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Has ANYONE ELSE ever built a deep sea vessel with carbon fiber hull?
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Date: June 20th, 2023 3:20 PM Author: overrated self-absorbed senate This is the only other submersible I could find that has a CF hull, and it only goes to 30m.
https://blog.carbonfibergear.com/taking-carbon-fiber-to-the-next-level-below-sea-level/ |
Date: June 20th, 2023 3:22 PM Author: Racy fat ankles tbf, it doesn’t seem like these guys did it either. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450189) |
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Date: June 20th, 2023 3:39 PM Author: arousing massive weed whacker (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450265) |
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Date: June 20th, 2023 3:59 PM Author: Cracking Tanning Salon (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450348) |
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Date: June 20th, 2023 4:22 PM Author: stirring church mother (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450498) |
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Date: June 20th, 2023 3:41 PM Author: cerebral maize athletic conference wait, it's not even a metal frame? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450269) |
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Date: June 20th, 2023 3:42 PM Author: Racy fat ankles lol. do you think people would pay $300k to visit the titanic? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450274) |
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Date: June 20th, 2023 3:44 PM Author: overrated self-absorbed senate One section is titanium, the rest is carbon fiber. I wonder how it was bonded/sealed. With bicycle frames you want all CF or all metal, no mix and match like people tried to do in the 90s. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450285) |
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Date: June 20th, 2023 3:46 PM Author: Unholy twinkling stain Tbf lugged carbon is a beautiful look
https://www.roadbikereview.com/attachments/110886-151fa3618d1648f2a9dc3e1af018472f-jpeg.306144/
https://ilovebicycling.com/wp-content/uploads/2015/10/What-is-a-Lugged-Frame.jpg
http://1.bp.blogspot.com/_K3LsaGxYIZg/TM-bBEPfMhI/AAAAAAAABW4/PAj-6Mtpj-k/s400/iflugged4.jpg |
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Date: June 20th, 2023 3:48 PM Author: overrated self-absorbed senate Yes those bikes make great wall decorations at theme restaurants. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450292) |
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Date: June 20th, 2023 3:46 PM Author: Unholy twinkling stain I thought the pressure vessel was titanium? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450287) |
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Date: June 20th, 2023 3:50 PM Author: overrated self-absorbed senate Engineered and built by OceanGate, Titan, is comprised of carbon fiber and titanium. The filament wound cylinder that forms the center section of the pressure vessel is 5" thick and made from over 800 layers of carbon fiber material. The entire pressure vessel is comprised of two titanium hemispheres, two matching titanium interface rings, and the 142 cm (56") internal diameter, 2.4-m (100") long carbon fiber wound cylinder – the largest such device ever built for use in a manned submersible. The use of carbon fiber reduces the overall weight compared to other deep-sea submersibles.
"Interface rings" leaves a lot to the imagination. |
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Date: June 20th, 2023 3:55 PM Author: Unholy twinkling stain Interface rings are just two matching flanges that bolt together. They're used on spacecraft, subs, boilers, reactors, etc. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450325) |
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Date: June 20th, 2023 4:01 PM Author: overrated self-absorbed senate None of the things you just listed have metal "interfaced" with carbon fiber. Did they use glue or what? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450364) |
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Date: June 20th, 2023 4:08 PM Author: Unholy twinkling stain "Interface rings" doesn't refer to the ti-carbon interface; it refers to the interface between the pressure vessel hemispheres (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450401) |
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Date: June 20th, 2023 4:12 PM Author: overrated self-absorbed senate The hemispheres are connected to a CF hull somehow. I assumed "interface" refers to whatever connects the hemispheres to the hull. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450423) |
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Date: June 20th, 2023 4:17 PM Author: Unholy twinkling stain Nah, it's basically how the door seals. See the metallic ring between the gray half-sphere and the white cylindrical hull? Those are interface rings
In this pic its the ring with all the bolts.
https://www.rigal-bennett.com/images/Product/n7744-05/n7744-05_18808.JPG |
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Date: June 20th, 2023 4:20 PM Author: overrated self-absorbed senate If your house was subjected to immense external pressure, the doors would blow out before the main structure. Your second pic doesn't show CF bolted to metal. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450487) |
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Date: June 20th, 2023 4:29 PM Author: Unholy twinkling stain Cf isn't bolted to metal. It's bonded with epoxy. I'm showing you what interface rings are, which has nothing to do with the carbon-metal interface.
That's why the "door" is a hemisphere of the pressure vessel. It's the easiest way to open the pressure vessel to allow passengers to enter. |
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Date: June 20th, 2023 4:36 PM Author: overrated self-absorbed senate Ok, but interface rings are still the linkage between the CF portion of the hull and the titanium hubs. There isn't titanium running the full length of the hull.
So you have titanium at one end with an interface ring that's attached to another titanium interface ring that encircles the CF hull. It sounds like the titanium rings would have to be attached to the hull with some sort of epoxy.
I don't know what epoxy bonds to both titanium and CF with enough strength to reliably withstand these pressures. I am only aware of hybrid CF/metal designs being used to save cost at the expense of durability. That's what I meant when I said this leaves a lot to the imagination. |
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Date: June 20th, 2023 4:43 PM Author: Unholy twinkling stain I agree. I imagine that the cf-ti bond is the experimental part. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450631) |
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Date: April 28th, 2025 4:24 PM Author: overrated self-absorbed senate NSAM ahead of the headlines by 96 hours at least (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#48888050) |
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Date: June 20th, 2023 3:51 PM Author: multi-colored cruise ship JFC at making a submarine out of carbon fiber. It gets stressed unbelievably easily and will simply collapse. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450306) |
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Date: June 20th, 2023 3:52 PM Author: overrated self-absorbed senate You'll get no warning. No ominous creaking or bending, just instantaneous total failure. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450308) |
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Date: June 20th, 2023 4:00 PM Author: Unholy twinkling stain It's woven around ti hemispheres. They've made compressed gas tanks that way for years (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450356) |
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Date: June 20th, 2023 4:05 PM Author: overrated self-absorbed senate What's the internal PSI of those tanks? This thing was designed to withstand several tons of pressure. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450388) |
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Date: June 20th, 2023 4:09 PM Author: Unholy twinkling stain 4000 psi (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450404) |
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Date: June 20th, 2023 4:11 PM Author: overrated self-absorbed senate link
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Date: June 20th, 2023 4:22 PM Author: Unholy twinkling stain https://www.amazon.com/4500psi-Pressure-Composite-Cylinder-Paintball/dp/B09CPRRLGY/ (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450495) |
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Date: June 20th, 2023 4:23 PM Author: overrated self-absorbed senate That's a monocoque structure. CF isn't bonded to metal. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450503) |
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Date: June 20th, 2023 4:28 PM Author: Unholy twinkling stain https://ams-composites.com/choosing-the-right-gas-cylinder-type-1-type-2-type-3-or-type-4/
Read about type 2 and 3 |
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Date: June 20th, 2023 4:33 PM Author: overrated self-absorbed senate For type 2 it literally says "Type 2 cylinders are suitable for a variety of applications where cost is more important than low weight and high pressure."
Type 3 is a hollow monocoque structure with a layer of aluminum in the center. |
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Date: June 20th, 2023 3:58 PM Author: overrated self-absorbed senate "While the vessel was designed to operate down to 4,000 metres, and would have had a safety margin to go deeper, industry experts said other deep-sea vessels used steel or titanium alone to ensure their hulls could take the pressure. Carbon fibre is widely regarded as an untested material: when it fails, it can fail catastrophically."
https://www.theguardian.com/uk-news/2023/jun/20/missing-titanic-submarine-best-and-worst-case-scenarios |
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Date: June 20th, 2023 4:02 PM Author: contagious public bath pocket flask oh god oh- (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450371) |
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Date: June 20th, 2023 4:07 PM Author: multi-colored cruise ship Assuming a tube structure 60” in diameter, how thick should a carbon fibre hull be constructed to safely reach the titanic and maintain an atmosphere of pressure.
GPT4:
The wreck of the Titanic lies about 3.8 kilometers (or 12,500 feet) below the surface of the North Atlantic. At that depth, the pressure is enormous, around 380 atmospheres or about 38 MPa (Megapascals).
If we aim to build a cylindrical submersible to reach this depth, the pressure on the hull can be approximated by considering the hydrostatic pressure, which is the pressure exerted by a fluid at equilibrium due to the force of gravity. The formula to calculate this is P = ρgh, where:
• P is the fluid pressure, • ρ is the fluid density, • g is the acceleration due to gravity, and • h is the height of the fluid above the point in question.
The density of seawater is about 1025 kg/m3, and gravity is about 9.8 m/s². The depth to the Titanic is 3800 meters, so the pressure is about 38 MPa.
Carbon fiber has a tensile strength that can vary depending on the specific type, but let's consider a high-quality carbon fiber with a tensile strength of 2000 MPa.
The hoop stress (stress in the circumferential direction) for a thin-walled pressure vessel like a cylinder can be approximated using the formula σ = Pr/t, where:
• σ is the stress on the material, • P is the internal pressure, • r is the radius of the cylinder, and • t is the thickness of the cylinder wall.
We can rearrange this to solve for thickness: t = P.
Now, we want to add a safety factor. This could be around 2 to account for uncertainties in material properties, imperfections in manufacturing, and unexpected loads. This means we'll use half the tensile strength of carbon fiber in our calculations, i.e., σ = 2000 MPa / 2 = 1000 MPa = 1000 N/mm².
The internal pressure P is the pressure at the depth of the Titanic, 38 MPa = 38 N/mm².
The radius of the vessel r is 60"/2 = 30" = 762 mm.
Substituting all values into the formula gives: t = (38 N/mm² * 762 mm) / 1000 N/mm² = 28.8 mm.
Therefore, the hull of this theoretical submersible, when built with high-quality carbon fiber and with a safety factor of 2, should be roughly 28.8 mm thick. This, however, is a highly simplified calculation and real-world design would require more detailed analysis and likely thicker walls due to factors like buckling, possible impact loads, and material imperfections. Additionally, local regulations and standards would also play a role in determining the safety factors and therefore the final thickness. Always consult with a professional engineer for such calculations. |
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Date: June 20th, 2023 4:10 PM Author: overrated self-absorbed senate I think the bigger issue is how you seal it if it's not a monocoque frame. If part of the frame is CF and part is titanium, what's attaching them together? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450408) |
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Date: June 20th, 2023 4:15 PM Author: Exhilarant Domesticated Degenerate Chapel It sounds like the carbon fiber is a liner.
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Date: June 20th, 2023 4:17 PM Author: overrated self-absorbed senate That's what I thought too, but it sounds like it was necessary since they had a system to monitor its integrity, and it still has to be affixed to the hull somehow. You can't weld it so how did they do it? (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450457) |
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Date: June 20th, 2023 4:26 PM Author: Unholy twinkling stain It's basically bonded to metal with epoxy, then the cf is impregnated with resin. The joint is probably some custom designed interface that maximized the surface area of the bond. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450533) |
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Date: June 20th, 2023 4:28 PM Author: overrated self-absorbed senate A resin that's formulated bond to titanium and carbon fiber with more or less equal resilience. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450553) |
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Date: June 20th, 2023 4:36 PM Author: Unholy twinkling stain No idea, but it sucks to be the passengers if the answer is "no." (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450593) |
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Date: June 20th, 2023 4:27 PM Author: Vigorous ivory indirect expression a deep sea vessel made entirely out of thinkpads (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450539) |
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Date: June 20th, 2023 4:40 PM Author: cerebral maize athletic conference tbf, better than a vessel made out of any other laptop (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450616) |
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Date: June 20th, 2023 5:25 PM Author: At-the-ready Bright Set Internal Respiration i make my deep sea vessels out of TOUGHBOOKS (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450906) |
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Date: June 20th, 2023 5:22 PM Author: Learning disabled stage Why can’t a dolphin just dive down and rescue them? I heard they do this all the time like no big deal. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46450886) |
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Date: June 20th, 2023 7:51 PM Author: overrated self-absorbed senate http://www.xoxohth.com/thread.php?thread_id=5359335&mc=2&forum_id=2 (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46451575) |
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Date: June 20th, 2023 8:06 PM Author: thriller clown I’m an avid scuba diver. I’d never get in a submarine not operated by a first world navy. (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#46451622) |
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Date: April 28th, 2025 4:23 PM Author: overrated self-absorbed senate OP here (http://www.autoadmit.com/thread.php?thread_id=5359130&forum_id=2#48888048) |