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#31
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Latest candidate for SpaceX pad explosion
JF Mezei wrote:
On 2016-10-21 23:48, Fred J. McCall wrote: THERE IS NO LAMINATION, YOU IGNORANT ****!!!! Everytime you have multiple layers of carbon threads (or fabric) they are laminated agianst each other and help in place by the matrix/resin. Go look up the meaning of 'laminate', you ignorant ****. Did you find the word 'laminate' or 'lamination' ANYWHERE in that article? No, you did not, BECAUSE THERE IS NO LAMINATION, YOU IGNORANT ****. Your professionalism rivals that of Trump. Your intellect rivals that of Alfred E. Newman. If you want 'professionalism' you can pay my consulting rate. You'll have to pay a premium if you intend to argue when things you don't understand are explained to you. Otherwise, I don't have to put up with your stupidity. -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson |
#33
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Latest candidate for SpaceX pad explosion
Jeff Findley wrote:
Helium leaks through the smallest of cracks. You *do not* want to design a leaky COPV for a second stage, especially when that tank would leak directly into your LOX tank, totally throwing off the LOX tank pressurization. I think these helium tanks are pressurized to 10,000 psi. That's why when the helium tank blows it blows the oxygen tank and everything else. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Dryden |
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#35
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Latest candidate for SpaceX pad explosion
Jeff Findley wrote:
In article om, says... There are two areas of concern: leak via porosity and leaks at the seam between the carbon fibre structure and metal pipe fitttings. Having a metal inner liner that also has the pipe fittings that go out of tank solves both. My area of concern is the fact that you keep spewing things that are simply not true about the way that a COPV is designed and built. You're a much more patient man than I am, Jeff. I got fed up with him not knowing what he was talking about and then arguing with people who explained it to him a while ago. -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson |
#36
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Latest candidate for SpaceX pad explosion
In sci.space.policy message
aweb.com, Sat, 22 Oct 2016 00:31:48, JF Mezei jfmezei.spamnot@vaxinati on.ca posted: ... It is more likely that the ultra cold O2 simply went below the carbon fibre's minium teperature, it became brittle and broke, releasing the He2 which then caused failure of the LOX tank. See https://en.wikipedia.org/wiki/Helium_dimer. He2 exists; but it is not what is being put in the tank. -- (c) John Stockton, Surrey, UK. Turnpike v6.05 MIME. Merlyn Web Site - FAQish topics, acronyms, & links. |
#37
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Latest candidate for SpaceX pad explosion
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#38
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Latest candidate for SpaceX pad explosion
Is this perhaps a confusion/whatnot as to the "degree" of
pores/cracks/whatnot in the overwrap? I am getting the impression that the carbon fribre overwrap is kinda/sorta like an exoskeleton for the tank. A nice, thin, lightweight metal inner tank/liner that is largely helion-tight but on its own would not be able to withstand the pressure desired, but can once it is wrapped some number of times with resin-impregnated carbon fiber. Some quantity of sufficiently small and spaced-apart holes/pores/cracks in that carbon fibre overwrap is "OK" in that the structure as a whole will persist. Once there are either too many, or too large holes/pores/cracks in that overwrap it becomes "a bad day." When Oxygen freezes, does it form sharp points/edges as it solidifies? Might such things then be able to pierce the liner and/or overwrap? Or just push out the liner or overwrap to the point that there is enough void to mean the two are no longer complementing one another structurally and then one or the other snaps/cracks/whatnot. rick jones -- "You can't do a damn thing in this house without having to do three other things first!" - my father (It seems universally applicable these opinions are mine, all mine; HPE might not want them anyway... feel free to post, OR email to rick.jones2 in hpe.com but NOT BOTH... |
#39
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Latest candidate for SpaceX pad explosion
Mr Mezei, you are an idiot and not qualified to express an opinion in
this discussion. You need to learn to STFU and not argue with people who are trying to explain to you how things actually work. JF Mezei wrote: On 2016-10-24 06:13, Jeff Findley wrote: It's a spectrum. You forgot carbon fiber tape. Tape is either narrow strips of cloth or is (more commonlty, and as pictured in that document), multiple strands being layed at same time. Laying it as multiple strands allows for far better control over direction it is being laid. Cloth tape is good for patches, but because horizontal threads are very short and cut at each side of tape, they do not yield as much strength as continuous fibres. A crack in any composite structure is a severe failure. You are WRONG, WRONG, WRONG in this case. Did you even read that NASA document on COPV? Sorry, but a crack in composite means both fibre and resin have cracked and the crack risks propagating. And if you look at the pictures of the COPV in that document, you see that the finished product is smooth and no visible carbon patterns. When a process yields such a finished product, (as opposed to artisanal laying of fibre), there are no openings and the resin has filled every gap between strands. This doesn't solve the issue of porosity or the joining of carbon structure with metal fittings. But the use of the word "crack" as a normal feature of carbon is plain wrong. A crack in a carbon fibre structure is a failure, not a normal happening. |
#40
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Latest candidate for SpaceX pad explosion
JF Mezei wrote:
On 2016-10-24 17:50, Jeff Findley wrote: No, microscopic cracks or pores between the lengths of carbon fiber that would otherwise render it unable to hold helium at thousands of PSI will not result in structural failure, just leakage. You are forgetting that composites are a misture of carbon fibres and resin. The major role of the resin is exactly to fill the gaps between the fibres to keep them in place. You are forgetting that you don't know what the **** you are talking about. The strength of such structures comes from fibres beung tightly packled against eache other (laminated against each other) ... Go look up the meaning of the word 'laminated'. You persist in misusing it. ...and held in place by the resin "matrix"). This means a full surface without holes. You make it sound like the structural strength is in the RESIN, which is exactly backward. And if you look at the finied prodycrt, you do not see fibres on the surface becayse there is a uniform layer of resin above the topmost layer of fibres to protect it. There are no holes or cracks or voids on that type of surface. Stick 10,000 psi helium in it without an inner metal liner and it will leak like a sieve. Again, that's why they use a liner in a Composite OVERWRAPPED Pressure Vessel. Note the emphasis on OVERWRAPPED!!!!!!! I have not argued against the use/need of a liner. The composite overwrap is likely sufficiently porous that it does not contain those light gases well for long periods. But this is quite different from stating there are cracks or holes in the composite that would not contain the H2. Except that there are, whether you can see them or not. Perhaps if you pulled your head out? snip idiocy -- "Ignorance is preferable to error, and he is less remote from the truth who believes nothing than he who believes what is wrong." -- Thomas Jefferson |
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