Rotordynamics/Bearing Loads in ANSYS

[Michael1968]

Hello experts,

I'm doing a rotordynamic analysis (in ANSYS) of a shaft with journal bearings. There are time-independent loads (fixed in space) and unbalance. The journal bearings are simulated with matrix27 stiffness and damping elements with unsymmetric factors (C11, C12, C21, C22, D11, D12, D21, D22). I make a transient analysis with unbalance load. If I make a fsum in ANSYS of the matrix27 elements (both, stiffness and damping) I get periodic forces and I see, that a very large amount of the sum comes from damping ! I now want to check the pressure on the (stationary) bearing housing (outer part..). Which forces come to the bearing housing ? Do both come: stiffness and damping ? Which force would you take for calculation of a dynamic pressure on the stationary part ?
Thank you for your comments.

Michael

 

[cbrn]

Hi,
I don't clearly see your point. I suppose the MATRIX27 connect "something" on the shaft to "something" grounded, i.e. with all DOFs to zero. Thus, I'd simply *GET the force results on these "something grounded". Being grounded, they are the last part which reacts, so they will give you the "external reaction force(s)".
I think...

Regards

 

[Michael1968]

Hello,

I also posted my problem in "Bearing design, manufacture.." and the first reply also was, that the problem is not clear I described it in this forum more exact.

Michael