Troubleshooting Cantilever Beam Simulation in COMSOL

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SUMMARY

The forum discussion focuses on troubleshooting eigenfrequency and frequency-response simulations of a cantilever beam using COMSOL's 3D MEMS Module, specifically Solid, Stress-Strain. The user encounters issues with an unexpectedly high z displacement of 3.33m despite a calculated resonant frequency of 49kHz. The discussion reveals that the amplitude of mode shapes can be normalized and emphasizes the importance of correctly specifying frequency units. Additionally, it highlights potential errors in boundary conditions and mesh density affecting simulation results.

PREREQUISITES
  • Understanding of COMSOL Multiphysics, particularly the 3D MEMS Module.
  • Knowledge of eigenfrequency analysis and frequency-response simulations.
  • Familiarity with boundary conditions and constraints in finite element analysis.
  • Basic principles of vibration theory and modal analysis.
NEXT STEPS
  • Review COMSOL documentation on "Normalizing Mode Shapes" for better understanding of displacement amplitudes.
  • Learn about specifying frequency units in COMSOL to avoid common errors in frequency-response analysis.
  • Investigate best practices for meshing in finite element models to improve simulation accuracy.
  • Explore the implications of boundary conditions on eigenfrequency results in COMSOL simulations.
USEFUL FOR

Engineers, researchers, and students involved in mechanical simulations, particularly those using COMSOL for vibration analysis and finite element modeling of cantilever beams.

  • #31
I was wondering how would you solve this problem (Eigenfrequency Analysis) if you were to include ''air damping'' any user of COMSOL has any idea? because i kinda have the same problem. i want to include air damping in my eigenfrequency analysis...
 
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  • #32
Lucas84 said:
First of all thank you very much for your help alephzero.

I've look at COMSOL help, and the input is in Hz as well as the results. However, I did a simulation on a wide range of frequency and here's what I got :

I have a question concerning performing the simulation over a wide range of frequency in comsol. You mentioned you could do it in the comsol, can you tell me how? When I did the eigenfrequency analysis, it shows me a set of frequencies from which I have to select but not the frequencies of my choice. Thanks for your response!
 

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