Skip to main content
SpringerLink
Log in

Dynamic behavior of nonuniform lumber in stress-grading machines

  • Published:
Wood Science and Technology Aims and scope Submit manuscript

Summary

A finite element model is developed to predict the dynamic behavior of nonuniform lumber in stress-grading machines of the constant deflection type. Simulations carried out with the model showed that speed largely effects the accuracy with which grading machines can identify low-point modulus of elasticity (E) oflumber. Tests conducted at 15 and 315 m/min on lumber members containing a low E zone confirmed model predictions. However, as demonstrated in this study, machine ability to detect low-point E at high speed can greatly be improved from filtering the load signal measured by the machine.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Galligan, W. L.; Snodgrass, D. V.; Crow, C. W. 1977: Machine stress rating: practical concerns for lumber producers. USDA For. Serv. Gen. Tech. Rep. FPL 7, For. Prod. Lab., Madison, WI

  • Grant, D. J. 1986: Computermatic timber-grading machine: laboratory evaluation of performance with respect to feed speed and the dynamic/static deflection relationship. N. Z. J. For. Sci.16: 187–196

    Google Scholar 

  • Huot, B. 1990: Effet de la vitesse sur le classement par machine de bois non homogènes. M.Sc. Dissertation, Faculté de foresterie et de géodésie, Université Lavai, Québec, Canada

  • Kass, A. J. 1975: Middle ordinate method measures stiffness variation within pieces of lumber. For. Prod. J. 25: 33–41

    Google Scholar 

  • Oppenheim, A. V.; Schafer, R. W. 1975: Digital signal processing. Englewood Cliffs. N.J.: Prentice-Hall

    Google Scholar 

  • Orosz, I. 1976: Relationship between apparent modulus of elasticity, gage length and tensile strength of lumber. Wood Sci. Technol. 10: 273–291

    Google Scholar 

  • Reddy, J. N. 1984: An introduction to the finite element method. New York: McGraw-Hill

    Google Scholar 

  • Samson, M. 1985: Finite element model for predicting modulus of elasticity of lumber measured by stress-grading machines. Wood Fiber Sci. 17: 490–503

    Google Scholar 

  • Samson, M. 1986: Predicted and actual performance of two laboratory stress-grading machines employing different support conditions. Wood Fiber Sci. 18: 478–489

    Google Scholar 

  • Samson, M. 1987: Effect of speed on the accuracy of stress-grading machines for lumber. Wood Sci. Technol. 21: 281–292

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Departement des Sciences du Bois, Faculté de Foresterie et de géodésie, Université Laval, G1K 7P4, Ste-Foy, Quebec, Canada

    M. Samson (Associate Professor) & B. Huot (Grad. Res. Assistant)

Authors
  1. M. Samson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. B. Huot
    View author publications

    You can also search for this author in PubMed Google Scholar

Additional information

Financial support of the National Science and Engineering Research Council of Canada and the Ministère de l'Energie et des Ressources du Québec is gratefully acknowledged

Rights and permissions

Reprints and permissions

About this article

Cite this article

Samson, M., Huot, B. Dynamic behavior of nonuniform lumber in stress-grading machines. Wood Sci.Technol. 24, 327–337 (1990). https://doi.org/10.1007/BF00227053

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00227053

Keywords

Search

Navigation