simulating a ball end...

[PAULKORENKIEWIC]

Guru's,

I have a "link" part that has a ball feature on one end and a pin
feature on the other. The pin is offset from the ball; looks like this:


I am trying to run a simple bearing load on it and have tried several
ways to handle the ball end. I've tried just fixing part of the ball
end spherical surface and I've tried fixing a point at the center of the
ball but freeing up all rotations. The former ran but seems to have a
large bending load. The later won't run; I keep getting "One or more
points are constrained but are not part of any elements." I added a
weak spring but that didn't seem to help. (yeah, that was a flyer... )
Any suggestions? I could just swap the load and constraint; fixing the
pin end and applying a surface load to the ball end, which might be the
easiest option. HOWEVER, I have another analysis where I am trying to
do something similar; freeing up a constraint, simulating a ball joint
that I can't get to work either. Any comments or suggestions???

thanks in advance...


Paul Korenkiewicz
FEV , Inc.
4554 Glenmeade
Auburn Hills, MI, 48326-1766

[RodGiles]

Dear Paul,

You have two options:

1) Create a spherical co-ordinate system at the ball-centre, then
constrain the surface using this co-ordinate system in r only.
2) Create a rigid link between the surface and the point at the
centre. Then constrain the point in translation only. Since you already
have a point, this would be the simpler option.

Regards,

Rod


Rod Giles
Senior Design Engineer
Polaris

[PAULKORENKIEWIC]

These are the suggestions I received... I did get the expected results
with the first suggestion using the weighted link to the fixed ball
center point...