Frequency response dynamic stiffness

Arul
Arul Altair Community Member
edited March 18 in Community Q&A

Hi ,

 

Can anyone explain how to calculate / Plot dynamic stiffness from frequency response analysis in Optistruct?

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited February 2017

    Hi,

     

    Double Integrate Acceleration to get the Displacement and inverse of that displacement divided by input force will give dynamic stiffness.

     

    You may need to load the preference file using File > Load > Preference File > Vehicle Safety Tools > Load.

     

    Once you load this, click on Math > One Curve > Double Integral and select the Acceleration curve to get the Displacement curve.

  • Arul
    Arul Altair Community Member
    edited February 2017

    Thank you

  • Arno Heidkamp
    Arno Heidkamp Altair Community Member
    edited March 18

    Dear both,
    I know this is fairly old, but I have a question:
    When I do dynamic stiffness, I do FRF analysis.
    So, I get results in frequency domain.
    In frequency domain, the integral is calculated by multiplication/division with the radial frequency.

    Therefore:
    Displacement over frequency is calculated from acceleration as:
    u(f)=a(f)/(2*pi()*f)²

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