2. where MOR is the bending modulus of rupture (MPa), P is the maximum force (N) at the mid-span, L is the span length (m), b is the width (m), and h is the depth (m). Madison, WI: U.S. Dept. “Latewood density in relation to wood fibre diameter, wall thickness, and fibre and vessel percentages in Quercus robur L.,” IAWA Journal 18(2), 127-138. The load was applied at a rate of 0.003 in/in (0.00762 cm/cm) of nominal specimen length/min. of Agriculture, Forest Service, Forest Products Laboratory, 2010, Chapter 5, pp. 5. For red oak, compression parallel values ranged from 47 to 80 MPa, with a mean value of 61 MPa and coefficient of variation of 11.47%. A) Comparison of modulus of rupture; B) Comparison of modulus of elasticity MOE. Other expressions of density, such as those based on air-dry weight and volume or on weight and volume of green wood, have a certain practical importance, as in shipping wood, but are not accurate. In general, latewood, because of its thicker cell walls and smaller cell cavities, is denser than earlywood, and with increasing ring width its proportion decreases in softwoods and increases in ring-porous hardwoods. Overall, red oak exhibited higher MOE and MOR values compared to white oak. The t test for MOR comparison revealed a significant difference (p = 0.004). 3-C). Natural lustre is characteristic of some species (for example, spruce, ash, basswood, and poplar) and more prominent on radial surfaces. “Standard grading rules for southern pine lumber,” SPIB, Pensacola, Florida, 147 pp. Both measurement techniques followed Southern Pine Inspection Bureau (SPIB) standard grading rules (SPIB 2014). A two-sample t test revealed a significant difference between the two means at the .05 level (p = <.0001). Article submitted: January 21, 2020; Peer review completed: April 18, 2020; Revised version received and accepted: May 6, 2020; Published: May 13, 2020. In general, the evaluated mechanical properties values of red oak are significantly different from the white oak. “Standard test methods for small clear specimens of timber. In this sense, the purpose of this study was to evaluate physical and mechanical properties of red oak and white oak to supplement available information on these species. In the tangential direction, red oak hardness values ranged from 3.8 to 10.5 kN with a mean of 6.3 kN and coefficient of variation of 19.13%. Durability is the first priority for any kind of engineering material. Keywords: Modulus of elasticity; Modulus of rupture; Compression parallel; Compression perpendicular; Janka hardness, Contact information: Department of Sustainable Bioproducts, Mississippi State University, P.O. Determination of the density of wood is more difficult than for other materials because wood is hygroscopic (see the section Hygroscopicity); both its weight and volume are greatly influenced by moisture content. Oven dried weight of the specimens were recorded after the mass was stabilized. 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.This process is known as secondary growth; it is the result of cell division in the vascular cambium, a lateral meristem, and subsequent expansion of the new cells. For white oak, compression parallel values ranged from 42 to 75 MPa, with a mean value of 60 MPa and coefficient of variation of 12.90%. The growth rings counting from the current study were found to be lower compared to the literature. Because the changes in the ring width of oaks has been more associated with change in width of latewood, the percentage of latewood increase alongside ring width. Rao, R. V., Aebischer, D. P., and Denne, M. P. (1997). In tangential direction, MOE values ranged between 7,920 and 15,900 MPa, with a mean value of 11,300 MPa and coefficient of variation of 16.48%. ASTM International (2009). Oven-dry volume is difficult to determine, at least by immersion in water, because of wood’s hygroscopicity. Kretschmann, D. E. (2010). Oak (Quercus spp.) These characteristics are generally required by stairway manufacturers. Balsa wood, which is considered a hardwood, is a rather soft wood when compared to the hardness of most softwoods. The load span was 14 inches (35.6 cm). Standards are oven-dry weight (practically zero moisture content) and either oven-dry or green volume (green referring to moisture content above the fibre saturation point, which averages about 30 percent). Compression Parallel and Perpendicular values, for Red Oak and White Oak. In diffuse-porous hardwoods latewood is not clearly distinct, and ring width is not an indication of density. So with wood, the fewer holes (cells), the more wood substance. Physical Properties of Wood - Designing Buildings Wiki - Share your construction industry knowledge. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. MOE values for white oak were slightly lower than Newlin and Wilson (1917), Markwardt and Wilson (1935), and the Wood Handbook (Kretschmann, 2010) (see Fig. 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. The origin of the material came from Northeast, Upper Midwest, Southeast Mid-South, Appalachian, and southeastern region and the boards were donated by staircase manufacturers. The SG12% followed the specifications of ASTM 2395 (ASTM 2017) standard. The average MOR for red oak varied between 65 and 170 with a mean of 120 MPa and coefficient of variation of 18.49%. Each specimen was weighed and measured before testing. Wood, the principal strengthening and nutrient-conducting tissue of trees and other plants and one of the most abundant and versatile natural materials. A two sample t-test revealed a significant difference between the two means (p = <.0001) for compression parallel to the grain, and no significant difference between the two means for compression perpendicular to the grain (p = 0.98). (2014). Growth rings counting for red oak varied between 1.1 and 18.5 with a mean of 7.3 and a coefficient of variation of 48.52%. is a genus composed of a diverse group of tree species that have been reported as one of the most widely used hardwoods in Europe and North America (Merela and Čufar 2013). For specimens that are regular in shape, volume can be calculated on the basis of their dimensions. The tests were performed on 1 × 2 × 6 inch (2.54 × 5.08 × 15.24 cm3) specimens. A good timber should be durable enough to resist the actions of chemical agents, biological agents, physical agencies, etc. Other wood products. Although physical and mechanical properties of oak are known, there is an uncertainty with respect to the average values. For white oak, Janka hardness values in the radial direction ranged from 2.9 to 9.2 kN, with a mean value of 5.9 kN and coefficient of variation of 21.26%. The experiments were carried out on defect-free specimens extracted from boards supplied by the Stairbuilders Manufacturers Association (SMA) members. Static Bending Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) values, in radial and tangential directions, for Red Oak and White Oak. The failure type was recorded for each specimen. Box 9820, Starkville, MS 39759 USA; *Corresponding author: fn90@msstate.edu. Compression perpendicular to the grain was found to be higher than the values published in past studies. Wood has many other interesting characteristics. Brown, H. P., Panshin, A. J., and Forsaith, C. C. (1949). This study will provide useful information to perform future calculations or adjustments in published design values for staircases. Fig. Table 1. Depending on the nature of these cells, some woods have more or less solid wood substance for a given sized piece. and the physical properties of wood. Physical and Mechanical Properties of Clear Wood from Red Oak and White Oak, Marly G. Carmona Uzcategui, R. Daniel Seale, and Frederico José Nistal França *. For white oak, the density varied between 599 and 887 with a mean of 756 and a coefficient of variation of 8.91%. The test was conducted using center point loading with a test speed of 0.05 inches (0.127 cm) per minute (Fig. 7. pp. Compression parallel and compression perpendicular results for red oak and white oak are listed in Table 3. Features The mahogany tree can reach more than 150 feet in height and 6 feet in diameter.