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SFXBTPD t1_jacneqw wrote

Reply to comment by ShEsHy in TIL the last B-52 Bomber produced for the US left the factory 10/26/1962 - the same day as the climax of the Cuban Missile Crisis - they're still used 60 yrs later. by GoGaslightYerself

Basically to get unlimited fatigue life with aluminum parts you need to keep the cyclic loading below 5% of ultimate.

So all the aluminum will eventually need to be replaced.

I don't know what the 'safe life' or a B52 is, but they estimate a number of hours/cycles for crack growth to begin and base maximums around that.

The air force does damage tolerance analysis too (for life after crack formation), but I think that started after the b52 program (and i cant remember details offhand)

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