# Bearing carrier, only constrain axial movement

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Hello,

what is the best technique to constrain a bearing carrier?

So i want to constrain every axial movement of several nodes,

but the rotation around a center point should still be free.

How do I model this?

Thank you!

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HI,ChrisSchlenk

You can use 1D elements (say RBE2) and constraint the independent node in all Translational directions and release in rotation around a center axis to allow rotation.

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On 11.3.2015 at 5:06 AM, Prakash Pagadala said:

HI,ChrisSchlenk

You can use 1D elements (say RBE2) and constraint the independent node in all Translational directions and release in rotation around a center axis to allow rotation.

Hi Prakash,

when i create a single node and many RBE2 elements pointing from several nodes to this one independant node, i receive wierd model behavior.

I would like to create a node in the center of a drilled hole, then create several RBE2 elements pointing from the many nodes of the drilled hole to this one independant node in the center of the hole. The independant point should, as you said, be allowed to rotate but not to translate.

When i create this kind of model, i get wierd model behavior  My Stresses seem to be okay, but the displacement is waaaaaay off. Also i get this wierd vanishing of the model when i change the view to the next step.

Any idea?

Best regards,

Nik

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Hello,

Can you please check if you constrained all the translation degrees of freedom as well as all rotational except the one which is along your drilled hole (In your case as i can see the z axis).

Please leave only the rotational along z axis unconstrained and constrain everything else and check.

Thank you

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Hello Sanjay,

i checked it and i constrained everything as you said. Only DOF6 of the center node is not locked. All the other Degreess of Freedom are locked to 0. I also set the DOF1,2,3,4,5 to 0 and released DOF6 of the RB2-Elements.  When i scale down the "Model Percent" in HyperView to the value of 5 and then move the model, i can see that it actually moves correctly along the rotational axis in the drilled hole. I guess there must be a general problem with the element-type of the RB2 elements? Maybe they are not suitable for this kind of operation?

Thank you a lot for your help!

Nik

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Hello,

This is the best option for doing this kind of operation. You can also try and constrain directly the nodes rather than creating an RBE2 element. You can do this by using the option "Select nodes by Face" while setting up the constraints, but i don't think the results should be any different.

Thank you

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3 hours ago, Nikolas Tsombanis said:

Hello Sanjay,

i checked it and i constrained everything as you said. Only DOF6 of the center node is not locked. All the other Degreess of Freedom are locked to 0. I also set the DOF1,2,3,4,5 to 0 and released DOF6 of the RB2-Elements.  When i scale down the "Model Percent" in HyperView to the value of 5 and then move the model, i can see that it actually moves correctly along the rotational axis in the drilled hole. I guess there must be a general problem with the element-type of the RB2 elements? Maybe they are not suitable for this kind of operation?

Thank you a lot for your help!

Nik

I think Prakash wants to say :

- enter 1d>rigids

- select "multiple nodes" for "dependent"

- select "calculate node" for "independent"

- select nodes in hole and let all dof1-dof6 checkbox ON => create

- enter analysis>constraint> create an spc at the independent node with dof6 checkbox OFF and others dofs ON

do not check OFF dof6 in rigid panel

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Thank you everybody for your help. I will try asap and report if i have results. We have another nonlinear-static analysis running, if it works i guess we dont need the linear static one. Lets see.

Thanks again,

Nik

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