Wood and Fiber Science (E-Journal)
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Predicting Performance Of Oriented Strandboard Under Concentrated Static Loading Conditions Using Finite Element Modeling
Get PDFOriented strandboard (OSB) panels were tested under a concentrated static load (CSL). A finite element (FE) model with variation of stresses and strains in the thickness direction was established to simulate the deflection of OSB under 890-N CSL. The CSL ultimate load of each OSB panel was simulated by increasing the load in the FE model until the calculated stress met the corresponding measured strength. Comparison of the calculated and the experimental data showed that the initial failure had two modes: failure initiated by interlaminar shear stress in the major direction near the central layers and edge of the panel when modulus of rupture (MOR) to interlaminar shear strength ratio in the major direction was greater than 18.8, and failure initiated by bending stress in the major direction near the bottom layers and the loading spot when MOR to interlaminar shear strength ratio in the major direction was less than 17.4. Panel thickness determined the initial failure mode when the ratio of MOR to interlaminar shear strength in the major direction was between 17.4 and 18.8. The vertical density profile affected the distribution of bending stresses and MOR in the profile of panels and influenced the accuracy of the prediction of the FE model
Case Study of the Economic Feasibility of a Red Oak Small-Diameter Timber Sawmill and Pallet-Part Mill
Get PDFThe economic feasibility of producing lumber, cants, pallet parts, and residues from hardwood small-diameter timber (SDT) has not been investigated. To assess the potential for utilization of this resource, an economic feasibility analysis was conducted based on the results of a related SDT yield study. The economic feasibility analyses used in this research included: break-even, net present value (NPV), and internal rate of return (IRR). These analyses were used to determine the economic viability of a sawmill and pallet-part mill that would utilize red oak small-diameter timber. Twelve scenarios were evaluated using these analyses: two processing levels (sawmill-only, and sawmill and pallet-part mill), two yield levels (actual and average), and three log costs (74/m3 (500,000, and the IRR was approximately 11%
Influence of Moisture Content on Longitudinal, Radial, and Tangential Ultrasonic Velocity for Two Brazilian Wood Species
Get PDFThe effects of MC on longitudinal, radial, and tangential ultrasonic wave velocity and on the respective terms of the stiffness matrix were examined for Brazilian pine (Araucaria angustifolia) and cupińba (Goupia glabra). The ultrasonic wave velocity tended to increase with a decrease in MC, and the effect of MC on the ultrasonic wave velocity below the FSP was greater than above. Below the FSP, the stiffness terms tended to decrease with increasing MC, but above the FSP, they increased with increasing MC because of the influence of water on the bulk density. This result may be corrected by using the effective density above FSP, which depends on the mobility of free water and differs for the two species
Physical and Mechanical Properties of Red Pine (Pinus Resinosa AIT.) From Three Provenances
Get PDFPhysical and mechanical properties of 44-year-old red pine (Pinus resinosa Ait.) trees from three different provenances, Oscoda, MI (USA); Kent, NB (Canada), and Manitoba, MA (Canada) grown in Allegan State Forest, Michigan were evaluated. One-way analysis of variance of the properties showed that the differences in the mean values of physical and strength parameters were not inherent to the provenances. The results indicate there is very low genetic diversity of red pine across the wide geographic range of the species
Distribution of Phenol-Formaldehyde Resin in Impregnated Southern Pine and Effects on Stabilization
Get PDFTwo low-molecular-weight phenol-formaldehyde (PF) resins impregnated at 20% resin-solid concentration in southern pine (SP) wood and cured at 180°C for 20 min were studied by various microscopic methods. The micrographs indicated that the ray tracheids of SP were the main flow path of resin, rays were reinforced by cured resin, and flow of resin into lumens was more difficult for higher-molecular-weight resin. Some PF resin deposits were found in lumens. PF resin deposits were formed to connect ray tracheids and longitudinal tracheids, resulting in interlocking bridges that possibly reduced dimensional changes of wood in the tangential direction. These resin deposits appear to be responsible for the high dimensional stability observed in this direction. The diffusion of PF resins into cell walls appears to occur through rays or primary walls, but not through lumens or the warty layer
Customer Value in the Oriented Strandboard Industry
Get PDFThis study examines the attributes of oriented strandboard (OSB) sheathing that influence OSB wholesale buyers' perceptions of OSB value when choosing alternative OSB products/brands or suppliers in the marketplace. Mail surveys sent to a sample of 323 OSB wholesale sheathing buyers in the roof, wall, and floor segments in North America in Fall of 2003 generated a response rate of 22.3 percent (n = 72). The responding wholesale buyers represent 330 million square meters (10-mm thickness basis) of OSB sheathing products purchased in 2002.As expected in a commodity forest product, survey results indicate that price plays an important role in influencing wholesale buyers' perceived value of OSB sheathing. However, the value derived from low price by the OSB wholesalers is not as important as service and supplier attributes such as on-time delivery and personal relationship with the OSB supplier firm. In addition to the three attributes (delivery time, relationship, and price), packaging (in roof/wall sheathing segments) and brand image (in the floor sheathing segment) also significantly contribute to the value perceptions of responding OSB wholesale sheathing buyers.Study findings show that the perceived value of an OSB supplier and their sheathing products and services positively affects the volume of OSB purchased from that supplier. In other words, OSB wholesale buyers' largest supplier, accounting for 58 percent of their volume of OSB purchased in 2002, is perceived as their highest valued supplier for OSB sheathing products and services (a calculated value score of 2.4) compared to their second largest supplier (23 percent of OSB purchased in 2002 and a value score of 1.9) and their third largest supplier (accounting for 13 percent of OSB purchased in 2002 and a value score of 1.75)
Consumer Perceptions and Preferences on Solid Wood, Wood-Based Panels, and Composites: A Repertory Grid Study
Get PDFKnowledge about consumer perception and preferences on solid wood, wood-based panels, and wood-based composites is important for product development and marketing. The aim of this study was to identify attributes and associations that people use to describe different types of wood materials and to explore how they relate to preferences. The study involved nine samples that were evaluated with the Kelly's repertory grid technique and content analysis. Based on respondents' answers, 19 core categories reflecting sample attributes were extracted. General preferences for each sample were also recorded. Principal component analysis generated two factors describing 1) naturalness, wood-likeness, softness, unprocessed origin, living, pleasant, and high value; and 2) solid and homogeneous impression. A third, preliminary factor included categories describing irregular pattern, sleekness, and smoothness. The wood samples were most liked, whereas composites and panels were not appreciated. Preferred core categories were naturalness, wood-likeness, smoothness, living impression, and value. The least liked core categories were processed, hard, and high weight. The implications of the results for product development and marketing are discussed
Creating A Standardized and Simplified Cutting Bill Using Group Technology
Get PDFFrom an analytical viewpoint, the relationship between rough mill cutting bill part requirements and lumber yield is highly complex. Part requirements can have almost any length, width, and quantity distribution within the boundaries set by physical limitations, such as maximum length and width of parts. This complexity makes it difficult to understand the specific relationship between cutting bill requirements and lumber yield, rendering the optimization of the lumber cutting process through improved cutting bill composition difficult.An approach is presented to decrease the complexity of cutting bills to allow for easier analysis and, ultimately, to optimize cutting bill compositions. Principles from clustering theory were employed to create a standardized way to describe cutting bills. Cutting bill part clusters are part groups within the cutting bill's total part size space, where all parts are reset to a given group's midpoint. Statistical testing was used to determine a minimum resolution part group matrix that had no significant influence on yield compared to an actual cutting bill.Iterative search led to a cutting bill part group matrix that encompasses five groups in length and four groups in width, forming a 20-part group matrix. The lengths of the individual part groups created vary widely, with the smallest group being only 5 inches in length, while the longest two groups were 25 inches long. Part group widths were less varied, ranging from 0.75 inches to 1.0 inch. The part group matrix approach allows parts to be clustered within given size ranges to one part group midpoint value without changing cut-up yield beyond set limits. This standardized cutting bill matrix will make the understanding of the complex cutting bill requirements-yield relationship easier in future studies