Aluminum has a finite fatigue life. That doesn't mean it will fail one day after it's expiration date. Different alloys have different characteristics and their strengths age at individual rates.
Some day it will fail under load. Chances are good that a properly designed structural aluminum for a car will out last the owner of the vehicle.
I'm sorry, but I don't believe you understand how loads and fatigue works...
How and if something fails, depends on how it was designed, regardless of the material...
I guarantee I could lay an aluminum I beam on the floor with some 2x4's under each end, and jump up and down on it till the day I die, and it won't fail...
Take the same beam, cut it in 1/2, weld it back together and have fat lady do the same thing, still won't fail...
Take 100 load and apply it to a beam that will only withstand 100 lbs, and yes eventually it will fail.
Now apply that load to a beam that will withstand 1000 lbs.
It will never fail.....
CR
