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Hankinson's equation (also called Hankinson's formula or Hankinson's criterion) [1] is a mathematical relationship for predicting the off-axis uniaxial compressive strength of wood. The formula can also be used to compute the fiber stress or the stress wave velocity at the elastic limit as a function of grain angle in wood .
[citation needed] PSL can be made from any wood species, but Douglas fir, southern pine, western hemlock, and yellow poplar are commonly chosen [9] because of their superior strength. The product is manufactured as a 12-by-12-inch (300 mm × 300 mm) or 12-by-18-inch (300 mm × 460 mm) billet in a rectangular cross-section, which is then ...
It is a generic building material and is used in building just about any type of structure in most climates. Wood can be very flexible under loads, keeping strength while bending, and is incredibly strong when compressed vertically. There are many differing qualities to the different types of wood, even among same tree species.
In 2011, Douglas-fir represented 34.2% of US lumber exports, to a total of 1.053 billion board-feet. [ 42 ] [ 13 ] Douglas-fir timber is used for timber frame construction and timber trusses using traditional joinery, veneer , and flooring due to its strength, hardness and durability. [ 43 ]
The ultimate strength is the maximum stress that a material can withstand before it breaks or weakens. [12] For example, the ultimate tensile strength (UTS) of AISI 1018 Steel is 440 MPa. In Imperial units, the unit of stress is given as lbf/in 2 or pounds-force per square inch. This unit is often abbreviated as psi.
When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. [3] The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the ...
Specific modulus is a materials property consisting of the elastic modulus per mass density of a material. It is also known as the stiffness to weight ratio or specific stiffness.
Pseudotsuga / ˌ sj uː d oʊ ˈ t s uː ɡ ə / [1] is a genus of evergreen coniferous trees in the family Pinaceae (subfamily Laricoideae).Common names for species in the genus include Douglas fir, Douglas-fir, Douglas tree, Oregon pine and Bigcone spruce.