When I watched a documentary about how the sub was built...I was shocked at how little purchase the titanium rings had that were bonded to the CF cylinder ends. The bonding was full width of the CF but the cylinder seated barely an inch into the titanium rings. In my opinion....they should have had a mechanical connection strong enough to hold the load and not just rely on the bonding strength of the end epoxy connection. At depth even the strongest material is going to suffer some compressive movement and this would try to lever the epoxy joints apart with no reinforcement from a thick sleeve that I think should have been encasing inner and outer surfaces of the CF from the titanium rings. These would have massively increased the bonding surfaces as well as stabilized the end joints. No doubt that the sub failed at these glue joints.
THanks for this comment, I am preparing a more in-depth look at the glue connection, it is hard to model though, therefore it took a while, will release it next week
This stems from a lack of understanding of the joint forces. It's a double lap shear joint on a huge cylinder so the bonding area would actually be quite large. Combined with the fact it's under compression which would push the joint together, not apart, means this is very unlikely the point of failure. More likely defects in the manufacture of the composite cylinder and cyclic fatigue caused failure.
@@banjobarnett85When the CF cylinder deforms under pressure...which it must...where will it deform the most? In the unsupported center which will bow in which is why nobody uses a cylinder for deep submerging vessels. Submarines that incorporate a long cylindrical pressure hull have many supporting bulkheads down the length to prevent the middle of the cylinder from deforming. When that cylinder starts to bow in the middle what happens to the ends? Of course the outer edges start to try to pull away from the titanium ring.
@@recoilrob324 sorry, but again this is a fundamental misunderstanding of the forces. You're taking an even cylindrical pressure and expecting it to perform as if a simply supported beam in bending. The centre should deform no more than the extremities of the cylinder unless held by a stiffer ring. I'm not convinced the thinner titanium ring and dome would shrink any less than the thicker carbon tube. Also 1/3 of the force is axial, so a large component pushing the titanium semi spherical ends and joints onto the carbon tube. I think you're confusing the method of using a thin metal hull not stiff enough alone to take the crush forces, supported by bulkheads or rings that will increase strength and stiffness in those areas causing a bending effect between bulkheads/rings. This wasn't the case and shouldn't be thought of as such. If there was a failure at this joint it wasn't due to design it was due to sealing in the joint failing and causing a high pressure water jet to enter the hull.
@@hnrwagner I had no issue understanding your English from previous videos if that's a concern for you. It feels more authentic. I did wonder if that was a David Attenborough clone.
@@hnrwagnerit’s not David Attenborough. It’s a computer and it’s disingenuous. You’re effectively stealing someone’s identity. Be honest, be genuine, use your own voice.
@@tubularmonkeymaniac I am not stealing anything, I paid the license to use it. Also, it saves me a ton of time. Have to check how the response in general is though.
Relying strictly on epoxy and the carbon fiber cylinder to hold the titanium ends in place was super sketchy IMO. It should have had an inner 'rib cage' made😊 of structural steel connecting the two ends together and spanning the inside of the tube to support the carbon fiber walls. This would convert some of the inwards pressure on the end caps into outward pressure on the CF hull via the beam loading, countering the inwards pressure it was feeling.
@@hnrwagner aircraft cargo vented to atmosphere, large thin steel structures subject to seismic loads, aircraft substructures with large bending/compressive loads
References: Future structural stability design for composite space and airframe structures www.sciencedirect.com/science/article/abs/pii/S0263823114000676 A Micro-macro Damage Mechanics-based Model for Fatigue Damage and Life Prediction of Fiber-reinforced Composite Laminates link.springer.com/article/10.1007/s10443-022-10039-y Microcracking in fiber composites and degradation of thermo-elastic properties of laminates www.semanticscholar.org/paper/Microcracking-in-fiber-composites-and-degradation-Loukil/4a273f2f7954af446d4d105a381789bde1be63ea Google Scholar: scholar.google.de/citations?user=a4sKEKsAAAAJ&hl=en Researchgate: www.researchgate.net/profile/Ronald-Wagner OrcID: orcid.org/my-orcid?orcid=0000-0003-2749-1455 Timecodes: 0:00 - Introduction 0:38 - Limit Load 1:00 - Ultimate Load 1:10 - Degradation of Composite 1:24 - Implosion Simulation 1:33 - Reserve Load 1:43 - Safety Factor 2:11 - Composite Hull of Titan 2:44 - Required vs Actual Design 3:33 - How the Composite Hull of the TITAN should have been designed?
@@hnrwagner Glad to hear that more is to come. The video cut out just as it was beginning to get interesting and I was wondering if there was a problem with the feed itself.
How much weight will the extra thickness add and do cracks in carbon fibre show up in xrays or other test equipment? If continuously cycled how many cracks are allowed?
thats the problem with carbon fiber. the most dangerous thing is the delamination of the individual layers and it is virtually impossible to detect with anything we have atm
Huh?? We can easily detect desalination with ultrasonic ndt machines, but perhaps you mean if the cracks happen under pressure, when the pressure I'd removed they are undetectable.
While carbon fibre composites are weaker in compression, for a UD (unidirectional) layup it is still as strong or stronger than steel for a much lower weight. So actually still a great material to use in compression.
I enjoy seeing the work you do. However on recent videos the inclusion of the AI voice is distracting for me. There is a vast amount of misinformation and spam videos all of which use voice generation it felt jarring hearing it on your videos (which contain factual information).
Using ai voice makes my life much easier, i am really annoyed by the fact that my overall watchtime of my videos is so low, i can always see that like 70 % of viewers stop watching as soon as the hear my voice, with ai it much much less. I will try it for one month and compare the overall results
do you think a stiffened CFRP cylinder would be better ? I am in the process of looking into it, Dont like the very thick composite design as well, it would be hard to manufacture.
When I watched a documentary about how the sub was built...I was shocked at how little purchase the titanium rings had that were bonded to the CF cylinder ends. The bonding was full width of the CF but the cylinder seated barely an inch into the titanium rings. In my opinion....they should have had a mechanical connection strong enough to hold the load and not just rely on the bonding strength of the end epoxy connection. At depth even the strongest material is going to suffer some compressive movement and this would try to lever the epoxy joints apart with no reinforcement from a thick sleeve that I think should have been encasing inner and outer surfaces of the CF from the titanium rings. These would have massively increased the bonding surfaces as well as stabilized the end joints. No doubt that the sub failed at these glue joints.
THanks for this comment, I am preparing a more in-depth look at the glue connection, it is hard to model though, therefore it took a while, will release it next week
@@hnrwagnerCool! Will be interesting to see what you come up with. Thanks!
This stems from a lack of understanding of the joint forces. It's a double lap shear joint on a huge cylinder so the bonding area would actually be quite large. Combined with the fact it's under compression which would push the joint together, not apart, means this is very unlikely the point of failure. More likely defects in the manufacture of the composite cylinder and cyclic fatigue caused failure.
@@banjobarnett85When the CF cylinder deforms under pressure...which it must...where will it deform the most? In the unsupported center which will bow in which is why nobody uses a cylinder for deep submerging vessels.
Submarines that incorporate a long cylindrical pressure hull have many supporting bulkheads down the length to prevent the middle of the cylinder from deforming.
When that cylinder starts to bow in the middle what happens to the ends? Of course the outer edges start to try to pull away from the titanium ring.
@@recoilrob324 sorry, but again this is a fundamental misunderstanding of the forces. You're taking an even cylindrical pressure and expecting it to perform as if a simply supported beam in bending. The centre should deform no more than the extremities of the cylinder unless held by a stiffer ring. I'm not convinced the thinner titanium ring and dome would shrink any less than the thicker carbon tube. Also 1/3 of the force is axial, so a large component pushing the titanium semi spherical ends and joints onto the carbon tube. I think you're confusing the method of using a thin metal hull not stiff enough alone to take the crush forces, supported by bulkheads or rings that will increase strength and stiffness in those areas causing a bending effect between bulkheads/rings. This wasn't the case and shouldn't be thought of as such. If there was a failure at this joint it wasn't due to design it was due to sealing in the joint failing and causing a high pressure water jet to enter the hull.
Is this video using AI voice over?
Yes. I couldn’t watch it for that reason.
You dont like david attenborough?
@@hnrwagner I had no issue understanding your English from previous videos if that's a concern for you. It feels more authentic.
I did wonder if that was a David Attenborough clone.
@@hnrwagnerit’s not David Attenborough. It’s a computer and it’s disingenuous. You’re effectively stealing someone’s identity. Be honest, be genuine, use your own voice.
@@tubularmonkeymaniac I am not stealing anything, I paid the license to use it. Also, it saves me a ton of time. Have to check how the response in general is though.
Relying strictly on epoxy and the carbon fiber cylinder to hold the titanium ends in place was super sketchy IMO. It should have had an inner 'rib cage' made😊 of structural steel connecting the two ends together and spanning the inside of the tube to support the carbon fiber walls. This would convert some of the inwards pressure on the end caps into outward pressure on the CF hull via the beam loading, countering the inwards pressure it was feeling.
The cage idea is obviously a good solution not really sure why the final design is so like your Suggestionen maybe too expensive
Mag die englische Stimme mit deutschem Akzent lieber, ist authentischer und wirkt kompetenter :)
Danke, ich mach vieleicht bei so "Doku" videos mal 2 Versionen, eine von mir gesprochen und eine mit AI voice ;)
Seen buckling issues like this pop up in other industries. It's not that widely understood, unfortunately.
Can you give some examples? I for one know about buckling in general pressure vessels or rocket structures. Also, thanks for the comment.
@@hnrwagner aircraft cargo vented to atmosphere, large thin steel structures subject to seismic loads, aircraft substructures with large bending/compressive loads
References:
Future structural stability design for composite space and airframe structures
www.sciencedirect.com/science/article/abs/pii/S0263823114000676
A Micro-macro Damage Mechanics-based Model for Fatigue Damage and Life Prediction of Fiber-reinforced Composite Laminates
link.springer.com/article/10.1007/s10443-022-10039-y
Microcracking in fiber composites and degradation of thermo-elastic properties of laminates
www.semanticscholar.org/paper/Microcracking-in-fiber-composites-and-degradation-Loukil/4a273f2f7954af446d4d105a381789bde1be63ea
Google Scholar:
scholar.google.de/citations?user=a4sKEKsAAAAJ&hl=en
Researchgate:
www.researchgate.net/profile/Ronald-Wagner
OrcID:
orcid.org/my-orcid?orcid=0000-0003-2749-1455
Timecodes:
0:00 - Introduction
0:38 - Limit Load
1:00 - Ultimate Load
1:10 - Degradation of Composite
1:24 - Implosion Simulation
1:33 - Reserve Load
1:43 - Safety Factor
2:11 - Composite Hull of Titan
2:44 - Required vs Actual Design
3:33 - How the Composite Hull of the TITAN should have been designed?
Thanks!
More is to come! What do you think of the AI voice? is it understandable?
@@hnrwagnerClear enough
@@hnrwagner Glad to hear that more is to come. The video cut out just as it was beginning to get interesting and I was wondering if there was a problem with the feed itself.
Fabulous content as usual. How much weight would the 55mm add to the structure?
would add about 500 kg to the whole sub, from 10.4 tons to about 11 tons
How much weight will the extra thickness add and do cracks in carbon fibre show up in xrays or other test equipment? If continuously cycled how many cracks are allowed?
thats the problem with carbon fiber. the most dangerous thing is the delamination of the individual layers and it is virtually impossible to detect with anything we have atm
Huh?? We can easily detect desalination with ultrasonic ndt machines, but perhaps you mean if the cracks happen under pressure, when the pressure I'd removed they are undetectable.
it will nearly double the weight of the composite cylinder
Compression forces.
Not what carbon-fiber is made for.
Pretty simple, I would have to say.
I will prepare a video which compares different materials for this purpose, thanks for the comment
While carbon fibre composites are weaker in compression, for a UD (unidirectional) layup it is still as strong or stronger than steel for a much lower weight. So actually still a great material to use in compression.
@@banjobarnett85 yes the its actually better than steel or titanium
For American audiences, the narrative voice from “how it’s made” is amazing. Guy named Brooks Moore
just checked my "AI voice service" its unfortunately not included, thanks for the tip
What a terrible AI rendition of a great man's voice. 👎
Do you know a better ai voice? Would be glad to hear your opinion
I enjoy seeing the work you do. However on recent videos the inclusion of the AI voice is distracting for me.
There is a vast amount of misinformation and spam videos all of which use voice generation it felt jarring hearing it on your videos (which contain factual information).
Using ai voice makes my life much easier, i am really annoyed by the fact that my overall watchtime of my videos is so low, i can always see that like 70 % of viewers stop watching as soon as the hear my voice, with ai it much much less. I will try it for one month and compare the overall results
@@hnrwagnerI understand. I hope you post the results of AI vs none AI in a month.
I don't recomend building to these specs. Or maybe do it was an intresting news story at the time.
do you think a stiffened CFRP cylinder would be better ? I am in the process of looking into it, Dont like the very thick composite design as well, it would be hard to manufacture.