Journal Bearing Model with FEM

[fer72]

I would like to model a journal bearing to calculate the whirling frequency of a shaft inside the its case.
I have done some models using a "point radial restrictions", and then I have model the bearings using a two point restriction per bearing (along its length) at the results were quite different (as it should be). I know that there is another approach to model journal bearings using rotational springs in the "point per bearing model" but I don't know how to estimate the spring value.
Any suggestions?

Shaft length between bearings: 3.5 m
Shaft diameter:250 mm
Bearing length:260 mm

 

[gio1]

The "spring" should be a model for the oil film, which is highly non-linear. Be warned: modelling a journal bearing with a linear spring -no matter which stiffness- is definitely unappropriate.
I suggest you look on some tribology books for an oil-film model. Implementing this model is a separate issue, which depends on the tools your software can provide.

Gio1