Physical properties of wood pdf

Moisture relations and physical properties of wood. For others, such as douglas fir, it can be very thick, sometime more than 10 centimetres. It is a ratio of the density of a substance to the density of water. Mechanical and physical properties of wood fiberreinforced. This book provides a fundamental understanding of physical properties of foods. Because wood is a natural material and the tree is subject to many constantly changing influences such as moisture, soil conditions, and growing space, wood proper ties vary considerably, even in clear material. Variability, or variation in properties, is common to all materials. This moisture relationship has an important influence on wood properties and performance.

Density lesson 1 showed that wood is a porous material made up of cells of various kinds. Includes discussion of designing with wood and wood based products along with some pertinent uses. Physical and mechanical properties of selected wood species. Mechanical properties refer to the strength characteristics of wood. The chapter begins with a broad overview of wood water relations, defining key concepts needed to understand the physical properties of wood. Pdf physical and mechanical properties of timber wood. Some properties, such as tension parallel to the grain, and all properties. Cellulose, the major chemical component of fiber wall and contributing 4045% of the woods dry weight, is composed of linear chains of dglucose linked by. Growing ecological awareness tends to result in using fewer chemical preservatives. Physical and mechanical properties of mdf board from bamboo dendrocalamus strictus kapil sihag, anil negi, pawan kumar poonia and dp khali abstract medium density fibre board has unique properties like uniform, dense, smooth, and free of knots and grain patterns, it may be an excellent substitute for solid wood in many applications.

Earlywood is lighter in weight, softer, and weaker than latewood. Standard test methods for evaluating properties of wood. Students will investigate the density, stiffness, and elasticity of several species of wood. Included are such properties as moisture content, density, dimensional stability, thermal and pyrolytic fire properties, natural durability, and chemical resistance. The aim of this research was to study the physical and chemical properties of fly ashes from combustion process and carbon residue from gasification process whilst comparing the results between.

Understanding how materials behave in their natural state and under certain conditions will help them to understand why objects are made of specific. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. It is well known that decaying wood can absorb many times its dry weight in water 10 because woody tissue is highly hygroscopic 11, and additionally, water is produced after fungal. Wood, in the strict sense, is yielded by trees, which increase in diameter by the formation, between the existing wood and the inner bark, of new woody layers which envelop the entire stem, living branches, and roots. 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. 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. In bangladesh, tectona grandis has been considered as the standard for comparing the wood properties as it is very good timber for all purposes. All physical properties change from panel to panel depending on the natural characteristics of the wood used to make the panel. Nearly every culture throughout history has attributed magic properties to wood. Compression wood shows big differences from normal wood in conifers, for all physical and mechanical properties. Physical and chemical properties of wood ash from burning and gasification processes.

Optimized material composition to improve the physical and mechanical properties of extruded wood plastic composites wpcs. Progressive lumber operators are carefully studying how to keep their forest. This chapter discusses the structure of wood, its physical and mechanical properties, and the manufacturing and grading processes for sawn lumber and glulam. Pdf physical and chemical properties of wood ash from. 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. Sg for the major, usually used structural species ranges from roughly 0. Physical and mechanical properties of selected wood.

This research shows two common horticultural substrate components, pine bark and pine wood have varying physical properties and water release patterns at similar particle sizes. The first layer, the outer bark, provides protection for the tree. The amount of water absorbed by a material when immersed in water for a period of time. Mechanical, physical and chemical properties of wood, heat. And, just as shrinking and swelling of wood vary in the radial, tangential, and longitudinal directions, so do various mechanical properties of wood. Magic properties of wood wood is a remarkable substance, a gift from nature itself. 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. Softwoods comprise more than 80 percent of the total volume of standing timber in. Part of the workshop companion, a collection of information on wood, woodwork, woodworking skills, woodworking materials, and woodworking plans that together form the core knowledge needed by woodworkers, furniture makers, cabinetmakers, turners, and other practioners of the wood arts to become competent.

In trees, moisture content can range from about 30% to more than 200% of the weight of wood substance. Cellulose and lignin are responsible for some of the properties of a wood, such as the wood s ability to absorb moisture and. The chapter begins with a broad overview of woodwater relations, defining key concepts needed to understand the physical properties of wood. There was an overall increase of wood s physical and mechanical properties from the breast height to the top of the tree. Specific gravity is a measure of the amount of solid cell wall substance and is also known as relative density. Characteristics the wood is hard, strong, and machines well. The properties of materials and their everyday uses children need to have experience of, and explore as many different materials substances as possible in order to make sense of their world.

Following properties of wood makes it good for use in consruction. Material and method in this research wood based panels were produced from a mixture of wood chips and textile waste of acrylic fibers. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. The physical and mechanical properties of wood are important factors used in determining the suitability and application of wood material, these in turn depends on the wood specie.

To protect wood from the influence of moist air, the surface of wooden parts and products is covered with various paint and varnish and film materials. Generally, specific gravity sg and the major strength properties of wood are directly related. It provides an overview of wood based products and exposes students to structural systems in wood. Wood properties forest products laboratory usda forest service. This study was conducted to determine the effect of wood species on some physical properties density, specific gravity, %. In order to prevent cracking of eucalyptus species during drying treatment and enhance the physical properties of natural eucalyptus wood, the species have been impregnated with waterbased solutions of chemicals stamm 1977. Understanding the physical properties of foods is important as they are used in process design, product and process optimization, product development, food quality control and food process modeling. A chart of the physical properties of woods worlwide, excluding north america.

These properties are represented as the average mechanical properties of the species. It also has no characteristic taste or odor, making it suitable for woodenware, food containers, and novelties. Urea formaldehyde glue was used to hold the components together. Dry wood, placed in a very humid environment, is strongly moistened, which worsens its physical and mechanical properties, reduces biostability, etc. Physical properties and moisture relations of wood pdf 495 kb appearance moisture content shrinkage weight, density, and specific gravity working qualities decay resistance thermal properties electrical properties coefficient of friction nuclear radiation chapter 4. This chapter discusses the macroscopic physical properties of wood with emphasis given to their relationship with moisture content. The quality can be ensured by investigating the properties of timber. Followings are the physical and mechanical properties of timber. Here we have discussed both physical and mechanical properties of timber which affects timber quality. This course introduces students to the physical and mechanical properties of wood. Many of the challenges of using wood as an engineering material arise from changes in moisture content or an abundance of moisture within the wood. Pdf moisture relations and physical properties of wood. In our case, the ovendry od weight of a wood sample is used as the basis. 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.

Determination of some physical and mechanical properties. These trees bear cones and most of them have needle. Directcurrent electrical properties of wood 11 conception the electrical properties of wood are measured by its resistivity, orspecific resistance, orby its reciprocal, conductivity. In softwoods, the moisture content of sapwood is usually greater than that of heartwood. Wood is made up of about 50 percent cellulose, 28 percent lignin, and minor quantities of other materials. Physical and mechanical properties of mdf board from. Wood main physical properties archiline wooden houses. Comparative strength properties of woods d we are now on the threshold of the timljercrop period, which is based on the conception that timber is reproducible, like any other crop, except that the period of rotation is longer. Summarizes information on wood as an engineering material.

Pande wood anatomy discipline, forest research institute, dehradun 248 006 p oplars are among the worlds fastest growing industrial wood, which is grown in pure or mixed plantations as well as in association with agricultural crops. Properties of wood there are fewer species of conifers. Part of the workshop companion, a collection of information on wood, woodwork, woodworking skills, woodworking materials, and woodworking plans that together form the core knowledge needed by woodworkers, furniture makers, cabinetmakers, turners, and other practioners of the wood arts to become competent craftsmen. How do the physical properties of matter affect our everyday lives. Physical properties of world woods workshop companion. This lesson covers the physical and mechanical properties of wood. Wood main physical properties wooden house, log house. Physical and mechanical properties of selected wood species in. Properties of wood swst international society of wood. Moisture exchange between wood and air depends on the relative humidity and temperature of the air and the current amount of water in the. Physical and mechanical properties of reaction wood request pdf. Weight, shrinkage, strength, and other properties depend upon the moisture content of wood. Wood moisture and properties associated with its change 3.

The influences of fiber feature and polymer melt index on mechanical properties of sugarcane fiberpolymer composites. Properties of wood building and construction technology. The physical properties of wood, including color, weight, texture, grain, and pattern. Cellulose and lignin are responsible for some of the properties of a wood, such as the woods ability to absorb moisture and its resistance to corrosion by salt water. Wood is one of the most versatile and widely used materials in the world. Some physical properties discussed and tabulated are influenced. This paper examines physical and mechanical properties of wood and their variations within the tree stem of petersianthus macrocarpu. Physical and mechanical properties of beech wood harvested in the greek public forests. Lesson two the physical and mechanical properties of wood. Physical, chemical, and biological properties of soil. Wood handbookchapter 3physical properties and moisture. The results of the physical and mechanical properties of swietenia macrophylla grown in mixed and monoculture plantation are presented in the table 1.

Physical properties of wood designing buildings wiki share your construction industry knowledge. Physical properties are the quantitative characteristics of wood and its behavior to external. Because of the greater density of latewood, the proportion of latewood is sometimes used to judge the strength of the wood. 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.

Physical, chemical, and biological properties of soil under. 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. Some hold one type of wood to be sacred, while others believe that all wood has magic properties. The quality of timber must be ensured before using it for a purpose. 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. Pdf a lecture material at timber engineering class find, read and cite all the research you need on researchgate. Zelinka, materials research engineer 41 wood, like many natural materials, is hygroscopic. Status of anatomy and physical properties of wood in poplars. Sometimes it grows over 90 metres high and four and one half metres in diameter. Physical properties of wood designing buildings wiki. The important factors that affect the physical and mechanical properties of plywood are the density of the wood, species of. Physical properties of two tropical wood species from mozambique. Basic techniques for physical measurement and mechanical testing are introduced by conducting and analyzing several laboratory experiments. The combination of high relative humidity or mc and high temperatures, in unventilated attic areas, can have serious effects on roof sheathing.

Pdf physical and mechanical properties of beech wood. Because its physical and mechanical properties are so balanced, it rates highly for nearly all wood machining processes. Some properties, such as tension parallel to the grain, and all properties for. Physical properties of wood the properties of wood found in tests that do not lead to a change in chemical composition are called physical properties. This chapter discusses the physical properties of most. The properties of materials and their everyday uses. Many of the mechanical properties of wood tabulated in this chapter were derived from extensive sampling and analysis procedures.

Canada, and account for most of canadas commercial lumber and wood. This chapter discusses the physical properties of most interest in the design of wood products. Variations of the physical and mechanical wood properties of. So, wood is anisotropic in both its hygroscopic behavior as well as its mechanical behavior. The mechanical properties of wood open education process okfn, india the mechanical properties of wood including a discussion of the factors affecting the mechanical properties, and methods of timber testing samuel j. Status of anatomy and physical properties of wood in poplars p. Durability is the ability of wood to resist degradation tension, compression, bending, shear, etc. Wood handbookchapter 4mechanical properties of wood. There are several easily visible layers in the tree.