Titanic submersible confirmed destroyed with loss of all five souls onboard.

pc-guy said:
Carbon fibre composite suffers brittle failure. That’s probably the main reason why it is not used for such application. Ie evident in this sub - it was ok for a few use then suddenly it goes pop without a warning.

Otherwise the composites has very high tensile as well as compressive capacity if cross weaved.

The fundamental flaw of the sub design I guess is a deviation from a spherical design to a tube design which means the stress build up in the materials will be highly concentrated around where the end bells connect to the tube and the likely failure point. The tube fiber hwould have been primarily weaved to deal with hoop stress but the longitudinal stress can be exceptionally high as well meaning the tube is prone to high end compression and if not dealt with the tube will just fail.

That’s probably where titanium composite excel ie it’s strength is not uni-directional and it is ductile so gives you plenty warning and ability to inspect and predict failure.
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I would be very worried about the joint between the titanium and the carbon fibre. Different reactions to pressure would worry me. In fact, using carbon fibre would worry me full stop. It's not a widely used material in marine applications, there just isn't enough data.

And you are right about the way it was woven. It was woven in hoops with almost no longitudinal strength. I guess they thought it didn't need it. I wouldn't know. But I would certainly worry about that.
 
pc-guy said:
Only in mainstream media do you get a complete different version of reality

5 people decide to go into a questionable tube and get themselves killed on a tourism trip to bottom of the Atlantic - everyone else calls them idiots; media calls them heroes.

There has never been a time that such disparity in media and general consensus been so starkly different. And no wonder populism is one the rise everywhere and peole are not interested in mainstream news anymore.
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I know that’s Alex Johnson’s take in his column in the Mail today, but that’s just him being him, a professional edge Lord to the bitter end. Has this been echoed anywhere else?

Just seen a photo on Reddit taken from the interior of the Titan, and it shows that the monitors were attached to the hull with screws driven directly into the carbon fibre. It seems the more that comes out about this Ocean Gate outfit, the stupider it gets.
 
SpellowHouse said:
I would be very worried about the joint between the titanium and the carbon fibre. Different reactions to pressure would worry me. In fact, using carbon fibre would worry me full stop. It's not a widely used material in marine applications, there just isn't enough data.

And you are right about the way it was woven. It was woven in hoops with almost no longitudinal strength. I guess they thought it didn't need it. I wouldn't know. But I would certainly worry about that.
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I don't think that would have been a major problem as the pressure of the titanium end caps are essentially pushing them down onto the carbon fibre cylinder. Think of it like a man with an accordion pushing from either side as the pressure would have been concentrated at the ends instead of all around evenly like you would have with a sphere.
 
The Funktopus said:
Just seen a photo on Reddit taken from the interior of the Titan, and it shows that the monitors were attached to the hull with screws driven directly into the carbon fibre. It seems the more that comes out about this Ocean Gate outfit, the stupider it gets.
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there was an interior shell plus heating elements (insulation too I guess) - it's cold - sitting in a fridge for 4+ hours wouldn't be comfortable.

[e:
adam cool dude said:
Think of it like a man with an accordion pushing from either side as the pressure would have been concentrated at the ends instead of all around evenly like you would have with a sphere.
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I would think crack/weakness point is going to be half way along cylinder wall - those earlier oil drum collapse videos had that characteristic,
did the tube get thicker towards the middle (which would be the reverse of a double butted bicycle construction)
]
 
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adam cool dude said:
I don't think that would have been a major problem as the pressure of the titanium end caps are essentially pushing them down onto the carbon fibre cylinder. Think of it like a man with an accordion pushing from either side as the pressure would have been concentrated at the ends instead of all around evenly like you would have with a sphere.
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What concerns me, though, is that the pressure down there is over two tons per square inch. Although the joint is being pressed by enormous force, that pressure is also trying to push through the epoxy joint. If there is any difference in the reaction of the titanium and carbon fibre to the massive pressure, temperatures and so on, then small cracks could appear in that joint. It was my understanding that this is why they typically do not use different materials in deepwater subs. Any difference in the way the material behaves will ultimately cause a problem.
 
wesley said:
Perhaps the weight ballast came off from the implosion?
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Once the vessel imploded, it was never coming all. All the buoyancy of the air contained in the body was gone so it would have been instantly very negatively balanced. It would take more than a few blocks of ballast being removed to make it positively buoyant so that it could raise.
 
So the tube construction. Was it literally created by winding the fibre round and round something akin to say string round a toilet roll tube? Or did they do anything fancy like chuck some steal rings in too, wind horizontally etc?
 
SpellowHouse said:
I would be very worried about the joint between the titanium and the carbon fibre. Different reactions to pressure would worry me. In fact, using carbon fibre would worry me full stop. It's not a widely used material in marine applications, there just isn't enough data.

And you are right about the way it was woven. It was woven in hoops with almost no longitudinal strength. I guess they thought it didn't need it. I wouldn't know. But I would certainly worry about that.
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I think worrying about all of it is a good approach! I'm totally and utterly convinced that fatigue and dynamic behaviours and his arrogance in ignoring this aspect are the reason for avoidable deaths.

The Funktopus said:
I know that’s Alex Johnson’s take in his column in the Mail today, but that’s just him being him, a professional edge Lord to the bitter end. Has this been echoed anywhere else?

Just seen a photo on Reddit taken from the interior of the Titan, and it shows that the monitors were attached to the hull with screws driven directly into the carbon fibre. It seems the more that comes out about this Ocean Gate outfit, the stupider it gets.
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Do you have that photo or link to it?

From what I've seen there is an inner mesh panelling system, it has strip lights behind it and most stuff looks attached to that..
kAz3yOB.jpg
 
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The Funktopus said:
I know that’s Alex Johnson’s take in his column in the Mail today, but that’s just him being him, a professional edge Lord to the bitter end. Has this been echoed anywhere else?

Just seen a photo on Reddit taken from the interior of the Titan, and it shows that the monitors were attached to the hull with screws driven directly into the carbon fibre. It seems the more that comes out about this Ocean Gate outfit, the stupider it gets.
Click to expand...

Anyone who calls them heroes should be given a free ticket for the next dive.

Seriously? They screwed in to the carbon fibre? Dear God. As you rightly say, this just gets stupider every minute.
 
I feel somewhat sceptical of anyone thinking it’s a good idea to screw into the shell of a submarine willy nilly, although it’s all got to be attached somehow.
 
Anyway, luckily it seems we as a nation avoided a catastrophic national disaster and the production company pulled out of a dive in that very "sub" that would have seen Ross Kemp going down to the titanic.

Phew!

www.bbc.co.uk

Ross Kemp had planned to film TV show on Titanic sub

Five people died after OceanGate's Titan sub imploded during a trip to the Titanic wreck this week.
www.bbc.co.uk
 
Mercenary Keyboard Warrior said:
Mercenary Keyboard Warrior said:
Anyway, luckily it seems we as a nation avoided a catastrophic national disaster and the production company pulled out of a dive in that very "sub" that would have seen Ross Kemp going down to the titanic.

Phew!

www.bbc.co.uk

Ross Kemp had planned to film TV show on Titanic sub

Five people died after OceanGate's Titan sub imploded during a trip to the Titanic wreck this week.
www.bbc.co.uk
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Thank heaven. All the EastEnders "Phil's greatest moments" shows would have driven me crazy.

I note that "Mr Kemp's agent at InterTalent, professor Jonathan Shalit, said the production company had carried out checks on the OceanGate submersible, but had deemed it unsafe.".

It just underlines that if you can afford to go then you can afford to pay someone to check out the sub. They aren't heroes, they are zeros. The Mail headline should be "Titanic blunder".
 
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The Funktopus said:
Here’s a link to the Reddit post that shows the photo. I’m trying to embed the link, but for some reason the link button does nothing on my phone when I press it.

Reddit - Dive into anything

www.reddit.com www.reddit.com
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Thats the mesh inner panelling.

I get how it looks from that angle, look at my image above and it's rather more obvious there is an inner mesh panel with lighting behind it.. which indicates a gap to the hull.
kAz3yOBh.jpg


I don't want to defend something I know was ultimately unsafe, no doubt due to arrogance, but the internet is full of idiots who are ten times worse than the CEO...

The reality is that this would have been fatigue related and the entire area of composite fatigue and how to monitor it is not well developed, not the static design intent.

The reason opinion is divided is the difference between adventurers and explorers. explorers have a healthy risk averse approach, and will spend 10x doing things responsibly. Adventurers will take risks and do it cheaply/affordably... People get freaked out climbing everest when they are hiking by dead bodies.. all avoidable, but money and experience are probably the biggest factors in doing it safely, yet we still have people dying on Everest...
 
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You know things are bad when the TV production crew for an actor on Eastenders deems your submersible, an area of which they probably have little experience, even deems it unsafe!
 
mrk said:
You know things are bad when the TV production crew for an actor on Eastenders deems your submersible, an area of which they probably have little experience, even deems it unsafe!
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No, it would be risk assessed by the media company for H&S/insurance purposes and would immediately have failed on unsafe grounds when the simple question of certification was brought up..

But TV company Atlantic Productions deemed the Titan not "fit for purpose".
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