composite sandwich panel with 2d faces and 3d core

[jlrp]

hello all
I am trying to simulate a simple composite sandwich panel with 2D laminate elements for the top and bottom faces, and 3D elements (isotropic material) for the core
Geometry: 3D solid made in rhino, exported as .stp
Mesh: I first meshed the solid, then the top and bottom surfaces with the same element sizes
Constraints: I have fixed curves all around the panel
Load: pressure load applied on the top surface
Analysis: static
Result: doesn't work, I get fatal error 9137. when I run with PARAM,BAILOUT,-1 I can see that only the surface where I have applied the pressure load is deflecting. The 3d core and the bottom surface have 0 translation, so I understand that the 2D and 3D mesh are not connected.
What am I doing wrong ?
I can upload my model if you want

thanks in advance

 

[crostolo]

You have to set up a contact condiction between the faces and the 3D core.

Why do you use 3D elements for the core? It would be easier and faster to model the whole sandwich panel with laminate-composite elements (all 2D)

 

[jlrp]

thanks crostolo, I'll try that

why 3d for the core ? because I want to look into free edge effects and the 2d laminate elements don't allow that (I think)

 

[dracos]

From the sounds of it you need to merge coincident nodes in your model.

>> Tools >> Check >> Coincident Nodes

 

[rb1957]

that's what i'd look at too. Or if you're being very sophisticated and want to model the glue, then add a glue contact between the meshes.

another day in paradise, or is paradise one day closer ?

 

[jlrp]

merging coincident nodes didn't work

and I am having a hard time making the glued contact between the 2d shell and the 3d core. the two regions I am trying to connect have effectively the same surface ID.

I am a bit lost here, I would be grateful for some help

 

[dracos]

Have you tried to build the model an alternate way.

Create a surface mesh on one side of the panel then copy it to the other. Extrude the mesh from one face to the other to create the core solid mesh.

 

[Naffoussi]

Hi,

Could you drop your model then we can look at it.



Seif Eddine Naffoussi, Stress Engineer

http://www.Innovamech.com

33650 Martillac û France