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Frequency Domain not Converging
Posted Apr 28, 2019, 10:49 AM EDT Version 5.3 1 Reply
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I'm trying to design a nonlinear MEMS energy harvester: * I am using a fine swept mesh. * Material: Silicone polycrystiline * physics: solid mechanics. * Boundary conditions: fixed at one end. * 1g gravity applied to the domain. * Study: eigenfreuquency and frequency domain.
I used the eigenfrequency study to find the first three modes, and it converged to the right soluction with no issues.
When I use the frequency domain study with conditions I stated above, I set the freuquency to the first mode freuncy that was found by the eigenfrequency study, and it coverges with no problems.
The problem When I specify a range of frequencies around the first mode/resonant frequency, the solver works for the frequencies up to the actual resonant frequency that is within the range specified, and it stops converging.
I am not sure to what I should attribute the problem to in my settings. I have tried running an Adaptive Mesh in the frequency domain study, a parameter sweep for the gravity to improve convergence with no luck.
I think what happens, is that the deflection is really high at the resonant frequency and that, somehow, messes the mesh up. as I have read something about how elements of the mesh can get inverted when the mesh deforms, which in my case, the mesh is moving and deforming for the boundary conditions I am using.
I have tried to solve the problem by adding damping to reduce deflection at the resonant frequency, that didn't work either.
I would really apreciate your input or pointer to my problem.