Learning Forum

[Morgan Ramanauskas]

Hi All,

I'm looking for some help with a issue I am having utilising bearing contacts and getting rigid body motion. I have a large shaft supported on two bearing contacts with a centralised load. I have set the stiffness values of the bearing contacts to values I've calculated for large spherical roller bearings (1E7 N/mm). I have simplified the assembly all the way back to basics in order to try and determine the issue and it appears the bearing contacts are not supporting the model as expected and are allowing the shaft to move radially.

I have a remote displacement support on one end of the shaft to stop it rotating and sliding around it's axis.

Please see the screenshots below. Any help would be greatly appreciated.

 

 

 

 

Thanks, Morgan

[Erik Kostson]

 

Hi 

Can you try and solve with 1 N force (also you might just want to switch on in analysis settings weak springs to on, eventh. I think your model seems to be restrained ok).

Finally run a modal analysis, and see if there are any rigid body modes.

All the best

Erik

 

[Morgan Ramanauskas]

Hi Erik,

Thanks for your reply and suggestions. I've enabled weak springs which allows the analysis to run however, the shaft is undergoing rigid body motion at 45 degrees in the XY plane and is moving 9mm under the 1N load. It's like the bearing constrains aren't doing anything.

Kind regards,

Morgan 

[Erik Kostson]

Hi

Have not used this much - combin214 elements.

If we take away K12 and K21 it should not move in 45 deg. and behave strange anymore.

All the best and I hope someone else has some more feedback.

Erik