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Contact creation for spherical bearing

Atul Bhardwaj

I need to simulate a spherical bearing for a part of my setup. I have to add contact between two cylindrical shafts as such as bearing. Right now I am confused how to add contact between the two parts such that the inner cylinder is stationery and the outer cylinder can rotate on the inner one on its axis. Which contact type should be used for it- maybe a slide contact type, or a contact with friction, or use no contact, and attach two parts with RBE with DOF?

In the image the yellow part should rotate on purple part, while the purple part should not rotate and remain fixed in contact with red shaft.

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Adriano Koga_20259

For OptiStruct you could have all of your options. It really depends on what do you need to calculate.

I would suggest you to go for Contacts between the 2 parts if you need a good representation on the force distribution.

For contacts take care to use FINITE or CONTINUOUS sliding approach, and also take care to avoid frictionless contacts, as you might get some rigid body movements, that might ruin your convergence. Make sure that your model is properly constrained to avoid convergence issues.

RBE2 would probably give you a good result in terms of kinematics but not so accurate in terms of distribution.

Atul Bhardwaj

For OptiStruct you could have all of your options. It really depends on what do you need to calculate.

I would suggest you to go for Contacts between the 2 parts if you need a good representation on the force distribution.

For contacts take care to use FINITE or CONTINUOUS sliding approach, and also take care to avoid frictionless contacts, as you might get some rigid body movements, that might ruin your convergence. Make sure that your model is properly constrained to avoid convergence issues.

RBE2 would probably give you a good result in terms of kinematics but not so accurate in terms of distribution.

Thank you @Adriano Koga for replying.

I have tried by both- making RBE and contacts. But my issue has been how to give correct contacts so as to simulate the bearing. I have tried using the finite sliding approach with a friction coefficient of 0.1, but how is it ensured that the in the slide contact, the outer part is sliding over the inner one and the inner one is fixed and not rotating. Does it depend on which part I assign Master and which part as Slave?

Also, I tried with RBEs but then again the same issue how to assign one part as fixed and outer part as easliy rotating.

I am getting similar results in both cases but I am unsure if I am correctly simualting the working of bearing or not, i.e., The outer parts is easily rotating on inner shsft.

Adriano Koga_20259

Thank you @Adriano Koga for replying.

I have tried by both- making RBE and contacts. But my issue has been how to give correct contacts so as to simulate the bearing. I have tried using the finite sliding approach with a friction coefficient of 0.1, but how is it ensured that the in the slide contact, the outer part is sliding over the inner one and the inner one is fixed and not rotating. Does it depend on which part I assign Master and which part as Slave?

Also, I tried with RBEs but then again the same issue how to assign one part as fixed and outer part as easliy rotating.

I am getting similar results in both cases but I am unsure if I am correctly simualting the working of bearing or not, i.e., The outer parts is easily rotating on inner shsft.

You could change one contact interface to FREEZE, which would make both parts to move together just as if they were bonded. (no relative displacement)

Or if your part is really not moving at all, you could add a boundary condition to it (SPC).