OceanGate Submersible Design More Conservative Than Reported...

[Fred Bloggs]

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

 

[Flyguy]

On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I am not sure who mislead whom; OceanGate fraudulently stated that the submersible was designed with the collaboration of NASA, U of Wa, and Boeing - NONE of this turned out to be true, it was just marketing hype. This video details the issues:
https://www.youtube.com/watch?v=TKLamhyJ6bE

 

[John Larkin]

On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.

The ultimate mistake was putting people, thrill-seekers, into that
kluge. People had no function.

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 9:54:12 AM UTC-4, John Larkin wrote:

On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch, which makes sense if you want to keep hull penetration to an absolute minimum. Rush was quoted as saying the titanium endcaps were resisting 22 million pounds at depth, so the viewport had to have a few million on it.

They could have bumped into something near the wreck. Since the submersible was 20,000 pounds mass, even a minor fender bender would produce a crushing impact.

Recent news is that the support ship lost communications 1 hour 45 minutes into the dive. Another story stated the Titan descent rate is routinely 50 meters per minute. So they were most likely at full depth when the mishap occurred.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

That\'s the crux of it, they didn\'t have enough money.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.

The ultimate mistake was putting people, thrill-seekers, into that
kluge. People had no function.

Passengers are money.

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 12:39:29 AM UTC-4, Flyguy wrote:

On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:
Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion.. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I am not sure who mislead whom; OceanGate fraudulently stated that the submersible was designed with the collaboration of NASA, U of Wa, and Boeing - NONE of this turned out to be true, it was just marketing hype. This video details the issues:
https://www.youtube.com/watch?v=TKLamhyJ6bE

The hull was designed and manufactured by Spencer Composites. The company has been in business for nearly twenty years and has probably produced thousands of different carbon fiber composite products for all kinds of applications. They have more experience than NASA, Boeing, and UWa combined, and they\'re exactly the kind of operation you want to be making something critical.

The carbon fiber composite is the strongest material known to mankind, with unsurpassed strength to mass density ration, specific strength, much stronger than even the best steels. The Boeing Dreamliner is 100% \"composite\" so they may have a PR problem to deal with now that all the know-nothings in the press are publicizing so much misinformation from a bunch of know-nothing movie directors, scuba divers, and whomever they can dredge up.

And as far as how carbon fire affects you, the U.S. , and others I\'m sure, is extending the lifespan of crumbling concrete structures, mostly bridges, using carbon fiber wraps on the critical members like beams and columns, and it\'s working out quite well.

Carbon fiber is THE answer for submersibles. The Koreans and Japanese are pursuing it in a big way. Didn\'t the Dreamliner wings come from Japan? I think they did.

 

[bitrex]

On 6/29/2023 9:53 AM, John Larkin wrote:

On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fredbloggs.fred@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.

The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

Sadly eventually one of the parts was tested to destruction

The ultimate mistake was putting people, thrill-seekers, into that
kluge. People had no function.

Yeah sort of like manned space flight

 

[Lasse Langwadt Christensen]

torsdag den 29. juni 2023 kl. 16.45.27 UTC+2 skrev Fred Bloggs:

On Thursday, June 29, 2023 at 12:39:29 AM UTC-4, Flyguy wrote:
On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:
Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I am not sure who mislead whom; OceanGate fraudulently stated that the submersible was designed with the collaboration of NASA, U of Wa, and Boeing - NONE of this turned out to be true, it was just marketing hype. This video details the issues:
https://www.youtube.com/watch?v=TKLamhyJ6bE
The hull was designed and manufactured by Spencer Composites. The company has been in business for nearly twenty years and has probably produced thousands of different carbon fiber composite products for all kinds of applications. They have more experience than NASA, Boeing, and UWa combined, and they\'re exactly the kind of operation you want to be making something critical.

The carbon fiber composite is the strongest material known to mankind, with unsurpassed strength to mass density ration, specific strength, much stronger than even the best steels. The Boeing Dreamliner is 100% \"composite\" so they may have a PR problem to deal with now that all the know-nothings in the press are publicizing so much misinformation from a bunch of know-nothing movie directors, scuba divers, and whomever they can dredge up.

And as far as how carbon fire affects you, the U.S. , and others I\'m sure, is extending the lifespan of crumbling concrete structures, mostly bridges, using carbon fiber wraps on the critical members like beams and columns, and it\'s working out quite well.

Carbon fiber is THE answer for submersibles. The Koreans and Japanese are pursuing it in a big way. Didn\'t the Dreamliner wings come from Japan? I think they did.

submersibles are in compression, carbon fiber works in tension in compression it is just epoxy

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 10:53:49 AM UTC-4, bitrex wrote:

On 6/29/2023 9:53 AM, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.
The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

They did no such thing. It was not smoke, it was extremely hot exhaust gas that is well-known to erode and destroy the o-ring.

http://engineeringfailures.org/challenger.html

Temperature was too low at launch and rainwater prevented the o-ring from seating adequately.

They did the same thing with the heat shield failure on the second disaster.. There was ample engineering test forewarning of a problem.

Sadly eventually one of the parts was tested to destruction
The ultimate mistake was putting people, thrill-seekers, into that
kluge. People had no function.
Yeah sort of like manned space flight

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:12:41 AM UTC-4, Lasse Langwadt Christensen wrote:

torsdag den 29. juni 2023 kl. 16.45.27 UTC+2 skrev Fred Bloggs:
On Thursday, June 29, 2023 at 12:39:29 AM UTC-4, Flyguy wrote:
On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:
Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I am not sure who mislead whom; OceanGate fraudulently stated that the submersible was designed with the collaboration of NASA, U of Wa, and Boeing - NONE of this turned out to be true, it was just marketing hype. This video details the issues:
https://www.youtube.com/watch?v=TKLamhyJ6bE
The hull was designed and manufactured by Spencer Composites. The company has been in business for nearly twenty years and has probably produced thousands of different carbon fiber composite products for all kinds of applications. They have more experience than NASA, Boeing, and UWa combined, and they\'re exactly the kind of operation you want to be making something critical.

The carbon fiber composite is the strongest material known to mankind, with unsurpassed strength to mass density ration, specific strength, much stronger than even the best steels. The Boeing Dreamliner is 100% \"composite\" so they may have a PR problem to deal with now that all the know-nothings in the press are publicizing so much misinformation from a bunch of know-nothing movie directors, scuba divers, and whomever they can dredge up.

And as far as how carbon fire affects you, the U.S. , and others I\'m sure, is extending the lifespan of crumbling concrete structures, mostly bridges, using carbon fiber wraps on the critical members like beams and columns, and it\'s working out quite well.

Carbon fiber is THE answer for submersibles. The Koreans and Japanese are pursuing it in a big way. Didn\'t the Dreamliner wings come from Japan? I think they did.
submersibles are in compression, carbon fiber works in tension in compression it is just epoxy

You\'re exactly the kind of person the media wants to talk to.

 

[bitrex]

On 6/29/2023 11:15 AM, Fred Bloggs wrote:

On Thursday, June 29, 2023 at 10:53:49 AM UTC-4, bitrex wrote:
On 6/29/2023 9:53 AM, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.
The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

They did no such thing. It was not smoke, it was extremely hot exhaust gas that is well-known to erode and destroy the o-ring.

http://engineeringfailures.org/challenger.html

\"Just after liftoff at .678 seconds into the flight, photographic data
show a strong puff of gray smoke was spurting from the vicinity of the
aft field joint on the right Solid Rocket Booster.\"

Smoke is what they called it there too, take it up with them.

It had also been seen on previous flights.

Temperature was too low at launch and rainwater prevented the o-ring from seating adequately.

They did the same thing with the heat shield failure on the second disaster. There was ample engineering test forewarning of a problem.

 

[Anthony William Sloman]

On Friday, June 30, 2023 at 12:45:27 AM UTC+10, Fred Bloggs wrote:

On Thursday, June 29, 2023 at 12:39:29 AM UTC-4, Flyguy wrote:
On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:

<snip>

> Carbon fiber is THE answer for submersibles. The Koreans and Japanese are pursuing it in a big way. Didn\'t the Dreamliner wings come from Japan? I think they did.

I do know the Dreamliner tailplane and fin came from Australia - one of my acquanitances worked for Boeing in Australia and put them together. He comes from an interesting family - his uncle (whom I\'ve known since we were undergraduates) is a professor of oncology and his wife - who trained as a physicist - got an M.A in Statistical Methods and ran the Cancer Registry for the state of New South Wales for year. Two of their sons work for Microsoft. I think my nephew who works for Google trumps that, but they don\'t.

--
Bill Sloman, Sydney

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:28:20 AM UTC-4, bitrex wrote:

On 6/29/2023 11:15 AM, Fred Bloggs wrote:
On Thursday, June 29, 2023 at 10:53:49 AM UTC-4, bitrex wrote:
On 6/29/2023 9:53 AM, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.
The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

They did no such thing. It was not smoke, it was extremely hot exhaust gas that is well-known to erode and destroy the o-ring.

http://engineeringfailures.org/challenger.html
\"Just after liftoff at .678 seconds into the flight, photographic data
show a strong puff of gray smoke was spurting from the vicinity of the
aft field joint on the right Solid Rocket Booster.\"

Smoke is what they called it there too, take it up with them.

\"The black color and dense composition of the smoke puffs suggest that the grease, joint insulation and rubber O-rings in the joint seal were being burned and eroded by the hot propellant gases.\"

That would not be reasonably construed as a \"safety margin\" by anyone. Recovered o-rings would have been visibly damaged and not reused.

It had also been seen on previous flights.
Temperature was too low at launch and rainwater prevented the o-ring from seating adequately.

They did the same thing with the heat shield failure on the second disaster. There was ample engineering test forewarning of a problem.

 

[John Larkin]

On Thu, 29 Jun 2023 07:13:58 -0700 (PDT), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

On Thursday, June 29, 2023 at 9:54:12?AM UTC-4, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch, which makes sense if you want to keep hull penetration to an absolute minimum. Rush was quoted as saying the titanium endcaps were resisting 22 million pounds at depth, so the viewport had to have a few million on it.

They could have bumped into something near the wreck. Since the submersible was 20,000 pounds mass, even a minor fender bender would produce a crushing impact.

Good point. A tiny impact could trigger the buckling positive
feedback.

 

[Lasse Langwadt Christensen]

torsdag den 29. juni 2023 kl. 16.14.03 UTC+2 skrev Fred Bloggs:

On Thursday, June 29, 2023 at 9:54:12 AM UTC-4, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.
That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch,

no it wasn\'t, the whole endcap was bolted on

https://www.thestatesman.com/wp-content/uploads/2023/06/22154398-0557-417F-95C5-D7A3DC911BB8.jpeg

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:59:47 AM UTC-4, Lasse Langwadt Christensen wrote:

torsdag den 29. juni 2023 kl. 16.14.03 UTC+2 skrev Fred Bloggs:
On Thursday, June 29, 2023 at 9:54:12 AM UTC-4, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.
That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch,
no it wasn\'t, the whole endcap was bolted on

https://www.thestatesman.com/wp-content/uploads/2023/06/22154398-0557-417F-95C5-D7A3DC911BB8.jpeg

That makes more sense.

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:59:47 AM UTC-4, Lasse Langwadt Christensen wrote:

torsdag den 29. juni 2023 kl. 16.14.03 UTC+2 skrev Fred Bloggs:
On Thursday, June 29, 2023 at 9:54:12 AM UTC-4, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.
That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch,
no it wasn\'t, the whole endcap was bolted on

https://www.thestatesman.com/wp-content/uploads/2023/06/22154398-0557-417F-95C5-D7A3DC911BB8.jpeg

My idea about the viewport as a hatch came from a published interview with an MIT marine engineer who said the viewport was the hatch. He was also faulting them for going with a cylinder instead of a sphere. But he did favor the composite material and the neutral buoyancy.

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:33:27 AM UTC-4, Anthony William Sloman wrote:

On Friday, June 30, 2023 at 12:45:27 AM UTC+10, Fred Bloggs wrote:
On Thursday, June 29, 2023 at 12:39:29 AM UTC-4, Flyguy wrote:
On Sunday, June 25, 2023 at 4:38:18 AM UTC-7, Fred Bloggs wrote:
snip
Carbon fiber is THE answer for submersibles. The Koreans and Japanese are pursuing it in a big way. Didn\'t the Dreamliner wings come from Japan? I think they did.
I do know the Dreamliner tailplane and fin came from Australia - one of my acquanitances worked for Boeing in Australia and put them together. He comes from an interesting family - his uncle (whom I\'ve known since we were undergraduates) is a professor of oncology and his wife - who trained as a physicist - got an M.A in Statistical Methods and ran the Cancer Registry for the state of New South Wales for year. Two of their sons work for Microsoft. I think my nephew who works for Google trumps that, but they don\'t.

Right- it was truly an international effort. We\'re seeing more and more of that process used to make cutting edge products.

--
Bill Sloman, Sydney

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 11:59:47 AM UTC-4, Lasse Langwadt Christensen wrote:

torsdag den 29. juni 2023 kl. 16.14.03 UTC+2 skrev Fred Bloggs:
On Thursday, June 29, 2023 at 9:54:12 AM UTC-4, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters
I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.
That was my guess too. The viewport was problematic for the chief engineer because it was neither rated for nor tested at hydrostatic pressure for a 4,000 meter depth. The viewport was also the hatch,
no it wasn\'t, the whole endcap was bolted on

https://www.thestatesman.com/wp-content/uploads/2023/06/22154398-0557-417F-95C5-D7A3DC911BB8.jpeg

The same engineer also faulted them for not have a hatch with interior locking mechanism. The hatch and hull have mating beveled surfaces that make it water tight to extreme depths. He was at a loss to explain how Ocean Gate didn\'t do that, and used this dangerous exterior bolt-on approach. The jpeg looks a little bit like beveling is used there.

 

[bitrex]

On 6/29/2023 11:34 AM, Fred Bloggs wrote:

On Thursday, June 29, 2023 at 11:28:20 AM UTC-4, bitrex wrote:
On 6/29/2023 11:15 AM, Fred Bloggs wrote:
On Thursday, June 29, 2023 at 10:53:49 AM UTC-4, bitrex wrote:
On 6/29/2023 9:53 AM, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.
The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

They did no such thing. It was not smoke, it was extremely hot exhaust gas that is well-known to erode and destroy the o-ring.

http://engineeringfailures.org/challenger.html
\"Just after liftoff at .678 seconds into the flight, photographic data
show a strong puff of gray smoke was spurting from the vicinity of the
aft field joint on the right Solid Rocket Booster.\"

Smoke is what they called it there too, take it up with them.

\"The black color and dense composition of the smoke puffs suggest that the grease, joint insulation and rubber O-rings in the joint seal were being burned and eroded by the hot propellant gases.\"

That would not be reasonably construed as a \"safety margin\" by anyone. Recovered o-rings would have been visibly damaged and not reused.

The rings were a structural component, they weren\'t supposed to ablate
at all.

That was the job of the ablative putty ahead of them, which it seems
wasn\'t that good at its job.

Noting ablation of the O-rings should have been a \"stop everything\"
moment, not a \"well, we sure can\'t re-use these\" moment.

 

[Fred Bloggs]

On Thursday, June 29, 2023 at 12:43:38 PM UTC-4, bitrex wrote:

On 6/29/2023 11:34 AM, Fred Bloggs wrote:
On Thursday, June 29, 2023 at 11:28:20 AM UTC-4, bitrex wrote:
On 6/29/2023 11:15 AM, Fred Bloggs wrote:
On Thursday, June 29, 2023 at 10:53:49 AM UTC-4, bitrex wrote:
On 6/29/2023 9:53 AM, John Larkin wrote:
On Sun, 25 Jun 2023 04:38:13 -0700 (PDT), Fred Bloggs
bloggs.fred...@gmail.com> wrote:

Background article linked below, looks like OceanGate was mislead by the overconfidence of the composites industry. They used the same manufacturer commissioned by Stephen Fossett to design and build a composite hull rated for a depth of 10,000 meters. The build was just finished up when Fossett was killed, so that was the end of it and it was never put to any kind of tests. OceanGate was also mislead into believing an acoustic sensing system on the hull would give them sufficient warning to move the submersible to shallower depth or surface to avoid a buckling failure. The truth of the matter is that buckling failure is poorly understood, there are large deviations between modelling and observed results of hydrostatic chamber testing of scaled cylindrical hulls, up to nearly 25%, and the buckling results in very rapid total structural failure. The same kind of testing also revealed a 2:1 deviation of ultimate strength of a cylindrical hull as a function of the helical pitch of
winding the fiber, in additions to other kinds of very strong sensitivities to any kind of imperfections in the material, the winding process, and the final geometry of the structure e.g. less than perfectly formed cylinder.

The push for composites or similar material is to achieve neutral buoyancy, which means the submersible can loiter at any depth without propulsion. It\'s a power conservation measure. They\'ll get it right some day, but that day is not now.

article from 2017:

https://www.compositesworld.com/articles/composite-submersibles-under-pressure-in-deep-deep-waters

I can imagine that a buckling failure could happen in milliseconds,
without warning. Or the acrylic window shattered.

It should have been tested to 2x the depth of the Titanic.
Periodically. If more money had been available, at least one hull
could have been tested to destruction, possibly in a test chamber.

I routinely test parts to destruction, because electronic parts are
cheap and easy to test. It\'s good to know the safety margins.
The NASA/Thiokol management kept watching smoke puff past the SRB
O-rings on the first couple dozen launches, when nothing too untoward
happened they thought that implied they had a \"safety margin.\"

They did no such thing. It was not smoke, it was extremely hot exhaust gas that is well-known to erode and destroy the o-ring.

http://engineeringfailures.org/challenger.html
\"Just after liftoff at .678 seconds into the flight, photographic data
show a strong puff of gray smoke was spurting from the vicinity of the
aft field joint on the right Solid Rocket Booster.\"

Smoke is what they called it there too, take it up with them.

\"The black color and dense composition of the smoke puffs suggest that the grease, joint insulation and rubber O-rings in the joint seal were being burned and eroded by the hot propellant gases.\"

That would not be reasonably construed as a \"safety margin\" by anyone. Recovered o-rings would have been visibly damaged and not reused.

The rings were a structural component, they weren\'t supposed to ablate
at all.

Not sure you can call a seal a structural component.

That was the job of the ablative putty ahead of them, which it seems
wasn\'t that good at its job.

Normally they\'re not exposed to hot rocket gas unless it vents through them..

Noting ablation of the O-rings should have been a \"stop everything\"
moment, not a \"well, we sure can\'t re-use these\" moment.

The o-rings were recovered after each launch, inspected by Thiokol and returned for re-use based on that inspection. One Thiokol engineer found excessive embrittlement of the rings and urged Thiokol to not re-use them. There was nothing wrong with the o-ring design, manufacture, or o-ring seal performance when they were new. The problem was re-using them.