Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 112-123). Also available on the World Wide Web.

Favorable properties of Balsa wood make it an interesting alternative in a number of applications including thermal insulation or as a lightweight core material in sandwich composites. Increasing use in construction necessitates a better understanding of its mechanical and failure properties. In the present work, mode I and mode II fracture toughness for different types of balsa wood and a sandwich structure (balsa as core and fiber glass as skin layer) are studied experimentally by using load-displacement diagrams and visually acquired crack growth data. / Graduation date: 2013

Thesis (M.S.) -- Mississippi State University. Department of Forest Products. / Title from title screen. Includes bibliographical references.

The objective of this project was to evaluate methods to remediate a wood I-joist with a single, circular hole in the web while leaving utilities in place. The methods were experimentally evaluated with a full-scale bending test using four equally spaced point loads. There were three depths of joists with varying flange widths and two span lengths (4.88 m & 2.44 m). Failure modes for the long span joists without holes were in the flanges in either tension, compression or lateral buckling; but once a hole was introduced the majority were classified as shear failures. Effectiveness of the remediation was evaluated based on three criteria: strength, stiffness, and ease of installation/cost. The OSB collar patch was effective for 8 out of the 12 series tested. A maximum reduction of load from a joist with no hole to one with a hole was 49% for the long span and 58% for the short span. The OSB collar was not as effective in returning stiffness to the joists, but was easier to install and less expensive than the LSL patch. / Graduation date: 2013

Graduation date: 1999

Thesis (Ph.D)--Mississippi State University. Department of Forest Products. / Title from title screen. Includes bibliographical references.

Thesis (Ph.D.)--Mississippi State University. Department of Forest Products. / Title from title screen. Includes bibliographical references.

No description available.

Engineered wood I-joists have grown in popularity as flooring and roofing structural systems in the past 30 years, replacing solid sawn lumber joists. Typical wood I-joists are manufactured with a very slender section, which is desirable to achieve higher flexural capacities and longer spans; however, this makes them susceptible to lateral torsional buckling failure. Continuous beam spans and uplift forces on roof uplift are potential scenarios where lateral instability can occur and reflects the need to investigate the lateral torsional buckling behavior of wood I-joists. Within this context, the present study conducts an experimental investigation on the material properties and the critical buckling load of 42 wood I-joist specimens. A 3D finite element model is built using the experimentally determined material parameters to effectively predict the observed buckling behavior of the specimens while also accounting for initial imperfections in the joists. The adequacy of other analytical models to predict the critical buckling load of wood I-joists are also investigated. It is demonstrated that the American design standard underestimates the critical buckling load of wood I-joists while the classical theory provides an adequate estimate of the buckling capacity. Furthermore, the effects of initial imperfections on the lateral torsional buckling behavior are discussed. The developed and verified FE model is used to reproduce the nonlinear buckling behavior of the wood I-joist and also to provide an accurate estimate of the lateral torsional buckling capacity using the linear buckling analysis.

<p>In this study new value-added products were developed from four commercially available refined waxes for use as commercial emulsifiers via the technique of maleation. This research was performed in collaboration with an industrial partner with the hope of developing a wax emulsifier product that could replace commercially used wax emulsifiers in engineered wood product emulsions at a cost reduction by beginning with the design of a cost effective process that could be incorporated into an existing factory production line. Through the investigation and subsequent optimization of this process, a highly maleated product was achieved using 6 different quick and simple approaches. A standardized experimental design was applied to the parameters of the experiment: reaction time, peroxide, starting wax, maleic anhydride concentration, and temperature to observe and understand the individual effects of each on the resultant final product. Three organic peroxide initiators were evaluated; di-<em>tert</em>-butyl peroxide, di-<em>tert</em>-butyl peroxybenzoate and benzoyl peroxide, as well as a thermally initiated approach. The resultant waxes were then identified by their acid number and drop melt point; and from this, the overall efficiency of the combined parameter levels was calculated as a function the initial maleic anhydride amount versus that of the final. The maleated wax emulsifiers were incorporated into emulsions and applied to engineered wood products. Emulsifiers made via the thermally initiated approach showed statistically significant improvements in the desired properties, water absorbance and thickness swell, of the engineered wood products as compared to a commercial control formulation.</p> / Master of Science (MSc)