Understanding Campbell Plot

[FadliM21]

Hi,

I'm a beginner for Rotor dynamics. Can you please help me to understand the campbell plot? What is the meaning of Forward, Mixed and Backward in campbell legend?

Thank you

[jguarato]

Hi, @FadliM21!

The Campbell diagram is a key tool in rotordynamics used to analyze the vibration characteristics of rotating machinery. The curves on the plot represent the natural frequencies (Y-axis) of the system as a function of rotor speed (X-axis). These frequencies change as the rotor speed increases due to the gyroscopic effect and other dynamic interactions within the system.

The terms "Forward", "Backward", and "Mixed" refer to the direction of rotation of the vibrational modes relative to the rotation of the rotor. The Forward mode occurs when the mode rotates in the same direction as the rotor spin. The Backward mode occurs when the mode rotates in the opposite direction to the rotor spin. The Mixed mode can occur when the vibration mode rotates in both forward and backward directions. Lastly, the Critical Speeds are the rotor speeds at which the natural frequencies coincide with the excitation frequencies (typically harmonics of the rotor speed).

For a more comprehensive understanding, we highly recommend consulting the reference book, specifically sections 3.5–3.6 and 5.9.

Apologies for the delayed response.

Reference:

🔗 M. I. Friswell, J. E. T. Penny, S. D. Garvey, and A. W. Lees, Dynamics of Rotating Machines, Cambridge: Cambridge University Press, 2010, pp. 76–123.

[jguarato]

You can use the plotly library to export the diagram as an image by adjusting the width and height:

from plotly import io as pio
fig = campbell.plot(harmonics=[1, 2], frequency_units="Hz")
pio.write_image(fig, "figure.png", width=600, height=800, scale=1)

[FadliM21]

Hi @jguarato ,
I have tried to use that code, unfortunately the code didn't finish the calculation, I've waited for 15 minutes and the calculation is still not done yet as the picture below:

Could you please give me some advises for that case?

Thank you in advance

[jguarato]

I'm not sure what the problem could be in this case, as the tests I ran were successful.

Here is the link to the script I used: [Link].
You may need to make a copy of my notebook and upload your ".xls" file to replicate this test.

[FadliM21]

Thank you very much @jguarato, I think there is a failed installation in my python, I'll try to reinstall again

And one more thing, I've tried to find the code to hide some of line on campbell but it is not found yet, could you please inform what the code to hide some of parameter such as forward, backward and mixed mode and remains the torsional mode?

Thank you in advance

[jguarato]

for trace in fig['data']: 
    if trace['name'] in ['Forward', 'Backward', 'Mixed', 'Axial']: 
        trace['visible'] = 'legendonly'

[FadliM21]

Hi @jguarato
Thank you for sharing.

Regards,
Fadli