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The analytical influence of all types of knots on bending

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Abstract

The influence of different types of knots and fiber deviations on the bending of wood, as managed using visual grading standards, was analytically discussed in this research by means of the finite element method. The effect of each geometrical variable on the strength and stress distribution has been studied individually. This was accomplished after validating a previously presented finite element model that accounted for the three-dimensional shape of the knots and fiber deviations. The simulated sizes and positions were those commonly managed by the standards for strength grading. The research presents the effect of: (1) the size and position of cylindrical face knots; (2) size and position of truncated conical face knots; (3) size and position of shallow conical face knots; (4) size and position of conical edge knots; (5) inclination of face knots. In each case, the analytical predictions of the modulus of rupture and stress distribution are detailed. Seven characteristic positions with distinct mechanical behavior were found, which should be accounted for in order to improve the wood grading efficiency.

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Acknowledgments

The authors are very grateful to both the Spanish Ministry of Education for its financial support through the National training program of University lecturers (FPU) and the Barrie de la Maza foundation for its postdoctoral research program.

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  1. Pablo Guindos

    Present address: Department of Construction and Structural Engineering, Fraunhofer Wihelm-Klauditz-Institut, Bienroder Weg 54 E, 38108, Braunschweig, Germany

Authors and Affiliations

  1. Department of Agroforestry Engineering, University of Santiago de Compostela, Benigno Ledo, 27002, Lugo, Spain

    Pablo Guindos & Manuel Guaita

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  1. Pablo Guindos
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  2. Manuel Guaita
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Correspondence to Pablo Guindos.

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Guindos, P., Guaita, M. The analytical influence of all types of knots on bending. Wood Sci Technol 48, 533–552 (2014). https://doi.org/10.1007/s00226-014-0621-8

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