Material flexibility was always a problem with composites. Looks like they 'cured' it. (/pun)
The current problem with composites is the difficulty of identifying internal cracking/crazing (or whatever). One phase of testing includes thumping on the suspect part like its a watermelon. Perhaps better non-destructible methods now exist--but I am not keen to see aircraft careening across the landscape/skyscape because of rudder or other control surface failure.
I remember the first composite rotor blade that Boeing was using on its entry in the contest to replace the Huey (Sikorsky won that with the Blackhawk). Back in 1975, Boeing brought a section of a composite blade down to Quantico to show at HMX-1, the Marine Presidential and R&D helo squadron. This rotor blade spar had been shot through by 7 rounds of 23 mm ammo (non-HE Soviet). The blade was then bolted to a test rig and run at 100% rpm, for two hours, I believe, and held up just fine.
A similar metal blade would have developed fatigue cracks from the stress riser caused by one bullet hole then the blade would have broken. Loss of one blade on a CH-53 helo causes the center of gravity of the rotor system to move 24". The rotor now wants to oscillate about this new CG at 3 cycles per second imparting a 30G to 50G load on the aircraft. Not a good thing! The helo appears to explode in flight from the shaking.
Composite blades are our friends!
I have found that over the years with the sun beating down on them ,composites get brittle . Hope they have solved that.
Gee, you were just making a pun and you got some serious technical replies!