**Joined:** 04/07/2023

### Whirl,unbalance and critical bearing stiffness

Good Day !

I have questions concerning whirl,unbalance and critical stiffness this time!

I am trying to:

Compute the asynchronous and synchronous whirl on my system.

Do an unbalance force analysis

Estimate the critical bearing stiffness of my system (5% of the value of the stiffness which would make my 35k rpm critical speed impossible to reach)

Whirl

I am not seeing any whirl output in AxRD, instead i notice in the Harmonic analysis an Amplitude-Frequency response, is it the tab which indicates the whirl of my system?

If yes i would have a question about the excitation frequency, my target speed is going to be 35k rpm is it right to only input for omega_0

If not , what is the way to evaluate omega 1 and 2 ? ( a specific formula to apply).

What would be the procedure to compute the asynchronous whirl on AxRD ?

Unbalance

Based on my critical speed simulation, I have the behavior of the shaft depending on the mode. Does the unbalanced analysis apply only for the 1st mode? if not how can i compute it for n modes ?

Does this formula sound correct to compute the unbalanced force of my mass elements on my shaft ?

IF(N)= mass*Radius*2*PI*f

Critical stiffness

To estimate my critical bearing stiffness (5% critical value which would make my target critical speed impossible to reach) would it be best to use the critical speed map and do a graphical estimation ? If not what would be the procedure to estimate such parameters ?

Thank you very much for your time !

Have a nice day !

Regards,

Shayman-Reza Labadlia

I have questions concerning whirl,unbalance and critical stiffness this time!

I am trying to:

Compute the asynchronous and synchronous whirl on my system.

Do an unbalance force analysis

Estimate the critical bearing stiffness of my system (5% of the value of the stiffness which would make my 35k rpm critical speed impossible to reach)

Whirl

I am not seeing any whirl output in AxRD, instead i notice in the Harmonic analysis an Amplitude-Frequency response, is it the tab which indicates the whirl of my system?

If yes i would have a question about the excitation frequency, my target speed is going to be 35k rpm is it right to only input for omega_0

If not , what is the way to evaluate omega 1 and 2 ? ( a specific formula to apply).

What would be the procedure to compute the asynchronous whirl on AxRD ?

Unbalance

Based on my critical speed simulation, I have the behavior of the shaft depending on the mode. Does the unbalanced analysis apply only for the 1st mode? if not how can i compute it for n modes ?

Does this formula sound correct to compute the unbalanced force of my mass elements on my shaft ?

IF(N)= mass*Radius*2*PI*f

Critical stiffness

To estimate my critical bearing stiffness (5% critical value which would make my target critical speed impossible to reach) would it be best to use the critical speed map and do a graphical estimation ? If not what would be the procedure to estimate such parameters ?

Thank you very much for your time !

Have a nice day !

Regards,

Shayman-Reza Labadlia