Re: spoke fatigue troll

Ben C wrote:
On 2008-04-26, jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:
Ben C wrote:
[...]
For inbound spokes it won't though-- they get a tensile loading on the
inside of the bend in use, where there is the small tensile residual.

Although not the highest region of tensile residual, it still might
accelerate fatigue that starts on the surface due to a surface
imperfection. I think that's Cole's point.
peter cole is just fixated on the fact that because there may be a residual stress, there will definitely be fatigue. which is not the case here because it's not observed to be initiating in that high residual zone.

Well I think you're right about that.

But I'm not sure Peter Cole has claimed the presence of residual stress
means there will definitely be fatigue (premature fatigue that is-- that
there will be fatigue in cyclically loaded aluminium is as certain as
death and taxes).

But Brandt _does_ appear to claim that residual stress causes spoke
failure and that stabilization works by stress-relieving. That's a step
too far for me.

the thing for me is that it's not like he couldn't go out and acquire evidence if he really believed it to be true. hard data is where it's at, not assertion based on fundamental misconception such as the belief that he can eliminate fatigue from a material with no fatigue endurance limit.
.

Relevant Pages

  • Re: Touring frame recs
    ... well constructed frame. ... Alas, the s ame problem. ... that led to fatigue failure. ... Any minor amount of residual stress suggested by the slight mismatch ...
    (rec.bicycles.tech)
  • Re: Touring frame recs
    ... well constructed frame. ... Alas, the s ame problem. ... that led to fatigue failure. ... Any minor amount of residual stress suggested by the slight mismatch ...
    (rec.bicycles.tech)
  • Re: Mavic
    ... would predict that more failures would start on the outsides of the ... insides of all other spokes, assuming fatigue always nucleates from the ... never on the sides where the residual stress of forming ...
    (rec.bicycles.tech)
  • Re: Mavic
    ... it's not at the fatigue nucleation points. ... would predict that more failures would start on the outsides of the ... never on the sides where the residual stress of forming might be. ... but the elbow does /not/ have that residual stress profile at the nucleation points, thus it has no role in fatigue. ...
    (rec.bicycles.tech)
  • Re: New hub from Shimano
    ... The reduced cross-section and stress concentration at the fatigue crack could cause failure. ... Since you content your wheel with missing spokes is a functional wheel, ... these include surface finish, composition, environment, etc. and eventually residual stress. ...
    (rec.bicycles.tech)