Development of a Method to Predict the Bending Strength of Lumber Without Regard to Species Using X-Ray Images

Authors

  • Jung-Kwon Oh
  • Kug-Bo Shim
  • Hwanmyeong Yeo
  • Jun-Jae Lee

Keywords:

Knot depth ratio, X-ray, Equivalent Density Model, species independence

Abstract

Several models have been developed for predicting bending strength of lumber using X-rays, but most require species-specific classifications. However, the classification is very difficult because logs or cants can arrive without leaves or bark. This study was carried out to develop an alternative bending strength prediction model that does not lose precision when the species is unknown. The study proposes an Equivalent Density Model (EDM), in which a cross-section is quantified as equivalent density. Because the relationship between density and strength of small clear specimens is not affected by species, the EDM was expected to correlate to strength regardless of species. This model predicted the modulus of rupture in two species with R2 = 0.73, although the two were mixed. Therefore, it may be possible to predict bending strength using X-rays without classifying lumber by species.

References

Markwardt LJ, Wilson TRC (1935) Strength and related properties of wood grown in the United States. USDA Tech Bull No 479.nOh JK, Kim KM, Lee JJ (2008) Development of a knot quantification method to predict strength using an X-ray scanner. J Korean Wood Sci Tech 36(5):33-41.nOh JK, Kim KM, Shim KB, Lee JJ (2009a) Use of adjacent knot data in predicting bending strength of dimension lumber by X-ray. Wood Fiber Sci 42(1):10-20.nOh JK, Shim KB, Kim KM, Lee JJ (2009b) Quantification of knots in dimension lumber using a single-pass X-ray radiation. J Wood Sci 55(4):264-272.nSahlberg U (1995) Influence of knot fibers on TMP properties. Tappi 78(5):162-168.nSchajer GS (2001) Lumber strength grading using X-ray scanning. Forest Prod J 51(1):43-50.nSchniewind AP, Lyon DE (1971) Tensile strength of redwood dimension lumber. II. Prediction of strength values. Forest Prod J 21(8):45-55.nThelandersson S, Larsen HJ (2003) Timber engineering. John Wiley & Sons Ltd. pp. 29-30.n

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Published

2010-01-18

Issue

Number 1 / January 2010

Section

Research Contributions

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