It's incorrect to say that *any* metal that is cyclicly loaded will fatigue and fail eventually. Steel and titanium alloys have a fatigue limit, which means that there is an amplitude of stress below which the material will not fail no matter how many cycles of stress are applied. Aluminium, OTOH, does not have a fatigue limit and will eventually fail at any repeated stress. See for example, the diagram plotting stress against number of cycles to failure for steel and aluminium at http://en.wikipedia.org/wiki/File:S-N_curves.PNG. However, given proper design, the number of cycles to failure becomes extremely high. After all, there are still airlines flying DC-9s that are getting on for 40 years old, many airfreight 747s are over 30 years old, and the USAF is planning to keep B52s in the air until about 2040, by which time they will be getting on for 80 years old. And all those have aluminium airframes.
In about 40 years of riding, the only pair of handlebars I've had break were a pair where the handlebar bag mount looped over the top of the bars each side of the stem and (I discovered after the bars broke) had worn a substantial groove in the bar. Outside of bars being damaged like that, I only replace bars if they've been crashed and bent. I think the oldest pair I have in use are about 30 years old - Cinelli Campione del Mondo. On Tuesday, 19 March 2013 08:10:09 UTC+11, William wrote: > > You pose two questions: > > 1. Anyone know anything about aluminum bar life? > > I know a little bit about fatigue life of materials. Any metal that is > cyclicly loaded will fatigue and fail eventually. > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
