XPost: alt.politics.usa, alt.fan.rush-limbaugh, alt.survival
On 5/26/25 10:22 AM, Frank wrote:
On 5/25/2025 8:31 PM, c186282 wrote:
https://www.dailymail.co.uk/news/article-14746421/The-Titan-submersible-
DOOMED-dive-Revealed-forensic-horrifying-shocking-catalogue-neglect-
criminal-oversight-left-victims-trapped-death-tube.html
. . .
Worth reading.
Mistake #1 was using fiber-epoxy construction instead
of steel or titanium. Yes, it IS strong, but is also
more flexible. Repeated flexing CRACKS the epoxy. Even
on the very first dive there were 'exploding' sounds
which the owner just laughed about. With cracks, the
carbon fiber itself will soon begin to tear, invisibly.
The SHAPE was mistake #2 ... anything meant to go
THAT deep should be ROUND, not a tube.
Other aspects of the design and engineering and
maint were also condemned. Even the electrical
system was fer-shit.
Composite materials DO have many good uses, but
SERIOUS engineers have to put each of those under
the proverbial microscope BEFORE you use the stuff.
Physical tests, simulation tests, detailed
examination during lifetime tests.
The sub owners kinda skipped all that ....
Composites have different strength in different directions. They are strongest under tension but less so under compression. Shear strength
is even less and adhesion of fiber to resin maybe be one tenth the
tensile strength.
No really "perfect" material - though titanium comes
fairly close, albeit $$$
I never saw anything describing the exact shape of
the pressure hull. A perfect cylinder and the center
part will bow inwards, making the whole thing shorter.
That would be tension. But it it was slightly 'football'
shaped that same change would start with compressing
the central area, making the whole thing a bit longer
in the process - UNTIL you pass a critical point and
the first case takes over rather abruptly.
And you're right - for some fiber-epoxy composites the
weakest point is the resin. Mechanical cycling, UV and
ageing make it progressively weaker. I have some concerns
for aircraft because of this, they've gone more and more
over to composites. We PRESUME aircraft designers have
top-notch experts and have done proper testing ... but
you never know for sure ....
Resin cracks and there goes the stiffness. Not so great
for an airplane wing.
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