Originally Posted by
Sunfish
How many cycles/hours is a 787 airframe good for? Do we know or is there an extended life test article somewhere? QF may be showing very good sense in getting rid of these airframes now before structural issues appear.
My limited understanding is that damage to carbon composites accumulates and once laminates start separating the degradation accelerates partly due to what is called “the free edge problem” in Engineering stress analysis terms, it’s akin to the phenomenon of wood splitting along grain lines.
Furthermore, my perhaps dated understanding is that you can never repair damaged carbon to 100% of initial strength, no matter how much you spend, but that may not be true these days if there have been new advances in adhesives and bonding.
Google is your friend
https://www.aerospacetestinginternat...e-testing.html
The Boeing 787’s carbon composite structure can take over three times the stresses of its design lifetime, according to recently reported test results.A five-year fatigue test simulated more than 160,000 take-offs and landings, more than the design life of 44,000 cycles, says a report in Aviation Week and Space Technology.
Fatigue life testing is SOP for a new aircraft - something you
should know...