Characterizing the Nonlinear Behavior of Flakeboards

To predict accurately the failure load of a layered flakeboard in bending, the stress-strain relations appropriate for each layer must be known. This paper describes the application of a method for characterizing the nonlinear behavior of a flakeboard material subjected to axial stresses. The model permits prediction of the stress-strain curve to the ultimate stress and ultimate strain points for the material regardless of fiber alignment or board density. Comparisons are made between traditional failure criteria, experimental results, and the model predictions

Spaceboard II Panels: Preliminary Evaluation of Mechanical Properties

This preliminary evaluation of the properties of Spaceboard II (SBII) was undertaken to establish the potential of a pulp-molded product in structural-use applications and to develop a basis upon which to optimize the Spaceboard pulp molding process. Various tests were implemented to characterize significant engineering properties, including static concentrated load, panel bending, panel shear, bearing strength, and coupon tension and compression strength. Although these tests were preliminary in nature, they were nonetheless adequate to show that SBII panels perform quite satisfactorily under "dry" conditions, relative to the current performance requirements established for structural-use panels. Our tests on SBII demonstrated that with proper formation and densification, a three-dimensional pulp molding process such as Spaceboard provides the opportunity to create structural products from fiber and to obtain the performance required of conventional products

Improving the fatigue resistance of adhesive joints in laminated wood structures

The premature fatigue failure of a laminated wood/epoxy test beam containing a cross section finger joint was the subject of a multi-disciplinary investigation. The primary objectives were to identify the failure mechanisms which occurred during the finger joint test and to provide avenues for general improvements in the design and fabrication of adhesive joints in laminated wood structures

Prefabricated Wood Composite I-Beams: A Literature Review

This paper reviews the available literature on the state of the art of prefabricated wood composite I-beams. The results of analytical and experimental investigations illustrate the effects of materials, joint, geometry, and environment on the short- and long-term performance of I-beams

Dimensional stability and creep behavior of heat-treated exterior medium density fiberboard

A series of commercial phenol-formaldehyde bonded MDF panels were exposed to a post-manufacture heat-treatment at various temperatures and durations using a hot press and just enough pressure to ensure firm contact between the panel and the press platens. Physical properties and static flexural strengths of the post heat-treated MDF panels were evaluated according to ASTM D 1037 (2002). The results indicated that the post-manufacture heat-treatment of the exterior MDF panels resulted in improvement of thickness swelling. Water absorption and linear expansion properties were adversely affected by the heat-treatment. Modulus of rupture and modulus of elasticity values of the heat-treated panels decreased with increasing treatment temperature. A series of three 12-week creep tests were performed in climatic chambers conditioned at 65% RH, 90% RH, and cyclic 65-90% RH, all at a steady temperature of 20 A degrees C. The creep tests generally followed procedures as specified in ASTM D 6815-02a (2002). Creep deflections of the panels increased with increasing temperature of the post heat-treatment

Proceedings: Linking Healthy Forests and Communities Through Alaska

Wisconsin. Images are of the Starrigavan Estuary and Bird Viewing Platform north of Sitka on the Tongass National Forest. Papers were provided in camera-ready form for printing by the editors, who are therefore responsible for the content and accuracy. Opinions expressed may not necessarily reflect the position of the U.S. Department of Agriculture. The use of trade or firm names is for information only and does not imply endorsement by the U.S. Department of Agriculture of any product or service