A Mathematical Solution for Calculating the Springback of Laminated Beech Stacks Molded within the Elastic Range

Sanne, Moritz; Ahn-Ercan, Gudrun; Pfriem, Alexander

doi:10.3390/f11070725

Cited by 6 publications

(2 citation statements)

References 14 publications

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“…The possibility of manufacturing large wood products also in curved shapes by gluing together thin wood pieces (lamellas or veneers) in a relatively simple and rapid process is another benefit of such composite material (Keskin 2009;Sanne et al 2020). Due to these and other factors such as increased interest in wood buildings and benefits of long-term carbon storage, the importance of engineered wood materials has increased considerably (Hart and Pomponi 2020).…”

Section: Introductionmentioning

confidence: 99%

The potential of improving wood preservative penetration into glued wood products bonded with one-component polyurethane by discontinuous adhesive bondline design

et al. 2021

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As a vast majority of glued wood products are intended for outdoor use or for building construction, impregnation with different agents is important for ensuring proper performance. It has been shown that the impregnation prior to gluing has several disadvantages, therefore the possibility of carrying out impregnation after gluing is analysed in the present research. Impregnation efficiency as well as the effect on the bond quality is evaluated for the one-component polyurethane glued wood specimens. The results showed that the impregnation with Cu preservative after gluing did not affect the shear strength of the glued wood specimens, but did significantly restrict Cu preservative penetration due to the adhesive bondlines. Considering the results, the possibility of improving the impregnation efficiency was also investigated. By using specific adhesive application designs, which cover the bondline only partially, it was possible to improve the impregnation efficiency. However, the Cu distribution was inhomogeneous and the improvement was noticeable only up to the second bondline. The partial adhesive application design also affected the bond strength of glued wood specimens, which resulted in a decrease both in dry and wet state. However, the reduction was not so sever as to cause delamination during three consecutive wetting and drying cycles.

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Section: Introductionmentioning

confidence: 99%

The potential of improving wood preservative penetration into glued wood products bonded with one-component polyurethane by discontinuous adhesive bondline design

et al. 2021

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“…The application of the same technique to full-size composite wood panels was also investigated [16,17] and new equations were developed to calculate the equivalent shear modulus of plywood from the shear moduli of the individual lamellae [18]. Since plywood can also be given spatial forms, the springback effect must be taken into account [19].…”

Section: Introductionmentioning

confidence: 99%

Determination of Elastic Properties of Beech Plywood by Analytical, Experimental and Numerical Methods

Merhar

2020

Forests

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This research article examines the application of various methods to determine the effective elastic properties of beech veneer-wood composites. Using laminate theory, the theoretically calculated effective values of the in-plane and out-of-plane modulus of elasticity as well as shear modulus are compared with the values determined from the natural frequencies of flexural, torsional and longitudinal vibrations of samples having different orientations and numbers of composite layers. The samples are also modelled using the finite element method, and their natural frequencies are calculated by the modal analysis. Research has shown that the laminate theory, which is well established and applied in the world of synthetic composites, can also be applied to beech plywood composites, where the theoretically calculated effective values can be up to 15% higher. Similarly, due to the higher calculated effective elastic properties, higher natural frequencies of flexural, torsional and longitudinal vibrations are also calculated by the finite element method.

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Tribological properties and related effects of compressed, thermally modified and wax-impregnated wood

Waßmann,

Ahmed

2024

Eur. J. Wood Prod.

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This paper develops a process for the preparation of modified wood with low friction and low wear for tribological applications such as self-lubricating bearings. Two types of wood, beech (Fagus sylvatica) and robinia (Robinia pseudoacacia), have been studied and the results compared with naturally lubricated native lignum vitae. The process developed consists of plasticisation followed by compression in a mould, thermal modification and subsequent wax impregnation. Plasticisation was carried out by conditioning the samples to a low equilibrium moisture content of 10%, followed by heating to a sample core temperature of 80 °C. This process protects the internal wood structure from mechanical damage during densification. After plasticisation, the wood was compressed in a press mould. A low springback effect (SBE), resulting in compression of up to 40%, was achieved by unloading the mould without opening it. This step optimises compressive strength and hardness. Subsequent heat treatment reduces thickness swelling by up to 85%. Finally, a wax impregnation was applied to reduce friction. Sliding wear tests on modified beech wood have shown that the lowest wear occurs in the cross-sectional orientation (load perpendicular to the fibre ends; rxt orientation). Sliding friction studies using a steel ball on a ball-on-disc tribometer showed that compressed and thermally modified samples impregnated with rapeseed wax or beeswax exhibited coefficients of friction in a range of 0.08 to 0.09. These values are almost four times lower than those of plain compressed wood and even lower than those of lignum vitae, which was used for plain bearings decades ago. This study clearly demonstrates the high potential of compressed, thermally modified and wax-impregnated wood.

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A Mathematical Solution for Calculating the Springback of Laminated Beech Stacks Molded within the Elastic Range

Cited by 6 publications

References 14 publications

The potential of improving wood preservative penetration into glued wood products bonded with one-component polyurethane by discontinuous adhesive bondline design

The potential of improving wood preservative penetration into glued wood products bonded with one-component polyurethane by discontinuous adhesive bondline design

Determination of Elastic Properties of Beech Plywood by Analytical, Experimental and Numerical Methods

Tribological properties and related effects of compressed, thermally modified and wax-impregnated wood

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