Effect of fatigue and annual rings’ orientation on mechanical properties of wood under cross-grain uniaxial compression

Miksic, Amandine; Myntti, M.; Koivisto, Juha; Salminen, Lauri; Alava, Mikko J.

doi:10.1007/s00226-013-0561-8

Cited by 15 publications

(14 citation statements)

References 45 publications

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“…That is why its mechanical properties differ significantly in the direction of longitudinal, radial and tangential axes of the wood. The direction of force in relation to annual rings also affects the mechanical properties in the longitudinal direction of the wood [11][12][13][14][15]. This study was aimed at examining the effect of a ring angle on the bending strength parallel to the grain of the wood.…”

Section: Introductionmentioning

confidence: 99%

Annual ring orientation effect on bending strength of subfossil elm wood

2016

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The effect of annual rings' orientation on bending strength was examined on subfossil elm wood. Elm is extremely rarely found as subfossil wood, and during the last 50-60 years it has almost disappeared from natural forest stands of southeastern Europe, due to the Elm Dutch disease. The samples were cut from approximately 670 years old subfossil elm trunk retrieved from the bed of the river Sava in the area between the villages Grebnice and Domaljevac in north Bosnia. The wood was identified to the genus level based on optical microscopy analysis of three wood sections-transverse, tangential and radial. Bending strength was determined by the three-point bending test. The load was applied to the longitudinaltangential surface (LT) and to the longitudinal-radial surface (LR). The bending strength values of subfossil elm do not differ from the values of recent elm, despite the 700-year resting in anoxic river conditions. Bending strength in LT direction was slightly higher than bending strength in LR direction. The coefficient of variation and the standard deviation of the arithmetical mean were higher for LT direction. It was found that the measured bending strength for both directions follows Weibull distribution. Coefficient of determination of Weibull functions was close to 1 for both directions. The Weibull shape parameter was higher for LR direction.

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Section: Introductionmentioning

confidence: 99%

Annual ring orientation effect on bending strength of subfossil elm wood

2016

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“…Reviewing the literature, a study on axial compression tests was performed on samples of Norway spruce wood with different orientations of the annual rings relative to the load direction performed to obtain the stress-strain measurement results. The results of this study showed us that permanent deformation in honeycomb-pinewood exhibited a nonlinear mechanical behavior [1].…”

Section: Introductionmentioning

confidence: 69%

Microscopic Characterisation of <i>Pinus sylvestris</i> Cell Structures under Compression Loading

Günay¹,

Golmohammadi²,

Kaya³

2014

MSA

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This study is mainly focused on the 3D mechanical cell deformations of 20 × 20 × 60 mm sized softwood specimens under 35-40 MPa compression loading at room temperature of 20˚C. The moisture content of the specimens was 6%-7%. The data of microscopic images were measured and compared in terms of the permanently degenerated individual cell structures each in micro-scale () μm. 3D cell deformations of tissues were observed with a magnification of (×100)-(×1500) and in the range of 3.0-5.0 kV voltage under the SEM microscope. The specimens were examined under magnification and photographed before and after the compression loading applied parallel to the grain angles to the wood samples. Specimens were painted with gold liquid (12 × 12 × 12 mm sized specimens) in obtaining the SEM images. Under the SEM, these specimens were photographed and lengths between the cell walls ranged between 15 to 40 micrometers. In this study, relative deformations of pinewood cells were determined statistically considering the percentage permanent deformation under the compression loading. It was performed by using knowledge of structural mechanics, considering the measurement of permanent deformation in honeycomb-pinewood structure material.

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“…This phenomenon is caused by the specific microstructure of wood. It isn't characteristic of all wooden species, neither for all the properties [11,[21][22][23].…”

Section: Resultsmentioning

confidence: 99%

“…This study has investigated the bending strength of subfossil elm wood with loads applied to the longitudinal-tangential surface (angle of 08-longitudinal-tangential) and to the longitudinal-radial surface (angle of 908-longitudinal-radial). The experimentators decided to expand the previous research and examine also the bending strength with load-to-annual ring direction with angle of 458 (L45) and compare it with previous results [11][12].…”

Section: Introductionmentioning

confidence: 99%

Bending strength dependence of load-to-annual ring direction

Rede

Essert

Šokčević

2017

Mat.-wiss. u. Werkstofftech.

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The bending strength was studied for load‐to‐grain direction at angle of 90° and load‐to‐annual tree ring direction at angle of 45° of almost 700 years old subfossil elm wood from Sava riverbed. Elm wood is widely used because it is solid and hard regarding its weight. However, due to the Elm Dutch disease and mass drying of elm trees in 1950s, nowadays it is almost impossible to find in natural forest stands of south‐eastern Europe a tree of reproductive age. The value and uniqueness of the studied material lies also in the fact that the subfossil elm wood is even rarer than the recent one, and is highly appreciated for its aesthetic and mechanical qualities. Bending strength has been determined by a three‐point bending test. The mean bending strength value is within the limits for recent elm wood. This investigation has shown that such load‐to‐annual ring direction has almost 20 % higher value for bending strength than for loads applied to the longitudinal‐tangential surface (angle of 0°) and to the longitudinal‐radial surface (angle of 90°). This proves that the ring orientation plays an important role in the measurement of mechanical properties of elm wood and that the measurement of the angle of 45° should always be considered for investigation of bending strength.The coefficient of determination of Weibull functions has been close to value of 1, so it has been concluded that the measured bending strength follows Weibull distribution.

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Effect of fatigue and annual rings’ orientation on mechanical properties of wood under cross-grain uniaxial compression

Cited by 15 publications

References 45 publications

Annual ring orientation effect on bending strength of subfossil elm wood

Annual ring orientation effect on bending strength of subfossil elm wood

Microscopic Characterisation of <i>Pinus sylvestris</i> Cell Structures under Compression Loading

Bending strength dependence of load-to-annual ring direction

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Effect of fatigue and annual rings’ orientation on mechanical properties of wood under cross-grain uniaxial compression

Cited by 15 publications

References 45 publications

Annual ring orientation effect on bending strength of subfossil elm wood

Annual ring orientation effect on bending strength of subfossil elm wood

Microscopic Characterisation of &lt;i&gt;Pinus sylvestris&lt;/i&gt; Cell Structures under Compression Loading

Bending strength dependence of load-to-annual ring direction

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Microscopic Characterisation of <i>Pinus sylvestris</i> Cell Structures under Compression Loading