Treesearch

Recently, synchrotron based X-ray fluorescence microscopy (XFM) and X-ray absorption near edge spectroscopy (XANES) were used to examine the metal fastener corrosion in copper-treated wood. XFM is able to map the copper concentration in the wood with a spatial resolution of 0.5 µm and is able to quantify the copper concentration to within 0.05 µg cm-3. XANES was used as a complimentary technique to differentiate between oxidation states of copper in the wood. While the primary goal of these measurements was to better understand the corrosion mechanisms, the measurements also give insights...

This paper presents a simplified analytical model and balanced design approach for modeling lightweight wood-based structural panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical performance of panels based on experimental results. The bending deflection, normal strain and shear strain of the panels with various configurations were investigated using four point bending test. The results from the analytical...

This paper presents static and fatigue bending behavior for a wood-based structural panel having a slot and tab (S/T) construction technique. Comparisons were made with similarly fabricated panels without the S/T construction technique. Experimental results showed that both types of panels had similar bending properties in the static tests. However, the panels with S/T construction had better fatigue results. The failure modes were different for the two fabrication techniques. The panels without S/T debonded at the core:face interface. Whereas, the panels with S/T had cracks that propagated...

Tropical exposure often represents a more severe environment for treated wood and wood based products. Accelerated tropical decay rates are typically attributed to higher mean rainfall and temperatures. The Forest Products Laboratory (FPL) in Madison, WI has been conducting tropical field tests in a variety of locations since the early 1940’s. This paper summarizes FPL tests conducted in the tropics from 1945-2005 and discusses some of the difficulties in assessing tropical field data. Where appropriate, test results from tropical sites are contrasted with field data from temperate and...

Salt damage is a frequent problem in wood exposed to seawater and other saline environments. Symptoms of salt damage are often referred to as fuzzy wood and have been historically considered non-structural damage, but a growing number of customer inquiries have prompted a re-evaluation of this phenomenon. This paper details several case studies involving salt damage, discusses current knowledge on the underlying mechanisms and highlights on-going work at the Forest Products Laboratory to investigate the causes and effects of salt on wood. A better understanding of the salt damage process...

This project demonstrates newly invented, biobased construction materials developed by applying lowcarbon, biomass waste sources through the Authors’ engineered fiber processes and technology. If manufactured and applied large-scale the project inventions can divert large volumes of cellulose waste into high-performance, low embodied energy, environmental construction alternatives that lessen society’s dependence on greenhouse gas emitting products associated with global warming. Biobased materials produced in this work include: 1. High strength-to-weight-ratio “bioboards” as a dense,...

This paper reports the influence of raw and sonicated cellulose nanocrystals (CNCs) on the micro-structure of cement paste. A novel centrifugation method is designed to measure the concentrations of the adsorbed CNCs (aCNCs) on the cement surface, and the free CNCs (fCNCs) which are mobile in water. It is found that, the majority of the CNCs (>94%) are aCNCs. More importantly, sonication does not significantly reduce the amount of aCNCs (reduction of less than 2%). We surmise that, after sonication, the aCNCs are primarily dispersed over the cement surface, instead of becoming fCNCs via...

Stress and strain concentrations and in-plane and out-of-plane stress constraint factors associated with a circular hole in thick, loaded orthotropic composite plates are determined by three-dimensional finite element method. The plate has essentially infinite in-plane geometry but finite thickness. Results for Sitka Spruce wood are emphasized, although some for carbon-epoxy composites are included. While some results are similar to those for isotropy, there are significant consequences due to material orthotropy. Maximum stress and strain concentration factors occur at midplane for thin...

This report describes the current state and near-term perspective of the U.S. economy supported by general and statistical information on forest products markets in terms of production, trade, consumption, and prices. Market developments are described for sawn softwood, sawn hardwood, softwood log trade, wood-base panels, paper and paperboard, fuelwood, forest products prices, and housing starts. Policy initiatives that can affect domestic markets and international trade in wood products are also discussed in some detail. Data are provided through the end of the year 2014 with estimates...

Ipê is an extremely difficult species to bond because of its high density, interlocking grain, and high volumetric swelling–shrinkage under prolonged wet conditions. Despite its difficulties, the wood is known to be extremely durable in exterior conditions because of its resistance to microbial and insect degradation. Therefore, investigating its bondability with exterior wood adhesives will broaden its use in applications in which fasteners are not feasible. In this study, ipê wood was bonded with five ambient-curing exterior-grade wood adhesives (epoxy, emulsion polymer isocyanate, two...