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Good Read Spacecraft Launch Vibration

10/08/2017 11:32 PM

Hi guys, any good read references about rocket launch vibration?

References is much appreciated. Thank you.

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Pathfinder Tags: Rocket Launch Vibration
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#1

Re: Good Read Spacecraft Launch Vibration

10/09/2017 12:55 AM

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Guru

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#2
In reply to #1

Re: Good Read Spacecraft Launch Vibration

10/09/2017 1:04 AM

Pennywise or Mc Donald? Perhaps a jester?

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#3
In reply to #2

Re: Good Read Spacecraft Launch Vibration

10/09/2017 1:13 AM

That's Pogo ...click on him

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Engineering Fields - Electrical Engineering - Been there, done that, still doing it. Engineering Fields - Control Engineering - New Member

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#9
In reply to #1

Re: Good Read Spacecraft Launch Vibration

10/10/2017 10:07 AM

Wait a minute. Isn't that ornament patterned after John Wayne Gacy's clown costume?

Sick, very sick.

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#10
In reply to #9

Re: Good Read Spacecraft Launch Vibration

10/10/2017 10:57 AM

Ouch! It is.

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#16
In reply to #9

Re: Good Read Spacecraft Launch Vibration

10/11/2017 12:10 AM

Sorry, the association was unintentional...

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#17
In reply to #16

Re: Good Read Spacecraft Launch Vibration

10/11/2017 9:01 AM

I find that clown totally offensive, and sentence him to a Chinese Fire Drill in a Yugo.

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#18
In reply to #17

Re: Good Read Spacecraft Launch Vibration

10/12/2017 7:59 PM

Chinese no good fire drill

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#19
In reply to #18

Re: Good Read Spacecraft Launch Vibration

10/13/2017 9:04 AM

Lovely! Now she has to go to America, and be sentenced to working at a donut shop.

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#12
In reply to #1

Re: Good Read Spacecraft Launch Vibration

10/10/2017 2:02 PM

Is that a dastardly clown cookie? Why I believe it is! Thank you not for the dastardly clown cookie.

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#4

Re: Good Read Spacecraft Launch Vibration

10/09/2017 3:32 AM

Is Google not available in that part of the world?

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#7
In reply to #4

Re: Good Read Spacecraft Launch Vibration

10/09/2017 8:58 PM

Yes, there is. Just fishing down here. Someone might be into it, who knows.

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#13
In reply to #4

Re: Good Read Spacecraft Launch Vibration

10/10/2017 2:03 PM

They have to bang two coconuts together to activate Google over there.

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#5

Re: Good Read Spacecraft Launch Vibration

10/09/2017 11:38 AM
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#6
In reply to #5

Re: Good Read Spacecraft Launch Vibration

10/09/2017 8:56 PM

I appreciate it Lyn, thanks.

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#8

Re: Good Read Spacecraft Launch Vibration

10/10/2017 7:51 AM

Long ago I worked in a environmental test lab. One important lesson I learned was that most prime movers respond to vibration as a function of their speed. For those applications we often did our vibration testing using a swept sine wave. Not true with rocket motors. They generate white noise, which essentially means the superposition of many frequencies. This means that two loads that would normally respond separately under swept vibration may respond simultaneously under white noise conditions and cause substantial damage. Rockets change everything.

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#11
In reply to #8

Re: Good Read Spacecraft Launch Vibration

10/10/2017 1:59 PM

White noise vibration yields sum, difference and the two originals, just like voltage modulation does and does so simultaneously.

Sine sweeps find the individual resonances, and white nose vibration recreates their real-world interactions.

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#14
In reply to #8

Re: Good Read Spacecraft Launch Vibration

10/10/2017 2:05 PM

Are you saying that vibrational mechanical modes (including pogo) in a rocket system can exchange energy freely and rapidly? I think that almost has to be true.

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#15
In reply to #14

Re: Good Read Spacecraft Launch Vibration

10/10/2017 5:13 PM

A productive way to think about this is to consider two cantilevers with different resonant frequencies mounted on a support at right angle to each other. When the support is driven by a swept sine wave, one cantilever will resonate at its natural frequency. As the frequency is changed, that cantilever's oscillations will be reduced and the second cantilever may become resonant. So, during this sweep, each cantilever goes into, and out of resonance, just once, and neither cantilever interferes with the other. Under white noise excitation however, both cantilevers can become resonant it the same time and cause significant damage.

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