#1 2019-10-24 13:42:45

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Mass point

Good morning!

I would like to know how to add a mass point to a geometry.

thank you.

dezsit

Member

Registered: 2012-06-27

Posts: 69

Website

Re: Mass point

Hi,

you have to create 0D elements (POI in aster) on the nodes, where you want to apply mass element, then use DISCRETE element modelisation on these 0D elements. (more keywords: AFFE_MODELE->DIS_T, AFFE_CARA_ELEM->DISCRETE->M_T_D_N)

Check Jean Pierre Aubry's excellent book: framabook.org/beginning-with-code_aster/, eg. you will find an example on the 31.page.

BR
dezsit

Last edited by dezsit (2019-10-31 09:21:25)

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

Good morning dezsit,

Thank you for the help. I followed your tips but there is an error that I can't solve. See the error bellow and help me again if you can.

Thank you again.

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Attachments:
WhatsApp Image 2019-11-01 at 09.45.35.jpeg, Size: 46.48 KiB, Downloads: 341

jeanpierreaubry

Guru

From: nantes (france)

Registered: 2009-03-12

Posts: 4,049

Re: Mass point

hello

without knowing the time this error arises it is impossibleo give any advice
please post the fumm message file

jean pierre aubry

---

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

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

This is the hole massage that appears

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Attachments:
ERROR.txt, Size: 23.2 KiB, Downloads: 635

jeanpierreaubry

Guru

From: nantes (france)

Registered: 2009-03-12

Posts: 4,049

Re: Mass point

                     CREA_GROUP_MA=_F(NOM='TOUT',
                                      GROUP_MA='Steel_SOLID',
                                      TYPE_MAILLE='POI1',

in the above code if you replace GROUP_MA by GROUP_NO you will create a POI1 on ALL the node belonging to 'Steel_SOLID'
if you want to create a POI1 on one node you have to create a group on this node in the mesh before hand

NOM='TOUT' is not very clever

---

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

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

Hi,

I tried to do what you said and a new error appeared. It looks like my POI is included in another mesh.
It calculates the frequencies but does not consider the mass point.

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Attachments:
message.txt, Size: 50.08 KiB, Downloads: 453

dezsit

Member

Registered: 2012-06-27

Posts: 69

Website

Re: Mass point

Hi,

you defined the DIS_T in separate modelisation (model0) which is not used at all.
You have to define everything in the same model, what you want to use in an analysis, eg:

  model = AFFE_MODELE(MAILLAGE=mesh,
                      AFFE=(_F(PHENOMENE='MECANIQUE',
                              TOUT='OUI',
                              MODELISATION=('3D', ),),
                                 _F(PHENOMENE='MECANIQUE',
                               GROUP_MA='0D',
                               MODELISATION=('DIS_T', ),),),
                      INFO=1,
                      VERI_JACOBIEN='OUI',
                      DISTRIBUTION=_F(PARTITIONNEUR='METIS',
                                      METHODE='SOUS_DOMAINE',),
                      )

BR
dezsit

Last edited by dezsit (2019-11-04 22:24:37)

jeanpierreaubry

Guru

From: nantes (france)

Registered: 2009-03-12

Posts: 4,049

Re: Mass point

right deszit
that is it
+ a few other mistakes

---

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

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

thanks again,

I ran the code aster analysis following your steps and got the frequencies. However, when I ran ansys the frequencies gave very different values. What could have happened in code aster?

Just remembering, I want to add a mass point and distribute it on a face or edge.

Sorry for my ignorance, I'm having difficulties with language.

Bruna Justo

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Attachments:
message.txt, Size: 42.46 KiB, Downloads: 427

jeanpierreaubry

Guru

From: nantes (france)

Registered: 2009-03-12

Posts: 4,049

Re: Mass point

the run looks like ok
the error is somewhere else
we need the mesh to understand and the values calculated by ansys

---

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

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

Good Morning,

I can't send the mesh file, but I'm sending some images, hope it helps.

thanks.

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Attachments:
masspoint.PNG, Size: 133.06 KiB, Downloads: 278

brunajusto

Member

Registered: 2019-10-24

Posts: 7

Re: Mass point

more information about the mesh.

I used NATGEN 1D-2D-3D

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Compute.PNG, Size: 15.51 KiB, Downloads: 277