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Title: Improved models for predicting the modulus of rupture of lumber under third point loading

Source: FS Research Paper

Author(s)Verrill, Steve; Owens, Frank C.; Shmulsky, Rubin; Ross, Robert

Publication Year: 2021  View PDF »

Category: Research Papers

Abstract: To properly evaluate the reliability of lumber structures, good models for the strength distributions of their components are needed. Modulus of rupture (MOR) distributions of structural lumber grades have often been modeled as two-parameter Weibulls. However, in a series of papers, Verrill and others have established that strength properties of visual and machine stress rated grades of lumber are not distributed as two-parameter Weibulls and that modeling them as two-parameter Weibulls can yield large over- or underestimates of probabilities of breakage. Instead, grades of lumber have “pseudo-truncated” distributions. Recent research also established that the appropriate MOR model can change significantly with location and time and that model differences have practical significance. Verrill and others concluded that “there may be significant efficiencies that can be obtained through the development of computer models that yield real-time in-line estimates of lumber properties based on measurements of stiffness, specific gravity, knot size and location, slope of grain, and other strength predictors.” In this paper, we discuss models that predict the MOR of a piece of lumber from modulus of elasticity, specific gravity, slope of grain, and knot data.

Keywords: modulus of rupture; modulus of elasticity; specific gravity; slope of grain; knots; Weibull distribution; pseudo-truncated distributions; strength prediction models; lumber strength models

Publication Review Process: Informally Refereed (Peer-Reviewed)

File size: 877 kb(s)

Date posted: 12/14/2021

This publication is also viewable on Treesearch:  view
RITS Product ID: 10401
Current FPL Scientists associated with this product (listed alphabetically)
Ross, Robert J.
Supervisory Research Gen. Engineer
Verrill, Steve P.
Mathematical Statistician

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