Re:Titanic tourist sub goes missing sparking search
by dredmorbius on Monday June 19, 2023 @08:34PM
(#36398240)
NB: Aluminium is rather notorious for its tendency to develop invisible hairline fractures which fail suddenly. Particularly around high-stress regions.
The BOAC Comet failures (cracks propagating from squared-off window corners) is a notorious example, with multiple total hull losses in flight.
I've experienced somewhat less significant failures of bicycle components (though they could easily have proved far worse). It's a good idea to replace components after a wreck or even hard-cornering of a crankset.
Re:Titanic tourist sub goes missing sparking search
by pfdietz on Monday June 19, 2023 @11:12PM
(#36399291)
The window corner thing is an urban legend.
https://www.youtube.com/watch?v=-DjnG74DDno
The cracks actually started on the top of the plane, at cutouts for radio antennas. The windows always had rounded corners (although they made them even rounder later, which may have led to the confusion.)
Re:Titanic tourist sub goes missing sparking search
by dredmorbius on Tuesday June 20, 2023 @08:24AM
(#36403012)
Interesting, and a good explanation from Mentour Pilot as well.
Thanks!
I’m by no means a structural engineer, but with bike parts — in steel or aluminum, if you get a tiny 1mm chip in the material, you can more-or-less just treat it as if the steel is 1mm thinner. With engineering tolerances it is irrelevant.
But in a carbon fiber, that 1mm chip could be totally unnoticed for months, while slowly causing an invisible hairline crack, until the entire component suddenly explodes with no warning.
Maybe someone can verify if that is possible at a larger scale, but I feel like it must be to some extent.. especially if there is an invisible manufacturing imperfection due to the higher precision required in carbon fiber