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Forced Vibration

  1. Sep 9, 2013 #1
    In forced vibration, amplitude of vibration changes periodically. Is it right ? I think it is a correct statement, since the amplitude of vibration is a periodic function.
  2. jcsd
  3. Sep 9, 2013 #2


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    Are you suggesting that you get a 'beat'?
    You don't get a beat, just a reduced amplitude of response. The level will depend on the Q of the resonator and the frequency offset.
  4. Sep 9, 2013 #3


    Staff: Mentor

    I think there may be a bit of a terminology confusion here. The displacement is a periodic function in vibration. The amplitude is the maximum displacement, so it is not periodic.
  5. Sep 9, 2013 #4
    So, does it decays exponentially then....... ( I mean amplitude of the forced vibration)
  6. Sep 10, 2013 #5


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    The term 'forced vibration' means that a steady vibration frequency is applied. The result is a 1/exponential growth in amplitude takes place over time, until a max amplitude is reached. When the exitation is removed, there is an exponential decay in amplitude. There is no change in frequency at any time except for a small possible 'ringing' due to a discontinuity on switch on and switch off. But that is not usually considered.
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