Learning Forum

[Deepesh]

Consider a Solid Shaft. I performed harmonic analysis on it. To fix ends of the shaft, I used Bearings in Case 1 and Remote displacement in case 2.

In Case 1, I inserted the plane of rotation 

In case 2, I restricted every motion except the one for the rotation

But in both the cases, the answers I got in Deformation, stress were different.

Can someone explain me how and why is it so? because since both the options I used were to do same things i.e restrict particular motion and allow particular motion.

 

Thanks in advance.

[peteroznewman]

Bearings have a field to type in the bearing stiffness, so you are adding flexibility to Case 1.

Remote displacements can be of Type: Rigid or Deformable, but in either case, you are not adding flexibility in Case 2.

The different flexibility between Case 1 and 2 will lead to different results.

[Deepesh]

Is there any value of stiffness that I can give to bearings so that it acts exactly as Rigid one just like remote displacement?

[peteroznewman]

Use a very large stiffness value, but not too large or you will cause numerical problems.