Description
A model has been developed to modify Euler-Bernoulli beam theory for wooden beams, using visible properties of wood knot-defects. Treating knots in a beam as a system of two ellipses that change the local bending stiffness has been shown to improve the fit of a theoretical beam displacement function to edge-line deflection data extracted from digital imagery of experimentally loaded beams. In addition, an Ellipse Logistic Model (ELM) has been proposed, using L1-regularized logistic regression, to predict the impact of a knot on the displacement of a beam. By classifying a knot as severely positive or negative, vs. mildly positive or negative, ELM can classify knots that lead to large changes to beam deflection, while not over-emphasizing knots that may not be a problem. Using ELM with a regression-fit Young's Modulus on three-point bending of Douglass Fir, it is possible estimate the effects a knot will have on the shape of the resulting displacement curve.
Details
Title
- Optimal Modeling of Knots in Wood
Contributors
- Sexton, Thurston Bryant (Author)
- Takahashi, Timothy (Thesis director)
- Jones, Donald (Committee member)
- Barrett, The Honors College (Contributor)
- Mechanical and Aerospace Engineering Program (Contributor)
- School of Mathematical and Statistical Sciences (Contributor)
- School of Human Evolution and Social Change (Contributor)
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2015-05
Resource Type
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