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[ Spring pendulum ] Centrifugal Force transmissibility

  1. Dec 5, 2011 #1
    Hey folks,

    I just wonder how you guys think about this.

    Assume that there is a spring pendulum rotating at hinge (Free swing or forced swing).

    In this case, can I calculate force transmissibility (transmitted force amplitude to ground via spring devided by centrifugal force amplitude) ?

    or is it not logical because centrifugal force is not excitation force to the system ?

    The point is, if there is a rotation, spring would vibrate more than the case w/o rotation. So I want to quantify how much the rotation affect to the vibration.

    Does it make sense to you?

    Any kind of comment will be very appreciated. Thanks!
  2. jcsd
  3. Dec 18, 2011 #2

    Simon Bridge

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    If you construct a pendulum so the usual string is replaced by a spring, you get what is more usually the case - a real pendulum string is a bit stretchy. The restoring force from the spring provides the tension keeping it on a curved path.

    The other image that comes to mind is a rotor made from a mass on the end of a spring.

    To both systems you could add oscillations.

    If you wanted to know how the normal mass-on-a-spring oscillations are affected by being in a rotating system - then it would make sense to use centrifugal force (eg. if you did the mass-on-a-spring experiment inside a rotating space-station).
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