Engineering Failures Behind Titan’s Implosion!
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- Опубликовано: 26 сен 2024
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From the get go, the use of different materials like Titanium and Carbon Fiber together gripped me and got me thinking if this was bad or good engineering that just went unlucky. What does innovation mean and why did this submersible fail?
Well done sir. There have been many videos posted by others attempting to explain the engineering and design flaws in this tragic situation. This video is simply the most articulate, concise and yet informative.
Thank you 😊
should we blame the carbon fiber inventor for the implosion or the user's stupidity?
selling a sub on its tensile strength is like bragging about the crush strength of a blimp. Mental!
@@weepeeteeeeNo we shouldn't and no one did.
Amen... and in such a cool manner.
The more I learn about this, the more surprised I am that it lasted as long as it did.
ikr??
Wouldn't have gotten me into that device in the first place
Absolutely, at that depth the carbon fibre composite had about 5% of contraction, the titanium had basically zero. I more surprised someone very experienced in deep sea exploration was convinced to get in it. It's pretty miraculous it lasted that long.
How can someone be so arrogant as to think they know better than an entire community of experts waving red flags at them? It would be bad enough if it was just his life he was putting at risk but to hold that arrogance whilst being responsible for several other lives is just disgusting.
@@88Cardey I hear you can drown in a cup of water and you don't even have to get in a sub
That part
I always assumed they used an autoclave with that mandrel setup. Yikes. Your rope demonstration was vey good, simple yet shows the concept really well.
They cured it in an oven for 7 days as per the article from Composites World but did not use an autoclave. Have to wonder if that was enough!
Besides, the video is from the first hull, which failed during test dives in 2019... but I have not been able to find how they "repaired it" as Rush commented in a couple of interviews.
I was impressed with the rope demonstration too. It really caught my attention.
I just recently heard he skipped the autoclave curing process to save time and money. It's horrifying. I bet if every one of those other passengers had known what REALLY was going on they wouldn't have signed those waivers!
Best explanation I've watched since I've followed the disaster
Thank you! That's really kind of you
Its only for this comment that i watched the video. All videos now are: What realy!!! Happend. But some weeks ago en some from today
@@beyondengineering
I never heard of any non destructive testing for 5in thick carbon fiber.
@@beyondengineering
I haven't seen any parts retrieved other than the end caps. It seems at this time that there is nothing left of the carbon fiber cylinder.
Agreed!
One telling point was that Oceangate said that they had to use acoustic sensors because the material could not be scanned. If that assertion is true, then it disqualifies the construction method from being considered. If a material cannot be checked for integrity, that inability to check it is itself grounds for rejecting that construction method.
one thing everyone has been ignoring is the glue holding the carbon fiber to the titanium. the glue was put onto the titan very poorly, with someone touching the end caps with his bare hands and getting his hand oil all over it. the oceangate engineers also mixed the glue by hand and didnt use a vacuum chamber after, which introduced air bubbles and made it a lot weaker. combine the glue being terrible and the carbon fiber cracking, and you get the titan incident
I also think the main failure point is the junction of carbon to titanium. The overlap seems way to small from judging from the videos and the jump in stiffness is too sudden. Then the bonding was done very amateurish. Applying the glue and then sliding the parts together, can push the glue off. I would have injected the glue in the cavity after the parts are assembled.
Very amateur work.
I used to work at spacex and some of the composites parts that were reused were always ultrasonically scanned probably 5 different times during the initial build of the part and after every single launch
That’s innovation done right!
This is the most objective piece of engineering analysis that I've seen on the Titan disaster. You provide good supportiong rationale for any of the statements you make.
They (OceanGate) basically didn't do the engineering work required to ensure a successful design. The fact that they were using new materials, processes, and approaches in a high-risk environment requires more analysis, testing, and verification, not less. This was seemingly the vision of one man, with everything under his control, and with an unwillingness to have the design reviewed by others. It appears he went out of his way to limit the possibility of scrutiny or competing ideas, by hiring very few experienced people and even firing at least one that did offer both experience and criticisms. It's a sad ending for all involved.
Facts
Good video and good comment. The remarkable thing to me is not just the “bad engineering,” but the evasion of legal requirements and affirmative use of the legal system to suppress warnings. That goes beyond bad engineering to a darker and more reckless place. And even that is being kind
@@greggorsag9787 All too true.
Agreed. Rush had a severe case of cognitive dissonance where he rejected any information that he didn't like.
They way they assembled it all looked like some lame science fair project, lol
$250,000 to see a sunken ship through a 55cm window, in an unapproved shack, with no bathroom, no opening from the inside and limited oxygen, with doubtful or cut off communications to the outside, with 2 different molecular structures with glue, one of which which would not commonly support the pressure like the window approved for a third of the intended depth. You really have to spare or you are very tired of life.
It seems ridiculous when you put it like that.
To look out the widow you basically had to sit on the "toilet".
@@davesmith3023 they could have paid 15 mill to Triton Submarines to buy a proper safe craft to get to the Titanic and that would have had a much larger view
@ toomanyaccounts
And even more appealing, their bodies would stay intact!
As if a hatch that could be opened from inside never mind the huge hydrostatic load on it could have saved them
“Move fast and break things” didn’t work out so well in finance, so no surprise it failed the abyssal-plain challenge. That said, so sad for the deceased teenager and his grieving family.
I'm amazed that thing made it to the Titanic even once. It seems there were so many warning signs and red flags from those that are experienced in this area. It's sheer negligence that they took paying passengers. I'm sure they were heavily sold on the idea "we've made xxx number of times, everything is safe".
The worse part about this design is that the more you dive, the more confident you get (out of ignorance) and the more risk you take every time without even knowing
The bottom line here is the sub was doomed from the start and Stockton was destined to die in the sub, the sad part was allowing others to die with him..
Rush touted his "innovative" use of carbon fiber, but he knew less about it than those who had worked with it. Convinced of his own brilliance, he turned away the experts who tried to advise him, and he took the lives of four others along with his own as he stubbornly pursued his folly.
İ think he knew about it just had some weird death fetish
Data is everything, you ignore it at your own risk
@@beyondengineeringexplain that to little brexiteers. They r as arrogant and ignorant as this man the ceo.
@@je7647 Rush more likely painted himself into a corner, both technically and financially, by the hype he used to market his project. Calling paying customers "explorers" after a few hours or days of cursory instruction is an example of this hype. If it served Oceangate's purpose, they would do it, no matter how it related to reality. But isn't that the way the whole world is increasingly being run?
Dunning Kruger is applicable to anyone, even engineers
I think you’ve put out the best analysis I’ve seen on this. I would like to see more engineering based commentary on the sub in the media, especially as good as this. Hopefully this incident doesn’t completely turn the public off from carbon fiber for all applications. Rush didn’t think at all about any of the potential consequences of the corners he cut. Not only was he risking other people’s lives he risked causing harm to the whole submersible industry and to carbon fiber’s reputation with the public.
Thank you! I think it’s brought more attention to the material but it probably won’t affect it much as 99% applications use it in the right areas
He knew what he was doing. He knew it wouldn’t pass and then it would officially have to be scraped. He took a chance and paid the price.
Yeah! Stockton Rush thought he was the smartest guy in the room, and he knew better than the experts. He killed himself and his passengers.
Could've verywell been Y he didn't go thru testing. It would prove his naysayers right even though it was coming from engineers and experienced professionals within the deep sea submersible community at least itll give him insite where and how to improve upon titan. This existing titan can be used for other underwater activities just not titanic depths. This way all the money invested to this project isnt scapped wasted. they can redesign rebuild a more capable sub. Theres a video showing how a composite wing off a plane being tested. They managed to engineer there own testing rig. If they can test something on that enormous scale, pretty certain something the size of a titan can be built to test it. Rush said its never been done before so theres no way to test it. So ridiculously bonkers that idea. Wat are engineers in this world for then. Almost Everything in this world are thought up, designed, tested, redesign are done by engineers etc. On a professional industrial level.
@@diverguy3556 You might say he was in a some kind of rush.
Stockton Rush was avoiding the truth about his flawed design and the cost of correcting it.
@@hbrucewilliamson1787 You might say he stocked some rush and then imploded.
There's a good reason why engineering is such a conservative profession. You absolutely do not want to learn every lesson the hard way. I feel bad that this tragedy was not prevented, as it could have been if they'd listened to the engineers.
That is one way to look at it. The other is a whole new level of safeguards will arise. The man took a risk and then further exceeded tolerances.
Stockton rush was an engineer
@@MoonstormsAn aerospace engineer.
@@MoonstormsNot a good one
If the sub was forced to be certified than maybe this accident would have been prevented.
Beyond Engineering, lots of hypothesis going on here. I was employed by Hercules Inc. in 1980 at the filament winding facility. We mostly manufactured solid rocket cases for defense and offense missile systems. My project was different it was a launch tube for the Peacekeeper missile rail based system concept. It was to be the largest graphite structure in the world. The launch tube overall was 69 ft long X 96” diameter X 1.625 “ thick. We made two versions 3 ea. 23 ft sections and later a 46 ft and 23 ft section. For Westinghouse the prime.
This work allowed Hercules to be selected to manufacture carbon fiber rocket cases for the Space Shuttle secret Air Force program. I was the senior process engineer on that program these cylinders were 12 ft diameter X 30 ft long X 1.5” thick. You can see them at Huntsville Alabama. The testing of the cases was done in Utah and the first test surprised NASA! We had to interface with existing shuttle hardware so the joint to the dome was identical to the Thiocol steel cases. The steel cases are tool steel 1/2” thick and operate at 1000 psi during launch. Our structural engineers calculated the tube to be stiffer than the steel dome. During the first test the dome inflated and the tube did not move. The joint opened up and we launched a space shuttle dome into the top of the test fixture.
So two things without supplemental compaction during winding tow tension does not provide enough radial pressure to consolidate the 90 degree prepreg unidirectional layers and underlying hoop layers. Winding pressure is additive and underlying hoops micro buckle. We had to use supplemental compaction with an endless belt tensioned to 180 lbs per inch as we wound the hoops over the 15 degree axial layers. This was a 24-7 day effort for 15 days nonstop to make a quality tube.
I listened to Spencer Manufacturing at a SAMPE chapter meeting presenting on the Challenger Deep project for Steve F. Before he died. They were very thin on details as to how they achieved such a low void content in their tube. Now I know they drowned it in epoxy instead of consolidating it. The wet winding epoxy has a pot life of an hour or so after that the viscosity builds until it gells into a solid. After 24 hrs the wet winding epoxy cures to 70 % strength. The pre impregnated axial layers stay semisolid until autoclave cure. The final vacuumed bag and autoclave cure did very little to consolidate 5” of composite material it just cured the high temperature epoxy in the axial layers and post cured the winding epoxy. Spencer manufacturing has no clue just following the print supplied.
My opinion.
Clearly the intricate details of the process can substantially add to or subtract from the native material choices. Poor material choices, poor process controls, poor failure analyses, and poor mission decisions look like a sound basis for the failure investigation. Good engineering has always been the counterweight to hubris in the technical arena, rarely are all the engineers shown the door so myopically in such a megalomaniacal enterprise. Even rarer is hubris drowned in such deep, dark karma.
Yes to all of the above. I think that the claim of less than 1% porosity is a bogus. Without autoclave pressure proper compaction is very hard to achieve - particularly with a thickness of 5". What about evacuation of volatiles ? What about heat released during cure - when thick laminate is cured ?
I have no experience with filament winding - but 40 years of experience with design, analysis and fabrication of composites using prepregs. I have no idea how Spencer managed to achieve low porosity and good compaction in a process which did not meet basic requirements. But - obviously they did not...
Wow, thank you for this! Probably the best in depth explanation out there! I had to read this 3,4 times to fully understand it as there is so much information here. 👌
6:18 finally someone mentioning it, did you do a bit of number crunching to see how much more even the strongest polymer compresses compared to titanium? Im surprised that glue held up any dives
The guy who claimed he built the non implodable vehicle said he bought the bonding material blue Tiger Seal $6 400ml off ebay and used it to stick the Titanium chamber to carbon fiber body. Basically whole work came out of his garage, and cost almost nothing considering 250K per ride for each.
Well there is the hungry investors wanting a return
Supply ship is probably a large cost too
Source for this?
@@trentvlak Tiger seal is world leading bonding material used to fix all car's windows throught the world by manufacturers. Stockton Rush said he harvested all required material off from high street shops, Amazon, Ebay. Stockton Rush was a nobel man with roots to Royal families. He was a first blood, not a common people. I see no reason not to believe him.
And don’t forget the 10 450ml tubes of Kitchen Silicone he got from Home Depot for stocktons little project.
Excellent video! Really appreciate all the details you went into, I’ve watched a lot of videos about the Titan at this point and this was one of the best about its carbon fibre hull!
Thanks for confirming what I suspected - the resin matrix is the weak link in compressive (& shear?) loading.
I cannot get over how shallow the titanium groove is and how poorly the glue was applicated. Well done on a great vid.
You explained this so well, even I as a lay person understood it clearly. This engineering analysis is one of the best I've seen thus far.
Did anyone notice, during the offloading of Titan parts, one of the titanium rings that was circular came back oval in shape. Although it was partially obscured by a tarp, the oval shape was obvious.
I am surprised the glue holding the carbon fibre to the titanium ring was strong enough to remain attached while the ring bent under the pressure.
Actually, it looked intact.
@@davesmith3023 … yes titanium flexes… it’s why it is such a great material. A material that doesn’t flex, snaps!
Did the carbon fiber do anything at all under compression? Might the Titan have been safer if the'd simply molded a 13-cm-thick epoxy cylinder for the hull?
Thats exactly what I was thinking. That Carbon Fiber wasnt probably doing anything, it was only the epoxy that was holding the pressure.
It did manage to perform a few dives at the bottom with no issues. But the problem is it's simply degrading upon every dive. If the 2nd last trip caused crackling of the hull, then it must have bin a absolute red flag because the cracking means it's losing it's strength upon every dive.
@@vanderlinde4you Yep, the hull was strong enough for a few deep dives, despite the crackling noises. But was its strength due in any way to the carbon (which is pretty useless under compression), or just to the epoxy? So, ironically, did the presence of carbon fiber in the epoxy actually weaken it? I'm not sure OceanGate did any real analysis of this at all.
Best all around engineering description of the Titan/OceanGate failed composition. Thank you
Wow, thank you! 😀
Good video. Clear and concise. I will add, one thing that really stood out to me was the pressure vessel being spec'd with a FoS of 2.25. Being a pressure vessel, I would have expected a FoS of 4.25 minimum, and even to the higher end, say 5-6, seeing as they were using CF, owing to its unusual properties, as you indicated. As I've pointed out to people, the concept itself wasn't/isn't flawed, but the design and construction of Titan was egregiously consumated. Thanks again for the video.
For human safety, outside of military aircraft applications, a minimum safety factor of 5.0 is considered to be good practice.
That said, the performance of carbon fiber composites under extreme compressive stresses, especially when cycled multiple times, is not well understood, and more testing data is necessary before this material can be reliably used in this sort of application at such extreme pressures.
As you can well understand, a structure may well be excellent for its first stress cycle, but after a small number of cycles it can degrade to an unacceptable degree.
There are other issues with regards to the mechanical management of tear-out stresses in the interface between the composite and the titanium, so I think that there will need to be quite a bit of development work performed before a composite hull design can be safely constructed for deep sea submersible craft.
@@chemech ... well, Stockton Rush came from an Aviation background. Many people don't realize a FoS of 1.25-1.5 is a standard practice in design of aircraft. It may be that his background in aviation was instrumental to his downfall.
@@wendyvic4046 I recall from back in my grad school days that a safety factor of ~1.5 was the norm for fighter aircraft..,
I think that it is clear that Rush's experience with the F-18 program colored his opinions, and was a factor in the failure.
His arrogance regarding testing and the assumption that everything can be definitively resolved by computer modeling (ignoring GIGO) was a major factor.
His failure to employ the services of experienced pressure vessel engineers - too old & conservative, even if many aren't white anymore - was instrumental in his demise.
The simplest explanation with a looped string you gave, explains very well the fatal flaw of carbon fiber in submersibles. For a bit I was thinking there might be some practicality in using composites in deep sea diving, as carbon fiber is commonly used as pressure tanks from gas tanks, to aerospace, but your simple string explanation completely turned my perspective.
One of the best explanations of what the issues were with the Titan I’ve seen. Thank you.
Thank you so much!
An engineer once jokingly told me that one important thing to know is "You can't push on a rope". This misplaced use of fiber made me recall that.
One place you don't want to break rules is at 3500 meters under water.
Thank you. Your explanation was excellent. It was simple and covered the complex nature of carbon fiber. You have a new subscriber!
Finally the video I wanted to see in order to understand the engineering flaws completely in a simple and straightforward manner. Thanks
Thank you. That’s what I aimed for. Glad it helped
@@beyondengineering sure it did.
I have been fascinated by this topic since all this happened. Carbon is a great material just the way they did it blows my mind how poorly it was manufactured not even vacuum injected or fibers crossed in X and Y. .. I could have done a better job at home. This was a death trap from the start and any logical person that understands fiber construction would see this massive flaw in the design.
Not to mention the epoxy process was not done in a cleanroom (like it should), but a dirty warehouse. Rush boasted he made the Titan from parts he bought at Camping World, well it shows.
@@scottgauley7722 Crazy stuff !!!! I dont get what was innovative about it when the workmanship was primitive.
This video really describes the problems with carbon fiber in a way that is very concise and clear without all the drama. Thank you so much for this explanation!
Thank you 😊
The Titan was doomed as soon as it submerged on this particular dive. The transcripts show the Titan submerging at twice the normal decent rate. They were literally an hour early reaching the the depth they were at. This indicates that water was already entering the sealed compartment with the electronics and battery A. It was literally sinking and not simply submerging since it’s decent rate was already accelerated at the first checkpoint so it was compromised. Close to the position and depth it imploded the system chat indicated a problem along with popping and snapping noises coming from the rear and battery A went offline causing them to switch battery B that was a backup in the crew section. Rush appears to have aborted the dive at this point and accent was noted as being extremely slow….. so the log shows Rush dropped the 4 barrels to reduce weight which showed little to no upwards movement and made the decision to drop the whole frame to lighten the load. Also no real improvement in surfacing speed and seconds after that log was sent it imploded. It looks to me that this wasn’t simply a implosion due to its lack of oversight and regulations. This was sub more than likely would have never imploded had they corrected the dive speed and let the hull compress at a slower rate. If they had saw and corrected the decent speed at the first checkpoint certainly by the second check point they still had time to dump all that extra weight and surface since that electronics area was taking in water. By the 1 hour mark they were doomed as the water that had gotten in exceeded the Titans max weight to surface no matter if excess weight was dropped or not. Pretty careless and weird that the decent rate didn’t set off any alarms off to at least the Frenchman given his background in this field or even top side when their depth was going to fast. So basically in the first 100 feet in depth it was compromised and from that point forward was sinking not diving.
The "transcript" was posted anonymously to TikTok. It shouldn't be considered evidence at this point. LIkewise with James Cameron's comments which are attributed to "the community".
They could have dropped ballast at 100m and been ok.
You're assuming that the 'transcripts' are authentic, which may or may not be true, but it's a very large assumption
"The transcripts show the Titan submerging at twice the normal decent rate"
Synchronicity -
Titanic also was rushing to New York to boast with the record and the unnecessary "King of The Hill" speed was crucial factor in the damage by hitting the iceberg.
I saw the transcript a few days ago and get your point But all experts say it was a ticking time bomb and the carbon hull was going to eventually yield with all the micro damage racking up…Maybe not on this drive if it hadnt taken on water right away but on the next one.
Awesome analysis...chill discussion of the issues with the engineering and construction of the submersible. Thank you for your excellent synopsis...best I've seen too date!
Thank you! You made my day!
Rush proved two things, a carbon fiber hull can make it to Titanic depth, and it will fail after repeated dives
Hence it means rover can be made cheaply for deep exploration but not human in it
I am not sure if the math supports using this for drones
I agree with everything except the end caps shearing off. At depth the end caps would be under extreme pressure and be pushing against the carbon fiber hull. Kind of makes me wonder if the hull cracked along the spine of the cylinder or did the end caps simply crush it. We know carbon fiber isn't good under compression.
The pressure would not be forcing the end bells tighter onto the cylinder. You are assuming there is a greater pressure pushing on the ends than along the cylinder. Pressure was uniform along the whole exterior. There was just as much pressure forcing the end bells on as there was pressure trying to dislodge them off the cylinder.
When we get down to the nanosecond intervals of the failure it's very complicated and entirely conjecture. I think the end caps certainly were putting longitudinal stress on the carbon fiber tube - and that is what maintained the seal despite the degradation of the adhesive. That would be until the instant the aft end of the tube fractured under that load and the crush of water on the sides was released at the point. We could call that the end cap being "sheared" off. Then there would be a pressure wave moving forward which separated the forward ring from tube, the front hemisphere from the ring, and blew the viewport out taking its retaining ring along with it. This seems to match what we can observe from the photos of recovered wreckage.
@@jeffro221 So you are saying that the glue joint between the end cap and the carbon fiber hull experienced zero force at depth? Neither compression nor tension?
spencer composites: "don't be name dropping us in these videos" lmao
They made what they were asked to make, it was Upto Ocean Gate to do the due diligence and ensure that what they asked them to make actually made sense
I have been following this event from an engineering stand point and your theory about contraction betwee the carbon fibre compared to the titanium rings with only an adhesive having to flex to cope fits my own thoughts.That was a very good video thankyou.
I feel that even in excellent manufacturing conditions, a carbon fiber hull in a submersible would eventually fail far quicker than a metallic hull. It’s just not a material to use when it is compressed inward. For internal pressure tanks, it is a different scenario all together. Pressure vessels made out of composites have seen great success. Scuba tanks are increasingly using carbon fiber even for pressures exceeding 2000psi. It really is a great material if manufactured and used correctly.
Well, this was the major problem with Titan. An oxygen CF pressure Vessel has its pressure internally so the CF is in Tension, all good. Titan had 1 bar of pressure internally but it’s CF Hull was surrounded by high water pressure particularly at 3-4thousand metres down, it was this compressive force that eventually caused the CF Hull to implode, probably at the joint between the end caps. A totally avoidable and foreseeable tragedy.
Exactly, you can run over an empty tank with a truck and crush it but it will handle thousands of PSI internally
Finally, someone who has an understanding of engineering giving us a no nonsense analysis!
Really. I've been leaning on the bathroom remodeler who is suddenly an expert.
Two things really bugged me about the OceanGate design: 1: it looked like the carbon fiber was applied in one direction only. Every use I've seen has multiple layers in different orientations. 2: most places I see carbon fiber the carbon fiber is under tensive load, not compression.
Totally agree, they should have tested an early version (perhaps a scale model) to destruction to see what gives out first, and to get an idea of how many cycles it could handle.
Excellent analysis. I’m not sure that fatigue is a relevant failure mechanism for carbon fibre? Cracks don’t propagate through CF the way they do in ductile materials? I think your observations about the lack of proper curing, together with poor toughness, and the risk of de-lamination are spot on. When combined with poor inspection as you also point out, this was really a disaster waiting to happen.
Now I want people to make a new one, just like this, test it and inspect it properly. Never with people inside. Produce a better version, see if it can be done with CF in multiple directions, apply the epoxy properly and heavily test and inspect that one. Just to get a good understanding how it fails, when and why. Makes me think of the most recent SpaceX rocket that failed and all the engineers were cheering saying: 'We now got so much data to work with'.
Would be very expensive and not worth it since conventional designs have already proven to work. But it would be very interesting.
@@tomghzel It would be interesting. In reality they should have built a number of prototypes and tested them to destruction. Starting with a 1/4 scale model wouldn’t have been that expensive. They could have put that through 50 or more pressure cycles and then subjected it to non-destructive and destructive testing. So much could have been learned from that process?
The carbon fibre body is smaller than the titan spheres. It should be vice versa because the carbon fibre is more compressed than the titan metal and so the glue has to work hard. If they made it vice versa than the pressure would support the glued connection.
Ya the whole thing was held together by an inch or two of thin carbon fiber inserted into ring
I don't think it would have made a difference. The carbon fiber would have failed along the spine of the hull. We don't know it might have done that anyway, or the end caps just crushed it.
There were two hulls built for Titan. The Spencer hull was abandoned years ago and a new hull was made by Electroimpact, which does know what it is doing. The Electroimpact hull is the hull that was being used when Titan imploded. The videos are all of the Spencer hull, not the second hull. I've never heard or seen any details on the Electroimpact hull.
That's very interesting to know.
Thank you for this information!
Beautiful explained everything! Thank you very much for your time and work!
Thank you
I recently heard someone hypothesize that it was most likely the carbon-fibre hull and the titanium front and back molecularly Contracting at different rates from the incredibly low temperatures of the water, and this would have caused the adhesive to fail that bonded the carbon fiber to the titanium, and it would have been not so much the same kind of implosion as so many has envisioned, but rather a breach caused from separation of the carbon fiber and titanium and it would have been the high-pressure compressed water from the deep ocean that would have rushed into the Hull at over the speed of sound obviously killing the occupants instantly, and this would account for why previous passengers were hearing crackling as they descended, and also why the remains of the hull of the vessel that was recovered did not look as though it exploded from an extraordinary implosion like we keep seeing in these animations.
By far the best video on this topic. Thank you.
You have said real analysis about composit material failure.I wonder how such basic properties is overlooked.
It’s shocking
Thanks for a clear, calm and informative explanation of the disatrous engineering failure that seems to have made the critical failure of this sub more an inevitability than it was an accident.
Five deaths have revealed the entrepreneurial swagger of the CEO as reckless arrogance and hubris. Although the implosion would have been practically instantantaneous, the delamination that preceded it most probably was not. If there were audible indications of what was about to happen, we can only imagine the fear and anxiety those on board must have experienced during their final moments in that alien and hostile environment.
The parallels with the 'unsinkable' ship they were intending to explore are beyond ironic. The discovery of Titanic's wreckage has yielded some amazing research which we can all enjoy safely, in museums, in print and on our screens; but the site is also a place of burial for 1500 souls, and of the most dangerous and inaccessible graveyards in the world. I do not think it should be a place for tourists, no matter how wealthy they are.
I deeply agree with all the other comments here. I subscribed to your channel because it is the best analysis of all, so I cant wait to see your other work. I think the CEO needed the money to continue testing and improving his submersible. He gambled that the dive would be safe once more. He obviously had little understanding of the proper way to test his product which your video points out, helping me to heal from the horror of the whole event.
Excellent discussion of this topic. It seems almost criminal that after the first dive, with sounds of cracking, they wouldn't have done at least a full scan with ultrasound to look for changes in the hull voids. Or at least remove the outer covering and scanned accessible areas with attention given to the area near the adhesive joints.
Carbon fibre is great for tensile strength like the inside of gas tanks. It's not very good under compression. The other thing to consider is they bonded it to titanium, the carbon fibre composite had about 5% contraction at that depth, the titanium had basically zero, which put the joints under immense pressure. (just got to the point in the vid this is mentioned)
After the engineering failure, it was the compressibility of water that killed them though and not the high pressure, as soon as the hull was breached the water decompressed almost instantly to well over the speed of sound, they mostly likely got smacked by over a ton of water going very fast basically.
This was a well made tasteful video though, it's nice to see you didn't stoop to clickbait.
Very nice video! The most succinct and clear video I’ve watched on this topic. Thank You!
Thanks, I appreciate it. Glad I helped a bit
Nailed the dynamic. Defies credulity. A veritable chorus of engineers came forward and said exactly what you summarized. Elementary to anybody who went to engineering school and has experience in industry. Rush didn't want to know. Likely on a subconscious level, he knew this CF hull design wouldn't pass destructive or non-destructive cyclic load testing with any kind of safety factor over and above 400 bar at 2.5 miles beneath the ocean surface.
Physics. Basic. Money driven decisions. CF is lower cost, more neutrally buoyant, lower static weight and vessel easier to transport.
A 'fool's errand' of mistakes. Heterogenous materials and shape with inequivalent stresses and material properties. The CF tube was oil canning in the middle causing a moment at respective ends where bonded to more rigid hemispherical end caps made from a different material.
Can't write a more faulty prescription. I just can't believe this collection of mistakes could ever happen.
Thank you for the great video. You are a credit to all engineers who go to work every day trying to save lives and the public because of our schooling.
Dude, you nailed it. Finally, someone with some real engineering chops to explain fully for us the science behind the fabrication of this vessel. You explained it better than James Cameron.
Thank you for watching!
That is the best engineering feedback that I have seen on this matter. Never mix two different materials in the same structure. Stiffness and thermal expansion must always be noted in any structure. This was my very first comment when I saw how this hull was made. And I agree, it was most likely the epoxy joint that failed.
I always taught my designers that you cannot reinforce an egg shell by adding elastic bands. Two different stiffnesses.
Thank you for the love Gavin! It means a lot.
Rush said so himself in an interview, saying that you never mix the two but he did it with hopefully good engineering behind him.
I would love to hear from engineers that worked on this project as they know a lot and can teach us a lot now
As a statistician, the majority of educated people are not cavalier. I don't think Stockton Rush / OceanGate actively avoided the testing. I think he made a rational decision after using a heuristic, but I think he was probably off by 1-2 orders of magnitude.
I think Stockton Rush thought there was 0.05%-0.5% chance of failure, and that this would very slowly increase over time, and that all the testing was unwarranted and expensive.
In reality the chance of error was somewhere between 5%-50% failure, and time to failure rapidly increased over time (# missions, cumulative stress, etc.).
There was a mission where a significant buckling sound was heard, and this is when his personal heuristic should have aligned with reality.
Yeah I agree with this, he just didn’t pay enough attention to align his perception of risk with reality
Very well done analysis. The best and most skillful I found. Keep it up and thank you.
I'm surprised we haven't heard from the lead engineer for oceangate, after all it wasn't Stockton Rush acting alone.
I think they never engaged the grey beards in the industry to truly see understand how many ways things can go wrong, so the team might not have themselves been aware of the risks they were undertaking. But yeah, I really wanna hear from that engineering team
What nightmare those last few minutes must’ve been. I know the implosion is milliseconds, but there had to have been terror and awful sounds preceding it. Great video 🫡
Yeah investigation would reveal what really happened. Can’t imagine
Thank you for this awesome video. You explained everything so well and so thoroughly.
You are welcome! Thank you, it means a lot
Well said at 7 minutes onwards. They should have made multiple hulls and subjected them to destructive testing.
They would have learned loads, could have written patents etc. Maybe even learned They are one use hulls.
That would have resulted in a better understanding of composites under compression and would have been true ‘innovation’
Perfect video, thank you! Concise, accessible to non scientists like me, and completely understandable. Even I was screaming "it's not a 787!" when I learned it was carbon fibre... it's designed to work in tension, all they achieved by adding to it to the resin (in my uneducated opinion!) was to introduce delamination :(
you are the first one i have seen that actually reveals the layup schedule to any degree. so there were longitudinal fibres not just radial.
I think because we have video only showing the radial, so a lot of people commented using that footage but the article from Composites World made it clear that they did it. They also cured it in an oven for 7 days but why did they not use an autoclave?! Even then could anyone guarantee that all layers would get cured equally
Gruesome Death awaits us all, but this was absolutely uncalled for. Audience wishes grieving survivors all the best. Cheers!
Absolutely, can’t imagine the pain they must feel
So far this has been the most forthright analysis of the failure of the titan sub, leaving out all of the pointless sensationalism and approaching it from a purely engineering perspective. Well done 👍
Thank you 🙏
This wasn't just bad engineering - this was INSANE engineering. This design was GUARANTEED to fail.
fiber hull wasnt dumb enough they also glued the ends of the sub on and used a window rated for 1/4 the depth :/
Beyond Engineering , thanks for the informative video.
I was wondering, given the bolts holding the carbon fiber titanium end ring were all sheared from the titanium end domes: what would be your opinion for the implosive forces - carbon fiber tube collapse or view port water jet distruction?
I think someone here in the comments had a good theory on how it happened. I definitely think it’s the hull that imploded and the resulting pressure wave broke the acrylic viewport
Stockton was bragging about working with NASA and Boeing but it turns out it's Spencer Composites that had helped them with the carbon fiber hull design.
I'm a chemistry major. Senior in college. I've had people blindly talk about how strong carbon fiber is but they don't understand that composite materials don't handle well under external pressure systems. All thr benefits of CF (of which there are many) vanish when dealing with pressure. I'm not an engineer but the basic chemistry behind it is easy to understand.
Excellent analysis of the problems with choosing wrong materials. Please correct me if I am wrong but, it looks like the end caps made of titanium transferred much more pressure to the edge of the carbon fiber glue seam than the hull pressure of the water.
And if two caps are pressing from each end if must have been extremely high. what do you think.
There is a cheap, easy way to get buoyancy, but it does make the sub bulkier. Simply attach to each side a thin walled cylinder filled with a light weight fluid....the fluid simply gets pressurized to the outside pressure, and as it can't be compressed (much) the cylinder retains it's shape and is buoyant.
Thank you for explaining this.
Thank you for watching 🙌
I absolutely agree. No idea what fibre fraction was achieved by Spencer composites in using their hybrid construction technique, but in a way, that isn't pertinent since the matrix takes the bulk of the load in compression. Would it have been better to make the pressure boundary out of polycarbonate?
“In reality it is just bad engineering” True, but sad conclusion. Good information in video, thanks.
Thank you
Pretty good explanation of what went down. The CF was expired stock bought on the cheap, apparantly, so that could also be part of the problem?
I also think that the CF hull was water-logged (from previous dive damage) & that's why it was struggling to ascend at the end (& possibly why it was descending 50% faster than normal, according to the leaked transcripts)
But Rush was.. Too confident (or arrogant?) to slow down, or try to when advised.
I don’t believe in the transcript but I think the expired one was maybe the old hull that was discarded? Not sure, I guess regardless of all those things, not the correct application for this material
Really liked the rope analogy.
🙌 Thank you
Finally someone points out the most obvious flaw. Carbon fiber is like a seat belt. It can hold a lot of weight but only in one direction:tension. Try building a house out of seatbelts. Not happening.
James Cameron summarised it pretty well too, I have massive respect for that guy now
Very in depth and informative analysis of why the Titan failed. The fact that these people died in such a senseless way, due to such recklessness and negligence, is truly a tragedy. I feel terrible for the father and son and their grieving loved ones. If Stockton was on a suicide mission, or better yet, playing Russian roulette, he should have been in the submersible by himself. It is a shame that the others with him did not investigate further into this deathtrap they were embarking on.
I build and work on high end carbon fibre road bikes. Torqure wrenches always gotta be used when tightening something on the carbon fibre frame. When over torqued And when you keep going.. CRACK and SNAP. Always.
Stockton took it too far deep where the torque pressure was waaay too high haha. Not sure if same idea lol but sounds like it.
Never underestimate the sea 🌊
No way would I have agreed to go on this fricking disaster.
agreed, always do your research
Details of the Oceangate submersible's design and fabrication are hard to find. Careful review of Oceangate's blog and several presentations by Stockton Rush shows there were two different shells for the Titan. Many videos of winding the composite shell with wet carbon fiber/epoxy are from 2017 by Spencer in Sacramento, (a marine composite fabricator}. Per Rush, all 5 inches were wound radially (no cross plies).The photos/videos of bonding the shell to the titanium rings (10:58) are from the first shell in 2017 also. "Problems" with this first shell arose during deep water testing in 2018 & 2019 so OceanGate derated it from 4000m to 3000m. Titanic is at 3800m so OceanGate built a new shell of the same dimensions (and maybe new rings) in 2020 at Electroimpact in Seattle (an aerospace composite fabricator) using, according to Rush, expired prepreg from Boeing and biaxially layup. Hopefully the investigation will reveal details eventually.
Stockton Crush probably chose Carbon Fibre for its bank account preserving property… Titanium & working with gets very expensive, fast.
Money seems to be the biggest factor
Thank you for sharing with everyone what I've already known about carbon fiber since its' first inception. The indifference between the two materials in relation to hardness and strength as well as durometer and elongation of the carbon itself as knowing that it cannot stand the same forces as steel and titanium in favour of a cheaper material to save money and be over confident doomed this vessel and its' crew! Sadly this is what happens when people are overly confident in themselves and technology. This video was very well made and eloquently so. Thank you again for sharing this with us to enjoy and enlighten others to the facts that many are still not aware of.
Thank you. I’m glad it helped 🫡
It’s a shame how many things they got wrong
The CEO Stockton thought he was building a rocket ship to be launched under water. His dream was to go to space. So he adopted his building ideas from NASA and tried to incorporate it to deep sea exploration. This is why he used glue with so much pride and confidence. Read this: “Because of its exceptional heat resistance, good thermal stability and low outgassing properties, Viton fluoroelastomer has been called on for a variety of assignments aboard the National Aeronautics and Space Administration's (NASA's) fleet of reusable space shuttles” Stockton idea of engineering was to assume the pressure of the water would keep the titanium glued tightly against the carbon fiber hull. 🙃
I feel that this disaster will have a negative impact on Boeing and Airbus. I don’t think people are going to feel comfortable with the knowledge that both companies use carbon fibre in the wings of their largest airliners. I think that there will be a profound knock on effect, because the Titan disaster is such public knowledge and carbon fibre has become a major talking point.
Not really. Carbon fiber had been an exotic choice for a multi-use submersible, but is an obvious choice for aircrafts
Submersibles have nothing to do with air travel and Boeing already said they didn't work with oceangate directly on the sub. Compression and expansion are 2 different types of forces. Carbon fiber isn't good for compression.
Good video, clearly explained. Thank you!
Thank you! This means a lot, I hope I can keep on it!
The best explanation that I have seen.
Thank you, this means a lot. I’ll improve as I go forward as well, I’m learning all the time
I think James Cameron put it best when he said "they were applying aviation engineering to deep diving submersible engineering"
He’s the whole reason I started researching this topic, I have massive respect for him. He described it so eloquently
Instead of "OceanGate broke many rules" can we just say it: "OceanGate made many mistakes".
Well put
My guess is that the Titan's viewport blew in. It was certified to a pressure of only 1,300 meters below sea level. Sea water then shot in, compressing the air and all five passengers into a tiny area in the opposite titanium cap which remained intact. I assume that this is the location where "presumed human remains" have been recovered. That cap has not been shown on public videos. At the same time the extreme and rapid compression of air into that titanium cap would cause tremendous heat. After that the carbon fiber hull would explode. The result would be one titanium cap without the viewport, one cap with about a ton of compressed, cooked human mush in it plus a lot of carbon fiber scattered around, which I believe is what has been found.
Based on the transcripts it seems more likely to be a hull issue and the viewport collapsed after the implosion of the carbon fiber tube in the middle.
@@justaregularguy115 Perhaps but although the transcript has been widely shared on social media platforms it has not been verified, and there is considerable doubt about its authenticity. My first guess was also the hull, or the connection of the hull to the caps, but considering the 1300 meter certification on the viewport, assuming that is accurate, I don't think there is anything else to discuss. It's like playing "catch" with a live hand grenade.
No need to tell more about how they got cooked and squashed, pressurized and made to touth paste.
@@thorsrensen3162 Well, thankfully this all happened before their nerves could tell their brains anything. I'm just speculating about what is the story with the "presumed human remains". If the hull would have imploded I expected the passengers would have been shredded into countless fragments which would not have been recoverable. That was apparently the initial expectation. In any case, RIP Titan customers. For Rush, I'm not sure I would say RIP. This was so criminal.
@@JacobStein1960 Don't be so petty minded. How would your family feel should you and others were killed and people said 'RIP to everyone except Jacob'. Please be adult and mature about this.
Rush did not know the difference between tension and compression forces... or the danger of joining materials with totally different characteristics. I also hear that the Titan was stored outside in freezing temperature, so any water inside the CF would have caused expansion damage to CF layers. The simple overlap way the CF was wound into the tube was also a very weak way to construct a tube...
It’s impossible to say what he did or did not know, It’s more clear they didn’t test or maintain as they should have done at the bare minimum
So the guy was looking out for other people’s lives, told them the carbon fiber wasn’t safe and he got sued, amazing world we live in
It’s a shame
When any Submersible is designed specifically to carry humans or even Paying Passengers to the bottom of the Ocean, irrespective of materials used, the main objective should be the Factor of Safety (FOS). In a harsh environment where the external pressures on the vessel are extreme, this FOS should be at least 5:1. This means (that at an external pressure of 300 Bar), the Vessel should be able to cope with 5 x 300 Bar = 1500 Bar. The Vessel (Titan) should have been subjected to rigorous Cyclic Testing prior to its' use. BTW, at 1500 Bar, this would equate to a huge external pressure of 21, 750 lbs per square inch - which is acting over the whole surface of the Internal Chamber. Experts and academics may argue that the Factor of Safety of the Submersible (Titan) would have been less than 2, as based upon its Track Record. In an ideal world, a Factor of Safety with minimum 10:1 would allay fears of any implosion occurring, and my prediction is that many decades will pass, before any attempt to go to the Ocean Depths to view the Titanic happens again. Your report has been a great education, and contribution to the knowledge with regards to Carbon Fiber, a most unsuitable material for the application. RIP to those 5 pioneers who braved the depths.
Excellent video!!!!
Wouldn't all these problems be exacerbated by having the sub tugged in rough waters for hundreds of miles? In order to save money, Rush used a much smaller ship, the Polar Prince, that could not carry the sub securely, but instead, tugged it for 800 miles.
The more I hear and read, the more I am convinced that Rush was suicidal.
Thank you!
I think that’s less of a factor, in fact it’s probably very efficient.
However, this kind of operation needs redundancy. If you look at the video of making of DSV Limiting Factor, they take multiple ROVs with them when they dive just so they can get out of trouble if needed.
@@beyondengineering thanks for the recommendation. The video was excellent.
@@claudiastokes6485 you are welcome
you nailed it, I believe the the port view viewing window blew out during the carbon fiber failure
Mr Rush literally built a giant soda can, and wrapped electric tape around it. Changed customers 250,000 for a trip to a unsinkable ship . Suicide mission 🤦🏾