I guess the Beatles really knew something 😂

@@JoediyLab it was made of crayon much better than tape

Yellow definitely easier to find pieces of...

@@lostpony4885 yellow wax, straight from Crayola, no exceptions. US marine corps owns the patent

The international silver string submarine band

Good point, thanks for the feedback

Lifting it by the carbon fibre would apply even more force to the joint. But none of that matters because carbon is useless in compression.

I wouldn't be too concerned about that. After all, entire airplanes are lifted up with wings that are glued to the fuselage. Also, 10 t is nothing in comparison to the forces applied a few km down below.

@@jcsjcs2 Yeah, by designed and designated points! Also pressure at few km is uniform, and cat's cradle is not!

@@davidelliott5843 : What do you think of the multiple accumulative effects of saline deposits in combination with extreme pressure from opposing different ocean currents into epoxy and carbon fiber, also, which does not occur to aircraft. To think that epoxy and carbon fiber will not over continued use begin to deteriorate indicates poor judgment. Stockton Rush may have developed a suicidal tendency due to his goals to achieve more than his restricted budget could afford. He certainly was quite a salesman, however, with no regard for the lives that he was about to sacrifice with his own. Attorneys are about to win a case against Oceangate due to this carbon fiber that exceeded its shelf life-a true red flag of which Rush was aware. And to think that an epoxy bond on titanium would react over time and stress in the same manner as over carbon fiber.

Thanks for the feedback.

@@JoediyLab the dolt who insisted on that material should have watched such a video instead of using earplugs and screaming "revolutionary"

Yes exactly. When that video first surfaced my reaction was, "oh my god there was zero engineering!" There is roughly a 2:1 ratio of load -- hoop : longitudinal (in idealized thin skins exactly 2:1). They built this thing as 1:0. The most remarkable part is that it made it back after 10+ dives! The cracking noises seem obvious to me: very low stiffness in longitudinal direction, elastic buckling on ever dive, growing cracks in the inner epoxy matrix. This was the most absurdly ridiculous POS I've ever seen. Astounding. And no strain gages! "acousitc monitor" was totally stupid. Where were the strain gages? They would have found the truth (Stockton couldn't handle the truth). They would have known immediately on the first dive what was actually going on. But no longitudinal or diagonals to appropriately balance the compliance and strength--what an idiotic situation.

Yeah that was a huge rookie mistake with the carbon fibre, even uneducated people can see that

there are not bolt holes on the end nose. it tell me it was glued. the bolt's was just another retaining ring of some sort

Because doing criss cross patterns was more time consuming and expensive. It was another corner he felt he could cut . With his so called logic and good engineering. He was wrong.

@@vibratingstring thanks for your feedback

Thanks for the comments, yes we use to use acid to etch parts for bonding.

A couple of cans of Flex Seal will seal it up real good.

Interesting and makes total sense, gives the epoxy something to grip onto.

Was it also a flawed process of having a gang of bods using decorating spatulas to hand coat the surfaces? I used to build small pressure housings for underwater flashguns as a kid, I was mortified to see the way this thing was put together, even with my extremely limited experience !!

Thanks for your comments

I would say they just used Gorilla Glue, but I think that was way to upscale for them.

Yes, that was on an old sub. On the Titan, they used pregreg tape wrapped around a mandrel. But we do not know what orientation and what cure they used. Thanks for the feedback

Quote from composites world “The biggest challenge, Spencer reports, was developing a manufacturable design that “would produce a consistent part with no wrinkles, voids or delaminations.” And without use of an autoclave. Spencer opted for a layup strategy that combines alternating placement of prepreg carbon fiber/epoxy unidirectional fabrics in the axial direction, with wet winding of carbon fiber/epoxy in the hoop direction, for a total of 480 plies. The carbon fiber is standard-modulus Grafil 37-800 (30K tow), supplied by Mitsubishi Chemical Carbon Fiber & Composites Inc. (Irvine, CA, US). Prepreg was supplied by Irvine-based Newport Composites, now part of Mitsubishi Chemical Carbon Fiber & Composites Inc. The wet-winding epoxy is Epon Resin 682 from Hexion Inc. (Columbus, OH, US). The curing agent is Lindride LS-81K frLindau Chemicals Inc.cals (Columbia, SC, US).”

A cylinder is the optimal shape, for getting the most paying passengers, er, 'mission specialists' inside the pressure, er, 'pay' vessel. I doubt Stockton charged himself, or PH. So really only 3 paying customers, so only $750K per run, and Stockton had complained that bunker (fuel) to the dive site & back was $1 MIL. So... I guess he really needed a longer submersible. Titan 2.0 might have resembled a paper towel roll. Oh dear. So where were all these carbon fiber specialists/commenters warning Stockton before this happened? In your industry, surely you would have heard of this singular application - so why didn't everyone in the carbon fiber industry warn him that he's doing every thing wrong that can be done wrong.

​@JoediyLab Great report Joe, in some photos you see contaminates in the winding. Shouldn't this be done in a clean?

​@@glcanonHe was warned, and people quitted their job due to the construction.

Yes new mic with pop filter on order

There are a lot of comment to reply to. I just got to yours. A new mic is on order with a pop filter. You very nice comment just shows what kind of troll you are.

@@JoediyLab Excellent!

@@thadollagenerale Thanks

AMEN !

Or a sock and cotton wool

For this video: High pass filter 200 Hz.

Mic is on order

Mic is on order

Never been in a plane or in an elevator or etc etc

In this case that is wise advice

You always walk, you don't go any structures of man-made, you swim through rivers?

What about cars

@@CharlieNasty-cd5hu Yes, all formula 1 chassis are made of carbon fiber. I even believe I read recently that Alfa Romeo just built their entire chassis out of carbon fiber. Google it it looks very cool.

Thanks for the clarification. Another Engineer indicated that the later sub did not use filament winding, but tape winding. So not sure who did the original filament winding then.

Thanks for your feedback

Thanks for the feedback

Thanks so much 👍

Thanks for the comment

Love the idea of tinsel strength. A useful standard, along with potato chip/crisp strength for bending, and meringue strength for compression.

@@timjackson3954Pasta has the same strength per unit weight and volume as concrete…

@@allangibson8494 pasta houses?

Many high end air guns use CF tanks and they last/do well. Almost never hear of failures.

@@N4CR5the cf filament itself is flexible line, like a high test fishing line. The cf wound in a multi directional pattern on an air tank acts as a woven sack that resists expansion with its tensile strength, with the resin added to help hold its desired form (including keeping it from collapsing from external force), and prevent the air from escaping through the cf woven structure. The two combined are a composite but also referred to as cf. The cf filament by itself won't stretch and doesn't snap easily, but it is still a flexible line. If you have a loop of cf or any flexible line/rope and pull outward from the center of the loop with equal pressure it will hold until you reach the strength to snap it. But take that loop and push inward and it collapses. That's why a cf composite works for holding greater internal pressure from expanding outward but not the inverse. When you squeeze the cf composite tank with greater external pressure the woven sack doesn't add much of, if any of its properties so all you're relying on is the resin's ability to resist compression (hold its form) so they were basically in a 5 inch thick walled epoxy resin tube/ jar with two metal (titanium)end caps and nearly 6000 psi squeezing it from all directions. It's amazing they got away with it the first few times. Sorry this is so long but wanted anyone else reading it to understand what the cf filaments & the resin's contribution to the cf composite are. Apparently it was rocket surgery to OceanGate's brilliant college educated "engineer" Stockton Rush and his college student interns (apparently just yes men).

Thanks for the feedback 🙂

@@JoediyLab I work at MAF in New Orleans La. There is an old Autoclave that gets alot of use on rocket parts. There is also a very big Ingersoll fiber placement machine here. mafspace.msfc.nasa.gov/

@@forrestgumpv9049 thanks for the link, I will check it out

Thanks, Yes I need to get a pop filter.

Thanks

Thanks for the feedback

Thanks for your feedback

new mic and pop filter has been ordered, Thanks for the feedback

Yes you are correct the metal cylinder is a mandrel, once cured the carbon fiber is pulled off of the mandrel, then the flanges are glued onto the carbon fiber tube. Thanks for the feedback

@@JoediyLab I want to see a very thin steel or titanium mandrel removed from the CF hull of that size. After curing both parts are glued together, if not realy, friction between parts is terrible. It is possible if you contract the inner mandrel by freezing but what influence on CF caracteristics?????

I hope Stockton is suffering in hell.🏴‍☠

Thanks for the feedback

@@JoediyLab Anytime! Yours is the first channel I've been able to find where someone who knows their stuff is discussing it without getting into the weeds with the conspiracy theories. I'm not saying some of their ideas are wrong but they tend to make a lot of assumptions based on shaky reasoning. I like your approach of more strictly sticking to the physics and engineering. Anyways keep up the great work!

Yes in wet layups some epoxy can have exothermic reaction if applied too thick. On prepreg that have to be cured at higher temps, they are designed for the higher cure temps as long as you follow the specs. Good question

Thanks

Thanks

Thanks

Great question, In the video of the earlier sub it only show the hoop wrapping. I understand that in a later process they wrapped pregreg in a more axially orientation in the long direction. But the older sub did still fail. On the titan sub they used pregrep carbon through out the entire sub and used a tape wrapping machine. I was told that they wrapped in the hoop orientation and in the axial directions. I heard that they wanted 7" of thickness, but for some reason they received 5" thickness. Not sure why, Maybe a cost situation that Stockton Rush later decided. But that is just a guess based on his logic of using acrylic viewing port rated only to 1300 meter instead of 4000 meters. I have also read that carbon fiber can be constructed for strength against compressive forces. I am anxious to see the findings that the Canadian NTSB comes up. Based on the images of the recovered sub it appears that the titanium flanges popped out with little trace of either adhesive or carbon fiber remains attached to the flange. Thanks for the great question.

Thanks

Thank-you sir for the feedback

Thanks for the feedback

The video is winding of an older pressure vessel. I spoke with an engineer that indicated the Titan use tape winding and not filament winding. Tape winding would be better as they could use prepreg tape and avoid the wet layup. It could also then be cured in an autoclave. But as far as we know they cured in an oven and not an autoclave.

I hit wrong key on that date it was done 2020 to fall of 2021. On hull

Thanks

Thanks

Thanks, just retired, doing KZfaq, currently a bit burned out on coding, but may do some in regards to composite failure.

Thanks for your feedback

Thanks for the feedback

Thanks

No seal, at depth the pressure would keep water out. Just have to make sure surfaces are very clean. Thanks for the great question 😊

Basically no bending or shear resistance other than the epoxy resin matrix.

Yes the first pressure vessel was filament wound and pregreg wrapped. The Titan pressure vessel was tape wrapped with pregreg. Pacific Coast Composites has the details. Thanks for the feedback

Looking at the recovery images, the titanium flanges were shown separated from the carbon fiber cylinder. It appears that when the carbon fiber section crushed, the titanium flanges were pushed out. There appeared to be no carbon fiber attached to the flanges that I could see.

Yup, I said old sub was made wet layup new sum was prepreg and I mentioned Spencer Composites

@@JoediyLab Oh got it. I didn't notice.

Do you remember the source for that info?

@@eurotrashdude8484 Check the following wikipedia page on Oceangate en.wikipedia.org/wiki/OceanGate

Also there is a video Posted in the description from the Oceangate KZfaq page showing the wet filament winding process.

Yes I would love to see the results of the investigation. Epoxy bonding with composites is common, but I do not think anyone has tested at these pressures.

Bonding composites to metals is a tricky business. Preparation of the surfaces is very important, as is ensuring complete contact.

@@TricksterJ97 Good information, thanks

@@TricksterJ97 thanks for your feedback

A KZfaqr scientist called “thunderfoot” done a very good vid the other day about the pressure. About how water does actually compress, very little of course ( about 1% at that depth), and how its basically like a massive infinate spring surrounding the sub. When exposed to one atmosphere, like a leak, the spring desprings if you like, at something like 4x speed of sound. When the water hits an object, the energy smashes it apart in micro seconds. The vid is well worth looking for 👍

Thanks for the feedback

Exactly! It's tensile strength vs it's weight is incredible, but it's not a good choice for this application. It would be well suited for containing internal pressures, but not at all suited for dealing with external pressure.

Carbon fiber is stronger, Kevlar is more abrasion resistant and impact resistant than carbon fiber.

Already done thanks

No the carbon was wrapped on a mandrel and pulled off when cured. Then the titanium flanges were bonded on.

@@JoediyLab I work with CF on a very limited basis, what would happen when say hardware is screwed into the CF? I noticed the monitors being mounted. And the illuminated handles he used that he got from Camping world.

That would cause isolated stress points around the area of the screws or bolts. I think they had s sub structure that they mounted hardware to.

Inside pressure is in tension, outside pressure is in compression, Big difference. Thanks for the comment

Thanks for the comments.

@@JoediyLab Welcome ... things to ponder.

Not in the titanium, in the images from recovery they appear intact. But I have heard from seen images that the viewing port was blown out. Thanks

Correct, The video does not show a later process of wrapping carbon in the axial direction. The Titan sub was actually wrapped using pregrep and a tape wrapping machine. Totally different than filament winding process. Thanks for your feedback

Check the description, should be there. Thanks, if not search Oceangate on KZfaq there is a video on there site

Perfectly safe. The pressure is the opposite way around. Carbon fiber is great at keeping pressure in, not so much at keeping pressure out. Tensile vs compressive strength.

Thanks for your feedback. Yes internal pressure is a different force.

Thanks

Thanks for the feedback

No you will still get support from the carbon fiber. the strength of the fiber is along the length of the fibers. So you orient the fibers along the areas of stress you need. If you cast structural resin that thick it would heat up to much and weaken. Even with slower curing resin it would shatter. The strength of carbon fiber is a combination of resin to carbon fiber matrix. Carbon fiber by itself is only good in tension. If designed correctly you can get good strength in both tension and compression, But more strength in tension. Thanks for the great question.

Correct it appears that the later sub may have used prepreg, but we really do not know for sure.

Great question, Here is a quote from Composites World "The maximum compaction pressure available at sea level with a perfect vacuum bag is 14.7 psi (29.92 inches or 760 millimeters of mercury.) This maximum available pressure drops approximately 0.5 psi (1 inch or 25.4 millimeters of mercury) for each 1,000 foot gain in altitude. "

If you draw a perfect vacuum under the bag, then what is pressing on the other side is whatever the atmospheric pressure is. More in Death Valley, less in Denver. Putting the vacuum bagged part in a pressurized autoclave results in greater than atmospheric compression.

That is a very complex question. There are several variables involved. Temperature, pressure, vacuum (yes you vacuum bag when using an autoclave) There is also temperature ramp up and ramp down times and how the resin flows with in the laminate. I am not a mechanical engineer. I would have to do alot of research on this topic. Sorry.

Carbon fibre composites are very good in compression.

Great information, yes the filament wound sub failed during testing. Yes it was pretty scary watching the first video.

yeah......except the space shuttle boosters were made from steel

@@mycammedia Yes the NASA booster cases are steel 1/2” thick DCAC tool steel. Before the Challenger was destroyed by the director of NASA the Air Force wanted to do a polar launch.Filament-wound cases were manufactured by Hercules Inc. I was the senior process engineer. Edit “In order to provide the necessary performance to launch polar-orbiting shuttles from the SLC-6 launch pad at Vandenberg Air Force Base in California, SRBs using filament-wound cases (FWC) were designed to be more lightweight than the steel cases used on Kennedy Space Center-launched SRBs.[30] Unlike the regular SRBs, which had the flawed field joint design that led to the Challenger Disaster in 1986, the FWC boosters had the "double tang" joint design (necessary to keep the boosters properly in alignment during the "twang" movement when the SSMEs are ignited prior to liftoff), but used the two O-ring seals. With the closure of SLC-6, the FWC boosters were scrapped by ATK and NASA, but their field joints, albeit modified to incorporate the current three O-ring seals and joint heaters, were later (after STS-51L) incorporated into the field joints on the SRBs used until the last flight in 2011.”

@@oneskydog6768 Really - didn't know about that - why was it not really common knowledge - I only ask because I never saw any reference to anything like that. That must have been some amazing set up in terms of size - any special arrangement for the interface of the segment 'body' to the steel joints? just curious. I was interested in all the issues surrounding the field joint design - rotation of the joint, etc. I also was deeply interested a long time ago about AA587 - the public hearings about engineering issues and the differences of approach / philosophy between Boeing and Airbus about what each was willing to do when it came to using carbon fiber. Airbus pushed the issue much further towards making moutings from cf - but Boeing were way more conservative then and were unhappy to make the actual mountings from cf. At that time, they wanted to stick to an experience base of 70 years around the fatigue issue with metal.

@@mycammedia operational security need to know basis

Thanks for the comment

I like reading comments like this. I am not scientific at all, and have a high school level understanding of math. But somehow I can infer the point you are trying to make.

I heard that in some data from Pacific coast composites that did run plys in the hoop and axial direction. But I have to confirm

@@JoediyLab I calculated that the composite carbon fiber cylinder would’ve experienced 29,700 psi compression in the longitudinal direction and 60,600 psi radial compression throughout the entire side wall at Titanic depths. I think Stockton felt safe with carbon fiber composite because it has a compressive failure pressure of approximately 250,000 psi if it’s not damaged. But fatigue cycling and differential strains between titanium and carbon fiber may have done him in.

@@jamesn3513 wow, very cool. Yes I agree with your thoughts.

@@jamesn3513 and just what if a horrible mistake was made an error in judgment that may very well not wish to get revealed RE: litigation; that Sunday noise was bottom brackets falling down, not any implosion. So rescue was not pursued underneath but above. Then when Canadian C-3 Orion plane heard 30 minutes of banging, is when those in charge rushed to have underwater ROV brought took hours to get there. All those days, nights, in ocean pressures, subjected to changing temperatures and freezing ones, Can be date of implosion as hull plus resin becoming more brittle to failure! Don’t be so positive on dates being thrown, consider there may become a hugh liability issue to develop, dates can make or break such possibilities!

Yes would be interesting to see what method they used on the new sub with the prepreg, could not find any data on the method

@@JoediyLab there's an 18 minute video where Stockton Rush gives a talk and he shows a few photos from the process. You can see the machine used to lay the fiber. It was a more complex tape laying machine.

@@matthew4878 I will search for that, do you know if Spencer Composites has an autoclave?

@@JoediyLab Their website says that they do. I doubt it's big enough for this though.

In college when we made parts like bulkheads and torsion tubed out of carbon fibre using prepreg we had to place the parts under vacuum wrapped in plastic and use an autoclave. Never did we orient at 90 0 for every layer.

Check out the later video on adhesive, Some adhesives are very strong.

Good question, deformation doe not scale linearly. Yes most research has been don on thin walled cylinders. thanks for your feedback

Yes I have not seen another video as well. I had heard that they wrapped prepreg in an axial orientation, but I cannot find any proof. Thanks

Hubris

$$$$$$

@@ericpalmer3588 thats not really an answer though...

There methods would not pass inspection. I spoke with a composite s engineer, he indicated that with a portable ultrasonic tester he could not get penetration in a composite that thick. Possibly with a larger unit. Thanks for the feedback

@@JoediyLab A larger ultrasound unit would not work well. The penetration of acoustic waves into materials is frequency dependent, not power dependent. The higher the frequency, the higher the energy loss through absorption and the less thickness your wave will be able to penetrate. Ironically you need to lower your frequency to penetrate a thicker layer. However this comes at the cost of spatial resolution, the lower your acoustic frequency the larger the feature need to be in order to be detected, also the thicker the material the higher the wave amplitude or the power you need to put into the signal to get a decent return signal through sound absorption. The wavelength of NDT ultrasound is anywhere between 200KHz to 50MHz, let's say they use a frequency of 5MHz. Wavelength is dependent on sound speed which is dependent on material density. A 5 MHz ultrasound signal in air has a wavelength of 0.07mm with a sound speed of 343 m/s. A 5 MHz signal in CF with a sound speed of 10000 m/s is 2mm, so anything smaller requires a higher frequency. If you went down to 1 MHz your wavelength increases to 10mm(1 cm). So any cracks smaller than the wavelength of the sound won't interact strongly with the wave to reflect a signal back, it's basically the diffraction limit as it's termed in optics. Ultrasound works very well because it can detect very small cracks within a relatively thin layer of CF, down to fractions of a mm but as you get thicker your resolution advantage is lost. Also because the CF hull is a curved piece there are geometry issues which can cause the ultrasonic beam to scatter and not properly reflect off any defects depending on how the defect is oriented. Because it's also a laminate these alternating layers of CF and epoxy will cause the ultrasonic waves to reflect and refract as well as diffract, this causes a lot of interference. Imagine looking through a curved window made of multiple alternating panes of glass and air and shining a flashlight through that stack to see any defects in the inner panes. Source: Not a materials engineer or a NDT specialist was trained in petroleum geophysics on how to interpret seismic wave propagation in the earth.

Thanks, yes new mic is on order

In the industry they use the term Pressure vessel, but inside of the vessel the pressure would stay ambient pressurei so vacuum would not be quite accurate.

@@JoediyLab got it. In my mind, in the environment this was destined to operate, that just seemed like a good analogue to me. Thank you and very interesting discussion.

@@spacecadet4876 thanks for the feedback

Thanks for the feedback

Hard to say why, he had an engineering degree. Maybe cost savings but a total disregard for rules and regulations.

@@JoediyLab I’d love to know why, maybe had to be different, wanted to be a pioneer but it was obviously flawed. I’d be very surprised if it was cheaper, lighter perhaps and maybe some ongoing cost saving but I don’t think the use of carbon fibre would have been cheaper to build and perhaps the other consideration is the ongoing cost of maintaining the integrity through NDT but it seems that they weren’t doing that apart from the acoustic monitoring

Yes it appears that acoustic monitoring was all they were doing. It appears that Stockton Rush was adverse to following standard industry rules and regulations.

Good questions, I really do not know, On one hand he indicated he wanted to be safe, His ex-business partner said he would never allow un-safe operations. But everything in the media indicates he disregarded following rules and regulations. He had a degree in engineering. But yet he wanted to cost cut. I heard servicing paying customers was not his goal. He wanted to do more research on the titanic. But he needs money to do that. He seems to hate the industry guidelines. It sure seems like he fooled himself into believing he could get away with it.

@@JoediyLab yes certainly interesting. Personally I know nothing about deep sea submersibles but with 3 trades, one of which is Industrial / petrochemical refrigeration there’s simply no justification for using pressure system components that don’t have pressure ratings that exceed the system requirements and that’s on systems that while they have potential to kill or injure someone it’s opportunity to do so is nothing like the criticality of having human lives depending on almost every component under 4000M of water and a 40MPa pressure differential. If this thing had been unmanned and remote operated then the catastrophic failure is of little consequence and perhaps a proving concept for a manned vehicle of similar construction. Anyway I guess we may never know why he went that path

There is more than likely an interior sub frame that they are using to mount hardware. Just like the flooring, a flat panel is used to sit on, thanks

Thanks for your input

yes new mic is on order