The Relationship of Structure to Transverse Anisotropy in Wood with Reference to Shrinkage and Elasticity

Boutelje, Julius

doi:10.1515/hfsg.1962.16.2.33

Cited by 58 publications

(38 citation statements)

References 15 publications

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“…The transverse anisotropy of cell wall material is, though related, not a phenomenon identical to the swelling anisotropy of cell tissue and wood at timber scale [11]. The swelling/ shrinkage coefficient is defined as the strain induced by a variation of 1% MC and is calculated from the slope of the strain curve plotted against MC.…”

Section: Discussionmentioning

confidence: 99%

Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

Rafsanjani

Stiefel

Jefimovs

et al. 2014

J. R. Soc. Interface.

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We document the hygroscopic swelling and shrinkage of the central and the thickest secondary cell wall layer of wood (named S2) in response to changes in environmental humidity using synchrotron radiation-based phase contrast X-ray tomographic nanoscopy. The S2 layer is a natural fibre-reinforced nanocomposite polymer and is strongly reactive to water. Using focused ion beam, micropillars with a cross section of few micrometres are fabricated from the S2 layer of the latewood cell walls of Norway spruce softwood. The thin neighbouring cell wall layers are removed to prevent hindering or restraining of moisture-induced deformation during swelling or shrinkage. The proposed experiment intended to get further insights into the microscopic origin of the anisotropic hygro-expansion of wood. It is found that the swelling/shrinkage strains are highly anisotropic in the transverse plane of the cell wall, larger in the normal than in the direction parallel to the cell wall's thickness. This ultrastructural anisotropy may be due to the concentric lamellation of the cellulose microfibrils as the role of the cellulose microfibril angle in the transverse swelling anisotropy is negligible. The volumetric swelling of the cell wall material is found to be substantially larger than the one of wood tissues within the growth ring and wood samples made of several growth rings. The hierarchical configuration in wood optimally increases its dimensional stability in response to a humid environment with higher scales of complexity.

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Section: Discussionmentioning

confidence: 99%

Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

Rafsanjani

Stiefel

Jefimovs

et al. 2014

J. R. Soc. Interface.

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“…Second, the mechanical properties change within the annual growth rings. Earlywood exhibits a marked anisotropic behavior (with large thin-walled cells aligned in the radial direction), while latewood exhibits a roughly isotropic behavior (with smaller and thicker-walled cells) (Boutelje 1962). Therefore, the proportion between earlywood and latewood affects the relationship between the radial-tangential moduli.…”

Section: Resultsmentioning

confidence: 99%

Effects of Convection and Microwave Drying Schemes on the Characteristics and Sound Absorption of Acoustic Oil Palm Boards

Dangvilailux

Charoensuk

2017

BioResources

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To perform a non-destructive evaluation of wood, the Christoffel equation is frequently used to describe the relationship between the ultrasonic wave velocity and the mechanical parameters. In the context of acoustical tomography imaging of standing trees, the key contribution of this numerical study is to determine the influence of mechanical parameters of the wood radial-tangential plane on the wave velocity computation using the Christoffel equation. Mechanical parameters from six species were selected. A sensitivity analysis was carried out by increasing and decreasing every parameter by a given percentage, and then by computing the variation of velocity for a set of wave direction of propagations. The evolution of the wave velocity, according to the direction of propagation, depended on the considered species; there was a difference between the softwoods and the hardwoods. The sensitivity analysis showed a bigger influence of the Young's moduli, followed by the Poisson's ratio, and finally by the shear modulus. However, these last two parameters cannot be neglected when using the Christoffel equation to solve the inverse problem of standing tree tomography. A proposed solution involves determining the propagation paths using the Young's moduli as variables and then inversing the set of equations in accordance with the overall parameters.

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“…In the case of the broad-rayed wood species, such as oak and beech, shrinkage results may support the hypothesis that rays are one of the factors responsible for transverse shrinkage anisotropy, because the ray volume is up to 17% -22% of the wood tissue in oak and beech ( Skaar 1988 ). However, Boutelje (1962) denied the importance of rays with this regard in softwood species.…”

Section: Introductionmentioning

confidence: 99%

“…In the R direction, both the EW and LW shrink independently, that is, they act in series and the total R shrinkage is the weighted mean shrinkage of the LW and EW ( Spear and Walker 2006 ). Pentoney (1953) and Boutelje (1962) tried to evaluate the influence of the M ö rath theory on the differential shrinkage. Kifetew et al (1997) suggested a relationship for calculating the gross T and R shrinkage of Scots pine based on the isolated EW and LW interaction.…”

Section: Introductionmentioning

confidence: 99%

Effects of cell wall ultrastructure on the transverse shrinkage anisotropy of Scots pine wood

2014

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Effects of cell wall ultrastructure on the transverseshrinkage anisotropy of Scots pine wood. Effects of cell wall ultrastructure on the transverse shrinkage anisotropy of Scots pine woodAbstract : A hypothesis for explaining the differential anisotropic shrinkage behavior of wood has been proposed, and it was based on the differences in the cell wall ultrastructure. The starting point of the consideration is that wood shrinkage is governed by its chemical composition, ultrastructure, and gross anatomy. It is also well known that the transverse shrinkage anisotropy of earlywood (EW) is more pronounced than that of the latewood (LW). In the paper, the cell wall ultrastructure and shrinkage anisotropy has been related to each other, and to this purpose, a set of crystallographic texture descriptors was applied. The descriptors are based on X-ray diffraction (XRD) experiments conducted on matched EW samples from different growth rings of Scots pine. The range of the microfibril angle (MFA) was identified. The ratio of the maxima of inverse pole figures (IPFs) of both the tangential (T) and radial (R) directions was determined. The ratios quantify the inhomogeneity of the spatial arrangement of the ordered areas. The results of the study clearly indicate that the transverse shrinkage of wood is governed mostly by a specific ultrastructural organization of moderately organized cell wall compounds.

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The Relationship of Structure to Transverse Anisotropy in Wood with Reference to Shrinkage and Elasticity

Cited by 58 publications

References 15 publications

Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

Hygroscopic swelling and shrinkage of latewood cell wall micropillars reveal ultrastructural anisotropy

Effects of Convection and Microwave Drying Schemes on the Characteristics and Sound Absorption of Acoustic Oil Palm Boards

Effects of cell wall ultrastructure on the transverse shrinkage anisotropy of Scots pine wood

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