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Main Boards => The Bowyer's Bench => Topic started by: Camp Creek on April 16, 2025, 09:00:23 AM

Title: Limb Bending Mechanics
Post by: Camp Creek on April 16, 2025, 09:00:23 AM
Is anyone here interested in looking a bit more in depth into the mechanics of limb bending?
I would think you could place a bow on a tillering board and carefully measure the deflection at several intervals, say every inch or two, as the bow is drawn and compare those measurements to the theoretical deflection predicted by P2L3/6EI or  ML2/2EI with similar type formulas for the deflection angle.  I would think that treating the bow limbs as several discrete segments would make the math significantly easier due to variations in cross section not to mention any deflex, reflex, or recurved portions.
If anyone is interested in this or has done something similar, I would definitely be interested in discussing it.  It's been several years since I've done any actual engineering, but I think this could be rather interesting and possibly informative regarding limb design, stored energy, etc.
Title: Re: Limb Bending Mechanics
Post by: Kirkll on April 16, 2025, 10:11:25 AM
You might try posting this in the bowyers bench part of the forum. There are a few guys that really get into geeking out on such things.

The only person I know that has dove deep into what you are looking at is another engineer named Alan Case. He wrote a program called Super Tiller a number of years ago, and could definitely give you some tech input.  He also is well known in the world flight shooting circuit.      Kirk
Title: Re: Limb Bending Mechanics
Post by: Roy from Pa on April 16, 2025, 11:54:03 AM
TTT
Title: Re: Limb Bending Mechanics
Post by: mmattockx on April 16, 2025, 01:21:26 PM
Quote from: Camp Creek on April 16, 2025, 09:00:23 AM
Is anyone here interested in looking a bit more in depth into the mechanics of limb bending?

Welcome new guy. This has been done by several people. As Kirk mentioned, Alan Case did Super Tiller a number of years ago. Along with that is an excel spreadsheet by David Dewey. He used to post on a number of the trad archery forums as woodbear and still occasionally pops up on the Primitive Archer site under that same username. The most current software seems to be a program called Virtual Bow. A google search will find it with no problem. I have used both Super Tiller and the David Dewey spreadsheet a fair amount and have tinkered with Virtual Bow a bit, but not done any actual analysis/design work with it.


Mark
Title: Re: Limb Bending Mechanics
Post by: Camp Creek on April 17, 2025, 11:02:41 AM
I couldn't find Super Tiller, but I did download Virtual Bow and will play around with it a bit.

Thanks for the info!