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Defectos comunes de la madera . Wood Oral Presentation. Presented by : Yureisly Suárez and Aaron Pineda. Introduction.
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Defectos comunes de la madera Wood Oral Presentation Presented by: Yureisly Suárez and Aaron Pineda
Introduction • The destruction of the world´s forest is in major concern in our age. This destruction is because mankind all along history has used this material in catastrophic proportions taking advantage of how available wood is.
Wood’sPhisycs Properties • Low density: floats on water, that’s why it’s used on ship’s fabrication. It has 2 densities: absolute and partial density. The first one it’s determined by cellulose and derivatives, and the second one depends on the water that its pores contains. Both densities give us the real density. • Toughness: it’s directly related with density, a higher density gives a higher toughness. The central area of a trunk it’s the hardest because it’s more compact than the rest. The humidity affects the toughness of the wood, leaving it soft when it’s very wet or fragile when it gets dry.
Wood’sPhisycs Properties • Bad electricity and heat conductor, that’s in dry wood, because of its cells full with air, can be used as a non-conductor material. • Texture: it’s the property of the wood that determined the surface look and its stability. • Durability: the hardwoods resist better conditions such as humidity and the contact with ground, which are the most damaging for general wood.
Wood’sPhisycs Properties • Anisotropy: wood presents different kind of behavior depending the fiber’s direction. • Flexibility: property that has most of the woods to be easily bend following the sense of the veins. • Veins are the most known characteristic of wood. Density pattern of the vein determines its resistance and with more pattern of vein in an specific area it’s more resistant.
Types of Veins Vertical vein: when the veins grows up parallel to the vertical axis of the trunk. Spiral vein: when the trunk’s growth is twisted Diagonal Vein: it can be seen when the trunk is growing up and doesn't finish its vertical axis. Interlace vein: it’s when veins grows up in opposite directions every year. Irregular vein: when the veins are diverted from the axis. Wavy vein: when the trunk is diverted every period of time in its growth.
Commercial Forms There are a lot of commercial woods, but the most important are: • Agglomerates: it can be obtained mixing chips and rest of other crushed woods with special glue and compressing them • Double veneer: union of several glued and pressed wood sheets • Fiberboard: is obtained by combining wood particles or fibers with a synthetic resin and then pressed • Laminate: are formed by an artificial base stuck with a very thin sheet of wood or plastic with wood vein.
Mechanical Properties of Wood • Resistance: it’s one of the most suitable material for traction and its special directional structure. Its resistance will be maximum when the force is parallel to the veins. • Indent on wood: property that shows the wood can break along the separation of these fibers by a transverse traction effort.
Common defaults of wood Bow: curve on the board side in longitudinal way Cup: concavity of the board side in the transverse way Crook: kwon as crown
Common defaults of wood Knot: loose or dead knots that may arise or have already left a hole Split: crack running through the whole piece of wood, usually at the ends Twist: The board is warped in many places
Common defaults of wood Check: a crack parallel to the annual growth rings that doesn’t cross all wood Shake: separation of the fibers between the growth rings
Most Important Uses • Agricultural tools, vehicles, tool handles, sports items, ship building, building structure, exterior carpentry, flooring, furniture, interior carpentry, professional and scientific instruments, cockpit, bridge, screws, carving, veneer, barrels, boxes, etc.
Conclusion • We think that the wood is a material available and easy to use. For Architecture and Urbanism the wood is an important construction tool, not only give the structure stability but it can be used as a decorative material, specially in a place that has a very classic theme. And for urbanism it’s more used in its original form (trees) to better up the view of a city.
