Properties of wood pdf

Wood an introduction to its structure, properties, and uses. Beams and columns deflection and stress, moment of inertia, section modulus and technical information of beams and columns. These properties are represented as the average mechanical properties of the species. Index numbers table 1 provide a convenient means of. Feb 23, 2018 directcurrent electrical properties of wood 11 conception the electrical properties of wood are measured by its resistivity, orspecific resistance, orby its reciprocal, conductivity. The combustion properties of various biomass and wood materials from various references and from our laboratory were reanalysed. Pdf physical and chemical properties of wood ash from. Dec 11, 2019 we say wood is anisotropic, which means a lump of wood has different properties in different directions. This chapter discusses the structure of wood, its physical and mechanical properties, and the manufacturing and grading processes for sawn lumber and glulam. Softwoods comprise more than 80 percent of the total volume of standing timber in. Weight, shrinkage, strength, and other properties depend upon the moisture content of wood. The hardwoods have a specific gravity ranging between 0.

Section properties aitc section properties these tables provide cross sectional area, section modulus and moment of inertia for both xx and yy axis, for standard glulam sizes. It is an organic material a natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Many of the mechanical properties of wood tabulated in this chapter were derived from extensive sampling and analysis procedures. Publications of the united states government on the mechanical properties of wood, and timber testing illustrations frontispiece photomicrograph of a small block of western hemlock 1. Update for combustion properties of wood components. The modulus of rigidity, also called shear modulus, indi cates the resistance to deflection of a member caused by shear stresses. Find materials for this course in the pages linked along the left. Includes discussion of designing with wood and woodbased products along with some pertinent uses. Bark properties should be distinguished from wood properties. And, just as shrinking and swelling of wood vary in the radial, tangential, and longitudinal directions, so do various mechanical properties of wood. Im working my way alphabetically by botanical name, so check out the latest added wood to see where im at in the queue.

Pdf improvement of wood properties by impregnation with. Beech can shrink considerably and is subject to movement more than other woods. This research was undertaken to examine the variation of the physical and mechanical properties within the stem of a tropical hard wood species, petersianthus. In strength properties other than shock resistance and hardness, it is stronger than most mainland woods of comparable density tables 1 and 4.

Adhesives with wood materials bond formation and performance charles r. Cork is the lightest wood having a specific gravity of 0. Part ii deals with the factors affecting the mechanical properties of wood. Fuel properties for combustion analysis of wood can be conveniently grouped into physical, thermal, chemical, and mineral properties. Attempting to understand wood in the context of wood technology, we have often overlooked. In many cases, more than one property of wood is important to the end product. Included are such properties as moisture content, density, dimensional stability, thermal and pyrolytic fire properties, natural durability, and chemical resistance. Wood is an orthotropic material with unique and independent properties in different directions. If a wood were of the same density as water, its specific gravity would be 1. Range of the 65 species of trees and shrubs called ash, sixwhite, pumpkin, blue, black, green, and oregon ash are commercially important for lumber and other wood products. We at goldentree wands believe that all wood has specific magic properties, unique to each species and variety.

Information on engineering with wood, properties of wood and designing with wood. Properties of wood the wood consists of rows of tube. The earlywood cells are usually broader because they carry more water in the spring for the leaves and new shoots. Wood is one of the most versatile and widely used materials in the world. Mechanical, physical and chemical properties of wood, heat. Density of various wood species density of various wood species apple, ash, cedar, elm and more. Wood, panel and structural timber products mechanical. The moisture content of wood is another property of timber which effects the quality of timber to. Physical properties of wood designing buildings wiki share your construction industry knowledge. Design values for wood construction dvwc materials covered ndimension lumber wvisually graded nwestern woods nsouthern pine wmachine graded ntimbers softwood and hardwood wvisually graded. The mechanical properties of wood including a discussion of the factors affecting the mechanical properties, and methods of timber testing language. For others, such as douglas fir, it can be very thick, sometime more than 10 centimetres. Wood properties forest products laboratory usda forest service.

Im slowly grinding my way through roughly 800 wood species that have still yet to be listed on the site. Wood is made up of about 50 percent cellulose, 28 percent lignin, and minor quantities of other materials. Mechanical properties of wood forest products laboratory. Wood materials used in cabinets and furniture are products of nature and include numerous color hues, grain patterns and other natural characteristics.

An updated version of this publication, released in 2010, is available at wood handbook, 2010 pdf, 15 mb. Mechanical properties of woodbased composite materials publication. For efficient use of wood in the future three major areas need to be addressed. Presents properties of wood and woodbased products of particular concern to the architect and engineer. The physical and mechanical properties of wood are important factors used in determining the. Physical properties of wood designing buildings wiki. In softwoods, the moisture content of sapwood is usually greater than that of heartwood. Publications and articles on the mechanical properties of wood, and timber testing part iii.

For example, to select a wood species for a product, the value of appearancetype properties, such as texture, grain pattern, or color, may be evaluated against the influence of. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same. Chapter 5 mechanical properties of wood modulus of rigidity. Miller contents bark, wood, branches, and cambium 21 sapwood and heartwood 22 growth rings 22 wood cells 23 chemical composition 23 species identification 24 references 24 he fibrous nature of wood strongly influences how it is used. Let me know if youve got something interesting that youd like to donate to the site. Wood chemical composition hemicellulose a celluloselike material in the wood cell wall that is easily decomposed by dilute acid to yield simple sugars extractives organic material deposited during heartwood formation gums, resins, oils, alkaloids. Includes discussion of designing with wood and wood based products along with some pertinent uses. Properties of wood swst international society of wood. Presentation pdf available october 2010 with 4,140. Pdf physical and mechanical properties of timber wood. Wood is a traditional building material, as popular today as ever.

The combination of high relative humidity or mc and high temperatures, in unventilated attic areas, can have serious effects on roof sheathing. Usage despite its hardness, beech wood can be worked. These tables provide cross sectional area, section modulus and moment of inertia for both xx and yy axis, for standard glulam sizes. Kretschmann contents orthotropic nature of wood 41 elastic properties 42 modulus of elasticity 42 poissons ratio 42 modulus of rigidity 43 strength properties 43 common properties 43 less common properties 424 vibration properties 425. Wood is a remarkable substance, a gift from nature itself. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the wood. Wood main physical properties archiline wooden houses. It has good strength properties and high abrasion resistance. Thermal degradation products of wood consist of moisture, volatiles, char and ash. The three moduli of rigidity denoted by glr, glt, and grt are the elastic constants in the lr, lt, and rt planes, respectively. Chapter 5 mechanical properties of wood modulus of rigidity the modulus of rigidity, also called shear modulus, indicates the resistance to deflection of a member caused by shear stresses.

So, wood is anisotropic in both its hygroscopic behavior as well as its mechanical behavior. Because of the orientation of the wood fibers, and the manner in which a tree increases in diameter as it grows, properties vary along three mutually perpendicular axes. Density lesson 1 showed that wood is a porous material made up of cells of various kinds. Standard test methods for evaluating properties of wood.

This chapter discusses the physical properties of most. What follows are general uses and working and drying characteristic of the most frequently used species, including several tropical hardwoods. Moisture relations and physical properties of wood. Standard test methods for evaluating properties of woodbase fiber and particle panel materials1 this standard is issued under the. Methods in astm standard d 245 involve adjusting strength properties of small clear specimens of wood, as given in astm standard d 255506 2011 establishing clear wood strength values, for effects of knots, slope of grain, splits, checks, size, duration. Mechanical properties strength robusta is a very strong wood.

Structural grades and related allowable properties for visually graded lumber. Because its physical and mechanical properties are so balanced, it rates highly for nearly all woodmachining processes. Physical and mechanical properties of timber wooddestroying organism, termite. There are several easily visible layers in the tree.

In trees, moisture content can range from about 30% to more than 200% of the weight of wood substance. Physical and chemical properties of wood ash from burning and gasification processes. Southern pine samples with different dimensions and bulk densities were impregnated with the multifunctional monomer ethyl. Department of agriculture, forest service, forest products laboratory.

Canada, and account for most of canadas commercial lumber and wood. Pdf this chapter includes a description of the anatomy of wood, a discussion on timber properties and the factors that influence these properties. Presents properties of wood and wood based products of particular concern to the architect and engineer. Physical properties refer to density and moisture relations that affect its use. We will discuss commercial wood species, wood structure, lumber grades, water movement in wood, how wood dries, specific gravity and weight of wood, wood shrinkage, stress development during drying, and electrical and thermal properties of wood. Pdf mechanical properties of wood duc hoang academia. Physical and mechanical properties of selected wood. It can be used in anything from wood carving and creating small wooden items, such as chairs and rocking horses, to building timber structures and sheds.

Although wood is an excellent heat insulator, its strength and other properties are affected adversely by exposure for extended periods to temperatures above about 100f. Stressstrain diagrams of two longleaf pine beams 2. Nearly every culture throughout history has attributed magic properties to wood. Baker abstract the fuel properties of wood can be summarized by ultimate and proximate analysis and determination of the high heating value. Physical properties of wood this is a handson lesson in which students investigate the relationship between physical properties of wood and its suitability for construction purposes. This moisture relationship has an important influence on wood properties and performance. Yildiz c the objective of this study was to evaluate the discoloration of european beech fagus sylvatica and scots pine pinus sylvestris specimens. Section properties american institute timber construction. As with any density measurement for wood, it is greatly dependent upon the woods moisture content. Some hold one type of wood to be sacred, while others believe that all wood has magic properties. Physical and mechanical properties of selected wood species. An updated version of this publication, released in 2010, is available at wood handbook, 2010 pdf. Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. Update for combustion properties of wood components mark dietenberger usda forest service, forest products laboratory, one gifford pinchot drive, madison, wi 537262398, usa email.

The fine sawdust produced when machining the dry wood is said to be responsible for allergic responses in certain individuals. Wood in this density class would require sharp knives to ensure the production of smooth surfaces in planing. Drill bits conversion chart convert between drill bit dimensions gauge numbers, inches and mm. Western hemlock tsuga heterophylla general description among the harder, stronger western softwoods, it is marketed and sold separately as well as in the hemfir species combination. As a manufacturer of wood components, woodcraft industries believes there is a crucial need to educate our company, customers, and consumers in regard to naturally occurring wood characteristics.

Wood handbookchapter 3physical properties and moisture. It also has no characteristic taste or odor, making it suitable for woodenware, food containers, and novelties. Chapter 4 moisture relations and physical properties of wood one portion all cell lumina may be empty and the cell walls partially dried, while in another part of the same piece, cell walls may be saturated and lumina partially or completely filled with water. Moisturerelated properties of wood and the effects of. Some properties, such as tension parallel to the grain, and all properties for some. Pdf introduction to timber as an engineering material. Structure and function of wood alex wiedenhoeft, botanist 31 wood is a complex biological structure, a composite of many chemistries and cell types acting together to serve the needs of a living plant. Students will investigate the density, stiffness, and elasticity of several species of wood. The strength and related properties of redwood 5 the last two columns of tables 1 and 2 are, respectively, percentage figures on the estimated probable variation in specific gravity of an individual tree as a whole from the corresponding average, and of an individual specimen of a tree from the same average.

Formation and properties of juvenile wood in southern pines. This lesson covers the physical and mechanical properties of wood. Top 6 properties of wood and timber used in construction. It is not valid to list these values for species since a species has not been adequately sampled and tested. The moisture content of wood means the relationship between the mass of water in it and the mass of the timber without the water. Hunt, research chemist 101 adhesive bonding of wood plays an increasing role in the forest products industry and is a key factor for efficiently.

Characteristics the wood is hard, strong, and machines well. May 01, 2004 the mechanical properties of wood including a discussion of the factors affecting the mechanical properties, and methods of timber testing language. Wood fuel properties and fuel products from woods a. Definition the mechanical properties of wood are its fitness and ability to resist applied or external forces the mechanical properties of wood considered are 1 stiffness and elasticity, 2 tensile strength, 3 compressive or crushing strength, 4 shearing strength, 5 transverse or bending strength, 6 toughness, 7 hardness, 8 cleavability, 9. The first layer, the outer bark, provides protection for the tree. Wood handbookchapter 4mechanical properties of wood.