Problems with contact elements in CATIA V5 analysis

[sb009441]

Good day everyone,

I am presently trying to learn myself to use the FEM package that comes with V5(R14 sp6e). To make things simple I decided to model 2 plates fastened with two rivets...seemed easy enough at the time!! I modelled the two plates clamped one the plates and loaded the other. I modelled the rivets as a solid and used contact elements with the faces of the holes in the plates and restrained the vertical translation in the top and bottom of my rivets (because on my first run the rivet jumped 39 in. out of the holes!!). My problem now, is that I always get the "singularity detected" message after computation, and the deformed plot shows that the only deformation in my model is one of the rivets growing radially from its original size to practically the size of the whole assembly. Since I'm using contact element, should'nt the radial growth from the rivets not even be happening at all?? I also tried using the user-defined contraints to model the rivets (in lieu of modelling as a solid) but I could not find a way to block the vertical translation and this also resulted in the constraint ending up 39 in. vertically out of the holes after computation (and with the "singularity" error)

I hope I made myself clear (this is my first post here!!)

Thanks for your help.

Simon

 

[silverunner]

Make sure you have connections defined between rivet-plate and plate-plate.

 

[sb009441]

I defined every possible connection (using analysis connections and then applying contact, slider and restraints to them) I can think of between the rivet and the plate...

If I don't correctly restrain the pin vertically it moves freely and creates a singularity...as soon as I restrain it vertically it creates the problem I had point above (pin grows radially outwards by 226 in!!)