Compressive strength parallel to grain of earlywood and latewood of yellow pine

Mankowski, Peter; Laskowska, Agnieszka

doi:10.4067/s0718-221x2021000100457

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…For control specimens, there is more or less a linear relationship between compressive strength and compressive ratio, which means that the structural deformation in LW specimens was uniform in function of time. The variation however in LW specimens was large, which corresponds to the ndings of other researchers (Mańkowski et al 2021). The difference of structural characteristics among specimens, i.e.…”

Section: Physical and Mechanical Propertiessupporting

confidence: 88%

The impact of earlywood and latewood on the compressive strength of Douglas fir

Yang

Wang³

et al. 2022

Preprint

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Mechanical performance of wood is determined by its structural characteristics, among others earlywood and latewood in softwoods. Given that thermal modification also affects the mechanical strength, it is key to understand how the modification affects earlywood and latewood and how this on its turn impacts compressive strength. In this study, Douglas fir blocks measuring 30×50×150mm3 were modified at 180°C (TM-180°C) and 210°C (TM-210°C). The compressive strength of pure earlywood (EW), pure latewood (LW) and a combination of earlywood and latewood (ELW) specimens was measured. The specimens were compressed in terms of 30% of their original thickness, and during the compression test the strain distribution of ELW was recorded. In addition, the microstructure before and after compression was investigated complemented with using SEM to understand the structural changes taking place. The results show that compressive strength of TM-180°C specimens was high, most probably because thermal modification increased stiffness of cell walls and homogenized strain distribution in ELW specimens. Control specimens had a higher compression set recovery than thermally modified specimens. Tracheid cell walls in EW and LW specimens were flattened and buckled respectively due to compression. While in thermally modified material, cell wall fissures and wood ray fractures in EW and LW specimens respectively were observed. For ELW specimens, structural changes in latewood were trivial, and structural changes in the earlywood part were less significant than in full EW specimens. Compared to EW specimens, earlywood in ELW showed higher compression set recovery. It seems that structural failure in earlywood is limited when in combination with latewood, resulting from homogenized strain distribution in earlywood.

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Section: Physical and Mechanical Propertiessupporting

confidence: 88%

The impact of earlywood and latewood on the compressive strength of Douglas fir

Yang

Wang³

et al. 2022

Preprint

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“…For the control specimens, there is more or less a linear relationship between the compressive stress and compressive ratio, which means that the structural deformation in the LW specimens was uniform as a function of time. The variation, however, in the LW specimens was large, corresponding to the findings of other researchers [29]. The different structural characteristics among specimens, i.e., the cell wall thickness, rays, and resin ducts, could have a substantial effect on the stiffness of LW.…”

Section: Physical and Mechanical Propertiessupporting

confidence: 83%

The Impact of Earlywood and Latewood on the Compressive Stress of Thermally Modified Douglas Fir

Wang¹,

Yang

et al. 2023

Forests

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Thermal modification can increase the physical stability and impact the mechanical strength of wood. It is necessary to understand the effects of modifications on the compressive stress of wood. In this study, Douglas fir (Pseudotsuga menziessi) blocks were modified at 180 °C (TM-180 °C) and 210 °C (TM-210 °C). The compressive stress of pure earlywood (EW), pure latewood (LW), and combined earlywood and latewood (ELW) specimens was measured. The specimens were compressed at 30% of their original thickness, and during the compression test the strain distribution of the ELW was recorded. In addition, the microstructures before and after compression were investigated, complemented with SEM to understand the structural changes taking place. The results showed that the compressive stress of the TM-180 °C specimens was the highest because the thermal modification increased the stiffness of cell walls and the homogenized strain distribution in the ELW specimens. The control specimens had a higher compression set recovery rate than the thermally modified specimens. The tracheid cell walls in the EW and LW specimens were flattened and buckled, respectively, due to compression. In the thermally modified materials, cell wall fissures and wood ray fractures in the EW and LW specimens, respectively, were observed. For the ELW specimens, the structural changes in the latewood were not obvious and the structural changes in the earlywood were less significant than in the full EW specimens. Compared to the EW specimens, the earlywood in the ELW specimens showed higher compression set recovery rates. It seems that structural failure in earlywood is limited when used in combination with latewood, resulting from the homogenized strain distribution in earlywood.

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Some physical and mechanical properties of particle boards produced with hazelnut husk and astragalus (Astragalus membranaceus) plant

Karahan,

Guler

2024

Maderas-Cienc Tecnol

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In this study, under laboratory conditions, hazelnut husk and astragalus plant were mixed separately into black pine wood chips, and multi-purpose boards were produced from the obtained chips with urea formaldehyde glue. After the hazelnut husk and astragalus plant were dried and ground, they were added to the chip and glue mixture in certain proportions. Hazelnut husk mixture ratios were applied as 100 %; 0 %, 75 %; 25 %, 50 %; 50 %, 25 %; 75 %, 0 %; 100 % to black pine wood chip in the particle board mixture. These ratios were made in the same way for the astragalus plant. From these mixtures, chipboard blanks of 16 mm thickness and densities between 0,68 g/cm3 and 0,72 g/cm3 were produced. Density, moisture content, thickness increase, water intake, bending strength, modulus of elasticity in bending and tensile strength perpendicular to the surface were tested in physical and mechanical experiments. According to the results obtained, as the participation rate of hazelnut shells and astragalus increased, the durability properties of the panels decreased. At the same time, it shows that the technological properties of the panels produced by adding up to 25 % astragalus plant and hazelnut shells to the mixture comply with the standards.

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Compressive strength parallel to grain of earlywood and latewood of yellow pine

Cited by 3 publications

References 14 publications

The impact of earlywood and latewood on the compressive strength of Douglas fir

The impact of earlywood and latewood on the compressive strength of Douglas fir

The Impact of Earlywood and Latewood on the Compressive Stress of Thermally Modified Douglas Fir

Some physical and mechanical properties of particle boards produced with hazelnut husk and astragalus (Astragalus membranaceus) plant

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