Orthotropic hygric and mechanical material properties of oak wood

Ożyhar, Tomasz; Mohl, Leander; Hering, Stefan; Haß, Philipp; Zeindler, Lars; Ackermann, Ralf; Niemz, Peter

doi:10.1080/17480272.2014.941930

Cited by 14 publications

(15 citation statements)

References 15 publications

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“…Further, the blue and red curves respectively refer to MFAs of 10 • and 20 • in the S2 layer of axial cells. Figure 13 illustrates the effective Young's moduli of oak as a function of the macro-scale moisture content m, together with the experimental data reported in [23,[81][82][83]. The Young's moduli in the radial direction ĒR , tangential direction ĒT , and longitudinal direction ĒL are presented in Figures 13(a), (b), and (c), respectively, and clearly show that a higher material density generally leads to a higher stiffness value.…”

Section: Effective Elastic Properties Of Oakmentioning

confidence: 80%

“…This result is comparable to the experimental value ĒR / ĒT ≈ 2 reported in [84] for a fully saturated Pedunculate oak wood sample with a dry density of 530 kg/m 3 . Figure 14 shows the effective Poisson's ratios of oak as a function of the macro-scale moisture content m, together with the experimental data reported in [23,[81][82][83]. The influence of the material density ρ on the Poisson's ratios νLT (Figure 14(a), tangential plane), and νRT (Figure 14(c), transverse plane) is mild, and on the Poisson's ratio νLR (Figure 14(b), radial plane) is negligible.…”

Section: Effective Elastic Properties Of Oakmentioning

confidence: 99%

“…These coefficients represent the diagonal elements of the hygroscopic expansion tensor; it has been indeed confirmed that the computed off-diagonal elements are negligible. The experimental results presented in Figure 16 are based on the test data presented in [42,65,81]; since the values of the moisture content at which the hygro-expansion coefficients were measured are not reported in these references, only the spread in experimental data has been displayed by means of a grey region of constant bandwidth. Note that the experimental bandwidths for the three hygroscopic coefficients indeed mostly fall within the ranges of the modelling results.…”

Section: Effective Hygro-expansion Coefficientsmentioning

confidence: 99%

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A 3D multi-scale hygro-mechanical model of oak wood

Livani

Suiker

Crivellaro

et al. 2023

Preprint

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A multi-scale framework is proposed for the prediction of the macroscopic hygro-elastic properties of oak wood. The distinctive features of the current multi-scale approach are that: i) four different scales of observation are considered, which enables the inclusion of heterogeneous effects from the nano-, micro-, and meso-scales in the effective constitutive behaviour of oak at the macro-scale, ii) the model relies on three-dimensional material descriptions at each considered length scale, and iii) a moisture-dependent constitutive assumption is adopted at the nano-scale, which allows for recovering the moisture dependency of the material response at higher scales of observation. In the modelling approach, oak wood is considered homogeneous at the macro-scale. The meso-scale description considers the cellular structure of individual growth rings with three different densities. At the micro-scale, the heterogeneous nature of cell walls is described by the characteristics of the primary and secondary cell wall layers. Finally, the nano-scale response is determined by cellulose micro-fibrils embedded in a matrix of hemicellulose and lignin. The oak properties at the four length scales are connected via a three-level homogenization procedure, whereby, depending on the geometry of the fine-scale configuration, an asymptotic homogenization procedure or Voigt averaging procedure is applied at each level to determine the effective hygro-elastic properties at the coarse scale. In addition, the moisture ad-sorption isotherms at each scale are constructed from a volume-weighted averaging of the moisture adsorption characteristics at the scale below. The computational results demonstrate that the moisture-dependent, hygro-elastic behaviour of oak wood is predicted realistically at each considered length scale, thereby revealing the influence of the material density, the micro-fibril orientation, and the hygro-elastic properties at the underlying scales. The computed macro-scale properties of oak are in good agreement with experimental data reported in the literature.

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Section: Effective Elastic Properties Of Oakmentioning

confidence: 80%

Section: Effective Elastic Properties Of Oakmentioning

confidence: 99%

Section: Effective Hygro-expansion Coefficientsmentioning

confidence: 99%

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A 3D multi-scale hygro-mechanical model of oak wood

Livani

Suiker

Crivellaro

et al. 2023

Preprint

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“…On the other hand, the comparison of the presently obtained data with that of other wood species show similar shear strengths in the LR-and LT-planes. Two hardwood species, oak (Quercus robur L.) and Sycamore maple (Acer pseudoplatanus L.) wood were tested using the shear block test and presented in Ozyhar et al [40] and Sonderegger et al [41], respectively. The values are higher by 3-15% compared to the ones of the current study, which is well within the range of natural variability of properties, especially considering different wood species.…”

Section: Experimentally Determined Shear Strengthmentioning

confidence: 99%

Estimating shear properties of walnut wood: a combined experimental and theoretical approach

et al. 2017

Self Cite

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In this study, several theoretical models to numerically estimate shear properties of orthotropic materials are introduced. These approaches are based on the combination of Hankinson's empirically derived formula with other empirical and analytical calculations. Next to shear moduli, which are estimated from the elastic moduli and Poisson's ratios, shear strengths are also estimated from the in-axis strengths. The models are validated by mechanical tests on walnut wood (Juglans regia L.), for which a sufficient data set can be found in literature. The Arcan test is used to estimate the shear moduli, while the shear block test is used to estimate the shear strengths. The results show that the model, which is based on a combined use of Hankinson's formula and tensor rotation, gives the best estimation of shear moduli as evaluated by the minimum differences to the experimentally obtained results. For the shear strengths, a combination of Hankinson's formula and Norris' failure criterion shows the best agreement in comparison to the experimental data. The theoretical calculations may be used for a time efficient estimation of shear modulus and strength in comparison to the very time-consuming experimental estimation.

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“…At low coating amount, the coating thickness is thin and insufficient coverage will be obtained, while with an excessive amount of coating, drying defects such as wrinkles, and bubbling may occur. Therefore, in this paper, a kind of fast water-based UV curing coating was synthesized in the laboratory, and applied on oak for its wide application in furniture, flooring and other industries due to its resource advantages and good decorative properties in the solid wood market [30,31,32]. The effect of coating amount on the surface properties such as the surface morphology, chemical changes, permeability and surface energy was studied, with the aim to provide some basic data and reference for the application of the fast water-based UV curing wood coatings.…”

Section: Introductionmentioning

confidence: 99%

Preparation of a Fast Water-Based UV Cured Polyurethane-Acrylate Wood Coating and the Effect of Coating Amount on the Surface Properties of Oak (Quercus alba L.)

Wang

Liu

et al. 2019

Polymers

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A fast water-based ultraviolet light (UV) curing polyurethane-acrylate (PUA) wood coating was prepared in the laboratory, and applied on oak (Quercus alba L.) at different coating amounts. The PUA wood coating can be fast cured within 22 min, which highly improved the drying speed compared to normal water-based wood coatings (often higher than 35 min). The coating amounts affected the coating properties after curing on oak. With the increase of coating amount, the adhesion, hardness and gloss value of surface increased to different extents. Meanwhile, the surface of sample became smooth gradually because the voids of the oak were filled. Thus, higher coating amount resulted in better coating properties. However, no significant increase of penetration depth was found. During curing, the hydroxyl groups of the wood reacted with the coating. The optimal parameter in this study was the coating amount of 120 g/m2, where the adhesion reached 1 (with 0–5% cross-cut area of flaking along the edges), with the hardness of 2H and the gloss of 92.56°, which met the requirement of Chinese standard GB/T 18103–2013, and could be used for engineered wood flooring.

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Orthotropic hygric and mechanical material properties of oak wood

Cited by 14 publications

References 15 publications

A 3D multi-scale hygro-mechanical model of oak wood

A 3D multi-scale hygro-mechanical model of oak wood

Estimating shear properties of walnut wood: a combined experimental and theoretical approach

Preparation of a Fast Water-Based UV Cured Polyurethane-Acrylate Wood Coating and the Effect of Coating Amount on the Surface Properties of Oak (Quercus alba L.)

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