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@Isotropic
OK, so stress analysis is done. time to see what we have.
Firstly, with the visualisation, i have set the maximum visualised load to 200MPa, anything above that will appear as grey. The yield strength of this steel is likely to be in the 600MPa region, by aiming at 200MPa, we have effectively set a factor of safety of 2. That is, I have to be wrong by a factor of 3 for it to fail (easily done when youre guessing quite a lot of stuff :P).
Heres a flange with a radial spoke pattern, loaded purely by a spoke tension of 150kg:
What we are looking is the von Mises stress (MPa) applied to the hub, red is bad, blue/green is good (or is it? well come to this later).
this is all fine, no high stress except around the spoke holes. The spoke hole stress is probably an analytical error assocaited with the manner to which im applying the load.
Now, lets imagine im on the bike. I weigh 70 kg, but in the near future i may put a load of weight on, so im assuming i weigh 100kg. the worst loading manner possible, is 100kg applied through a two spokes, one on each flange (this is not realistic, its a massive load in comparison to what you would typically expect, but over estimating is completely fine, its just under estimating).
With this loading, the hub now looks like this:
No prizes for guessing which spoke is loaded! the spoke width appears to be about spot on (complete fluke there...). We can also see an additional stress concentration on the outter most edge of the hub next to the loaded spoke.
Now, heres the fun part. lets look at what isnt under much load, and cut the material away. Looking at it, not much is going on around the body of the hub, or the material that connects adjacent spokes on the outer most edge. So i removed material from these two areas, and i will resubmit the geometry. The updated geometry is right here:
Just so we are all on the same page, this hub is still predominantly made of steel. its going to be heavy. i would be pretty happy if it ended up sub 200g :)