21 N22 N33 N32 E19 N20 N21 N32 N31 E18 N19 N20 N31 N30 E17 N18 N19 N30 N29 E16 N17 N18 N29 N28 E15 N16 N17 N28 N27 E14 N15 N16 N27 N26 E13 N14 N15 N26 N25 E21 N23 N24 N35 N34 E22 N24 N25 N36 N35 E30 N32 N33 N44 N43 E29 N31 N32 N43 N42 E28 N30 N31 N42 N41 E27 N29 N30 N41 N40 E26 N28 N29 N40 N39 E25 N27 N28 N39 N38 E24 N26 N27 N38 N37 E23 N25 N26 N37 N36 E31 N34 N35 N46 N45 E32 N35 N36 N47 N46 E40 N43 N44 N55 N54 E39 N42 N43 N54 N53 E38 N41 N42 N53 N52 E37 N40 N41 N52 N51 E36 N39 N40 N51 N50 E35 N38 N39 N50 N49 E34 N37 N38 N49 N48 E33 N36 N37 N48 N47 FINSF GROUP_MA NOM = G1 % Original part : 1 E1 E10 E11 E12 E13 E14 E15 E16 E17 E18 E19 E2 E20 E21 E22 E23 E24 E25 E26 E27 E28 E29 E3 E30 E31 E32 E33 E34 E35 E36 E37 E38 E39 E4 E40 E5 E6 E7 E8 E9 FINSF FIN
Then, the command file (file “prob19.comm”) :
# prob19 # NORMAL MODES EXAMPLE DEBUT(PAR_LOT='NON', ERREUR=_F(ERREUR_F='ABORT',), IGNORE_ALARM=('SUPERVIS_1','MODELISA4_8',),); MAIL=LIRE_MAILLAGE(FORMAT='ASTER', VERI_MAIL=_F(VERIF='OUI',),); MODMECA=AFFE_MODELE(MAILLAGE=MAIL, AFFE=_F(GROUP_MA='G1', PHENOMENE='MECANIQUE', MODELISATION='DKT',),); MAT00001=DEFI_MATERIAU(ELAS=_F(E=30000000.0, NU=0.3, RHO=0.00073038,),); CHMAT=AFFE_MATERIAU(MAILLAGE=MAIL, AFFE=_F(GROUP_MA='G1', MATER=MAT00001,),); B1P0=AFFE_CHAR_MECA(MODELE=MODMECA, DDL_IMPO=_F(NOEUD=('N12','N1','N45','N34','N23',), DX=0.0, DY=0.0, DZ=0.0, DRX=0.0, DRY=0.0,),); CAEL=AFFE_CARA_ELEM(MODELE=MODMECA, COQUE=_F(GROUP_MA='G1', EPAIS=0.1, VECTEUR=(0.9,0.1,0.2,), COQUE_NCOU=1,),); ASSEMBLAGE(MODELE=MODMECA, CHAM_MATER=CHMAT, CARA_ELEM=CAEL, CHARGE=B1P0, NUME_DDL=CO('NUMEDDL1'), MATR_ASSE=(_F(MATRICE=CO('RIGI1'), OPTION='RIGI_MECA',), _F(MATRICE=CO('MASS1'), OPTION='MASS_MECA',),),); RESU1=CALC_MODES(SOLVEUR_MODAL =_F(METHODE='TRI_DIAG'), MATR_RIGI=RIGI1, MATR_MASS=MASS1, OPTION='PLUS_PETITE', CALC_FREQ=_F(NMAX_FREQ=5), SOLVEUR=_F(METHODE='MUMPS', NPREC=8,), VERI_MODE=_F(STOP_ERREUR='NON',),); TEST_RESU(RESU=(_F(NUME_ORDRE=1, PARA='FREQ', RESULTAT=RESU1, VALE_CALC=133.6996, TOLE_MACHINE=0.02, ), ),); IMPR_RESU(FORMAT='RESULTAT', RESU=_F(RESULTAT=RESU1, NOM_CHAM='DEPL', VALE_MAX='OUI', VALE_MIN='OUI',),); IMPR_RESU(FORMAT='MED', UNITE=80, RESU=_F(RESULTAT=RESU1, NOM_CHAM='DEPL',),); FIN(FORMAT_HDF='OUI',);
You will also need a file to keep everything together ( file “prob19.export”). This file is the one needed to start the calculation on command line (“as_run prob19.export”) :
P actions make_etude P memory_limit 256.0 P mode interactif P mpi_nbcpu 1 P mpi_nbnoeud 1 P ncpus 1 P testlist verification sequential P time_limit 60.0 P version testing A memjeveux 375.0 A tpmax 172800 P memjob 3072000 P tpsjob 2880 F comm prob19.comm D 1 F mail prob19.mail D 20 F mess prob19.mess R 6 F resu prob19.resu R 8 F rmed prob19.rmed R 80
I created all 3 files into a folder named “prob19”: *.comm *.mail and *.export.
Then I type as_run.bat prob19.export and I get an error. Not sure what is going on. The exact same thing happened with prob6 from the other post.
If I try to run the test codes such as “forma02” it runs fine.
Could you please help me out on this? Are there some settings that I need to enable to run new files that are not on the test section?
Here’s the screen output for reference. Thanks!
C:\code-aster_fem\prob19>echo OFF
——————————————————————————–
Code_Aster execution
prepare environment in C:\Users\ab\AppData\Local\Temp\ju-comp1-interactif.545
——————————————————————————–
Copying datas
copying …\prob19\prob19.comm… copying …\prob19\prob19.mail… Parameters : memory 256 MB – time limit 60 s
——————————————————————————–
Content of C:\Users\ab\AppData\Local\Temp\ju-comp1-interactif.545 before execution
——————————————————————————–
Code_Aster run
Command line 1 :
C:\code_aster_13-3-win64-beta-0-2\install\13.3\bin\aster C:\code_aster_13-3-win64-beta-0-2\install\13.3\lib\aster\Execution\E_SUPERV.py -commandes fort.1 –num_job=545 –mode=interactif –rep_outils=C:\code_aster_13-3-win64-beta-0-2\install\outils –rep_mat=C:\code_aster_13-3-win64-beta-0-2\install\testing\materiau –rep_dex=C:\code_aster_13-3-win64-beta-0-2\install\testing\datg –numthreads=1 –suivi_batch –memjeveux=32.0 –tpmax=60.0
# ——————————————————————————————
# Impression du contenu du fichier de commandes à exécuter :
# ——————————————————————————————
# prob19
# NORMAL MODES EXAMPLE
DEBUT(PAR_LOT=’NON’,
ERREUR=_F(ERREUR_F=’ABORT’,),
IGNORE_ALARM=(‘SUPERVIS_1′,’MODELISA4_8′,),);
MAIL=LIRE_MAILLAGE(FORMAT=’ASTER’,
VERI_MAIL=_F(VERIF=’OUI’,),);
MODMECA=AFFE_MODELE(MAILLAGE=MAIL,
AFFE=_F(GROUP_MA=’G1′,
PHENOMENE=’MECANIQUE’,
MODELISATION=’DKT’,),);
MAT00001=DEFI_MATERIAU(ELAS=_F(E=30000000.0,
NU=0.3,
RHO=0.00073038,),);
CHMAT=AFFE_MATERIAU(MAILLAGE=MAIL,
AFFE=_F(GROUP_MA=’G1′,
MATER=MAT00001,),);
B1P0=AFFE_CHAR_MECA(MODELE=MODMECA,
DDL_IMPO=_F(NOEUD=(‘N12′,’N1′,’N45′,’N34′,’N23′,),
DX=0.0,
DY=0.0,
DZ=0.0,
DRX=0.0,
DRY=0.0,),);
CAEL=AFFE_CARA_ELEM(MODELE=MODMECA,
COQUE=_F(GROUP_MA=’G1’,
EPAIS=0.1,
VECTEUR=(0.9,0.1,0.2,),
COQUE_NCOU=1,),);
ASSEMBLAGE(MODELE=MODMECA,
CHAM_MATER=CHMAT,
CARA_ELEM=CAEL,
CHARGE=B1P0,
NUME_DDL=CO(‘NUMEDDL1’),
MATR_ASSE=(_F(MATRICE=CO(‘RIGI1′),
OPTION=’RIGI_MECA’,),
_F(MATRICE=CO(‘MASS1′),
OPTION=’MASS_MECA’,),),);
RESU1=CALC_MODES(SOLVEUR_MODAL =_F(METHODE=’TRI_DIAG’),
MATR_RIGI=RIGI1,
MATR_MASS=MASS1,
OPTION=’PLUS_PETITE’,
CALC_FREQ=_F(NMAX_FREQ=5),
SOLVEUR=_F(METHODE=’MUMPS’,
NPREC=8,),
VERI_MODE=_F(STOP_ERREUR=’NON’,),);
TEST_RESU(RESU=(_F(NUME_ORDRE=1,
PARA=’FREQ’,
RESULTAT=RESU1,
VALE_CALC=133.6996,
TOLE_MACHINE=0.02,
),
),);
IMPR_RESU(FORMAT=’RESULTAT’,
RESU=_F(RESULTAT=RESU1,
NOM_CHAM=’DEPL’,
VALE_MAX=’OUI’,
VALE_MIN=’OUI’,),);
IMPR_RESU(FORMAT=’MED’,
UNITE=80,
RESU=_F(RESULTAT=RESU1,
NOM_CHAM=’DEPL’,),);
FIN(FORMAT_HDF=’OUI’,);
You will also need a file to keep everything together ( file ?prob19.export?). This file is the one needed to start the calculation on command line (?as_run prob19.export?) :
P actions make_etude
P memory_limit 256.0
P mode interactif
P mpi_nbcpu 1
P mpi_nbnoeud 1
P ncpus 1
P testlist verification sequential
P time_limit 60.0
P version testing
A memjeveux 375.0
A tpmax 172800
P memjob 3072000
P tpsjob 2880
F comm prob19.comm D 1
F mail prob19.mail D 20
F mess prob19.mess R 6
F resu prob19.resu R 8
F rmed prob19.rmed R 81
# ——————————————————————————————
ERREUR DE COMPILATION DANS ACCAS – INTERRUPTION
>> JDC.py : DEBUT RAPPORT
CR phase d’initialisation
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Compilation impossible : File “fort.1”, line 77 !
! You will also need a file to keep everything together ( file !
! ?prob19.export?). This file is the one needed to start the calculation on !
! command line (?as_run prob19.export?) : !
! ^ !
! SyntaxError: invalid syntax !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
fin CR phase d’initialisation
>> JDC.py : FIN RAPPORT
Code_Aster run ended, diagnostic : _ABNORMAL_ABORT
——————————————————————————–
Content of C:\Users\ab\AppData\Local\Temp\ju-comp1-interactif.545 after execution
——————————————————————————–
Size of bases
——————————————————————————–
Copying results
copying …\fort.6… copying …\fort.8…
_COPYFILE no such file or directory: fort.81
_ABNORMAL_ABORT Code_Aster run ended
———————————————————————————
cpu system cpu+sys elapsed
———————————————————————————
Preparation of environment 0.00 0.00 0.00 0.00
Copying datas 0.00 0.00 0.00 0.02
Code_Aster run 0.00 0.00 0.00 0.71
Copying results 0.00 0.00 0.00 0.03
———————————————————————————
Total 0.08 0.02 0.09 0.97
———————————————————————————
as_run 1.13.9
————————————————————
— DIAGNOSTIC JOB : _ABNORMAL_ABORT
————————————————————
EXIT_CODE=4
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Hi,
I think that there is some text copied by mistake from the blog comments, probably in your prob19.comm file. The text you should look for is : “You will also need a file to keep everything together ( file ?prob19.export?). This file is the one needed to start the calculation on command line (?as_run prob19.export?) :”.
Best regards
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Thanks!
It ran fine now. I can see in the .RESU file the modes.
My question is: how do I get a .RMED file that I can visualize? I can see that it is requested in the .EXPORT file, but it does not get created.
Thanks again for all the help!
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Hi,
I am glad that you could solve this issue 🙂 If you have modes in .RESU file you should also have the .RMED file. One possibility is that, since it is bigger of other files, when you checked it was still being copied even if the .RESU was already available. Could you please check again now ? You should always wait for the command window to close before looking for result files. Could you please also check for the .MESS file ? It should have a last line like this : EXECUTION_CODE_ASTER_EXIT….=0 to indicate that everything was ok till the end.
Best regards
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I’m afraid I’ve had the same problem as described above with the inability to generate .RMED files. I’ve been running the commands through Windows Powershell, and I’m able to generate .mess and .resu files every time. In my .MESS file, the string ‘EXECUTION_CODE_ASTER_EXIT’ does not appear. In the powershell, I see a message saying ‘COPYFILE no such file or directory: fort.81’.
Thank you for any and all advice.
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If an error occurs during Code_Aster runtime, fort.81 (coresponding to .RMED file) may not be created and as_run is unable to retrieve it
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I changed the R 81 to R 80 in the .export file as is shown in the ‘Beginning with Code_Aster and Windows’ post, and that generated the .RMED file for me. I’ll keep on reading for the interim, but if there’s ever a chance to clarify proper generation of .export files, I’d be infinitely grateful. ASTK doesn’t work yet, correct? Thanks again.
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ASTK is no more maintained and was replaced by the AsterStudy Salome module
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