Posted on 06/26/2023 8:57:11 AM PDT by xxqqzz
The one-of-a-kind Titan submersible that imploded on its descent to the site of the Titanic this week, killing all five passengers, was made with experimental materials, including carbon fiber, which experts say has not been pressure-tested over time in such extreme depths.
Since the fatal dive, the innovation behind the Titan and OceanGate Expeditions — the company that owned and operated the vessel for paid tours to the Titanic — has come under increased and intense scrutiny.
Days after the Titan was reported missing, sparking a frantic search, the U.S. Coast Guard said Thursday that the 22-foot craft imploded, though officials do not yet know when or why.
(Excerpt) Read more at aol.com ...
Kraft paper, one of Niagara Daredevil’s experimental materials, comes under scrutiny.
I’m wondering how much weight savings played into his thinking with carbon fiber also.
I mean with aerospace it’s obvious, but given transport and logistics of a standard steel submersible both on land and the water I can’t help but think that huge savings in weight had something to do with them choosing it as well.
Carbon fibers have tensile strengths on the order of 400,000-700,000 psi (high strength steel is 180,000 psi) but the epoxy resin strength is on the order of 24,000 psi. If the vessel had no carbon fiber in the longitudinal direction it had virtually no strength or structural rigidity in the long direction. I simply can't conceive of anyone actually designing or building such a vessel because it breaks pretty much every design and fabrication rule in the composite world, but James Cameron seems to confirm that the videos are representative of the manufacturing process and the vessel was pretty much a hoop wound design. Which scared the heck out him - and rightly so.
I am not an engineer. However, 3 countries have had deep sea submusibles for 30-60 years, and their may be private ones. Why wouldn’t you copy what was already working rather than innovate? I guess a cylinder was better for carrying more paying passengers than a sphere.
The development process is long, expensive and tedious.
Apparently these dopes never had to deal with OSHA.
Don’t forget the recycled ballast , they had move to one side to get it to drop off and then I suppose the sub would lurch back the other way and drop the other side’s ballast ,scary
The best way to do multi-directional windings is hundreds of years old.
I have made sand molds where they subject sand with a binder in a high pressure press around a steel support. In fact the shape is almost identical to this sub, just much smaller. Aside from the two small holes at the ends where the support extends out of the sand the mandrel is 100% exposed and there is no limit to how you want to wrap it before the vacuum bag goes on and into the autoclave.
When it’s done it’s just a matter of pushing out the center bar, cutting the end a little bigger and vibrating the sand free and out.
That is why titanium is popular for this application.
Even the best designed thick wall composite pressure vessels just don't perform well in extreme high external pressure applications.
And composites are just not well suited for most submarine applications for a wide variety of reasons, most of which are practice in nature. . Which is too bad because the performance gains are substantial
I actually spent a bit time back in the day evaluating composites for retrofit into fast attack subs but they just did not meet the needs of the sub guys in all but a few select applications. In some cases they were flat dangerous.
I wonder if Rush was an engineer or just a slick talking huckster pimping his proruct?
The bane of fiberglass yachts. Dust between layers leads to delamination and your yacht comes apart in a good storm in the middle of the ocean.
Great point.
Of course, you can also get non-homogenous metals as well, but voids, inclusions, grain problems, and other problems can be found with 100% radiography. I was in the power industry for a long time and radiographing boiler tube welds was very common.
“Use By Date” — kind of weird to read that there is such a date on an inorganic material. It’s not like yogurt in the fridge or tomatoes on the counter.
The strength of carbon fiber layup is vastly overrated. S-glass is stronger in almost every way. Other important aspects include monolithic layup, multiple layers, and vacuum bagging (fabric-to-resin ratio).
Composites are fine for deep water applications. The deep end of my fiberglass pool is certified to six feet.
Fascinating Stuff..
I stumbled into it in the early ‘90s
and remember a British guy wrapping a part in cotton,attaching a vacuum bag around it and Then putting it into an oven for 12 hrs. We were upgrading a Penske chassis to run a Buick V6.
Carbon fiber times Out.
.
Fun times
I rather got the impression that he was a slick salesman.
Which would be fine, if he hired good engineers and LISTENED TO THEM.
But he didn’t.
That crap about middle-aged White men being “uninspiring” shows that the project was doomed from the start.
(And some retired engineers from Morton Thiokol are saying “here we go again ...”)
Real Seinfeld stuff There!
“If the reports are true, the vessel was almost completely hoop wound carbon fiber tows, which means the vessel had virtually zero strength in the longitudinal direction because there were no carbon fibers in that direction to hold it together. only weak epoxy type resin.”
Didn’t they test it without people in it in actual water at depth?? Multiple times??
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