This moisture relationship has an important influence on wood properties and performance. Pdf mechanical properties of pinewood pinus sylvestris. Correlations between fibre properties and paper properties. Wood, panel and structural timber products mechanical.
Density of various wood species density of various wood species apple, ash, cedar, elm and more. Many of the mechanical properties of wood tabulated in this chapter were. Most wood products are used in home building and construction, and are popular because they are a natural and renewable resource with good thermal and mechanical properties. Pdf improvement of termite resistance, dimensional. Mechanical properties of pinewood pinus sylvestris swollen. With the increase of tree rings and the associated decrease in the proportion of late wood, the density is reduced, mechanical properties also deteriorate only pine wood with wide growth rings from 4 to 6 mm din 40741 is suitable for construction. The major wood products we export are paper and paperboard, woodchips, sawn wood and panels. 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. Pure substances and aqueous solutions influenced the mechanical properties of wood in different ways. Poplar samples populus euramevicana were treated with hemicellulase, while samples of southern yellow pine pinus spp. Index numbers table 1 provide a convenient means of comparing properties of the various species. As with other coniferous woods, the properties of the wood depend upon the density of the annual growth rings. Mechanical properties of pinewood pinus sylvestris swollen in organic liquids. The average strength of green, clear wood speci mens of coast douglasfir and loblolly pine in compression parallel to grain is approximately 3,784 and 3,511.
A comparative study of some of the mechanical properties. The three moduli of rigidity denoted by glr, glt, and grt are the elastic constants in the lr, lt, and rt planes, respectively. Theres quite a range in density and strength when it comes to the pinus genus. Mechanical properties strength robusta is a very strong wood. Pine from intensively managed plantations finto antony, laurence r. Strengthgraded southern yellow pine is able to achieve strength classes of up to c30, making it one of the stiffest. Application of the product requires pressure treatment by an approved treating process and preservative for. Sensitive instruments can detect the penetration of light radiation through thick pine wood samples up to 35 mm. Strength properties of wood increase with its decreasing moisture content. Thus the mechanical properties of the clear wood may indicate that a species is an excellent wood for boxes for bulk commodities, but the lumber may be unsuited for such use because of a characteristic tendency of the knots to. Properties of thermally modified southern pine wood. One wide face and both adjacent narrow faces must be free of pith andor heartwood. Main uses ponderosa pine pinus ponderosa 1, sugar pine pinus lambertiana 2 and idaho white pine pinus monticola 3 are valued. Because lamination, the properties in x axis and y axis, axial direction are different.
Structural grades and related allowable properties for visually graded lumber. Mechanical properties of southern pine crosslaminated. Physical and mechanical properties of selected wood. Improvement of termite resistance, dimensional stability and mechanical properties of pine wood by paraffin impregnation. Mechanical properties of wood charles peterson signature wood. Scots pine the wood database lumber identification softwood. Wood is a hydrophilic material, very sensitive to water and other liquids. 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. Drill bits conversion chart convert between drill bit dimensions gauge numbers, inches and mm.
Kretschmann abstract bending and compression paralleltothegrain tests were conducted on approximately 200 dry southern pine 140 by 140mm 6 by 6in. Take one of the species of southern yellow pine, shortleaf pine, for instance. Tests to determine the effect of the time rate of applica tion of load on the mechanical properties of timber, including impact tests. Effects of seasoning and preservatives on the properties of treated wood. The widespread use of wood in the construction of buildings has both an economic and an aesthetic basis. It is established now that wood could be used effectively for neutron radiation shielding.
Strength properties of wood for practical applications. Wood handbookchapter 3physical properties and moisture. Pdf physical, chemical and mechanical properties of pinus. Stressstrain diagrams of two longleaf pine beams 2. In strength properties other than shock resistance and hardness, it is stronger than most mainland woods of comparable density tables 1 and 4. Kretschmann, research general engineer 51 the mechanical properties presented in this chapter were obtained from tests of pieces of wood termed clear and straight grained because they did not contain characteristics such as knots, cross grain, checks, and splits.
Mechanical properties of southern pine treated with copper. These trees bear cones and most of them have needle. The age of demarcation between juvenile and mature wood varied by species and property, ranging from to 20 years. The wood has a distinctive colour and grain, its sapwood. A comparative study of some of the mechanical properties of pine wood heat treated in vacuum, nitrogen, and air atmospheres the use of heat treatment to modify wood using different treatment heat transfer media, such as nitrogen, vegetable oil, steam, and vacuum, is preferable in many respects to other methods that use chemical treatments. Table 1 provides the design values for visually graded southern pine dimension lumber that became effective june 1, 20. 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. 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. Relation of the moisture content to the various strength values of spruce. At age 40, plantation trees sampled were projected to contain approximately 25% juvenile wood. Properties and benefits of nordic spruce and pine wood products. Includes discussion of designing with wood and wood based products along with some pertinent uses.
Beams and columns deflection and stress, moment of inertia. Scots pine, wooddensity components, wood quality, xray microdensitometry. Mechanical properties of clear straightgrained wood 426. Properties pine wood is mediumweight and relatively soft. Earlywood and latewood elastic properties in loblolly pine. Mechanical properties of glued laminated lumbers are depended on the species of laminations used. Effects of the wood preservatives on mechanical properties of. The mechanical properties of ew and lw and theirvariations ultimately influence the behavior of wood products. Mechanical properties of pinewood pinus sylvestris. The important factors that affect the physical and mechanical properties of plywood are the density of the wood, species of. Scots pine is easy to work with both hand and machine tools.
Such calculation fits perfectly the sapwood of scots pine but is not applicable to wood species with low permeability caused by limited number of opened pits e. Mechanical properties of both treated samples were investigated by nanoindentation. The higher the proportion of summerwood, the heavier and harder the wood. Spruce wood main physical properties wooden house, log. Presents properties of wood and wood based products of particular concern to the architect and engineer. Pine sapwood, swollen in aqueous solutions of ethanol, has better elastic properties compared to wood, swollen in other organic liquids used in this study. Burkhart a study was conducted to identify geographical variation in loblolly pine bark and wood properties at the wholetree level and to quantify the responses in wholetree. As a result, wood possesses material properties that may be significantly different from other materials normally encountered in structural design. Sprucebiological property of woodbenefits availabletrunk has a long soundknotted part.
However, specific gravity values also reflect the presence of gums, resins, and extractives, which contribute little to mechanical properties. A comparative study on the mechanical properties of. Xray radiation has almost no effect on the structure and mechanical properties of wood, so it is used for inspection of assortments. Mechanical and anatomical properties in individual growth. This gives it a hardness of 690 on the janka scale, making it ideal for decking or flooring in areas of heavy traffic. Wood handbookchapter 4mechanical properties of wood. Includes discussion of designing with wood and woodbased products along with some pertinent uses. Because its physical and mechanical properties are so balanced, it rates highly for nearly all woodmachining processes. Some property relationships are nearly linear and others exponential. International research group on wood preservation document no. Beams and columns deflection and stress, moment of inertia, section modulus and technical information of beams and columns.
Scots pine is readily treated with preservatives and can thereafter be used in exterior applications such as posts or utility poles. Properties and benefits of nordic spruce and pine wood. For example, airdried wood with average moisture content of 12 percent will have higher strength properties than that of wood with 20 percent moisture content. 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. Characteristics the wood is hard, strong, and machines well. Scots pine has a mild, resinous odor when being worked. Wood, panel and structural timber products mechanical properties density, fibre stress, compressive strength and modulus of elasticity of clear wood, panel and structural timber products. Properties of thermally modified southern pine wood pretreated with alkylalkoxysilanes cong chen, wang wang, jinzhen cao, qi qi, and wenbo ma the alkylalkoxysilane aas preimpregnation method and thermal modification were combined to improve the waterrelated properties of southern yellow pine pinus spp. Publications and articles on the mechanical properties of wood, and timber testing part iii. General description often referred to as the white pines, this is a commercially important group, known for its resinous odour and light colour. A comparative study on the mechanical properties of laminated veneer lumber lvl produced from blending various wood veneers. Effects of the wood preservatives on mechanical properties. The ability to construct wood buildings with a minimal amount of equipment has kept the cost of wood frame buildings competitive with other types. Scots pine the wood database lumber identification.
Physical and mechanical properties of selected wood species. Sometimes it grows over 90 metres high and four and one half metres in diameter. Pdf mechanical properties of papua new guinea balsa wood. The ability to construct wood buildings with a minimal amount of equipment has kept the cost of woodframe buildings competitive with other types. Mechanical properties of wood forest products laboratory. The objective of this study was to establish a database of individual elastic properties of matched ew and lw specimens, not only to provide mean values for loblolly pine, but also to indicate the variability of pro. Micrograph red pine ew early wood lw late wood rc resin canal r ray. Spruce wood is very soft and has an average density of 470 kg m. Mechanical properties of pinewood pinus sylvestris swollen in.
Gilbert, b tony dakin, a and adam faircloth a rotary veneers from spotted gum corymbia citriodora and white cypress pine logs callitris glaucophylla recovered from the. A comparative study on the mechanical properties of laminated. Properties of wood there are fewer species of conifers. Presents properties of wood and woodbased products of particular concern to the architect and engineer. This chapter discusses the physical properties of most. Plywood is produced from softwood and hardwood species of trees, and the species used in its manufacture determine the physical and mechanical properties of the plywood. Mechanical properties of ccatreated southern pine after posttreatment kiln drying.
Many of the mechanical properties of wood tabulated in this chapter were derived from extensive sampling and analysis procedures. It also has no characteristic taste or odor, making it suitable for. The colour of sound knots does not differ from the surrounding timber. Wholetree bark and wood properties of loblolly pine from. This is an exhaustive programme and can be carried out only after many years of work. The mechanical properties of wood composites depend upon a variety of factors, including wood species, forest management regimes naturally regenerated, intensively managed, the type of adhesive used to bind the wood elements together, geometry of the wood elements fibers, flakes, strands, particles, veneer. The major wood products produced in australia include sawn timber.
The heartwood has good natural durability except where it is in direct. 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. Average mechanical properties of juvenile wood ranged from 47% to 63% of those for mature wood in pine and from 62% to 79% in cottonwood. Bouldin, phd2 3 abstract 4 crosslaminated timber clt is. Pdf downloads of southern pine design value tables are available. The moisture content of wood also is an important parameter influencing almost all mechanical properties. 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. Design values for southern pine are comparable to other softwood species used in residential and commercial construction. Design values for structural glued laminated soft wood timber for member stressed primarily in bending are listed in nds table 5a.
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