[WalterBright]

> unlike a metal hull, carbon fiber hulls accumulate subtle damage on compression that's hard to detect

All metals suffer from that, too. It's called fatigue damage. It bedeviled the aviation industry for a long time because there was no reliable way to detect the fatigue damage.

Eventually, an ad hoc formula was developed to calculate the fatigue damage, and then replace parts that were getting close to the limits.

That's why airliners are scrapped after something like 62,000 flight cycles.

[watwut]

The standard testing for submarine involves 1000 cycles of going to full depth/pressure and up. And depth higher then the target depth.

Only after that you can use it for paying passangers. This submarine survived the depth around 23 times. (Most of the "trips" were 3m deep)

[hinkley]

Aluminum is especially bad this way. And we make airplanes out of it.

[Jtsummers]

And if you're USAF, you practically strip the aircraft to its frame every few years, inspect, repair, and reassemble it. The dangers are known and the process around it is there to deal with those dangers.

Most aircraft fleets operated by people who care will do something similar but perhaps not as extreme. In fairness to them they don't expect to fly the plane as long as USAF does (70+ years for the B-52, 50+ for many fighters).

[WalterBright]

These days it's carbon fiber.

[hinkley]

Not all of them. The 787 yeah, but it seems the 747-8 is still somewhat metal.