Bearing Support/Restraint

[corus]

For a 3D structure supported by bearings, which is the best way to restrain the structure at the bearing?
A point support at the centre-line bearing position gives infinite stresses which affects the results close by. This is ok for stresses away from the restraint but at positions close to the bearing I want to know the cummulative effect of the nominal stresses and the bearing stresses. Additional translational restraints at the bearing would give a rotational restraint, which wouldn't be right.
Can the stiffness of the bearing be incorporated somehow?


corus

http://www.corusresearch.com

 

[fsi]

Try a 90 degrees arc support instead of point support.
fsi

 

[DickButkus]

Have you looked at distributed coupling?

 

[corus]

A 90 degree fixed arc support would effectively give some rotational restraint again so I'd avoid that. Distributed coupling I'm not sure of. If it gave a result that gave reaction forces as a sino-soidal distribution around and along the bearing surface of the shaft then that would be ideal. Does this involve spring elements around the shaft of a certain stiffness or contact? If its contact then do you model the bearing as a solid and if so does how do you relate the bearing stiffness, in kN/m, to the bearing model Young's modulus? If coupling is by spring elements then are these applied radially with a stiffness that varies sino-soidally? If it's coupling by rigid links then I think that's the same as applying fixed restraints.

corus

http://www.corusresearch.com

 

[DickButkus]

Distributed coupling is new in 6.4. You have the option of how you want the distribution to occur, linear, quadratic, or cubic.

This looks like it allows for a load transfer into a surface. The points all move together in an average sense, but are allowed to move.

Look in the interaction module under constraints for the coupled constraint. In there, you will see a choice for distributed coupling - the alternative, and default, is kinematic which looks to be the same as rigid MPC's.

 

[corus]

Thanks kf9ri, I believe Santa is bringing 6.4 but I'll check in the new features to see if distributed coupling would give the results I want without having to resort to contact between surfaces in some manner.

corus

http://www.corusresearch.com

 

[brad]

kf9ri and corus--
"distributed coupling" is not new in 6.4; it's been around for a few releases.

Brad
PS- Corus--Santa came early for me; 6.4 is installed!