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max amount of load on a front, frame-mounted bike rack
(lemmy.world)
Im in the process on building something similar with the rack you see in the picture.
What I want to know is if its possible to determine the optimal length of the tube on the frame and on the rack to allow the max load under stress without the rack breaking/bending on a spot that its not mounted on the frame, and what would be the max load?
and if it is, how to calculate it? :)
things that i know:
- number of tubes
- length
- diameter
- thickness
- bending tube angle
- stainless steel type
worth saying that this is more of a learning exercise.
A quick rule of thumb for a cantilever beam is to have 2/3 of it supported. In other words, the length of the tube on the frame should be double the length of the tube on the rack. That's not a rigorous calculation, though. (And it's for just getting on with building the thing, rather than being a learning exercise. FWIW, I'm an engineer but I wouldn't bother doing any calculations for this kind of project. It's only worth it if you're planning to mass-produce it and want to optimize costs.)
As for going through with the learning exercise, these might help get you started:
https://www.egr.msu.edu/~harichan/classes/ce405/chap2.pdf
https://user.engineering.uiowa.edu/~design1/StructuralDesignII/BeamDesign.pdf
https://engineering.purdue.edu/~ce474/Docs/DA6-BeamFormulas.pdf
By the way, thanks for posting because that's a neat rack and now I want one, too.