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Strength Mechanical Properties of Wood

Mechanical properties or strength of wood is wood’s ability to hold a charge or load from outside. The intention is to charge external forces outside objects that have a tendency to change the shape and size of objects. Mechanical properties or strength of wood include: tensile constancy, constancy press / compression, shear firmness, determination arch (bending), stiffness, ductility, hardness and firmness sides.

Wood Structure
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Fig. Part of the wood

(1) Bark, located on the outer part of the stem. Bark consists of the outer skin and the skin. Dead outer skin serves as a protective tissue that is located inside the other. Skin serves as the transportation of photosynthesis from the leaves.
(2) Kambium, is a layer of cells that duty to form new cells. Direction in shaping the wood, to the outside to form new skin.
(3) Wood sapwood, is part of the wood that is still alive. Colored generally younger and brighter. Sapwood serves as Salu ran groceries from the roots to the leaves to be processed further and as a store of food reserves.
(4) Heartwood, is dead wood. Generally, darker and contains extractives. For wood that are toxic to the extractive orgnisme damaged wood, wood terrace to be more durable than sapwood.
(5) Heart Wood, located in the center of the circle. Early wood is formed by the tree is soft and rapuh.Jari-Finger Wood, a wood cell lines from the center of the circle towards the bark. Composed of cells of wood lying. Serves as a channel food to the radial direction.
(6) Circle of the Year, is seen as circles surrounding a wooden heart. Differences in growth during the rainy season and dry season look at the differences in the magnitude of the cells are formed. In the dry season, the cells formed smaller with thicker cell walls than the cells formed during the rainy season.
(7) Cell Wood, several types and patterns of cell structure and the arrangements in the timber will affect the properties of wood. There are some important differences in the wood cells coniferous and broadleaf wood.
(8) Variation Type Trees

Judging from the composition of the wood there are 4 kinds of variants
(a) Trees that have wood G and T, also called tree terrace. The difference between wood and wood T G evident. Wood T has a dark color, are adjacent to the shaft and the exterior is light-colored wood G

(b) The trees have wood G and M, have no wood porch. The difference between wood and wood T G is not so clear. If from outside to inside looks darker color, then it is said to cook outside.

(c) The tree that has a G wood completely, do not have a wooden porch. In other words, the tree is a tree heartwood timber that has not so hard. The entire cross section of the rod is a distributor of food and has a bright color.

(d) The tree that has a wood G, M, and T. mature trees of the wood has a small terrace, gradually enlarged. Three differences visible to the outside, namely timber T, F and G.

b) pull Firmness
Tensile strength or firmness of a type of wood is wood strength to withstand the forces trying to pull the timber

c) Determination press / compression
Firmness press a type of wood is wood strength to withstand the load of timber if the timber was used for a particular purpose. Distinguished two types of compression, the compression perpendicular to the direction parallel to the direction of fiber and fiber compression.

d) sliding Firmness
Firmness is to measure the shear strength of wood in terms of its ability to withstand the forces that make a piece of wood or bergelingsir gets shifted another nearby. In this case distinguished three kinds of shear persistence is constancy sliding parallel to the fiber direction, perpendicular to the shear firmness and constancy fiber sliding tilt.

e) Determination curvature (bending)
Firmness is curved or bending strength to withstand the forces trying to bend the wood or to resist loads other than dead or alive blows burden to be borne by the woodwork. Firmness distinguished curved arch static firmness and constancy arch o’clock. Firmness curved wood strength withstand static show style about it slowly and firmness curved wood at is the power that hits withstand the force of a sudden, such a blow.

f) Stiffness
Wood stiffness, both of which are used as belandar or pole is a measure of the strength in its ability to resist deformation or curved. The stiffness modulus of elasticity is expressed by the term derived from arcing constancy tests are static.

g) Tenacity
Tenacity is a term used to describe many properties of wood. Like a hard split wood, wood that is not broken before the shape change, is said to be a resilient wood. Tenacity can be defined as the ability of wood to absorb a relatively large amount of power or resistant to surprises or voltages Beru u lang-lang, beyond ibatas proportionate and lead peru k material bentu permanent and partial damage.

h) Strength
Strength is a measure of the strength of wood in the style hold up a notch or indentation happened to him. Violence wood can also be defined as the ability of wood to withstand abrasion (abrasion), as a measure of its resistance to wear wood.

i) Determination sides
These properties are used to express the strength of wood in resisting the forces trying to split the wood. Shopping voltage is a voltage that occurs because of the force that acts as a wedge.