Applications of underdamped systems?

  • Thread starter becs
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  • #1
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Main Question or Discussion Point

Hi,
We have covered underdamping, overdamping and critical damping in study, but I am unsure of a question,

The question says "define the type of system that would give this response" (and there is an image of an underdamped wave).

Are there systems that WANT to have underdamping?
 

Answers and Replies

  • #2
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So, underdamped means that there is oscillation?
 
  • #3
OldEngr63
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A stringed musical instrument better be underdamped, otherwise, the sound will simply be a dull thud. Same thing for a bell.

It is not so much a matter of an inanimate system "wanting" to be underdamped. Rather it is a case of systems that function while being underdamped. The torsional vibration of an IC engine driven machine train is an example of such a system. It does not "want to be underdamped," it simply is underdamped but it functions anyway.

A diving board/diver system is underdamped. Otherwise, the diver might just as well dive from the edge of the pool.
 
  • #4
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So, underdamped means that there is oscillation?
Correct, To my knowledge, underdamped is when the systems response oscillates and overshoots the final value.
However, I'm not sure how this would be wanted or useful application as the task seems to be after.
 
  • #5
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A stringed musical instrument better be underdamped, otherwise, the sound will simply be a dull thud. Same thing for a bell.

It is not so much a matter of an inanimate system "wanting" to be underdamped. Rather it is a case of systems that function while being underdamped. The torsional vibration of an IC engine driven machine train is an example of such a system. It does not "want to be underdamped," it simply is underdamped but it functions anyway.

A diving board/diver system is underdamped. Otherwise, the diver might just as well dive from the edge of the pool.
I kind of get you but not sure how to relate to my industry and the question (factory environment with conveyors etc),

What in a factory would have an underdamped response and why would it have that response?
Somewhere else in the question mentions a transducer so Im guessing this could be a sensor on a conveyor for instance?
 
  • #6
donpacino
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like oldengr said, in many cases systems are just naturally underdamped, desirable or not. one example of this is a servo response in a factory. in some cases, a higher rise time with some overshoot is a preferable solution over slower rise time with no overshoot.
 
  • #7
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Many analogue electrical and mechanical measuring devices/instruments are constructed to have heavy underdamped response (almost critical one).
 
  • #8
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Many analogue electrical and mechanical measuring devices/instruments are constructed to have heavy underdamped response (almost critical one).
Would the reason for this be to achieve the target value faster where an overshoot doesn't matter all too much? If not then what would the reason be?

Thanks everyone so far :)
 
  • #9
meBigGuy
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Some reasons to intentionally design an underdamped response (when you have a choice) are to initially get to a desired value more quickly, or to make use of the ringing or the peak.
 
  • #10
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Would the reason for this be to achieve the target value faster where an overshoot doesn't matter all too much? If not then what would the reason be?
Yes. The target is in narrow range between first maximum and first minimum. Time saving is important in a series of many measurements. This also better suits human perception than overdamped design where target is maximum and its' estimation is more difficult.
 
  • #11
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My 76 Chrysler was under-damped most of the years I had it, LOL (bad shock absorbers). As youngsters, it made it more fun.

Tesla loved to play with resonance of underdamped things. i.e. large currents in resonant LC circuits to excite nearby LC coils into sparking (Tesla coils)

Under damped LC networks are now finding their way into more compact switching power supplies and power transfer pads.
 
  • #12
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I vaguely remember that some system is designed with an under-damped response to speed up the system response time. This is my two cents.
 
  • #13
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Tesla loved to play with resonance of underdamped things. i.e. large currents in resonant LC circuits to excite nearby LC coils into sparking (Tesla coils)
In most of the cases, he wanted circuits/systems with high Q factors. To minimize dissipation and fill them with as much energy as possible in the same time. Sparking was indicator of the "limit".
 

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