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#1 2022-04-04 14:26:41

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

rbe2 and rbe3 / MPC / joints

Hello,
what is the correct way to create hinge (or any other constraint) using rbe2 or rbe3 in salome meca?

I tried LIAISON_DDL and LIAISON_RBE3 but I haven't found a way how to use it on simple solid.
I also read there is a way how to do it using springs where one could define local coordinate system, but I guess I would spent hours trying.

Last edited by jacob (2022-04-04 14:27:27)


Attachments:
LIAISON_DDL.rar, Size: 1.5 MiB, Downloads: 64

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#2 2022-04-04 14:53:14

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

hello

can you share the command file i am unable to extract them from the hdf file
also Mesh_2 seems strictly identical to Mesh_1
review your files before sharing

creating hinges on a line deined at mesh time is one of the easiest thing to do in code_aster
there are examples in my book

jean pierre aubry

Last edited by jeanpierreaubry (2022-04-04 14:55:01)


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#3 2022-04-04 17:23:03

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

Re: rbe2 and rbe3 / MPC / joints

Sorry I forgot to mention the file is hdf with AS, now hinge_beam_AS.hdf. The other hdf is for the mesh. I am using latest salome for the mesh but salomemeca2018 for solving.


Attachments:
solid_beam_hinge.zip, Size: 689.89 KiB, Downloads: 62

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#4 2022-04-05 08:13:05

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

i do not understand what you are trying to do

1- a quadratic is unnecessary here, maybe harmful?, please revert to a linear mesh

2- i do not understand what the  RBE3 is supposed to do
anyhow DRX, DRY and DRZ DOF are not allowed in 3D modeling

3- node 3424 belongs at Group_1 and Group_2 and Face_1? this is strange try to put it at Z= slightly below Face_1


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#5 2022-04-05 08:40:46

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

my way to create an hinge (used many times)

create one node at x=0, y=0, z=-0.1 (slightly below Face_1)
make a LIAISON_SOLIDE between that node and Face_1

create a another node at x=0, y=0, z=-a (value of a at your choice)
fix its  6 DOF
make a SEG2, line element, between these two nodes
model it as a K_TR_D_L and give it the required properties

there are some examples in my book


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#6 2022-04-05 10:05:50

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

Re: rbe2 and rbe3 / MPC / joints

What I am trying to do is this.

So it has to be modelled as you are saying, I have to use spring? I cannot just constraint DX DY DZ (leave rotations free) at master node and couple it with nodes on left face using LIAISON_RBE3 or SOLID?


Attachments:
image_2022-04-05_110206.png, Size: 36.02 KiB, Downloads: 65

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#7 2022-04-05 10:21:03

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

maybe
i have always done the way i describe
your problem as far as i understand is that the node supposed to be the hinge does not seem to be seen
maybe because it is lying at the same z as Face_1

i never use  Salome to build my mesh so i have no idea about that

Last edited by jeanpierreaubry (2022-04-05 10:22:41)


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#8 2022-04-05 12:44:02

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

Re: rbe2 and rbe3 / MPC / joints

Alright I managed to do that as you said and it works.

Thank you.

I also tried using K_TR_D_N (it seams more appropriate, so I don't have to use line element) and I guess it works.

Last edited by jacob (2022-04-05 12:44:47)


Attachments:
beam_fix_hinge_0d.rar, Size: 1.82 MiB, Downloads: 62

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#9 2022-04-05 12:58:31

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

jacob wrote:

Alright I managed to do that as you said and it works.

Thank you.

I also tried using K_TR_D_N (it seams more appropriate, so I don't have to use line element) and I guess it works.

NO !
it does not work the same way
have a  look at page 313 of my book


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#10 2022-04-05 13:27:06

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

Re: rbe2 and rbe3 / MPC / joints

So if I managed to do RBE3 like that I should rather use K_TR_D_L?

If I understood it correctly I guess it is wrong when used for joint but since it is just connection to the ground it is ok. In my case it should be ok.
Am I wrong?


Attachments:
beam_fix_hinge_RBE3.rar, Size: 1.44 MiB, Downloads: 65

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#11 2022-04-05 16:07:24

jeanpierreaubry
Guru
From: nantes (france)
Registered: 2009-03-12
Posts: 3,860

Re: rbe2 and rbe3 / MPC / joints

t would nice if you gave some explanation about the various files
i can see 5 diffrents command files
what does each of them


consider reading my book
freely available here https://framabook.org/beginning-with-code_aster/

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#12 2022-04-05 19:22:05

jacob
Member
From: Dolní Benešov
Registered: 2022-03-07
Posts: 65

Re: rbe2 and rbe3 / MPC / joints

Well if you look just on comm, the last one is important.
__________________________________________________
##LIAISON_SOLIDE


mesh = LIRE_MAILLAGE(UNITE=2)

model = AFFE_MODELE(AFFE=(_F(MODELISATION=('3D', ),
                             PHENOMENE='MECANIQUE',
                             TOUT='OUI'),
                          _F(GROUP_MA=('0d', ),
                             MODELISATION=('DIS_TR', ),
                             PHENOMENE='MECANIQUE')),
                    MAILLAGE=mesh)

elempro0 = AFFE_CARA_ELEM(DISCRET=_F(CARA='K_TR_D_N',
                                     GROUP_MA=('0d', ),
                                     VALE=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0)),
                          MODELE=model)

mater = DEFI_MATERIAU(ELAS=_F(E=200000.0,
                              NU=0.3))

fieldmat = AFFE_MATERIAU(AFFE=_F(MATER=(mater, ),
                                 TOUT='OUI'),
                         MODELE=model)

load = AFFE_CHAR_MECA(DDL_IMPO=(_F(GROUP_MA=('fix', ),
                                   LIAISON='ENCASTRE'),
                                _F(DX=0.0,
                                   DY=0.0,
                                   DZ=0.0,
                                   GROUP_NO=('node', ))),
                      LIAISON_SOLIDE=_F(GROUP_NO=('hinge', 'node')),
                      MODELE=model,
                      PRES_REP=_F(GROUP_MA=('press', ),
                                  PRES=10.0))

reslin = MECA_STATIQUE(CARA_ELEM=elempro0,
                       CHAM_MATER=fieldmat,
                       EXCIT=_F(CHARGE=load),
                       MODELE=model)

reslin = CALC_CHAMP(reuse=reslin,
                    CRITERES=('SIEQ_ELGA', 'SIEQ_ELNO', 'SIEQ_NOEU'),
                    RESULTAT=reslin)

IMPR_RESU(RESU=_F(RESULTAT=reslin),
          UNITE=3)

____________________________________________________

##LIAISON_RBE3


mesh = LIRE_MAILLAGE(UNITE=2)

model = AFFE_MODELE(AFFE=(_F(MODELISATION=('3D', ),
                             PHENOMENE='MECANIQUE',
                             TOUT='OUI'),
                          _F(GROUP_MA=('0d', ),
                             MODELISATION=('DIS_TR', ),
                             PHENOMENE='MECANIQUE')),
                    MAILLAGE=mesh)

elempro0 = AFFE_CARA_ELEM(DISCRET=_F(CARA='K_TR_D_N',
                                     GROUP_MA=('0d', ),
                                     VALE=(1.0, 1.0, 1.0, 1.0, 1.0, 1.0)),
                          MODELE=model)

mater = DEFI_MATERIAU(ELAS=_F(E=200000.0,
                              NU=0.3))

fieldmat = AFFE_MATERIAU(AFFE=_F(MATER=(mater, ),
                                 TOUT='OUI'),
                         MODELE=model)

load = AFFE_CHAR_MECA(DDL_IMPO=(_F(GROUP_MA=('fix', ),
                                   LIAISON='ENCASTRE'),
                                _F(DX=0.0,
                                   DY=0.0,
                                   DZ=0.0,
                                   GROUP_NO=('node', ))),
                      LIAISON_RBE3=_F(COEF_ESCL=(1.0, ),
                                      DDL_ESCL=('DX-DY-DZ', ),
                                      DDL_MAIT=('DX', 'DY', 'DZ'),
                                      GROUP_NO_ESCL=('hinge', ),
                                      GROUP_NO_MAIT=('node', )),
                      MODELE=model,
                      PRES_REP=_F(GROUP_MA=('press', ),
                                  PRES=10.0))

reslin = MECA_STATIQUE(CARA_ELEM=elempro0,
                       CHAM_MATER=fieldmat,
                       EXCIT=_F(CHARGE=load),
                       MODELE=model)

reslin = CALC_CHAMP(reuse=reslin,
                    CRITERES=('SIEQ_ELGA', 'SIEQ_ELNO', 'SIEQ_NOEU'),
                    RESULTAT=reslin)

IMPR_RESU(RESU=_F(RESULTAT=reslin),
          UNITE=3)

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