sub's hull was made with carbon fiber from Boeing that was past its airplane shelf li

Actually, the most likely point of failure in that "subs" design was the end rings that were used to bond the end bells to the tube.

If you go to about 11 minutes 20 on the video below you can see the manufacturing process used.


The two end rings, maybe an inch or so thick, are visible. These had to be welded on as separate pieces since machining them and the tube out of a single piece of metal would defeat the reason for carbon fiber use and cost savings. I would note that welding titanium is a HUGE PITA. It has to be done in a completely inert atmosphere or vacuum. Any oxygen or nitrogen present can cause the weld to oxidize or nitride and it becomes brittle and weak. I know because I had to figure out how to fix jet engine temperature probes for the Air Force at one point. These had a thin titanium jacket that fitted over them that could easily be cracked or broken. Welding them back using TIG methods is possible, but you have to be really careful with the gas conditions it's done in.

Those two rings represent a HUGE weak spot in the design. If the rings and carbon fiber compress at different rates it is fully possible, and very likely that the tube failed at the welds between it and the rings. One small crack and it would be fail city PDQ.

Given that they've found both end bells intact, I'd say those need inspection to see if the bonding material failed or the ring itself failed. Either way, that looks like a pretty good culprit for the reason the design failed to begin with.
 
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Lionfish said:
001_jpg-2862876-jpg.1313235
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Sad as this is, it is correct.
 
Geeko Sportivo said:
NO. What I see is Trump and his cult blame Biden for everything under the sun, no matter what he does or does not do, no matter what, just to try and score political points.

It's the same ole Pygmalion Theory, that because you hate Democrats no Democrat can ever do anything right and so therefore, everything a Democrat president ever will ever do is WRONG!

Well, let me tell you, Democrats are not falling for that, and neither are the Independents that actually makes the difference in all of our elections today.

SO you Disgruntled Republicans that hate Democrats keep harping away about Biden, no matter what he does or doesn't do, as if you think you can ultimately convince the Independents to see it your way.

So let's not argue about it, and just go and vote. THE PEOPLE WILL DECIDE WHO THEY THINK IS BEST TO RUN THIS COUNTRY.

Everybody in the race has to speak for themselves at some point, and that is what counts, and that is what the people will have to ultimately judge them by. All of our cheerleading, booing, and yea-ing in the background, just becomes he said/she said spaghetti on the wall.

But thanks for your opinion! The thing is, everybody has one! EVERYBODY!

See you on Poll Day!
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'Just vote'. You really ARE an idiot lizard. Democrats are responsible for the massive election fraud that caused the last two elections to fault. Disenfranchising voters is bad enough. Now you idiots deny what you did!
 
T. A. Gardner said:
There is a regulation set by the FAA on carbon fiber for aircraft giving a shelf life of 1 year. The fiber itself is pretty much the same for decades after manufacture, it's the resins used to bond it that have limited self life.
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The resins used have a shelf life, regardless of the resin used.
There is no shelf life for carbon fiber. There is no such FAA regulation.
 
T. A. Gardner said:
Actually, the most likely point of failure in that "subs" design was the end rings that were used to bond the end bells to the tube.

If you go to about 11 minutes 20 on the video below you can see the manufacturing process used.


The two end rings, maybe an inch or so thick, are visible. These had to be welded on as separate pieces since machining them and the tube out of a single piece of metal would defeat the reason for carbon fiber use and cost savings. I would note that welding titanium is a HUGE PITA. It has to be done in a completely inert atmosphere or vacuum. Any oxygen or nitrogen present can cause the weld to oxidize or nitride and it becomes brittle and weak. I know because I had to figure out how to fix jet engine temperature probes for the Air Force at one point. These had a thin titanium jacket that fitted over them that could easily be cracked or broken. Welding them back using TIG methods is possible, but you have to be really careful with the gas conditions it's done in.

Those two rings represent a HUGE weak spot in the design. If the rings and carbon fiber compress at different rates it is fully possible, and very likely that the tube failed at the welds between it and the rings. One small crack and it would be fail city PDQ.

Given that they've found both end bells intact, I'd say those need inspection to see if the bonding material failed or the ring itself failed. Either way, that looks like a pretty good culprit for the reason the design failed to begin with.
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Oddly enough, the bell ends of a submarine are stronger simply because of their shape, regardless of the material used. The weak spot is the tube itself.
 
Into the Night said:
Oddly enough, the bell ends of a submarine are stronger simply because of their shape, regardless of the material used. The weak spot is the tube itself.
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Those two end rings represent a much greater weak spot than the tube. They are welded on at right angles to the tube and are about an inch thick. If the carbon fiber delaminated from them, they become the weakest part of the hull and one crack and BOOM! The end bells are blown off the tube.
 
T. A. Gardner said:
There is a regulation set by the FAA on carbon fiber for aircraft giving a shelf life of 1 year. The fiber itself is pretty much the same for decades after manufacture, it's the resins used to bond it that have limited self life.
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I am imagining here that it was used under the argument that the FAA has ridiculous regulations that have nothing to do with reality....I have heard a lot of that over the years.
 
Hawkeye10 said:
I am imagining here that it was used under the argument that the FAA has ridiculous regulations that have nothing to do with reality....I have heard a lot of that over the years.
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That and it wasn't being used in an aircraft application so what does the FAA know...
 
Hawkeye10 said:
I am imagining here that it was used under the argument that the FAA has ridiculous regulations that have nothing to do with reality....I have heard a lot of that over the years.
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Terry is also anti-union because it cuts into profits and ties up efficiency, such as worker safety, with red tape.
 
Doc Dutch said:
Terry is also anti-union because it cuts into profits and ties up efficiency, such as worker safety, with red tape.
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You are wrong. I am anti-closed shop unions. That is, if you want to join a union go for it. Don't force me to join just because you want to however. I am pro Right to Work. Oh, and unions are hardly pro safety unless there is some financial gain for them involved.
 
This disaster is one more reason why we need government oversight for nonsense like this. If you offer a service to the public, then you should be required to abide by strict safety regulations.

I'm still waiting for Trump and the Republicans to claim that water pressure is "fake science."
 
Hawkeye10 said:
I am imagining here that it was used under the argument that the FAA has ridiculous regulations that have nothing to do with reality....I have heard a lot of that over the years.
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Regulations are your friends. They are what would have prevented this disaster. The ownership society will allow you to die or be in danger for profits. You are a rightys and read righty crap. That is why you hear about the onerous regulations and why the Repubs are so happy to slash your protections for more profits,
 
T. A. Gardner said:
https://www.faa.gov/documentlibrary/media/advisory_circular/ac_23-20.pdf
https://www.faa.gov/regulations_pol....cfm/go/document.information/documentID/99693
https://www.tc.faa.gov/its/worldpac/techrpt/ar02-109.pdf
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None of these specify a shelf life for carbon fiber.
AC20-107B specifies the procedure for documenting strength of materials used in composite aircraft.
AC23-20 specifies the requirements for documenting prepreg material and quality control procedures. It doesn't even discuss carbon fiber specifications and does not specify a shelf life of carbon fiber.
AR02/109 is a specification sheet for documenting the construction and shipping of prepreg, not carbon fiber.

The FAA does not specify a shelf life of carbon fiber.
 
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