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21 records – page 2 of 3.

Estimation of Radio Frequency Electric Field Strength for Dielectric Heating of Phenol-Resorcinol-Formaldehyde Resin Used for Manufacturing Glulam

https://research.thinkwood.com/en/permalink/catalogue1505
Year of Publication
2014
Topic
Connections
Material
Glulam (Glue-Laminated Timber)
Author
Yang, Sang-Yun
Han, Yeonjung
Park, Yonggun
Eom, Chang-Deuk
Kim, Se-Jong
Kim, Kwang-Mo
Park, Moon-Jae
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2014
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Keywords
Adhesives
Phenol-Resorcinol Formaldehyde
Larch
High Frequency
Specific Heat
Density
Dielectric
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
For enhancing productivity of glulam, high frequency (HF) curing technique was researched in this study. Heat energy is generated by electromagnetic energy dissipation when HF wave is applied to a dielectric material. Because both lamina and adhesives have dielectric property, internal heat generation would be occurred when HF wave is applied to glulam. Most room temperature setting adhesives such as phenol-resorcinol-formaldehyde (PRF) resin, which is popularly used for manufacturing glulam, can be cured more quickly as temperature of adhesives increases. In this study, dielectric properties of larch wood and PRF adhesives were experimentally evaluated, and the mechanism of HF heating, which induced the fast curing of glue layer in glulam, was theoretically analyzed. Result of our experiments showed relative loss factor of PRF resin, which leads temperature increase, was higher than that of larch wood. Also, it showed density and specific heat of PRF, which are resistance factors of temperature increase, were higher than those of wood. It was expected that the heat generation in PRF resin by HF heating would occur greater than in larch wood, because the ratio of relative loss factor to density and specific heat of PRF resin was greater than that of larch wood. Through theoretical approach with the experimental results, the relative strengths of ISM band HF electric fields to achieve a target heating rate were estimated.
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Evaluation of Delamination and Bending Performance of Composite CLT Reinforced with CFRP

https://research.thinkwood.com/en/permalink/catalogue2203
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Floors
Author
Song, Yo-Jin
Hwan Lee, In
Song, Da-Bin
Hong, Soon-Il
Organization
Kangwon National University
Publisher
Society of Wood Science and Technology
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Floors
Topic
Mechanical Properties
Keywords
Delamination
CFRP
Bending Strength
Japanese Larch
Research Status
Complete
Series
Wood and Fiber Science
Summary
To develop a high-performance, lightweight cross-laminated timber (CLT) floor, this study tested the delamination performance between carbon fiber-reinforced plastic (CFRP) and CLT and the bending performance of a CFRP composite CLT that was differently reinforced according to the shape of CFRP. The test results showed that the soaking and boiling delamination between CLT and CFRP of the CFRP composite CLT produced by spreading a polyurethane (PUR) adhesive at 300g/m2 were both less than 5%, satisfying the Korean standard. Furthermore, the composite CLT (3ply) of which the entire outer surface of the tension laminae was reinforced with a CFRP plate (thickness: 1.2 mm) showed a mean MOE and a mean MOR higher by 27% and 48%, respectively, than those of the unreinforced CLT (3ply). Furthermore, even though the weight of this CFRP composite CLT was smaller than that of 5ply CLT by approximately 40%, its bending moment was measured higher by 14% than that of the 5ply CLT (thickness: 175 mm) fabricated by limited state design (LSD) as specified in PRG-320.
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Evaluation of Horizontal Shear Performance of Larch CLT Walls According to the Edge Connection Shape

https://research.thinkwood.com/en/permalink/catalogue2205
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Author
Song, Yo-Jin
Hwan Lee, In
Hong, Soon-Il
Organization
Kangwon National University
Publisher
VUPC
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Topic
Mechanical Properties
Keywords
Shear Performance
Shear Walls
Larch
Cyclic Tests
Half-Lap
Research Status
Complete
Series
Wood Research
Summary
In this study, cyclic tests were performed on the larch CLT shear walls depending on the half lap reinforcement of half-lap connections and reinforced plywood of spline connections in order to evaluate the horizontal shear performance of the larch CLT walls. The test results show that there is no difference in residual strength depending on the reinforcement of half-lap connection, but their initial stiffness has been increased by 9%. There was no significant difference either in the residual strength of double spline connections depending on the application of reinforced plywood, while the spline reinforcement has failed to increase initial stiffness. All of the larch CLT walls constructed according to the edge connection shape were measured to have a strength reduction ratio of less than 10% in each horizontal displacement intervals and an equivalent viscous damping ratio of less than 10% for energy dissipation in the initial and final horizontal displacement intervals, thereby confirming that their excellent horizontal shear performance and seismic performance.
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Experimental Investigation into the Flexural Behavior of Hollow, Full, and Intermittently Stiffened (bamboo-like) Glulam Beams from Larch Wood

https://research.thinkwood.com/en/permalink/catalogue2461
Year of Publication
2019
Topic
Mechanical Properties
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Zhang, Xiaofeng
Luo, Lisheng
Fu, Haiyan
Sun, Youfu
Hui, Xiran
Organization
Nanjing Forestry University
Hainan University
Publisher
North Carolina State University
Year of Publication
2019
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Design and Systems
Keywords
Flexural Behavior
Larch
Failure Mode
Ultimate Bearing Capacity
Hollow
Research Status
Complete
Series
BioResources
Summary
Bamboo-like glulam beams with hollow section units and intermittent internal reinforcement pieces were produced with small-diameter larch-wood pieces and one-component polyurethane. To better understand the design reliability, the failure mode, ultimate bearing capacity, and application potential were evaluated. Three types of beams (solid glulam, hollow glulam, and bamboo-like rectangular glulam beams) were compared and analyzed in this work. Stiffener pieces glued inside the bamboo-like beam were found to increase the bearing capacity and improve the failure mode relative to the hollow glulam beam. Comparison of the hollow section with a similar outside diameter showed that the ultimate bearing capacity increased by approximately 12.3% when the spacing between the stiffeners was 270 mm, and the ultimate bearing capacity increased by approximately 18.0% when the spacing between the stiffeners was 135 mm. Compared with the solid timber beams, wood consumption was reduced by 26.4% and 25.7% for the hollow and bamboo-like glulam beams, respectively. Also, a parameter analysis of the reasonable spacing and thickness of the stiffener was proposed by the finite element method.
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Experimental Study of the Bending Performance of Hollow Glulam Beams

https://research.thinkwood.com/en/permalink/catalogue1437
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Shang, Peng
Sun, Youfu
Zhou, Dingguo
Qin, Kai
Yang, Xiaolin
Publisher
Society of Wood Science and Technology
Year of Publication
2018
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Larch
Four Point Bending Test
Bending Stiffness
Load Capacity
Midspan Deflection
Failure Modes
Modulus of Elasticity
Research Status
Complete
Series
Wood and Fiber Science
Summary
Hollow glilam beam has some advantages that the traditional solid glulam beam does not have, such as the convenience for wiring construction and comparably light weight. Four-point bending tests of three solid glulam beams and 15 hollow glulam beams with various sizes of rectangular holes produced from small-diameter larch timber were conducted to investigate the influence of the hollow ratio and wall thickness on bending stiffness and load capacity. The midspan deflection, cross-section strain, and ultimate load were obtained from the tests, and the detailed failure models and apparent MOE for all specimens are reported. Hollow glulam beams with the hollow ratio ranged from 25% to 40%, and the wall thickness greater than 20m after the assumption of plane section under bending moment. The apparent bending stiffness and ductility of hollow glulam beam were less than those of solid glulamb beam, and the apparent MOE is 0.86 times the elastic modulus value calculated by theory of elasticity. In addition, a calculation formula for the ultimate bending moment is proposed.
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Factors that Affect Bolted Joints in Japanese Larch Glulam

https://research.thinkwood.com/en/permalink/catalogue1560
Year of Publication
2016
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Zhao, Rongjun
Wang, Zi
Ren, Haiqing
Zhou, Haibin
Xing, Xinting
Zhong, Yong
Year of Publication
2016
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Japanese Larch
Bolted Joints
Loading Test
China
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 1458-1463
Summary
Japanese larch (Larix kaempferi) is an important species in China. The extensive use of Japanese larch can alleviate lumber shortage in China. Various grades of Japanese larch (Larix kaempferi) laminas were chosen to study the factors that affect the bolted joint performance. By comparing the loading test results with the required design values,it revealed that: (1) Bolt diameter affected the loading performance, then, bolt class, and the lamina grade was the least influential factor. (2) Japanese larch glulam can achieve the required designed value to be used as structural materials.
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Influence of Layer Arrangement on Bonding and Bending Performances of Cross-laminated Timber Using Two Different Species

https://research.thinkwood.com/en/permalink/catalogue2591
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Author
Kim, Keon-Ho
Publisher
North Carolina State University
Year of Publication
2020
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Walls
Floors
Topic
Design and Systems
Mechanical Properties
Keywords
Bonding Performance
Bending Performance
Shear Walls
Face Bonding Test
Three-Point Bending Test
Japanese Larch
Korean Red Pine
Research Status
Complete
Series
BioResources
Summary
Cross-laminated timber (CLT) is a wood panel product that can be arranged in different ways. The advantage of utilizing CLT is the ability to use lamination even with low density materials or those that have defects, like knots. This study evaluated the bonding and bending performances of CLT utilizing domestic species in a shear wall or floor via a face bonding test of layers and a three-point bending test. The tests were carried out with three-layered CLT made up of Japanese larch and/or Korean red pine in various configurations. The layer arrangement for lamination was divided according to the species and grade of the wood. The out-of-plane and in-plane bending tests were conducted on the CLT according to the applicable direction in a wooden structure. The results of the bonding test showed that the block shear strength and delamination of all types of CLT met the BS EN 16351 (2015) standard requirements. The results of the bending test based on two wood species showed that the bending strength of the larch CLT was higher than that of the pine CLT in single species combinations. For mixed species combinations, the bending properties of CLT using larch as the major layer was higher than those using pine as the major layer. This demonstrated that the major layer had more influence on the bending properties of CLT and that Korean red pine was more suited for the minor layer of CLT.
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Investigation Concerning Life Cycle Assessment of Worked Timber: Japanese Larch Glued Laminated Timber of Eastern Nagano Prefecture

https://research.thinkwood.com/en/permalink/catalogue961
Year of Publication
June 2014
Topic
Environmental Impact
Material
Glulam (Glue-Laminated Timber)
Author
Matsukata, Keisuke
Asano, Yoshiharu
Takamura, Hideki
Hayakawa, Yoshiro
Publisher
J-STAGE
Year of Publication
June 2014
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Environmental Impact
Keywords
Life-Cycle Assessment
Larch
Carbon
Finger joint
Research Status
Complete
Series
Japan Architectural Institute Technical Report
Summary
In a process before being finished in a sawing factory after felled in forest, we clarified the actual situation of the carbon income and expenditure with edge materials and the fuel, and calculated the carbon balance of the house made by Nagano’s local wood. In this report, we carried out the actual survey and a hearing investigation in the laminated lumber factory and, calculated carbon balance of Japanese larch finger joint wood and glued laminated timber of eastern Nagano prefecture.
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Predicting the Average Compression Strength of CLT by Using the Average Density or Compressive Strength of Lamina

https://research.thinkwood.com/en/permalink/catalogue3020
Year of Publication
2022
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Tian, Zhaopeng
Gong, Yingchun
Xu, Junhua
Li, Mingyue
Wang, Zhaohui
Ren, Haiqing
Organization
Chinese Academy of Forestry
Editor
Elustondo, Diego
Publisher
MDPI
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Compressive Strength
Density
Linear Regression Analysis
Monte Carlo Simulation
Plated Larch
Prediction Model
Research Status
Complete
Series
Forests
Summary
The compressive strength in the major direction of cross-laminated timber CLT is the key to supporting the building load when CLT is used as load-bearing walls in high-rise wood structures. This study mainly aims to present a model for predicting the average compressive strength of CLT and promoting the utilization of CLT made out of planted larch. The densities and compressive strengths of lamina specimens and CLT samples with widths of 89 and 178 mm were evaluated, and their relationship was analyzed to build a prediction model by using Monte Carlo simulation. The results reveal that the average density of the lamina and CLT were about equal, whereas the average compressive strength of the CLT was just about 72% of that of the lamina. Width exerted no significant effect on the average compressive strength of the CLT, but homogenization caused the wider CLT to have a smaller variation than that of the lamina. The average compressive strength of the lamina could be calculated by using the average density of lamina multiply by 103.10, and the average compressive strength of the CLT could be calculated according to the compression strength of lamina in major and minor direction, therefore, a new prediction model is determined to predict the average compression strength of CLT by using the average density of lamina or CLT, the average compression strength of CLT made in this study is about 74.23 times of the average density of the lamina. The results presented in this study can be used to predict the average compressive strength of CLT by using the average density of lamina and provide a fundamental basis for supporting the utilization of CLT as load-bearing walls.
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Tensile Performance of Machine-Cut Dovetail Joint with Larch Glulam

https://research.thinkwood.com/en/permalink/catalogue1509
Year of Publication
2010
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Park, Joo-Saeng
Hwang, Kweon-Hwan
Park, Moon-Jae
Shim, Kug-Bo
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2010
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Larch
Dovetail Joints
Tensile Strength
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
Members used for the Korean traditional joints have been processed by handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increasedby handicraft, especially with domestic red pine species. Dovetail joint is most commonly used in woodworking joinery and traditional horizontal and vertical connections. It is able to be processed much easier to cut by handicraft and machines. However, although it is processed straight forwards, it requires a high degree of accuracy to ensure a snug fit. Also, tenons and mortises must fit together with no gap between them so that the joint interlocks tightly. A few scientific studies on the dovetail joints have been conducted so far. For the effective applications of traditional joints and domestic plantation wood species, dovetail joints were assembled by larch glulam members processed by machine pre-cut. To identify the tensile properties of through dovetail joints, larch glulam with 150 150mm in cross section were prepared. Furthermore, various geometric parameters of dovetai joints such as width, length, and tenon angle, were surveyed. The ends in the mortise was cracked mainly at a low strength level in the control specimens without reinforcements. The maximum tensile strengths of reinforced specimens considering real connections such as capital joint and headpiece on a column, increased by two times with shear failures on the tenon than the control specimens. The maximum tensile strength was obtained in the specimen of 25 degrees, and no difference was observed in the changes of neck widths.
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21 records – page 2 of 3.