Great Deflection Beam

Christian
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9 years 11 months ago #7895 by Christian

Great Deflection Beam was created by Christian

Hi all,

I'm trying to model a beam with great deflections. The beam is exposed to a force at its tip. The simulation with 'normal' deflection gives good results compared to the theory. Now my question is, how to set up the STAT_NON_LINE solver to get the great deflection soltuion. Apparently the settings for the COMPORTMENT are crucial.

Thanks for your help!
H3000

Claus
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9 years 11 months ago #7896 by Claus

Replied by Claus on topic Re: Great Deflection Beam

You probably have to use deformation -> 'grot_gdep' or is it called 'Green' now? I can't remember and the Code_Aster site is down.

Are you simulating a 1D, 2D or 3D model? If you are in 1D you should look a the beam formulations and find one that suits great deformation and rotation. POU_D_something.

/C

Code_Aster release : STA11.4 on OpenSUSE 12.3 64 bits - EDF/Intel version

Christian
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9 years 11 months ago #7903 by Christian

Replied by Christian on topic Re: Great Deflection Beam

Okay, so grot_gdep (that's how it is still called) is the way to do it. So I need to find the right material properties for the 3D benchmarks. Thanks man!

Christian
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9 years 11 months ago #7918 by Christian

Replied by Christian on topic Re: Great Deflection Beam

I'm now trying to perfom my simulation with the simplest setup and I'm using the following solver settings:

RESOL_NL=STAT_NON_LINE(MODELE=hexaQ,
                       CHAM_MATER=MATE1,
                       EXCIT=(_F(CHARGE=char1,),
                              _F(CHARGE=load1,),),
                       COMPORTEMENT=_F(RELATION='ELAS',
                                    DEFORMATION='GROT_GDEP',),
                       INCREMENT=_F(LIST_INST=ListInst,),
                       NEWTON=_F(PREDICTION='TANGENTE',
                                 REAC_ITER=0,),
                       CONVERGENCE=_F(RESI_GLOB_MAXI=1e-4,
                                      RESI_GLOB_RELA=1e-4,
                                      ITER_GLOB_MAXI=10,),
                       ARCHIVAGE=_F(LIST_INST=Archive,),);

Therefor I set my material properties to:

stiff=DEFI_MATERIAU(ELAS=_F(E=207000, #MPa
                            NU=0,
                            RHO=2.713e-9,),); #T/mm3

Compared to the CA test cases this should work out. However I get the following error message:

! <S> Exception utilisateur levee mais pas interceptee. !
   ! Les bases sont fermees.                               !
   ! Type de l'exception : error                           !
   !                                                       !
   ! Erreur numérique (floating point exception).          !

Does anyone see the error?
Thanks!

RichardS
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9 years 11 months ago - 9 years 11 months ago #7919 by RichardS

Replied by RichardS on topic Re: Great Deflection Beam

Two quick questions:
- do you ramp your load, or apply the full load instantly?
- d0 you use automatic timestepping?

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Last edit: 9 years 11 months ago by RichardS.

Christian
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9 years 11 months ago #7920 by Christian

Replied by Christian on topic Re: Great Deflection Beam

I apply the load instantly and I define my time-steps in this manner:

ListReel=DEFI_LIST_REEL(DEBUT=0,
                        INTERVALLE=_F(JUSQU_A=10,
                                      PAS=0.1,),);


ListInst=DEFI_LIST_INST(DEFI_LIST=_F(METHODE='MANUEL',
                                     LIST_INST=ListReel,),
                        ECHEC=_F(EVENEMENT='ERREUR',
                                 SUBD_PAS=5,
                                 SUBD_NIVEAU=4,),);

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