swope

I think this is the Nature Communications article cited in the OP link:
https://doi.org/10.1038/s41467-023-39341-4

And ads.

Without reading the article, this smells a lot like #enshittification

At what point do lawyers cite a SCOTUS decision as precident and their opposition is like "yeah but that's an Alito decision" and they're like "oh yeah, oops."

I'm surprised this isn't a named sort of cognitive bias. I think there's a related thing where we humans tend to cite external causes outside our control when we are unfortunate or make mistakes, and we tend to cite our own virtues when we are fortunate and successful.

I agree with all of that. My intuition is that prior to curing, the polymers are less stable and may change in unpredictable ways depending on subtleties in the storage environment and handling. After curing, the polymers are much more stable and durable.

Metals definitely are more forgiving, and we have better tools for testing, especially non-destructive testing. Whether the CF flaws are due to fatigue or workmanship, it's easy to miss them in inspection.

I'm also curious what the sub designers saw as the advantage of CF for this application. Is light weight really all that advantageous for a submersible? Generally no one chooses CF if they are prioritizing cost.

Different loads, different failures, but still a valid safety concern.

I would not want my bike frame or fork to be made with expired resin. But the age of the bike after the CF is cured is a different matter.

From my limited experience with laying up carbon fiber, I know there's the raw carbon fiber cloth and there's liquid resin that you spread into the cloth. It's also very common to see carbon fiber cloth that is "pre-impregnated" - the resin is already applied to the cloth. Everyone calls this "pre-preg".

So I've seen a lot of folks online scratching their heads about "how can carbon expire?" or "my carbon fiber (bike/boat/etc.) is N-years old, is it expired?" but I think the most likely thing to expire is the resin. Once the resin is cured it is much more stable.

Any materials folks or structures engineers who want step in and correct me, please do.

Alabama has a federal reserve for rocket scientists & their whole ecosystem. There's a pretty neat safari you can go on where they've set up a bunch of enrichment toys and such for the rocket scientists to play on.

MSFC Test Stand

Apparently some people get sucked into jet engines twice. Enough that there's a medical code for Sucked into jet engine, subsequent encounter: https://www.aapc.com/codes/icd-10-codes/V97.33XD

Earlier this year I visited the NTSB's lab for recovering data from "black boxes" and other data recording devices on aircraft and other vehicles.

I remember my host said that NTSB is mandated to investigate every aircraft accident in their jurisdiction, but they can pick and choose which accidents to investigate in other modes. Also, for many nations that don't have the resources or expertise for an aircraft accident investigation, NTSB does the work pro bono.

Most aircraft accidents are general aviation (not commercial airliners) so it's a similar situation where a lot of NTSB resources are spent on what is largely a rich-people pursuit.

I saw this from an airplane recently. The scale is more than I could comprehend.