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unless the deformations go beyond a certain limit, it doesn't impact the overall load distribution that much though
A wheel designed to be only just up to the job will have the spoke tension drop to zero for at least one spoke under maximal load condition, unless the maximal load causes the tension of at least one spoke to rise to the yield point. A perfectly designed wheel will have at least one spoke at zero tension and at least one spoke at the yield point under maximal load condition 🙂
gbj_tester-
Ok that sounds good in theory, but that's not really how engineering works though. In practice I would not trust anyone claiming to have designed a wheel like that, because you don't really know the 'maximal load condition', and you always want some kind of safety factor anyway. In actual fact, almost everything in life is overengineered to a varying degree. The stuff that isn't is the stuff that occasionally breaks way too early and people get annoyed about. So you want to make sure you're not going to the limit on anything. I'd also rather pay for stuff to have a safety factor, than brake my bike with my face.
In any case, the tension in spokes being different is not what second-order effects refer to, that's just what happens due to the preload you mentioned earlier, and the way any wheel is built. That's too complicated to work out quickly on a sheet of paper, but there are computer programs that would allow you to figure it out relatively 'easily'. The really complicated stuff happens when you start to consider how the non-rigidity of the material subtly changes the way the forces apply, and how that in turns changes the deformations themselves again. You can then move on to third-order effects, but honestly it gets a bit pointless at that point.
But the thing is, because you always put on a safety factor and because those second-order effects are comparatively small unless your rim was to flex significantly, it's not really worth putting too much time into working out their exact impact, you don't want to be that close to failure anyway.
SwissChap
Yeah, those were called 'second-order effects' when I studied this kind of thing (in a civil engineering context though, and that was in German, so might be called something else in English). If I remember correctly, unless the deformations go beyond a certain limit, it doesn't impact the overall load distribution that much though. The thing is that here, a full model is already difficult to 'solve' fully for a rigid wheel.