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Homework Help: Finding the natural frequency of a set of data

  1. Mar 28, 2009 #1
    1. The problem statement, all variables and given/known data
    Hi all, I'm having an issue with a homework problem. I'm taking a vibrations class and in our lab we had a cantilever beam with a mass on the end. There is an accelerometer on the beam and we used an impulse hammer to hit the beam. We had software that recorded all the frequency, force and accelerations of the beam while it was vibrating and it was put all into an excel file. From this given data we then have to find the natural frequency of the beam. I am racking my brain trying to figure out how to go about doing this but I'm stumped. Does anyone have any suggestions?

    2. Relevant equations
    I know how to find the natural frequency with the given mass and stiffness values but we need to be able to find it using the given data that was recorded during the experiment.

    3. The attempt at a solution
    This is where I need the help
  2. jcsd
  3. Mar 28, 2009 #2


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    Welcome to PF.

    Has your class discussed Fourier Transforms?

    And if so, your professor should have made some software available to you for taking the Fourier Transform of your data
  4. Mar 28, 2009 #3


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    agindy86: In your output data, look for the maximum peaks of the displacement response magnitude. Obtain the time period between these maximum peaks.
  5. Mar 28, 2009 #4
    First off, thank you for your help. And no we have not discussed fourier transforms. I'll look into finding the maximum peaks between time periods. Thanks again
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