Reason for difference in Modal frequency

Akhil_22546
Akhil_22546 Altair Community Member
edited November 2023 in Community Q&A

Hello Community,

I ran a gauge optimization on a model with:

Load Step: Normal modes

Constraint: Frequency for mode 1 between 1280 Hz - 1300 Hz

Objective: Minimize Compliance

It gave a resulting thickness for my component and also the modal frequencies for the first 10 modes.

To verify this I input the thickness in my model and run a Normal modes analysis for the first 10 modes but there is a error of 4% between the values.

Does anyone know a possible reason for this?

Thank you.

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Answers

  • Johan Dahlberg_20306
    Johan Dahlberg_20306
    Altair Employee
    edited November 2023

    Hi Akhil
    Did you run with discrete thickness or did you let the software use floating number for the gauge?

    Compare the mass in the two files .out so they are the same!

    /johan


  • Akhil_22546
    Akhil_22546 Altair Community Member
    edited November 2023
    Johan Dahlberg_20306 said:

    Hi Akhil
    Did you run with discrete thickness or did you let the software use floating number for the gauge?

    Compare the mass in the two files .out so they are the same!

    /johan


    Hey johan,

    Thanks for the suggestion, I did run with both DDVAL and without. It was a model issue though.

    I have another question if you could help. 

    Can I use nonlinear load step for gauge optimization?

    Thank you for your time.

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