The effect of grain direction on the Young's moduli and rigidity moduli of beech and sitka spruce

Hearmon, R. F. S.; Barkas, Wilfred W.

doi:10.1088/0959-5309/53/6/306

Cited by 26 publications

(16 citation statements)

References 3 publications

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“…Further, since most of the available elastic moduli data presented in literature were measured in static tests, the comparison of the measurement results obtained in this study with literature data involves a comparison of different measurement techniques. However, the comparison with shear moduli values obtained in static tests at around 12 % wood MC (Stamer and Sieglerschmidt 1933;Hearmon and Barkas 1941) reveals reasonable similarity. Moreover, the values are in good agreement with shear moduli measured with the ultrasonic technique by Bucur and Archer (1984) and moisture-dependent shear moduli published recently by Hering et al (2012).…”

Section: Elastic Modulimentioning

confidence: 56%

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Determining moisture-dependent elastic characteristics of beech wood by means of ultrasonic waves

Ożyhar¹,

Hering²,

Sanabria

et al. 2012

Wood Sci Technol

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The present study investigates the influence of moisture content on the elastic characteristics of beech wood (Fagus sylvatica L.) by means of ultrasonic waves. A set of elastic engineering parameters (i.e. three Young's moduli, three shear moduli and six Poisson's ratios) is determined at four specific moisture contents. The results reveal the significant influence of the moisture content on the elastic behaviour of beech wood. With the exception of some Poisson's ratios, the engineering parameters decrease with increasing moisture content, indicating a decline in stiffness at higher moisture contents. At the same time, wood anisotropy, displayed by the two-dimensional representation of the velocity surface, remains almost unchanged. The results prove that the ultrasonic technique is suitable for determining the elastic moduli. However, non-diagonal terms of the stiffness matrix must be considered when calculating the Young's moduli. This is shown experimentally by comparing the ultrasonic Young's moduli calculated without, and allowing for, the non-diagonal terms. While the ultrasonic technique is found to be reliable to measure the elastic moduli, based on the measured values, its eligibility to measure the Poisson's ratios remains uncertain.

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Section: Elastic Modulimentioning

confidence: 56%

“…Poisson's ratios (-) Hearmon and Barkas (1941) 3. Stamer and Sieglerschmidt (1933), b shear moduli at x = 12.5 % technique presented in this study, in most investigations, a simplified equation is used to calculate the Young's moduli:…”

Section: Elastic Modulimentioning

confidence: 99%

Determining moisture-dependent elastic characteristics of beech wood by means of ultrasonic waves

Ożyhar¹,

Hering²,

Sanabria

et al. 2012

Wood Sci Technol

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“…However, especially in the case of hardwoods, complete data sets for the three main anatomical directions rarely exist that are sufficient for static calculations and modeling in wood construction, and for calculations on multilayered boards, parquet, or musical instruments with the finite element (FE) method. Several studies about grain angle dependencies were published, for example, by Hearmon and Barkas (1941), Suzuki and Sasaki (1990), Kabir et al (1997), Reiterer and StanzlTschegg (2001), Liu (2002), andYoshihara (2009). A comprehensive work about grain and ring angle dependent compression strength and elasticity was presented by Lang et al (2002), and the angle dependent elastic behavior within the RT plane of softwoods was investigated by Hearmon (1948), Kennedy (1968), and Garab et al (2010).…”

Section: Introductionmentioning

confidence: 99%

Anisotropic elastic properties of common ash (Fraxinus excelsior L.)

2014

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Hardwoods in principle show a similar orthotropic behavior as softwoods; however, the ratios of the mechanical parameters between the three anatomical directions and their magnitudes are different and depend strongly on the individual microstructure of the species. The aim of the current study was to characterize the 3-D elastic behavior of common ash (Fraxinus excelsior L.) by tensile, compression, and shear tests in the three anatomical directions and stepwise in between, by means of a universal testing machine in combination with a digital image correlation technique. Young's moduli, shear moduli, and Poisson's ratios have been determined for the different load directions. From studies on the radial-tangential plane of other wood species, it is known that the elastic moduli in the principal directions and the off-axis elastic moduli vary in a nonlinear correlation, depending on density gradients between earlywood and latewood. This angular dependency has been experimentally and theoretically proven for ash. Furthermore, the dependency of mechanical parameters on the fiber-load angle has been experimentally determined. The measurements for principal and off-axis load directions provide a sound basis for modeling of hardwood structures.

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“…While the grain angle dependencies were the focus of diverse studies (e.g., Hearmon and Barkas 1941;Suzuki and Sasaki 1990;Kabir et al 1997;Holmberg 2000;Liu 2002;Reiterer and Stanzl-Tschegg 2001;Yoshihara 2009), information on the angle-dependent elastic behavior within the RT plane is rather scarce for softwoods [for hardwoods, grain and ring angle-dependent compression tests were carried out by Lang et al (2002)]. One reason for this could be that preparation of specimens with orthotropic mechanical properties might be hampered due to the influence of the growth ring curvature.…”

Section: Introductionmentioning

confidence: 99%

Measurement of standard and off-axis elastic moduli and Poisson’s ratios of spruce and yew wood in the transverse plane

Garab

Keunecke²,

Hering³

et al. 2010

Wood Sci Technol

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It is well known that in the radial-tangential plane of softwoods, the elastic modulus in the principal directions is clearly higher than the off-axis elastic moduli, which decrease to a minimum at a growth ring angle a of about 45°. However, this angular dependency was experimentally proven by only a few early publications. The aims of this study were (1) to analyze this relationship with up-todate equipment in compression tests on miniature softwood specimens with varying growth ring angles and (2) to compare the experimental results with those calculated by a tensor transformation to assess whether it is admissible to treat the investigated wood species as orthotropic materials. Two softwoods with distinctly different anatomic structures (Norway spruce and common yew) were chosen, and further properties such as Poisson's ratios were determined. The results confirm the abovementioned angle-dependent tendency for spruce elasticity, but also show that it is not valid for softwoods in general since the behavior of yew was completely different. The tissue textures of both species, particularly density and density distribution, were discussed as possible reason for these observed differences. The determined Poisson's ratios for principal and off-axis load directions may be useful for modeling of material behavior.

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The effect of grain direction on the Young's moduli and rigidity moduli of beech and sitka spruce

Cited by 26 publications

References 3 publications

Determining moisture-dependent elastic characteristics of beech wood by means of ultrasonic waves

Determining moisture-dependent elastic characteristics of beech wood by means of ultrasonic waves

Anisotropic elastic properties of common ash (Fraxinus excelsior L.)

Measurement of standard and off-axis elastic moduli and Poisson’s ratios of spruce and yew wood in the transverse plane

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