Moment of beams
- Michele Mocciola
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17 years 9 months ago #1321
by Michele Mocciola
Replied by Michele Mocciola on topic Re:Moment of beams
@ Joël Cugnoni
Thanks for your files! They have been very useful.
In these days I've studied Joël's example and at last I obtained what I wanted. However playing with the options and changing some values, I've seen two strange things:
- if I apply a distributed load on a beam and if the mesh isn't little enough, the value of the moment on Salome is very different from the theoretical one; e.g. if I have a 1 meter beam divided in ten elements with a distributed load of 100N/m, fixed in the first vertex and free in the second, on the first vertex i have a moment of 45.2 N m, very different from the theoretical value ( 50 Nm ) (for more details look at the file tst-10el.tar.gz ); if I divide the beam in one hundred elements, the value is 49.5: a lot better ( tst-100el.tar.gz );
- my second problem is that if I use IMPR_RESU an if I use two fields RESU, Code_Aster gives an alert; if I use more than two RESU Code_Aster gives an error ( attached file is tst-3cmp.tar.gz ); my aim is to create a single MED file with all the components I need ( N, VY VZ, MT, MFZ, MFY).
Is this normal or I make something wrong?
Thanks!
Thanks for your files! They have been very useful.
In these days I've studied Joël's example and at last I obtained what I wanted. However playing with the options and changing some values, I've seen two strange things:
- if I apply a distributed load on a beam and if the mesh isn't little enough, the value of the moment on Salome is very different from the theoretical one; e.g. if I have a 1 meter beam divided in ten elements with a distributed load of 100N/m, fixed in the first vertex and free in the second, on the first vertex i have a moment of 45.2 N m, very different from the theoretical value ( 50 Nm ) (for more details look at the file tst-10el.tar.gz ); if I divide the beam in one hundred elements, the value is 49.5: a lot better ( tst-100el.tar.gz );
- my second problem is that if I use IMPR_RESU an if I use two fields RESU, Code_Aster gives an alert; if I use more than two RESU Code_Aster gives an error ( attached file is tst-3cmp.tar.gz ); my aim is to create a single MED file with all the components I need ( N, VY VZ, MT, MFZ, MFY).
Is this normal or I make something wrong?
Thanks!
Attachment files.tar.gz not found
- Joël Cugnoni
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17 years 9 months ago #1322
by Joël Cugnoni
Joël Cugnoni - a.k.a admin
www.caelinux.com
Replied by Joël Cugnoni on topic Re:Moment of beams
Dear Mickele,
as I have never used distributed loads with beams in Aster, i cannot tell you exactly why you get these results. To my opinion, it is probably because the method used for the computation of section forces & moments may not be accurate near a fixed boundary (to know the value at the boundary, you should extract the field \"REAC_NODA\" with the CALC_NO command.
But I also suggest that you post this question on Code_Aster forums as I am sure that the dev. team would like to have such feedback and could help you more precisely on this point.
For the multiple component output, the error comes from the fact that the field \"EFGE_ELNO_DEPL\" is already stored in the MED file (cannot write 2 fields with same name).
So I suggest that you modify your comm file to look like this :
[code:1]
IMPR_RESU(MODELE=MODMECA,
FORMAT='MED',
RESU=(_F(MAILLAGE=MAIL,
RESULTAT=RESU1,
NOM_CHAM='DEPL',),
_F(MAILLAGE=MAIL,
RESULTAT=RESU1,
NOM_CHAM='EFGE_ELNO_DEPL',
NOM_CMP='N,VY,VZ,MT,MFY,MFZ',),),);
[/code:1]
and in Salome, you can select which component to display when you create your plots (in the dialog box).
Regards,
J.Cugnoni
as I have never used distributed loads with beams in Aster, i cannot tell you exactly why you get these results. To my opinion, it is probably because the method used for the computation of section forces & moments may not be accurate near a fixed boundary (to know the value at the boundary, you should extract the field \"REAC_NODA\" with the CALC_NO command.
But I also suggest that you post this question on Code_Aster forums as I am sure that the dev. team would like to have such feedback and could help you more precisely on this point.
For the multiple component output, the error comes from the fact that the field \"EFGE_ELNO_DEPL\" is already stored in the MED file (cannot write 2 fields with same name).
So I suggest that you modify your comm file to look like this :
[code:1]
IMPR_RESU(MODELE=MODMECA,
FORMAT='MED',
RESU=(_F(MAILLAGE=MAIL,
RESULTAT=RESU1,
NOM_CHAM='DEPL',),
_F(MAILLAGE=MAIL,
RESULTAT=RESU1,
NOM_CHAM='EFGE_ELNO_DEPL',
NOM_CMP='N,VY,VZ,MT,MFY,MFZ',),),);
[/code:1]
and in Salome, you can select which component to display when you create your plots (in the dialog box).
Regards,
J.Cugnoni
Joël Cugnoni - a.k.a admin
www.caelinux.com
Moderators: catux
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