Originally Posted by
Peterpan1
If something has a finite lifespan that means it is working past yield (I'm just guessing here), that sounds kinda squishy to me.
A fatigue failure does not mean that there are stresses that exceed the yield strength of the tubing. That's the misunderstanding that caused the Brits to lose all those Comet passenger jets back in the '50s, the airframe was built to accept a load far higher than it would ever see in service.