Intra-Ring Wood Density and Dynamic Modulus of Elasticity Profiles for Black Spruce and Jack Pine from X-ray Densitometry and Ultrasonic Wave Velocity Measurement

Wassim Kharrat,Chedly Bradai,Ahmed Koubaa,Mohamed Khlif

doi:10.3390/f10070569

Wassim Kharrat, Chedly Bradai + Show 2 more

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https://doi.org/10.3390/f10070569

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Abstract

Currently, ultrasonic measurement is a widely used nondestructive approach to determine wood elastic properties, including the dynamic modulus of elasticity (DMOE). DMOE is determined based on wood density and ultrasonic wave velocity measurement. The use of wood average density to estimate DMOE introduces significant imprecision: Density varies due to intra-tree and intra-ring differences and differing silvicultural treatments. To ensure accurate DMOE assessment, we developed a prototype device to measure ultrasonic wave velocity with the same resolution as that provided by the X-ray densitometer for measuring wood density. A nondestructive method based on X-ray densitometry and the developed prototype was applied to determine radial and intra-ring wood DMOE profiles. This method provides accurate information on wood mechanical properties and their sources of variation. High-order polynomials were used to model intra-ring wood density and DMOE profiles in black spruce and jack pine wood. The transition from earlywood to latewood was defined as the inflection point. High and highly significant correlations were obtained between predicted and measured wood density and DMOE. An examination of the correlations between wood radial growth, density, and DMOE revealed close correlations between density and DMOE in rings, earlywood, and latewood

Highlights

Laboratoire des Systèmes électromécaniques (LASEM), École Nationale d’ingénieurs de Sfax, This manuscript is part of an M.S. thesis by the first author, available online at depositum.uqat.ca
The correlation coefficients obtained between the measured and predicted ring density data range range from 0.88 to 1.00, with an average well above 0.95. These results indicate that these models can from 0.88 to 1.00, with an average well above 0.95. These results indicate that these models can well well describe intra-ring wood density profiles obtained from black spruce and jack pine, and describe intra-ring wood density profiles obtained from black spruce and jack pine, and probably other probably other softwood species, as the coefficients are in good agreement with those obtained by softwood as black the coefficients
0.99, with an average well above (Table 1). These results indicate that high-order polynomials can describe dynamic modulus of elasticity (DMOE) profiles well for 0.90

Summary

Introduction

Laboratoire des Systèmes électromécaniques (LASEM), École Nationale d’ingénieurs de Sfax, This manuscript is part of an M.S. thesis by the first author, available online at depositum.uqat.ca. This method provides accurate information on wood mechanical properties and their sources of variation. Wood density is considered to be the most important wood quality attribute It is one of the most widely used parameters to predict the mechanical and other physical properties of wood, such as dimensional stability [2]. Wood density and all its related wood quality attributes are highly variable, with multiple sources of variation, including differences within and between trees, between sites, and between genetic origins. This high variability is due to genetic, environmental, and physiological factors [3,4]. Variations in wood density result from variations

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