Absolutely completely insane that Ocean Gate could hear their pressure chamber tearing apart on every dive and they didn’t immediately abort the design and restart from scratch.
I would have said ideally there wouldn't have been any snaps/pops etc. coming from the hull. Every one represents a small breakage in the structure, some flaw from manufacturing. However, that level of perfection might be unrealistic. With a sufficient (necessary) margin of safety you could cycle it (dive) unmanned and ensure there weren't too many pops/cracks or "adjustments"... But then, I wouldn't want to have *any* ongoing "accustic events" on subsequent dives. Those represent ongoing, *accumulating* damage, not a one-time settling-in. I believe you are correct, it was insane to continue using it, knowing the structure was weakening with every cycle. A catastrophic failure was a question of when, not if.
from watching this aluminium is just a little bit weaker than carbon fibre but it dont suddenly give way and its lighter and cheaper than titanium . id build my sub out of aluminium
@@PIlotrcm They also said in their message that they were listening to Under Pressure by David Bowie and Queen and Down Down deeper and Down by Status Quo on their music system
@@philipstaite4775Note that Titan did have its whole pressure hull replaced before. The hull that imploded is actually the second hull of that vehicle, not the first.
The number is the measurement of how much pressure is being built up. Not how much is being put on to the object. So the tougher object endure more pressure, showing a higher number.
Interesting to see the difference between the plastic deformation of aluminium and titanium, and the brittle sudden failure of the brass and steel alloys. Then naturally, in the light of recent events (and the naturally occurring morbid curiosity), the further comparison to various composites and acrylic became suddenly very topical and interesting in its own right.
This is a 3 point test in which the specimen is in shear and bending. If the bass was in a standard tensile test you would see that it did not fail suddenly.
Shows how the way things fail matters as much as how strong they are. Some purposes, you need them to hold shape, and if they fail all is lost, some things bent is better than broken
High speed steel (HSS) terminology probably comes from the factthat the drill bits, router bits etc. Made out of them can be run at higher cutting speed (and resulting temperature ) than high carbon steel ( traditional tool steel) can be. It can be run to red hot temperature, it will soften, but reharden to it original hardness upon cooling. Tool steel gradually softens above a few hundred degrees C. It needs to be quenched at red hot heat to reharden it an then tempered to the desired hardness to suit the tool's purpose. You can drill through steel without the use of coolant. Note that carpenters tools such as chisels, and metal working tools such as cold chisels, centre punches etc are made out of tool steel and not HSS. Such tools would fractures at the first blow with a hammer or mallet. Nothing structural is made from HSS , apart for entertainment I cannot imagine why such an unsuitable material was included in the tests. But the the whole exercise is inconclusive to me. I will add a comment.
Would be interesting to see the carbon fiber test redone comparing parallel and cross-hatched strand orientation at various angle combinations to determine the differences in strength and failure profile.
@@Splits-man as a novice unknowledgeable nube, I would have considered a multi-layer titanium-multiple opposing alternating cross hatched carbon fiber sandwich setup BUT that would still leave the issue of how to deal with joining the ends of the differing materials - a problem answered as to why gluing is now preferred to riveting on aircrafts these days to provide a smoother stress transition from 1 material to another but not sure if this would be even possible and/or work in a similar manner in extremely high inward deep-sea pressures
When the steel broke, it gave us an Excellent example of the Normal Force at work, proving that as the press pushed the Block into the table, the table pushed back against the press, launching the block upward as soon as the steel broke
For all practical purposes yes, but I think everything has a plastic deformation threshold below which it is elastic. So if the lead spring was designed not to flex beyond that point then it would work, although the length of travel would be very short.
It would be nice to see the final chart, summarizing the strengths versus mass on a single screen. It is also important to highlight if the material breaks or bends.
Im guessing titanium is used in submersibles for more reasons than just being strong and light. It also has other really good properties such as highly resistant to general corrosion in seawater and is an extremely stable metal as far as thermal expansion goes.
Don't they use steel instead? It's easier to form, and better understood. From what I'm reading, titanium helps create a sports-car kind of submarine because the light weight means you either get more internal room due to smaller engines or you get faster underwater speeds because you have excess power. But Titanium is like a sports car in that it requires a lot of money too. Titanium is an expensive metal so the initial cost is high. And materials research also hasn't yielded a strong yet flexible titanium alloy yet, so maintenance is a must or the titanium will start cracking sooner than an equivalent steel design.
And now I suddenly know why this video was being recommended to me. I watched several about that incident when it happened. That's one smart algorithm at work there.
@@tasa4904 the submersible with the deepest dive on record 5 times is the trinton 3600/2 or better know as the limiting factor. The pressure vessel is completely made out of titanium.
Idk if i just had low quality carbon fiber, but as soon as i heard thats what they used... that shit does not hold up well to friction, and the ocean is full of shit that increases it.
Same here. I've been researching all about carbon fiber and the construction of that vessel. Makes total sense once you research the shape of how submersibles should be, the size, the materials, xcetera
@@michaelyemariamlij2633 When you go over a broader scope of material options, I have wondered about doing more stainless steel for submarines. It seems you get the right stainless steel mix in there and it has some very good properties for a fraction of the price of other materials. SpaceX's Starship is made with a stainless steel alloy for different reasons and likely with different optimizations than what you would want for a submarine, but when you watch how much the structure of Starship over-performed in the 04/20 launch and they couldn't get the rocket to self-destruct, instead a massive structure cartwheeling through the air at multiple mach speeds while venting propellant through holes blown in the side of the rocket from the abort charges going off and after tumbling for a while, the venting propellant finally ignited as the rocket re-entered the thicker part of the atmosphere and destroyed the rocket, I mean that material held together through quite a bit. Titanium is extremely expensive and hard to work with. The SR-71 Blackbird's titanium came from Russia only to return over Russian skies later as spy planes as the USA was having trouble sourcing the titanium from elsewhere. Carbon fiber is extremely expensive and as we can see is the wrong material for a submarine. Stainless steel alloys are relatively cheap and can be customized to have very good properties for submarine use.
Carbon fiber is super lightweight, which makes it great for aircraft and spaceships. But in submersibles, that just means extra buoyancy which must be countered by adding ballast. The guy who constructed the Titan and died in it had a degree in aerospace engineering. The idiot was probably thinking that he was building an airplane.
@@BrokenCurtain This is the thing. There are people who study a subject and get the critical understanding to succeed or at least they have the right form if something goes wrong. Then there are idiots who are full of themselves and don't listen to the people who know what they are talking about. Just by listening to this guy's sales pitch, he was more of a salesman, full of himself, than a real engineer. He didn't listen to real engineers because he was too full of himself. This lead to his death. Like Elon Musk, however you feel about him, it is hard to deny that he is a real engineer. It doesn't mean things don't go wrong, but instead there is strong reasoning behind the engineering moves he makes and at the core, it is a good design. If he is dedicated enough, perfection is reached such as the Falcon 9 rocket. With a Tesla car, I think we all know that while the fundamentals are good, they are not perfect cars, but that is engineers also can have their quirks like being obsessed with Twitter and not finishing the job they started.
This just showed how amazingly strong and tough fibreglass can be, and how rigid carbon-fibre is! Titanium is of course an amazing metal having almost half the weight of steel. Tool steel did what I expected.
@@Ddog72 2004 was when it was first discovered and RECENTLY was when it was able to be manufactured to any amount that could really be used for anything other than testing. It is also been recently discovered that it is a superconductor at near room temperature and above.
@@bear76009it's stronger in some areas, but much like carbon fiber, apply a load in the wrong direction and it fails completely, whereas steel is able to handle high loads from just about any force. Steel isn't going anywhere anytime soon, it's cheap, easy to make, easy to work, and you can use it for just about anything outside of very specialized cases such as aircraft
The carbon fiber is wild, considering what we know about the imploded sub. First, sounds like gunshots/fireworks were described in earlier dives. Then in the texts between the sub and the surface, they reported "crackling" sounds. Then apparently failure of the hull. That's exactly what's shown and heard in this example.
Creaking is usually sliding or stretching, elastic deformation or strain, both in the common and technical terminology. Crackling is usually fracture, of structural elements. While creaking means a structure is absorbing energy by deformation, sometimes even becoming stronger before declining again, crackling means elements of the structure are failing, continuously weakening. Each broken fibre creates a miniature focal point for slightly increased load, so it is a self-magnifying problem.
@@mightymystery9204 for real like. Carbon fibers great! Its just also. Fibers. Which means as soon as a single fiber breaks its weakened, even if just a little. Even if the body of the sub was strong enough to withstand the depths at one point, the friction of the ocean could very well start breaking fibers, and in the end. Well.
And that Rush moron said that the carbon fiber popping sounds were because it was "settling in" and becoming more stable, when in reality it was just being damaged beyond plasticity.
to think some highly trained engineers though thought a material the cracks instead of bends was a good idea for a submarine that is constantly changing pressures.
Yeah , but it was cheap & “ hi tech “ , therefore it was easy to state bs like “ current methods of testing for safety are over the top & hinder innovation “ .
@@barbraabsalom4531 I can see that happening which just makes me laugh harder at these institutions and engineers that thought this was a good idea. I'm no materials expert but my limited experience with hockey sticks and knowing hard things tend to be brittle said that was a bad material. Feel bad for the victims, except the CEO.... It was his mistake after all.
Stainless steel are always have more popular with making submarines and ocean water ships battle cruiser world war 2 ships Aircraft carriers in America to now 2023 and no other types of material will change away from stainless steel since .
@@SilverStarHeggisist not sure why weight was a priority for a submarine. Much rather pay a bit more for the boat to move it around than have it crack under pressure.
Part of my job I build pressure vessels and steam headers as per ASME code. Carbon fiber and FRP are hard materials. They are brittle and fracture easily. Steel and titanium are tough. They bend and absorb forces. I'm far from building a sub, but never will I build it from carbon fiber or FRP.
4:00 imagine hearing this on every dive in a submersible nearly four kilometres beneath the surface of the ocean and being stupid enough to think: "Yep, this is fine!"
Nice tests. You should put up a table with the results and sort the list by weight, force, force/weight, material cost, cost/force etc. EDIT: I just noticed Kewin Taylor has presented some figures ;)
3:50 - That looks more like forged carbon fiber. The forged carbon fiber has different characteristics than the classic "woven" one. Also mind the Carbon fibre is orthotropic.
@@georgeklow4561 But it wasn't, it should have been stronger than titanium. That means something was not OK with that particular carbon fiber. When carbon fiber is used the correct way it's insanely strong.
Blows my mind that Oceangate went with carbon Fiber. I’m not an engineer; but after a little research on testing it, it would be a big no go for me! They were not dealing with the possibly of ‘if’ but a certainty of ‘when’…
With the exception of the carbon fiber one, I knew the outcome of all of them before they happened. The reason why I was uncertain about the CF is because I wassn't sure how the rod was made. Long fibers, short fibers, directional, non-directional, "randomness", woven fabric. So it was a surprise to see it both split and sheer.
It's quite possible to create a carbon fiber sample that would perform much better than a pure unidirectional sample. Uni fibers wrapped in +45/-45 would perform much better.
The passengers of Titan should’ve seen how poorly carbon fiber did when they paid $250k to go down in a tube of it with a Logitech controller. At least they got the full titanic experience
Quite interesting to see. Interesting that the metals in general didn't break, but just bended. But I was surprised to see that brass broke like that in an almost straight like. I was also surprised to see the steel break like it did - quite an unwarned snap. Other interesting things is that the carbon fiber didn't bend much compared to the other materials.
harneded steel shatters (like a drill bit). Annealed steel is a lot softer and will bend a lot (like a normal rebar from the hardware store, or angle iron.. those are mild steel ) Brass can also be hardened or aneealed. Both the steel and brass pieces were hardened and they did shatter. CF and fiberglass were weak due to the matrix (the resin). As the resin broke and delaminated the fibers. More evident on fiberglass but is also present in the CF example.
Wish you would have noted what grade of Ti alloy and HSS as well as heat treat conditions of the metals. Kinda a good overall example but more information on the specifics of all the constructions would be useful to better understanding of the strengths and weaknesses of each specimen.
Tbh in that case i would want like. A full video of just different alloys n all that of the same thing. Idk much about most of this but seeing how just heat treating affects it would be cool ya know?
i would like to see you try graphene enforced carbon fiber. it should be about 20 to 35% stronger than the same weave of carbon fiber without the graphene.
The pressure chamber was made with titanium and 5mn of carbon fiber . Carbon fiber are usefull when the pressure is from inside but not when pressure force come from the outside
@@davesmith9844Actually, it wasn't. It was all carbon fibre. Glued to titanium rings to attach the titanium end caps. A disaster waiting to happen. Even from the fact that it was a cylinder shape rather than a sphere. Much weaker.
@@isabelmauricio6394 Actually, it was not, take a look at the video showing them manufacturing it. You'll see a thin titanium tube onto which they apply the carbon fibre which is exactly what they say when explaining what they're doing. How else would they make a cylinder from what essentially looks like a roll of carbon fibre tape, it has to be applied to something.
You are asking for the "Yield Strength" of each material. If you google, you can find it for materials like 6160 aluminum quite easily. For more complex materials like carbon fiber it depends on the number of layers, orientation of the layers, etc so there is not just one standard number. This experiment could be redone with strain gauges and a stress strain chart could be made to find the Yield strength of each sample.
HSS being generally a Tool Steel for making cutting tools has higher carbon content and is more rigid in return, so even though it can handle more pressure it in turn is brittle once its breaking point is reached
@@DaysofKnight Yeah, lightweightness. But that's barely the only reason. Steel, on the other hand, is dozens times cheaper, better keeps strength under extreme temperatures than Al/Carbon fiber, MUCH easier in production and usability (cutting/welding). Steel is just more important in humanity' development, than these 3 combined imo. Humanity needs bridges, buildings and cheap cars more, than efficient planes and supercars. The most powerful rocket to fly, where lightweightness is the key to success, is being made with steel.
Yep, the solids in the fiberglass/carbon fiber fail at similar thresholds to the straight acrylic, but they have the fibers to keep the fragments tied together. Ain't gonna be much use under negative pressure.
Very interesting. I assume this is pure titanium, whereas in high quality applications it is used as an alloy. In bike we have 3-2,5 or 4-6 titanium alloy (3 Al-2,5 V and 6Al-4V), with better performances. Also, we know testing fiber-based composite in this kind of press it's pretty unfair, but it's quite instructive anyway. We can see why they fail sometimes.
Stainless is by far the best material to use for compression. Notice its not even on display here but it completely blows titanium and HSS steel away. Its heavy as hell though but that doesn't matter when it comes to submersible.
I wonder if a higher load force could be had using the same size bar but using a composite structure? Maybe a steel core with a titanium jacket? I would also have liked to see the breaking point of each bar when being held in place instead of the bending that occured. Interesting vid none the less.
Using that selection of materials, no, not without changing the size or shape of the specimens. The steel is strongest and replacing any part of that steel bar with a weaker material cannot make it stronger. By how much will depend on which part you swap. The top and bottom faces are most critical.
to get a stress strain curve, you need the cross sectional area, the weight is irrelevant. Since the bars were roughly the same size , you can almost factor it out. However, you're still looking at plastic failure, not elastic yield point. For real world results, you'd be more interested in the elastic yield point because usually after that point, your object won't work as intended anymore
Honestly wasn't expecting the brass to snap like that I also thought the titanium would have lasted longer than the steel, given that it's always said to have better tensile strength than steel. Impressive how the titanium never gave way fully Aluminium did more or less what I expected, although I did expect it to actually break at some point
As it deforms, it work-hardens and becomes brittle. If the piece had been thinner, it would have stayed soft. Or maybe it was already work-hardened. We don't know where the piece came from. Maybe it was rolled and never annealed. And titanium is comparable to a pretty mild low-carbon steel. Much stronger steels are available
fiber does brake faster of it is cut as a block or a square stick, if the material is broader than thick, like a sheet or a tube, the fiber appears to supports its structure longer, so that it can bend further than what we see here, like maybe 20%. Very curious whats left of the hull.
After watching a few videos of this type showing both compression and sheer strength I'm starting to think ocean gate coulda had the same success with brass...
I'm considering a yacht build, so thanks for this info. It's appreciated. My calcs show relative strength [stiffness] to weight ratios [in kg/g] of the following: Acrylic = 16 Fibre glass = 31 Aluminium = 25 Carbon = 46 Brass = 11 Titanium = 54 HSS = 50 I would love to see Titanium alloys of aluminium and chome-molly, etc [you seem to have access to a good variety of stock]. Sea bronze and admiralty brass too. Mild steel as a datumn? Cor-ten would also be great to see. As would other stainless allows such as 304, 316 and the 4 series. Your press-play rocks! :-)
You’ll not be surprised if you learn their real properties and application beforehand 😂 many thought that CF is some kind of magic material that can do everything LOL
4:00 I wonder if this is what the folks in the sub heard before it failed. The pressure at the Titanic wreck depth is about 6,500 PSI (~4570 KG/SI). I'd like to see a test of 5 inch thick carbon fiber, like they used on the Titan. The titanium end caps were 3.25 inch thick.
Can you do a Carbon Fiber+Kevlar combo. This is what is commonly used to beef up the carbon fibers strength. 5:1 carbon : Kevlar ratio. It’s what we used to use when I built race cars. I wonder how much stronger it is then just bare carbon
