Quantifying knots by image analysis and modeling their effects on the mechanical properties of loblolly pine lumber

Wright, Stephen Louis; Dahlen, Joseph; Montes, Cristián R.; Eberhardt, Thomas L.

doi:10.1007/s00107-019-01441-8

Cited by 13 publications

(6 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The values of MOE tend to decrease with increasing incidence of knots on the sawn wood surface. This confirms the results of previous studies (Klinea et al 2001;Krzosek 2002;Wright et al 2019) concerning the impact of knots in sawn wood on its strength, as illustrated by its MOE. Lack of continuity in the structure of the wood (knots) and the distortion of grain reduce the effective cross-section of sawn timber.…”

Section: Resultssupporting

confidence: 92%

“…Modulus of elasticity, the essential indicator of the technological value of wood, determines its usefulness not only in wood industry but also in the construction business. Being a directly correlated indicator of strength, it is also directly connected with the presence of structural defects of wood (Schajer 2001;Lam et al 2005;Fabisiak et al 2009;Roblot et al 2010;Hu et al 2018). In regards to Polish lumber from the thick end of a log, the surface of knots in the cross-section (knot area ratio) of the test sample has a noticeable impact on the value of MOE.…”

Section: Discussionmentioning

confidence: 99%

“…The fitting R 2 of the model (of the algorithms in question) for Douglas fir (Pseudotsuga Carriere) and for Norway spruce (Picea abies (L.) H. Karst) is estimated to range from 0.59 to 0.72, and from 0.42 to 0.5, respectively. Studies have shown that determination of the knot area combined with dynamic modulus of elasticity (MOEdyn) may provide an even more precise assessment of modulus of rupture (MOR) (Schajer 2001;Lam et al 2005;Roblot et al 2010;Briggert et al 2016;Hu et al 2018).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Elastic moduli of butt-end logs and the variable knots distribution in Scots pine from Western Poland

Mirski

Wieruszewski

Trociński

et al. 2021

BioRes

View full text Add to dashboard Cite

In studies on Polish pine wood, the parameters determining its usefulness for processing are highly variable. In contrast, international studies on the optimum utilization of coniferous sawn wood describes its visual features as those indicating the distribution of defects and their impact on the selected mechanical and physical properties of sawn wood. Knottiness is one of the qualitative properties of sawn wood that is essential for wood grading. The objective of this study was to determine a correlation between variable knots and their soundness on the one hand and their selected strength parameters on the other. One of the basic issues of this work includes structural timber optimization. For Polish sawn wood, these indicators are still relatively new. The study material involved edged butt-end log lumber from a 120-year-old forest stand. The results confirmed a correlation between knots frequency and modulus of elasticity. The correlation was strong, indicating that sound knots play a major role in the process of the strength assessments. The study did not demonstrate a significant share of rotten knots and their effect on strength.

show abstract

Section: Resultssupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Elastic moduli of butt-end logs and the variable knots distribution in Scots pine from Western Poland

Mirski

Wieruszewski

Trociński

et al. 2021

BioRes

View full text Add to dashboard Cite

show abstract

“…The results confirm the observations previously described by Lin et al [ 29 ], Lukacevic et al [ 56 ], and Wright et al [ 57 ] regarding the effect of knot presence on MOE values. In the case of analyzing the effect of the quantity of knots occurring on the wide planes, the Spearman’s rank coefficient was R = −0.67 at a significance level of p < 0.001, which can be described by the function y 0/1 = 3.0198x 2 − 273.02x + 15,881.…”

Section: Resultssupporting

confidence: 92%

The Strength of Pine (Pinus sylvestris L.) Sawn Timber in Correlation with Selected Wood Defects

et al. 2022

View full text Add to dashboard Cite

Pine timber of Polish origin intended for structural purposes is characterized by significant variability in the quality parameters. Technological suitability determined on the basis of relevant international classifications is based on the assessment of both selected mechanical and physical properties of wood. Moreover, the description of visual properties is also a valuable indicator regarding defect distribution. In the group of quality features playing a crucial role in the classification of sawn timber, there are knots, disruptions of grains, cracks, etc. Thus, the aim of the research was to determine the correlation between the presence of selected defects and the strength properties of individual timber pieces. This type of study is based on a nondestructive test method that allows for high optimization of sawn materials processing. In the case of sawn timber of Polish origin, the modulus of elasticity (MOE) determined using the sonic test is commonly used as a criterion. The research material was harvested from southern Poland. The results of the conducted studies confirmed a correlation between an increasing occurrence of particular types of defects and the results of MOE. Furthermore, as a result of the performed investigations, no significant effect of narrow surface cracks on strength properties was observed.

show abstract

“…The size and number of knots in the wood have a significant impact on its physical and mechanical properties (As et al, 2006;Koman et al, 2013;Montero et al, 2015;Burdarov, 2019;Kaiser, 2019;Wright et al, 2019). The presence of many defects in the wood, particularly wood knots, significantly reduces the final quantitative yields in the production of engineered wood products.…”

mentioning

confidence: 99%

Iskorištavanje borovine (Pinus sylvestris L.) s greškama za proizvodnju kompozitnog drva

et al. 2023

View full text Add to dashboard Cite

This study presents opportunities for the utilization of timber by-products with defects for manufacturing engineered wood panels. Three gluing methods were proposed for this waste raw material derived from Scots pine (Pinus sylvestris L.) wood. The methods used for combining and gluing enabled a more complete and complex utilization of wood with defects. The physical properties (density and moisture content) and mechanical properties (bending strength and modulus of elasticity) of the laboratory-fabricated engineered wood panels were evaluated in accordance with the European standards. The highest density of 643 kg/m3 and bending strength values (28.6 N/mm2) were obtained from the panels manufactured using method 3 and veneered with beech veneer sheets. The modulus of elasticity of the laboratory-made engineered wood panels reached values of up to 5580 N/mm2. This study demonstrated the feasibility of the utilization of defective wood pieces in the manufacturing of engineered wood panels.

show abstract

Quantifying knots by image analysis and modeling their effects on the mechanical properties of loblolly pine lumber

Cited by 13 publications

References 39 publications

Elastic moduli of butt-end logs and the variable knots distribution in Scots pine from Western Poland

Elastic moduli of butt-end logs and the variable knots distribution in Scots pine from Western Poland

The Strength of Pine (Pinus sylvestris L.) Sawn Timber in Correlation with Selected Wood Defects

Iskorištavanje borovine (Pinus sylvestris L.) s greškama za proizvodnju kompozitnog drva

Contact Info

Product

Resources

About