Tensile strength of Hickory

[Laserxenon]

Could someone please refer me to the tensile strength of American Hickory, parallel to the grain of the wood. I checked

http://www.matweb.com,

but only could find values for the tensile strength perpindicular to the grain. If the value cannot be found, how do the strengths differ perpindicular versus parallel to the grain?? Thanks for any help.

 

[boo1]

You can find it in Forest Products Laboratory. 1999. Wood handbook--Wood as an engineering material. Gen. Tech. Rep. FPL-GTR-113. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. PP5 CH4 at:

http://www.fpl.fs.fed.us/documnts/FPLGTR/fplgtr113/Ch04.pdf

 

[boo1]

Laser did the link i provided u, have the information you desired.

 

[Laserxenon]

boo1; sorry for the delay; i looked over the info, and was still only able to find the strength perpindicular to the grain. I did find the tensile strengths parallel to the grain of a few woods, excluding hickory (the website is a good reference though).
I am not sure why this value is cited so much more than parallel, as it seems that if u were to load the beam in tension, u would try to load it parallel to the grain, so i dont get why they always list perpindicular.
I could take the average ratio of say 10 woods of loading perpinicular vs. parallel, and then try and adjust the figure for hickory to get a ball park figure... what do u think??- drew

 

[jfhunt]

You need to read page 3 of chapter 4 of the wood handbook. "Tensile strength parallel to grain. Maximum tensile stress sustained in direction parallel to grain. Relatively few data are available on the tensile strength of various species of clear wood parallel to grain. Table 4–7 lists average tensile strength values for a limited number of specimens of a few species. In the absence of sufficient tension test data, modulus of rupture values are sometimes substituted for tensile strength of small, clear, straight-grained pieces of wood. The modulus of rupture is considered to be a low or conservative estimate of tensile strength for clear specimens (this is not true for lumber)."

 

[IFRs]

Here is a listing for tension:

http://www.fpl.fs.fed.us/documnts/FPLGTR/fplgtr113/Ch04.pdf

This is for pine, not hickory, but it does list tension parallel to the grain:

http://www.southernpine.com/designvalues1.htm

This one lists many woods, including Hickory, but NOT tensionat all:

http://www.woodbin.com/ref/wood/strength_table.htm

You may be able to use the second reference to compare pine to hickory and get a ballpark tensile value for hickory.

This link lists general properties and has some interesting data, but no numbers:

http://www.extension.iastate.edu/Publications/PM329.pdf

This one states that "Due to difficulties in testing and the limited use for such data, tension parallel to the grain has not been extensively measured and/or reported to date." :

http://members.cox.net/messman123/Laboratory results.htm

 

[Trussdoc]

The National Design Specification for Wood Construction (ANSI-AF&PA-NDS)Supplement gives basic design values for a Beech-Birch-Hickory group that include tension parallel to grain.

Loading any wood PERPENDICULAR to the grain in tension is not a good idea, because (1) the bond between wood fibers is weaker than the strength of the fibers (hence the large difference between parallel and perpendicular design values)(2) as wood dries, cracks may form between the layers of fibers, which reduce the effective cross sectional area.

To quote the NDS(Section 3.8.2 of the 1997 edition):"Designs that induce tension stress perpendicular to grain shall be avoided wherever possible..."

 

[boo1]

Hickory and Pecan Carya spp. Strength and mechanical properties can be found at:

http://www.hardwoodinfo.com/species_guide/display_species.asp?species=hickorypecan#

Tension Perpendicular to Grain (lbf/in2)
-- 680