modal result comparision

vinayak Imadi_22241
vinayak Imadi_22241 New Altair Community Member
edited June 5 in Community Q&A

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.

Tagged:

Answers

  • Adriano_Koga
    Adriano_Koga
    Altair Employee
    edited June 5

    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.

  • Sriramanuj_16
    Sriramanuj_16
    Altair Employee
    edited June 5

    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.

Categories