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resonance frequency

Posted 9 apr 2015, 04:48 GMT-4 Structural Mechanics Version 4.3 3 Replies

Rupali Layak
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I have built a 3d-rectangular cantilever structure .base is aluminium with dimension 100*30*4(micrometer)and piezoelectric material is aluminium nitride with dimension 100*30*2. I followed the following procedure to get the resonant frequency :
Go to study->select eigenfrequency->click on eigen frequency

In setting give Desired no. of eigen frequency =1

search freq = 0

and compute

the freq at which u get deformation(it will be symmetric) is a resonant frequency
result:
eigen frequency:6.70855e5 + 8.978721e-5 i potential=6.3295
then which part is the resonance frequency real part(6.70855e5 ) or imaginary part (8.978721e-5) ?
3 Replies Last Post 10 apr 2015, 04:35 GMT-4
Yoginder Kumar
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Posted: 10 years ago 9 apr 2015, 07:29 GMT-4
hyyy there, the first part is always real and second is imaginary.
one more thing is that you can select the frequency domain in study section and define the range in which you want to study or also define the search near frequecy in eign frequency too..
i am not working on cantileaver so don't know which domain you have to use.
if you are able to plot graph then can be use real(command) and imag(command) to differenciate in real and imaginary part.
hyyy there, the first part is always real and second is imaginary. one more thing is that you can select the frequency domain in study section and define the range in which you want to study or also define the search near frequecy in eign frequency too.. i am not working on cantileaver so don't know which domain you have to use. if you are able to plot graph then can be use real(command) and imag(command) to differenciate in real and imaginary part.
Rupali Layak
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Posted: 10 years ago 10 apr 2015, 03:41 GMT-4
Then how can i findout resonance frequency in frequency domain analysis ?? The frequency range is unknown.
Actually i want to know the above mention procedure for find out the resonance frequency in eigen frequency analysis is correct or not?
From the eigen frequency analysis i got eigen frequency=6.70855e5 + 8.978721e-5 i
But when put the frequency range 6.70855e5 in frequency domain analysis show error
“Failed to find a solution.
The relative error (73) is greater than the relative tolerance.
Returned solution is not converged.”
When i changed the relative tolerance 0.001 to 73, getting no error.But potential=1.164510^-4 10^-5 which is less than the potential getting in eigen frequency analysis !!!!
Then how can i findout resonance frequency in frequency domain analysis ?? The frequency range is unknown. Actually i want to know the above mention procedure for find out the resonance frequency in eigen frequency analysis is correct or not? From the eigen frequency analysis i got eigen frequency=6.70855e5 + 8.978721e-5 i But when put the frequency range 6.70855e5 in frequency domain analysis show error “Failed to find a solution. The relative error (73) is greater than the relative tolerance. Returned solution is not converged.” When i changed the relative tolerance 0.001 to 73, getting no error.But potential=1.164510^-4 10^-5 which is less than the potential getting in eigen frequency analysis !!!!
Yoginder Kumar
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Posted: 10 years ago 10 apr 2015, 04:35 GMT-4
there should be an analytical formla for resonance frequency calculation solve that and then define the approximate range to that value. i am working on resonator so i don't have sufficient knowledge about cantilever sory for that but when you calculate analytical value then the simulated value is also approximately equal. if still have a problem then give me some more info i will discuss that. thank you.
there should be an analytical formla for resonance frequency calculation solve that and then define the approximate range to that value. i am working on resonator so i don't have sufficient knowledge about cantilever sory for that but when you calculate analytical value then the simulated value is also approximately equal. if still have a problem then give me some more info i will discuss that. thank you.

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