linear elasticity two body

[fabioit]

Hi,
I've a geometry with two body in contact.
I've one fixed edge and one with a force.
This is a simple elastic beam with a reinforcement.
But with surprise the rinforcement is in contact only in two edge!

two bodies aren't welded togheter?
how is it possible?

please help me.
Fabio

[raback]

Hi Fabio

How did you create the mesh? It seems that nodes on the interface are given separately for the two materials making a discontinuous solution possible.

-Peter

[fabioit]

HI,
I exported the assembly as step then used netgen 4.9.13.
I really don't know how is it possible....
this is a very simple problem.

I give you the mesh.

thank you per help

[raback]

Hi Fabio

It seems that the meshes coming from netgen are nonconforming i.e. the nodes on the boundary are not shared between the two bodies. This means also that the physical solution cannot be continuous over the surface. To demonstrate it I uncovered the problematic internal boundary in the attached picture.

Elmer can only eliminate additional nodes if they are at exactly the same location. Also, there are some possibilities (used mainly to enforce periodic BCs) to glue nonconforming meshes. However, this is rather tricky since visually determining the correct boundaries is difficult as they occupy the same positition.

To conclude it would be easiest if you could cure theh problem in netgen. Maybe the original CAD file needs to modified so that the boundary is recognized as internal one, rather than just two different bodies sitting really close to each other.

-Peter