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resonant frequency of cantilever beam

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Hello,

I am New with COMSOL. I have to solve the following problem:

Simulate a beam with 100 um length, 10 um width and 0.2 um thickness. Find its fundamental resonant frequency.

I have the basic knowledge of simulation. But when it is asked about finding the fundamental resonant frequency. How to do that?

I am doing it like this.

In structural mechanics- i have added eigen frequency added parameters from geometry( height + length + width) Then i defined the material ( silicon) Then i selected mesh Then from study- i have selected eigen frequency 1 and simulated.

Here, my question is that if the eigen frequency 1 is the fundamental resonant frequency ? and do i have to do anything for completing the assignment that has been asked?


2 Replies Last Post 30 janv. 2018, 07:51 UTC−5
Dave Greve Certified Consultant

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Posted: 6 years ago 28 janv. 2018, 19:41 UTC−5

Before doing a simulation it is advisable to have at least a rough idea of what to expect.

Seems to me you can calculate the approximate fundamental frequency using analytic expressions from textbooks. It would be advisable to look for eigenmodes near this frequency. Also compare the simulated shape of this mode with what you expect for the fundamental mode.

Before doing a simulation it is advisable to have at least a rough idea of what to expect. Seems to me you can calculate the approximate fundamental frequency using analytic expressions from textbooks. It would be advisable to look for eigenmodes near this frequency. Also compare the simulated shape of this mode with what you expect for the fundamental mode.

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Posted: 6 years ago 30 janv. 2018, 07:51 UTC−5

Hello, Thanks. That worked great. But now if i have to add an electrode under the beam and plot the voltage versus displacement what changes should i made to my COMSOL simulation. It will be helpful if details steps could be provided. Suppose at which part(i guess in add physics) should i implement the potential. And what should i select for getting the displacement.

Hello, Thanks. That worked great. But now if i have to add an electrode under the beam and plot the voltage versus displacement what changes should i made to my COMSOL simulation. It will be helpful if details steps could be provided. Suppose at which part(i guess in add physics) should i implement the potential. And what should i select for getting the displacement.

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