To find Damping ratio through Harmonic dynamic analysis in ANSYS
To find Damping ratio through Harmonic dynamic analysis in ANSYS
(OP)
Hello friends,
I have done modal analysis on a sandwich beam.Once I got natural frequencies I did harmonic analysis and obtained response curve (i.e amplitude vs. frequency) without initially considering any damping.Then,I used half-power method (or 3dB method)to find damping ratio.I run the Harmonic analysis once again with constant damping ratio and beta damping values to obtained the actual damping ratio.
Is this process correct? I do have experimental results and I wanted to compare those to damping ratio obtained through ANSYS.
Please,tell me the procedure to consider damping ratio or how to find damping ratio in ANSYS.Thank you !!
I have done modal analysis on a sandwich beam.Once I got natural frequencies I did harmonic analysis and obtained response curve (i.e amplitude vs. frequency) without initially considering any damping.Then,I used half-power method (or 3dB method)to find damping ratio.I run the Harmonic analysis once again with constant damping ratio and beta damping values to obtained the actual damping ratio.
Is this process correct? I do have experimental results and I wanted to compare those to damping ratio obtained through ANSYS.
Please,tell me the procedure to consider damping ratio or how to find damping ratio in ANSYS.Thank you !!





RE: To find Damping ratio through Harmonic dynamic analysis in ANSYS
Could anyone please tell me how to find damping ratio in ANSYS(I am using ANSYS 11.0).
I am trying to obtained FRF (freq vs displacement curve )with guessing constant damping 2% and then to find damping ratio by half-power or 3 dB method.
Is it correct way ??.why we have to give damping if we have to find damping ratio?
Thank you!!!
RE: To find Damping ratio through Harmonic dynamic analysis in ANSYS
You are using circular reasoning.
Cheers
Greg Locock
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RE: To find Damping ratio through Harmonic dynamic analysis in ANSYS
In the past I have used Rayleigh damping in models where I determined the damping ratio at two frequencies by testing.