And any mechanical engineer would tell you this is where a ton of issues begin - when you start joining/combining materials next to each other when they have different Young's modulus/physical properties etc. If you were to weld a 2ft aluminum bar to a 2ft carbon steel bar to form a 4 feet long bar and then flex it, the ways that both materials resist that flexion amplifies stress at the join. Even in a mechanical join (like riveting/any other form of bonding - heck even doing a friction weld or casting) the weak point is the join. It appears like this craft had a titanium "nose" that was connected to a carbon fiber hull. It doesn't even matter if both materials on their own were rated to handle the 6000 PSI pressure down there, the fact they would handle that pressure differently creates the opportunity for massive failure.
Especially with respect to carbon fiber - what's really difficult to know is when potential failure points start propagating - even when you x-ray it (the only way to see internal faults in CF). For something that goes under pressure to that insane degree, it doesn't really matter how many layers you use - it will gradually start failing and the pressure just amplifies that. A Carbon fiber bike doesn't last forever for this reason - it also doesn't undergo 6000PSI. I would hypothesize this is why it could make a handful of trips without technically "failing" - but the stress on key points of the hull/construction was causing rapid degradation with no way of assessing that. The last trip was one time too many.
Another potential issue with a bond between titanium (or any metal) and carbon fiber is the different coefficients of thermal expansion. Carbon fiber often has a negative coefficient (gets smaller when heated, grows when cooled) whereas titanium is like any typical metal and has a positive coefficient. The bottom of the ocean at 12,000 feet deep isn’t that cold (33 degrees F per Google) but, if unaccounted for, that additional stress could lead to a failure.
100% - exactly right. Another perfect example of a environmental constant - in this case temperature, impact two materials which on their own may be satisfactory for the use purpose but when combined with/next to each other, react differently with disastrous consequences.
The twitter clip where he talks about breaking the rules but, in his opinion, with sound engineering principals/basis my head nearly exploded (no pun intended).
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
Another potential issue with a bond between titanium (or any metal) and carbon fiber is the different coefficients of thermal expansion. Carbon fiber often has a negative coefficient (gets smaller when heated, grows when cooled) whereas titanium is like any typical metal and has a positive coefficient. The bottom of the ocean at 12,000 feet deep isn’t that cold (33 degrees F per Google) but, if unaccounted for, that additional stress could lead to a failure.
100% - exactly right. Another perfect example of a environmental constant - in this case temperature, impact two materials which on their own may be satisfactory for the use purpose but when combined with/next to each other, react differently with disastrous consequences.
The twitter clip where he talks about breaking the rules but, in his opinion, with sound engineering principals/basis my head nearly exploded (no pun intended).
Curious how well one can test pressure vessels designed for great depths in facilities on land?
And if not well, or easily, is there a reason that you can't do a lot of testing at actual depth, but without occupants?
More broadly, what is the reason/excuse for exploring the great (and dangerous) depths with humans rather than ROVs? Ego, adventure, or....some actual scientific advantage(s)?
And yes, I realize that one could (and many have) ask the same questions about space exploration.
100% - exactly right. Another perfect example of a environmental constant - in this case temperature, impact two materials which on their own may be satisfactory for the use purpose but when combined with/next to each other, react differently with disastrous consequences.
The twitter clip where he talks about breaking the rules but, in his opinion, with sound engineering principals/basis my head nearly exploded (no pun intended).
Curious how well one can test pressure vessels designed for great depths in facilities on land?
And if not well, or easily, is there a reason that you can't do a lot of testing at actual depth, but without occupants?
More broadly, what is the reason/excuse for exploring the great (and dangerous) depths with humans rather than ROVs? Ego, adventure, or....some actual scientific advantage(s)?
And yes, I realize that one could (and many have) ask the same questions about space exploration.
These are good questions - I don't know the exact answers, I can only hypothesize.
We've all been glued to our TV sets hoping and praying that the 5 souls aboard the Oceangate Titan would come home safely, after being lost at sea. But sadly...
This is BY FAR the best and most well put together clip I've seen on this.
In a nutshell, it seems like Stockton Rush had an obsession with building this craft out of carbon fiber (hard-ons for carbon fiber nothing new amongst white men - just look at this message board and the perception of carbon fiber additives in footwear midsole plates). But all jokes aside, as this clip shows - there are other deep sea craft out there including one that went much, much deeper than this (Deepsea Challenger), but not made from multiple hull materials and definitely not CF.
Regarding your questions, my hypothesis is you can do all these things but as this video explains, the nature of carbon fiber is such that under these pressures the craft is basically in a state of rapid degeneration each and every time it approaches these insane pressures and with this particular composite, it's almost impossible to accurately assess when failure will happen. Getting back to metals etc, possible failure zones are easier to inspect for an find - visible deflections and cracks, x-ray, sonor inspection etc. CF not so easy to detect and that's why it's basically outlawed/not used in these types of crafts. Basically they could test this 2, 3, 5, 10, 20 times in a simulated pressure chamber and not see any weakness, but the very next test the thing could crumple like dropping a sledgehammer on an aluminum can. In a metallic craft the potential failure becomes obvious and then things become easy - repair it or don't go.
This is also what I believe Stockton Rush was referring to in his now infamous "I've broken some rules to make this.... the carbon fiber and titanium, there's a rule you don't that - well I did...
When it comes to physics, material sciences etc F--k around, find out...
This post was edited 44 seconds after it was posted.
100% - exactly right. Another perfect example of a environmental constant - in this case temperature, impact two materials which on their own may be satisfactory for the use purpose but when combined with/next to each other, react differently with disastrous consequences.
The twitter clip where he talks about breaking the rules but, in his opinion, with sound engineering principals/basis my head nearly exploded (no pun intended).
Curious how well one can test pressure vessels designed for great depths in facilities on land?
And if not well, or easily, is there a reason that you can't do a lot of testing at actual depth, but without occupants?
More broadly, what is the reason/excuse for exploring the great (and dangerous) depths with humans rather than ROVs? Ego, adventure, or....some actual scientific advantage(s)?
And yes, I realize that one could (and many have) ask the same questions about space exploration.
The James Cameron submersible, built in Florida by a submarine building company was pressure tested on land in the only facility in the world, located in Russia. It was successfully tested with a safety margin, to 10,800 feet deep. The titanic is at around 4,000 feet deep. From what I've seen, the gold standard passenger compartment for such submersibles is a titanium sphere, but the maximum number of occupants of such designs is three (the James Cameron submersible has room for one person). The titanium sphere design would be too big and heavy to accommodate five passengers.
Deepsea Challenger (DCV 1) is a 7.3-metre (24 ft) deep-diving submersible designed to reach the bottom of the Challenger Deep, the deepest-known point on Earth. On 26 March 2012, Canadian film director James Cameron piloted t...
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
Water is incompressible, and it is also in an open system, i.e. it is not in a container with the pressure inside being increased, in which case the container will blow apart at some point. The increase in pressure is due to the weight of water itself above water lower down. So it would kind of balance out if it were forced to undergo phase change, which it actually won't do anyway
Curious how well one can test pressure vessels designed for great depths in facilities on land?
And if not well, or easily, is there a reason that you can't do a lot of testing at actual depth, but without occupants?
More broadly, what is the reason/excuse for exploring the great (and dangerous) depths with humans rather than ROVs? Ego, adventure, or....some actual scientific advantage(s)?
And yes, I realize that one could (and many have) ask the same questions about space exploration.
The James Cameron submersible, built in Florida by a submarine building company was pressure tested on land in the only facility in the world, located in Russia. It was successfully tested with a safety margin, to 10,800 feet deep. The titanic is at around 4,000 feet deep. From what I've seen, the gold standard passenger compartment for such submersibles is a titanium sphere, but the maximum number of occupants of such designs is three (the James Cameron submersible has room for one person). The titanium sphere design would be too big and heavy to accommodate five passengers.
You said the Tititanic is 4,000 feet deep but I think you meant 4,000 meters, or 13,000 feet.
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
I've literally thought about this loads. I think 20 miles below the water could become ice. But then you are closer to the earth's mantle so the water would start to become more warmer instead of cold like it normally is at the bottom.
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
I wonder if billionaires will pay to view the wreck of the Titan submersible?
Lolz
Maybe this will result in a never-ending loop. A submersible to view the wreckage of the submersible that was supposed to view the submersible that was supposed to view the Titanic wreckage.
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
I've literally thought about this loads. I think 20 miles below the water could become ice. But then you are closer to the earth's mantle so the water would start to become more warmer instead of cold like it normally is at the bottom.
Our ocean doesn't go down that far. But IIRC the ocean on Europa orbiting ol' Jupiter is supposedly much, much deeper.
So, how deep would an ocean have to be before the water itself is severely affected by the pressure? What would happen to it, would it freeze, boil, turn into plasma, be ejected into another dimension?
I've literally thought about this loads. I think 20 miles below the water could become ice. But then you are closer to the earth's mantle so the water would start to become more warmer instead of cold like it normally is at the bottom.
