modal result comparision
Hi,
Good morning,
why we see the frequency difference (Modal Analysis) while comparing between different solvers, for example optistruct Vs Lsdyna or Optistruct Vs Ansys.
Answers
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there might be several reasons for that. A few comments below:
- each solver is different and their formulations differ as well. It is normal to have some difference.
- but assuming the model assumptions are close enough, you shouldn't see too much of difference.
- frequency could be related to a spring natural frequency, where f=sqrt(k/m) >> so, both stiffness and mass affect the results
- if the mesh is not the same, so stiffness is not exactly the same, thus frequency will be affected.
- connections and contacts for the bodies of your model >> this could influence overall stiffness
- check the mass of each model, making sure it is close enough
- boundary conditions should be the same in both models
- check for strain energy >> compare to check if both models present the same regions with higher strain energy
Apart from that, you should give more details on your models.
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I completely agree with @Adriano A. Koga, Also you can check if damping is considered it should be equal, the implementation of damping models can vary between solvers, affecting the natural frequencies.
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Altair Employee