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Triangular fixed-fixed nano-beam

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Hi all,

I am trying to evaluate the quality factor of the vibration of a nano-beam. The beam is etched in a diamond substrate so I model it as large pads on the sides of the beam (see attached image). When I use this model, even the eigenfrequencies cannot be simulated and the results are absured.

If I just use fixed-fixed boundary conditions the eigenfrequencis and mode shapes make sense but the quality factor is infinitly large because there are no support losses.

Would like to hear your suggestions how to evaluate the quality factor taking into account the support losses.

Cheers, Itamar



1 Reply Last Post Jan 27, 2021, 3:16 p.m. EST
Dave Greve Certified Consultant

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Posted: 3 years ago Jan 27, 2021, 3:16 p.m. EST

What type of loss do you have included in your model?

If there are no losses...and if the domain terminations are free or fixed...then infinite Q is the right answer.

Try using a PML or impedance termination or low-reflecting boundary. Physically there will be losses due to the radiation of acoustic energy into the support structure.

What type of loss do you have included in your model? If there are no losses...and if the domain terminations are free or fixed...then infinite Q is the right answer. Try using a PML or impedance termination or low-reflecting boundary. Physically there will be losses due to the radiation of acoustic energy into the support structure.

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