hmm. sarcasm doesn't translate well with color codes
I can't seem to sleep now that I'm retired/retarded
I crunched some numbers. I hope our authorities fish the wreck bits off the ocean floor and do an investigation. I would like to know how the hull failed of the Titan.
Composite pressure vessles are usually in tension like a SCUBA tank. Carbon fiber TOW is wound around an aluminum liner. The aluminum doesn't provide structure just the form for the fiber to be wound on. Some of the windings are circular and we call these hoops and some of the windings are diagonal. The hoops take the radial loads and the diagonals take the axial loads.
Now this submersible is loaded in compression. Carbon fiber/fiberglass/kevlar are very strong in tension and not great in compression.
Concrete is the other way around; great in compression and lousy in tension
I'm actually somewhat sympathetic to Stockton Rush because I can see how he may have went down the path of a composite hull. Its light, cheaper to manufacture than a metallic hull and you can get the neutral bouancy without resorting to tanks of gasoline like the Triest had.
So..since I can't sleep I was thinking about how much pressure is on the hull along the axis. I used these numbers
6000 PSI sea pressure
2.8 meters hull diameter or 110" for those of us who live in a country that put a man on the moon
hull thickness 5"
these are numbers I got off the internet somewhere, the sea pressure is really the only one I can be somewhat confident in
and I got 34500 psi in compression
This is within a good carbon fiber strength but that is when the fibers are lined in the direction of the load and that is not the case with this pressure hull.
The fibers in the hull are mostly hoops so the this load is 90 deg to the fibers. I don't think any of the fibers are alinged with the axis of the hull. The resin is taking much of the load along the axis and the strengths of resins vary.
Room temp cure resins are around 9000 psi tension and resins that need heat to cure are significantly stronger but nowhere near 34.5 ksi
If I had a time machine and could talk to Stockton Rush a couple years ago I would suggest that he build two hulls (or more) and have it fully instrumented and take it some place truely deep, like the Marianas Trench and lower it on a cable and see at what depth does the hull fail. Then take the other hull to the Titanic and lower and raise the hull at least 100 times.
Rush made the mistake of taking short cuts and if I can quote JRR Tolkien; Short Cuts Make Long Delays