A question came up on a model airplane forum, and I realized that my never-got-past-sophmore-year mechanical engineering chops aren't up to the task.
Can anyone point to any material -- particularly in handbook form, so I don't have to learn a whole new branch of science -- in predicting the torsional stiffness of a wooden shaft? I know how to do this for any isotropic material, but wood ain't isotropic.
Tim Wescott fired this volley in news:cbWdnQuGtZ3f88LNnZ2dnUVZ snipped-for-privacy@web-ster.com:
Torsional and Bending Behavior of Wood Beams
by Abolhassan Vafai, A.M.ASCE, (Asst. Prof. of Civ. Engrg., Univ. of Northern Arizona, Flagstaff, AZ) and George Pincus, M.ASCE, (Prof. of Civ. Engrg., Univ. of Houston, Houston, TX)
Journal of the Structural Division, Vol. 99, No. 6, June 1973, pp. 1205-
1221-00000000-
Keep in mind that wood in torsion (twisting along the grain axis) acts like a bundle of small pipes. The individual pipes just _might_ be isotropic in character... but I'm not versed in that.
Funny, that. I've made torsion-resistant wing spars in model aircraft. I ended up making a pretty fancy seven-layer, two-axis laminated composite of wood and carbon fiber ribbon to get the torsional strength I needed. It was for a LONG-winged sailplane with very heavy wing loading (high-start launched) and very light gross weight.
I used to joke that it was the strongest half-by-one piece of lumber in the world! 'Most expensive, too!
But everything I did was purely empirical... no tables or calculations involved.
LLoyd
Lloyd
On 9/23/2012 3:17 PM, Tim Wescott wrote: ...
It's a particular area I've not looked for, sorry, but if there's anywhere to start it's with the Forest Products Lab Handbook...
The various research universities in the Carolinas, Michigan, Vriginia (VPI, particualarly, there) etc., also do quite a lot w/ what is left of the wood manufacturing businesses...
--
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.