Complex Shape Assembly

3D Design Volume Model
1

Hi all

 

In order to do a finite element analysis I wanted to make my parts on catia. I would like to assemble a shell and a core. The contact method works when the shape is spherical, but if I switch to ellipsodies for example (see image below), Catia seems to no longer consider the surface (no way sign when I hover the mouse over it).

Eventually my goal is to make an assembly of a multilayer onion structure, with not simple shapes (paraboloids, etc). Is Catia simply suitable? Is there a way to make him understand that he can safely assemble these two identical surfaces?

When I do "interference detection" (once in position) it is happy, so I don't understand what blocks it to create the contact.

I think I'll use abaqus for the simulation since it's quite compatible with catia.

 

Thank you in advance for your answers!

1 Like
2

Are you sure that your ellipses are on the same plane to the eye we have the impression that the axes are shifted 

@+;-))

3
Hello, not sure if it's possible, why not create points? Otherwise See this link:

http://catiadoc.free.fr/online/cfyugasm_C2/cfyugasmrf0103.htm

4

No, I just shifted on the photo so that you can see the head of the surfaces, but it's well and truly aligned. For point creation, will I be limited to a single point between two solids, or can I create an infinite number of solids (and automatically if possible)?

5

On the link below, he says that it is impossible:

"In CATIA it does not seem possible to create a point contact constraint between a spherical surface and a freeform surface. "

Maybe interesting things in the other answers, see here:

http://www.eng-tips.com/viewthread.cfm?qid=323061

Edit: the only solution proposed is to make an offset of the surface to pass through the center of the sphere, but it is not a sphere here, so probably no solution.

For the points, it will only work if there is only one point of contact, otherwise, it doesn't seem possible either...

6

Hello.

You can't do it in CATIA without going through stitch construction.

If your two paraboloid surfaces are identical { Edit: and centered} you only have one degree of freedom (rotation).

So I will build my parabola in one of the two CATPart, then in the context of the assembly copy pasted with link of the parabola in the second CATPart.

 

1 Like
7

Thank you for the answers. If I do this, will deforming the outer layer into finite elements deform the inside? (because they are just surfaces positioned in contact, but no bond can be created)

8

I don't have Abaqus.

Maybe it would be better to ask this question in a new question on the forum.

in order to ask for help from potential users of Abaqus

9

After trying a lot of roundabout techniques, it seems that it is not feasible directly. I still test if with tampered "composites" I can get a nice parabolic onion, but I have little hope.

10

After some time if making a complex shape with onion-type layers is of interest to people:

Impossible indeed with splines extruded in revolution, but if you approach the curve by a polygon, this one by revolution will make cones (even if there are 100) and assembles well without detecting any conflict despite the number of important conical assemblies made (on my model at least), which is not the case for other types of contacts.

 

Of course, approaching your curve with segments is not the best, but it can be easily automated with a small python program to generate the points that you then import on Catia. Vl'a, it's the DIY solution but it works (especially since basically roughly with poligone a curved section is not so bad since we're going to mesher it later for the FEM)