Effect of Relative Humidity on Mechanical Properties of Birch Laminated Veneer Lumber

2010 ◽  
Vol 129-131 ◽  
pp. 576-579
Author(s):  
Bing Xue ◽  
Ying Cheng Hu ◽  
Fang Chao Cheng
Keyword(s):  
Relative Humidity ◽  
Shear Test ◽  
Bending Strength ◽  
Strength Properties ◽  
Bending Test ◽  
Betula Platyphylla ◽  
Vertical Load ◽  
Noticeable Effect ◽  
Laminated Veneer Lumber ◽  
Betula Platyphylla Suk

Laminated Veneer Lumber (LVL) panels made from birch (Betula platyphylla Suk.) veneers were tested for physical and mechanical strength properties in this study. The static bending test were conducted on the LVL, and bending test and shear test were conducted on veneer and three-lamination LVL. The effects of the relative humidity on the modulus of elasticity (MOE) and bending strength (MOR) of birch LVL with vertical load and parallel load were investigated. There were four relative humidities including 40%, 50%, 60% and 70%. The results showed that the MOE and MOR of LVL would diminished with the increase of relative humidity, the bending strength of veneer sample decreased as the relative humidity increased, and there was noticeable effect of relative humidity on shear strength of PF resin.

Analysis on Microstructure and Mechanical Properties of Birch Laminated Veneer Lumber

2010 ◽  
Vol 113-116 ◽  
pp. 2035-2038
Author(s):  
Bing Xue ◽  
Ying Cheng Hu
Keyword(s):  
Compression Ratio ◽  
Bending Strength ◽  
Longitudinal Vibration ◽  
Flexural Vibration ◽  
Bending Test ◽  
Vertical Load ◽  
Transmission Method ◽  
Vibration Method ◽  
Laminated Veneer Lumber ◽  
Betula Platyphylla Suk

In this paper, four different nondestructive testing (NDT) methods and the static bending test were conducted on the birch (Betula platyphylla Suk.) laminated veneer lumber (LVL). The NDT methods included the longitudinal transmission method, longitudinal vibration method, in-plane and out-plane flexural vibration method. The effects of the compression ratio on the static bending (MOE) and bending strength (MOR) of LVL with vertical load were investigated. There were four compression ratios for different ply numbers of LVL, 8.1% for eight-ply samples, 18.3% for nine-ply samples, 26.5% for ten-ply samples, 33.1% for eleven-ply samples, respectively. The microscopic structure of the LVL was analyzed with a scanning electron microscope (SEM). The results showed that the MOE and MOR of LVL were increased with increasing compression ratio, and there was a strong correlation between each dynamic Young’s modulus and the static MOE.

Effect of Relative Humidity on Reliability of Nondestructive Testing for Birch Laminated Veneer Lumber

2010 ◽  
Vol 129-131 ◽  
pp. 584-587
Author(s):  
Bing Xue ◽  
Ying Cheng Hu ◽  
Fang Chao Cheng
Keyword(s):  
Relative Humidity ◽  
Nondestructive Testing ◽  
Bending Strength ◽  
Longitudinal Vibration ◽  
Flexural Vibration ◽  
Bending Test ◽  
Destructive Testing ◽  
Vibration Method ◽  
Laminated Veneer Lumber ◽  
Elastic Module

Three different nondestructive testing (NDT) methods and the static bending test were conducted on the Laminated Veneer Lumber (LVL) made from birch (Betula platyphylla Suk.) rotary-cut veneers in this study. The NDT methods included the longitudinal vibration method, in-plane and out-plane flexural vibration method. The linear regression between dynamically elastic module and bending strength (MOR) and the effects of relative humidity on the reliability of NDT methods for LVL were investigated. There were four relative humidities including 40%, 50%, 60% and 70%. The results showed that the three non-destructive testing methods can be applied to test mechanical properties of birch LVL, the theory MOR result obtained by adjusted regression equation were reliable and can be applied in the actual project.

scholarly journals A Comparison of the Loading Direction for Bending Strength with Different Wood Measurement Surfaces Using Near-Infrared Spectroscopy

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 644 ◽  
Author(s):  
Yohei Kurata
Keyword(s):  
Near Infrared ◽  
Bending Strength ◽  
Tensile Force ◽  
Strength Properties ◽  
Bending Test ◽  
Tangential Section ◽  
Compression Force ◽  
Radial Section ◽  
Loading Direction ◽  
Light Acquisition

Wood is widely used throughout society for building resources and paper. To further expand wood’s use in the wood industry, we tested the bending strength properties of wood and certified its internal quality by using near-infrared spectroscopy (NIRS). In this study, the relationship between bending strength and loading direction was compared by changing the light acquisition point of wood surfaces to elucidate the anisotropy of the wood using NIRS. The two loading directions were defined by using a bending test as the radial section and the tangential section. Two light acquisition points with NIRS were also defined by a bending test as the loading position (the compression surface) and the opposite surface (the tensile surface), and a comparison was made between the prediction accuracy of the wood’s mechanical strength properties obtained via a bending test using two pieces of light acquisition data. The strength properties of the wood bending tests were the elastic modulus in bending (Eb), the bending strength (Fb) and density (DEN). Cryptomeria japonica was prepared and cut into a final size of 20 mm × 20 mm × 320 mm. Near-infrared (NIR) spectra were obtained from the compression force side and the tensile force side (calculating these averages), and a partial-least-squares regression (PLSR) was performed for the regression analysis. In the NIR measurement position, the best calibration results of the PLSR were the averaged data between the side undergoing the compression force and that undergoing the tensile force. Comparing the two loading directions, the result for the radial section was slightly superior to that of the tangential section. The radial section showed a good relationship between the spectra acquisition position and the arrangement of the wood’s structure. The estimation accuracy of bending strength properties differed depending on the location where the NIR spectra acquisition was performed.

Bending Strength of Glulam from Selected Malaysian Hardwood Timber

2014 ◽  
Vol 879 ◽  
pp. 237-244 ◽  
Author(s):  
Wan Hazira Wan Mohamad ◽  
Zakiah Ahmad ◽  
Ashari Abd. Jalil
Keyword(s):  
Shear Test ◽  
Bending Strength ◽  
Glue Line ◽  
Bending Test ◽  
Timber Species ◽  
Bending Performance ◽  
Glulam Beam ◽  
Heavy Medium ◽  
Malaysian Government

Malaysian government has already built the first glulam structure in Malaysia with the aim of demonstrating the potentialities of using indigenous hardwood timber for glulam. Since Malaysia possesses a vast variety of timber species, hence there is a need to identify suitable species for glulam manufacturing. This paper presents the bending performance of Malaysian hardwood glulam beams, manufactured from different categories namely heavy, medium and light hardwood timbers. A series of tests were carried out on the glulam beam that includes bending test, delamination test and shear test of glue line. Results in this study will be useful to manufacturers interested in using Malaysian hardwood for glulam beams.

scholarly journals The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part II: Strength Properties of Glued Laminated Timber

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4029
Author(s):  
Radosław Mirski ◽  
Dorota Dziurka ◽  
Monika Chuda-Kowalska ◽  
Jakub Kawalerczyk ◽  
Marcin Kuliński ◽  
...  
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Strength Properties ◽  
Bending Test ◽  
Structural Elements ◽  
Pine Wood ◽  
Glued Laminated Timber ◽  
The Individual ◽  
Horizontal Arrangement

The paper assessed the feasibility of manufacturing glued structural elements made of pine wood after grading it mechanically in a horizontal arrangement. It was assumed that the pine wood was not free of defects and that the outer lamellas would also be visually inspected. This would result in only rejecting items with large, rotten knots. Beams of the assumed grades GL32c, GL28c and GL24c were made of the examined pine wood. Our study indicated that the expected modulus of elasticity in bending was largely maintained by the designed beam models but that their strength was connected with the quality of the respective lamellas, rather than with their modulus of elasticity. On average, the bending strength of the beams was 44.6 MPa. The cause of their destruction was the individual technical quality of a given item of timber, which was loosely related to its modulus of elasticity, assessed in a bending test. Although the modulus of elasticity of the manufactured beam types differed quite significantly (11.45–14.08 kN/mm2), the bending strength for all types was similar. Significant differences occurred only during a more detailed analysis because lower classes were characterized by a greater variation of the bending strength. In this case, beams with a strength of 24 MPa to 50 MPa appeared.

The effects of the moisture content of laminated veneer lumber on bending strength and deformation determination via two-dimensional digital image correlation

2021 ◽  
pp. 095440622098618
Author(s):  
Eser Sözen ◽  
Kadir Kayahan ◽  
Timuçin Bardak ◽  
Selahattin Bardak
Keyword(s):  
Digital Image Correlation ◽  
Moisture Content ◽  
Digital Image ◽  
Bending Strength ◽  
Image Correlation ◽  
Bending Test ◽  
Homogeneous Distribution ◽  
Two Dimensional ◽  
Laminated Veneer Lumber ◽  
Strength And Deformation

This study determined the bending strength values of laminated veneer lumber (LVL) made with beech ( Fagus orientalis L.) veneer obtained by the peeling process and having four different moisture content values (0%/oven dry, 12%, 18%, and 25%). Bending tests were carried out in two different ways, i.e., for the flatwise and edgewise aspects of the LVL. Strain maps were created using two-dimensional digital image correlation (2 D DIC) and the samples having different moisture contents were compared. At the same time, the amount of displacement of the samples during the bending test was determined via conventional and DIC methods. Results of the study determined that the moisture content was effective in bending strength and tension zones. It was observed that increasing moisture content created homogeneous distribution of deformation. It was also observed that the data obtained by the 2 D DIC method were compatible with those obtained by the conventional method.

ASSESSMENT IN BENDING AND SHEAR STRENGTH OF GLUED LAMINATED TIMBER USING SELECTED MALAYSIAN TROPICAL HARDWOOD AS ALTERNATIVE TO TIMBER RAILWAY SLEEPERS

2016 ◽  
Vol 78 (5-5) ◽  
Author(s):  
Norshariza Mohamad Bhkari ◽  
Zakiah Ahmad ◽  
Afidah Abu Bakar ◽  
Paridah Md. Tahir
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Bending Strength ◽  
Bending Test ◽  
Structural Members ◽  
Tropical Timber ◽  
Bond Performance ◽  
Tropical Hardwood ◽  
Glued Laminated Timber ◽  
Bonding Characteristics

This paper presents a pilot study on bending and shear strength of glued laminated (glulam) timber using selected tropical timber namely, Kekatong (Cynometra spp.) and Melagangai (Potoxylon melagangai) as an alternative for timber railway sleepers. Selected timbers were manufactured in accordance with MS758:2001 and the bending test was conducted according to ASTM D198:2013. The shear test for glue line integrity was performed to observe the bond performance in glulam accordance to MS758:2001.The results showed both species can be used as structural members since the bending strength obtained from the laboratory work is greater than the allowable bending strength. In terms of the percentage of wood failure, the bonding characteristics of both glulam satisfied the bonding requirement stipulated in the standard and have the potential to be used as glulam timber railway sleepers.  

Analysis on Microstructure and Mechanical Properties of Pine Laminated Veneer Lumber

2010 ◽  
Vol 658 ◽  
pp. 479-482
Author(s):  
Bing Xue ◽  
Ying Cheng Hu ◽  
Fang Chao Cheng ◽  
Li Zhang
Keyword(s):  
Young’S Modulus ◽  
Compression Ratio ◽  
Bending Strength ◽  
Young's Modulus ◽  
Longitudinal Vibration ◽  
Flexural Vibration ◽  
Bending Test ◽  
Transmission Method ◽  
Vibration Method ◽  
Laminated Veneer Lumber

In this paper, four different nondestructive testing (NDT) methods and the static bending test were conducted on the pine (Pinus sylvestris L. Var. mongolica Litven.) laminated veneer lumber (LVL). The NDT methods included the longitudinal transmission method, longitudinal vibration method, in-plane and out-plane flexural vibration method. The effects of the compression ratio on the Young’s modulus and bending strength (MOR) of LVL were investigated. There were four compression ratios for different ply numbers of LVL, 8.1% for eight-ply samples, 18.3% for nine-ply samples, 26.5% for ten-ply samples, 33.1% for eleven-ply samples, respectively. The microscopic structure of the LVL was analyzed with a scanning electron microscope (SEM). The results showed that the microstructure of LVL changed greatly between different compression ratios. And the dynamic Young’s modulus and static bending (MOE) and bending strength (MOR) were greatly increased when the compression ratio increased form 18.3% to 26.5%.

Mechanical Grading of Structural Larch Dimension Lumber

2012 ◽  
Vol 517 ◽  
pp. 683-688 ◽  
Author(s):  
Wan Li Lou ◽  
Hai Qing Ren ◽  
Zhao Hui Wang ◽  
Xiu Qin Luo
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Strength Properties ◽  
Modulus Of Rupture ◽  
Bending Test ◽  
Total Production ◽  
Good Relationship ◽  
Dimension Lumber ◽  
Structural Applications ◽  
Viable Approach

Larch dimension lumber bending strength properties from full-size bending test were used to establish preliminary grade boundary settings for mechanical grading of lumber by modulus of elasticity. Simulated production using the grade boundary settings were evaluated for modulus of rupture, ultimate tensile strength, and ultimate compressive strength. The results showed a good relationship between modulus of rupture and modulus of elasticity, and the observed relationships between strengths properties were consistent with that assumed for the standard grades. Through mechanical grading, larch dimension lumber could be sort grades: M14, M30 and M40. Assuming the visual requirements are met, the M30 and M40 grades account for more than 80% of the total production. Mechanical grading of larch appears to be a viable approach for grading Chinese large for structural applications.

scholarly journals Density, hardness and strength properties of densified fir and aspen woods pretreated with water repellents

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hüseyin Pelit ◽  
Fatih Emiroglu
Keyword(s):  
Compression Ratio ◽  
Bending Strength ◽  
Linseed Oil ◽  
Vacuum Treatment ◽  
Strength Properties ◽  
Aspen Wood ◽  
Positive Effect ◽  
Water Repellents ◽  
Impregnated Wood ◽  
Compression Temperature

AbstractIn this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.

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