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muloto
Member

Join Date: Sep 2014
Posts: 7

Free Body Diagram of a Payload Fairing

09/06/2014 9:50 PM

Hello,

Though i know that it is not a standard practice in the space industry to employ conventional free body diagrams for sizing of fasteners and connectors,I am to size explosive bolts which are used in the payload fairing separation mechanism using conventional free body diagrams.

there are two halves with 4 spring actuators in each half these halves attached with a cylindrical barrel(2nd stage in actual) by two hinges.weight,forces in each springs,maximum aerodynamic flight loads(lateral and axial) are known.

how many bolts and of what size do i need to attach on the lateral and longitudinal separation planes? do i need to consider both the planes one by one or as a whole? does the hinge reaction need to be considered ?

the working philosphy goes: the springs exert an outward rotating moment on each half about the hinges but the bolts on the longitudinal plane restrain them from moving apart and likewise the bolts on the lateral plane restrain the halves from lifting and moving apart.during flight ,considering worst case scenario,we assume that the horizontal orientation of the fairing is what in which the fairing experiences the maximum lateral(weight plus aerodynamic flight load) and axial(due to drag) load.hence the bolts should be sized for this case.

also,is this system a planar or non-planar force system?

explosive bolts are rated by their tensile load capability but we can see that during the horizontal orientation the bolts in the lateral plane experience both tensile and shear loads while the bolts in the longitudinal plane(when the fairing is on ground ready for launch) only experience tensile loads due to both halves trying to move apart.

what safety factor is used in space industry for fasteners?

can maximum distortion theory be used to calculate equivalent tensile loads for sizing of explosive bolts?
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lyn
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Join Date: Oct 2008
Posts: 42355
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#1

Re: Free Body Diagram of a Payload Fairing

09/06/2014 11:43 PM

You've GOT to be kidding!

I'm really curious to know where you work, and what your title is.
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cuba_pete
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Join Date: Dec 2010
Posts: 1895
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#2

Re: Free Body Diagram of a Payload Fairing

09/07/2014 12:09 PM

Googling some key phrases results in random sites for various flight control systems.

Learning through the College of the Internet so someone can design their own missile systems.

Terrorist-U
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muloto
Member

Join Date: Sep 2014
Posts: 7
#3
In reply to #2

Re: Free Body Diagram of a Payload Fairing

09/07/2014 5:37 PM

sick remarks...go have a life please...
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cuba_pete
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Join Date: Dec 2010
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#4
In reply to #3

Re: Free Body Diagram of a Payload Fairing

09/07/2014 9:01 PM

Just sayin:

http://cyberarms.wordpress.com/2012/11/15/israel-using-air-strikes-tweets-and-youtube-in-the-battle-against-hamas/
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Ed Watts
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Join Date: Feb 2007
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#5

Re: Free Body Diagram of a Payload Fairing

09/07/2014 10:43 PM

I used to manage the test department at an aerospace explosives company in Torrance, California; they specialize in explosive bolts and so on. They can tell you everything you need to know, but it won't be for free. The company's name is Hi-Shear Technology Corporation, and they are at www.hstc.com

No one can solve your problem better than they can. I no longer work there, and I have no pecuniary interest in making this reference.
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rashavarek
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Join Date: Jul 2012
Location: Madison, WI.
Posts: 2074
Good Answers: 77
#6

Re: Free Body Diagram of a Payload Fairing

09/08/2014 9:22 AM

Ok, I really have to ...

I always want to work with rocket s but never had the patience for the math and tech learning necessary. It appears I am not the only one, but this fellow found a job in the field anyway.

Holy Sh** is this a serious post or just a joke?

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dj95401
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United States - Member - Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - RC Aircraft - New Member Engineering Fields - Aerospace Engineering - New Member

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Location: Saint Helens, Oregon
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#7

Re: Free Body Diagram of a Payload Fairing

09/08/2014 12:37 PM

I'll have to admit, this is one of the most elaborate posts of "How can I ....?" or "How do I ....?" home work questions I've seen in awhile.

Now they want us to design a Rocket-ship with departing loads too?

NASA offers "Launch Services Program" (LSP) on their web site just for the OP's questions.You can build, simulate launch and flight too!

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Brave Sir Robin
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#8

Re: Free Body Diagram of a Payload Fairing

09/08/2014 3:27 PM

Next up: DIY reactors.
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muloto
Member

Join Date: Sep 2014
Posts: 7
#9

Re: Free Body Diagram of a Payload Fairing

09/08/2014 5:19 PM

i dont get it..why are you ****tards trying to make it a fuss?? i am trying to perform a load analysis on a fairing LIKE structure..forget fairing it is BOILS high in you people..take it as a bracket.
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dj95401
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United States - Member - Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - RC Aircraft - New Member Engineering Fields - Aerospace Engineering - New Member

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#10
In reply to #9

Re: Free Body Diagram of a Payload Fairing

09/08/2014 5:42 PM

Take it as in ..... your over your head and not qualified to do this task. Don't you have superior's you can turn to for questions like this?

We are not at your office and you have not supplied any drawings of shape and size of this "bracket", only that it needs to explode at some certain time in flight.

This is anonymous site, you don't know our qualifications. I work in the airline industry, so I make it a point to keep my craft intact and not to have on-board explosions.

P.S. Name calling will get you absolutely nowhere here, if fact it might even piss a few of us off!

__________________
 Confucius once said, “ Ability will never catch up with the demand for it".
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rashavarek
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Join Date: Jul 2012
Location: Madison, WI.
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#11
In reply to #9

Re: Free Body Diagram of a Payload Fairing

09/08/2014 5:52 PM

http://www.amazon.com/s/?ie=UTF8&keywords=estes+rocket+launch+kit&tag=googhydr-20&index=aps&hvadid=31615417117&hvpos=1t2&hvexid=&hvnetw=s&hvrand=13302459046800292096&hvpone=&hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_7js2mwk29w_b

Ok, start here and work your way up.

There are no short cuts in rocket science dude.

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Munster
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Join Date: Nov 2011
Location: New Hampshire
Posts: 406
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#12

Re: Free Body Diagram of a Payload Fairing

09/12/2014 2:39 PM

Math homework for the masters degree physics class
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