Surface interactions inside another surface
Surface interactions inside another surface
(OP)
Hello all,
I have a structure like shown in [1] with a shell extrusion geometry like shown in [2]. And this structure will be axially crushed by a rigid plate (not shown).
As you can see, the structure is multi-celled. But defining the interactions of surface-to-surface (rigid plate to beam) and self-contact (beam with self), only one side of the interior surface can be picked. The same surface is shown at different angles in [3].
If I pick the external sides as expected and only ONE side of the internals, then the simulation is aborted due to the error:
"2 improperly defined surface(s). Please check your surface definitions. Make sure that all surface normals point outward."
And if I check the surface normals, this is what I can see: [4]
I have also tried creating a surface using part->Features->Surfaces and selecting both sides there but the simulation gets a different error in that case:
"Contact pair references surface/node-based surface/analytical rigid surface assembly_beam-1_surf-1 but this surface/node-based surface/analytical rigid surface cannot be used with *contact pair. Check previous warning messages for this surface to find the cause.
Contact pair references surface/node-based surface/analytical rigid surface but this surface/node-based surface/analytical rigid surface has not been defined or this surface is defined on the collapsed faces"
Does anyone have any ideas for solving this? Look forward to reading your responses!
[1]:
[2]:
[3]:
[4]:
I have a structure like shown in [1] with a shell extrusion geometry like shown in [2]. And this structure will be axially crushed by a rigid plate (not shown).
As you can see, the structure is multi-celled. But defining the interactions of surface-to-surface (rigid plate to beam) and self-contact (beam with self), only one side of the interior surface can be picked. The same surface is shown at different angles in [3].
If I pick the external sides as expected and only ONE side of the internals, then the simulation is aborted due to the error:
"2 improperly defined surface(s). Please check your surface definitions. Make sure that all surface normals point outward."
And if I check the surface normals, this is what I can see: [4]
I have also tried creating a surface using part->Features->Surfaces and selecting both sides there but the simulation gets a different error in that case:
"Contact pair references surface/node-based surface/analytical rigid surface assembly_beam-1_surf-1 but this surface/node-based surface/analytical rigid surface cannot be used with *contact pair. Check previous warning messages for this surface to find the cause.
Contact pair references surface/node-based surface/analytical rigid surface but this surface/node-based surface/analytical rigid surface has not been defined or this surface is defined on the collapsed faces"
Does anyone have any ideas for solving this? Look forward to reading your responses!

[1]:

[2]:

[3]:

[4]:





RE: Surface interactions inside another surface
RE: Surface interactions inside another surface
I'm expecting an axial crush but instead I get something like this:
RE: Surface interactions inside another surface
RE: Surface interactions inside another surface
So in that general contact mode, either I get the weirdness above or I get something that barely crushes and then rebounds.
Do you have any suggestions?
RE: Surface interactions inside another surface
I don't know what kind of results you expect. When you think that it collapses without a major lateral deflection, then I have my doubt if the structure isn't too slender for that.
You can try to use imperfections. Do a buckling analysis first and reuse the modes to seed imperfections into your structure. This usually produces much more realistic results in a postbuckling analysis. Look for *Imperfection in the Keyword Reference Manual and also read the chapters that are linked to that. There is also an example in the Example Problems Manual.
RE: Surface interactions inside another surface
That's why I reasoned it would be the contact that's the issue as that is the only difference between the two shapes (exactly the same length and roughly the same area)
RE: Surface interactions inside another surface