Ball and Roller Bearing Stiffness approximate Models for rough estimation

[Basit Shafi]

Hi,

For a quick initial rotor dynamic analysis many people assume that the bearing supports have infinite stiffness and they calculate the fundamental critical speed based on this assumption which is not true.

To add some reality to this , are there any simple mathematical models or free tools used to get a rough estimate for the radial bearing stiffness ? for both ball and roller bearings? I know you can get the entire stiffness matrix from the bearing supplier but at the moment it is not feasible for me.

Any Suggestions would help.

AbdAlBasit

 

[Tmoose]

What size bearings ?

1,000,000 lbs per inch radial, ± a lot.

Fabricated Bearing pedestals can be a lot less stiffer, especially in the horizontal direction.

 

[Basit Shafi]

Hi Tmoose,

where does this typical value of 1000000 lbs / inch come from any reference? will this apply for both rollers and balls ?

Thank you

 

[lucky-guesser]

I'm not up to date on my sarcasm skills but I'm pretty sure he was just joking with those figures, hinting that you need to give some more context, and preferably numerical values for us to be able to give a more informed answer.