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#1 Re: Salome-Meca usage » SHELL/3D versus SHELL/3D-SI » 2022-06-28 13:47:23

Hello Dr. Ackva,

of course, the square elements are preferable. I just wanted to understand with the linear elements the difference in approach Abaqus/Code_aster.  As I said, in Abaqus the under-integration is set as default for linear quadrilateral elements (2D) and also for the linear hexahedra. In addition, any control parameters are still used. The intention is to get a grip on locking and hourglass effects. I think we should end the discussion with this and I thank you expressly for your hints.

Best regards,
Hansbau52

#2 Re: Salome-Meca usage » 3D/DKT coupling, Create a vector » 2022-06-28 13:04:21

Hello Dr. Ackva,

sorry, of course I described that quite badly.  Regardless of the type of model (3D/shell), I have normal stresses in the cross-section of a clamped beam, which result quite generally from bending and tension/compression (normal in the sense of orthogonal to the section surface).  In my simple model, the x-direction is the longitudinal axis of the beam and only bending normal stresses occur.
In the meantime I have learned a little.
In the attachment you will find a result picture. On the left the solid geometry and on the right the shell. The shell stresses are shown on the top side and on the bottom side. I have shifted the geometries accordingly by half the thickness. But I am not yet satisfied with this, because I want a uniform scale without a jump at the transition. I thought I might have to create a new result vector for this, which contains e.g. only SIXX ???

Best regards,

Hansbau52

#3 Re: Salome-Meca usage » SHELL/3D versus SHELL/3D-SI » 2022-06-28 12:19:48

Hello Dr. Ackva,
thank you very much for your answer. I had of course set the cross-contraction to zero and also used the connection with COQUE-MASSIF without overlap. My question was about the reduced integration for the linear 3D elements. In Abaqus it is standard and leads to relatively good results. With Code_aster I did not notice any difference. Can you please tell me something about this?

Best regards,
Hansbau52

#4 Salome-Meca usage » 3D/DKT coupling, Create a vector » 2022-05-16 10:05:22

Hansbau52
Replies: 2

Hi community,

I want to create a vector that contains only the normal stress SIXX in a simple model. But it should be composed of SIXX from a 3D area and a DKT area (shell top side) of the model. Can someone please help me how to describe this.

Regards,
Hansbau52

#5 Introduce yourself / Présentez vous » Hello, I'am Hans » 2022-05-16 09:52:56

Hansbau52
Replies: 0

Hello together

I have been working in an engineering office for technical calculations and simulation for many years. I have a lot of experience with Abaqus and have recently started to work with Code_aster. I am particularly interested in coupled models (3D, shell, beam) because they are common in practical modelling.

Greetings from Germany

Hansbau52

#6 Salome-Meca usage » SHELL/3D versus SHELL/3D-SI » 2022-05-13 10:24:58

Hansbau52
Replies: 4

Hy community,

My test model (see attached picture) with linear elements (3D/DKT) produces a deformation of 1.77 mm. 
There is no difference between 3D and 3D-SI.  The same calculation with Abaqus gives a displacement of 1.79 mm with C3D8/S4 elements. If I replace C3D8 with C3D8R (reduced integration), I obtain a displacement of 2.64 mm.

I expect a result around 2.5 mm ( beam, analytically FL³/3EI). I also obtain this with a pure shell model.
Have I missed something (3D versus 3D-SI)?

Best Regards,

Hansbau52

#7 Salome-Meca usage » ParaViS: Stress visualisation for a coupled 3D/DKT model » 2022-05-10 13:48:41

Hansbau52
Replies: 0

Hi community,

I am using a mixed 3D/shell model (linear) for a simple test example (cantilever beam). I want to visualise the results (displacements, stresses) in ParaViS.  Do I have to create new fields in code_aster or can I organise the visualisation exclusively in ParaViS? What do I have to pay attention to?

Regards,