I worked in a big steam plant a couple of decades ago. If we had trouble with our turbines that was beyond what we could do, we consulted or hired the turbine manufacturer (GE). Expensive, but they knew the machines.
Navigating back then was not a perfect science. Celestial nav required clear skies. Get a few cloudy days and nights in a row and your dead reckoning can be pretty far off. In that case, officers need to err on the side of caution (as in keep farther off shore and slow down, etc). Wait until...
Not a structural engr here, but I have put a fair amount of thought into this.
Some here seem to have a LOT of experience in structural composites, and I certainly respect that knowledge.
But to this generalist, I came up with a few possibilities:
1. Non uniform distribution of stress in the...
I am no stress analysis type engr, but on that 5" thick CF cylinder in compression, are the stresses uniform throughout the laminate? I think not, but too lazy to research it.
I know our Navy subs use ribs internal to the pressure hull.
Wonder if this thing could have been built up with...
I read an interesting piece today in Vanity Fair. I'd post a link but I just burned up my free article. Now behind a paywall for me.
A few interesting take-aways:
1. There were basically no substantial pieces of CF found in the wreckage. They picked up some shards, that is it.
2. Some of...
I could see water migrating into the CF hull, either through the sides protected with Rhino Liner (really??), or from the edges where the TI ends glued on.
I do not think Rhino Liner has been tested to be non-permeable at 5000psi.
Fortunately could be a relatively easy fix. Cut out damaged section, fab new section (with proper reinforcement) and weld or rivet it in place. Could be done in situ. But who knows what the concrete already poured did.
That was a lot of rebar on that concrete deck. Could see where the engr...
I too think the different response of the Ti end caps and CF hull to huge external pressure may have factored in here. If the end caps had more strain, that would have been transferred to the CF, and increased stress there. Or to the epoxy joint.
No substitute for repeated deep dives with...
Stupid design. Top element from thin section should continue at least into next panel or two of the taller section.
I can see that right away, and my study was in thermo and fluid flow!!
I think analyzing what happened in the last few milliseconds (or microseconds) of this crafts life is an interesting, albeit academic exercise. Kinda like analyzing what happens in an airliner when it hits the side of a mountain at 3-4-500mph. Well, it hit the mountain and bad things happened...
I've read a fair amount about CF testing in compression. Some good stuff linked here..
But what about fatigue response in compression? Seems like a vital bit in this failure.
I could look it up, but I'm being a bit lazy!
I would give credit to OG if they took a prototype of their submersible to a deep part of the ocean and did like 100 dives to test depth (what ever that is) and preferably took it on last dive to failure. Then the next boat would have some cred.
Not clear at all what type of test protocol was...
I wonder a bit about osmosis on that laminate. 5-6000psi is a LOT of pressure and wonder if water can get pushed into the laminate at that pressure.
Also where the Ti end caps were glued to the CF cylinder ends. Osmosis there? The machined ends of the CF cylinder are particularly vulnerable...
