Rotor/Bearing definition in Simmechanics

Hi there,

this might be a really stupid question but I don't get it. I'm using Matlab R2012b with Simmechanics and got a second generation model of a test rig. Basically its a rotor with a bearing supports on both sides. The rotor is connected to the bearings using a cylindrical joint. Now, where do I specify the stiffness and damping coeff of the bearings? Pz or Rz? I don't quite understand this. Also where would I measure the x, y axis acceleration (for the vibration) at the bearing?

I have only started using Simmechanics and still try to fully understand it. However, I have not found good examples explaining the above.

Thanks for your help!

Answer 1

[Steve Miller]

Bearing damping (viscous friction that creates a force opposing the spinning of the bearing shaft) would be applied to the Internal Mechanics of the Rz primitive.

With "bearing stiffness and damping" together, perhaps you mean that the shaft can translate within the plane of the bearing. If that is the case, you should use a Planar Joint, and apply stiffness and damping along the Px and Py axes.

--Steve