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Characteristics of the Radio-Frequency/Vacuum Drying of Heavy Timbers for Post and Beam of Korean Style Housings Part II: For Korean Red Pine Heavy Timbers with 250 × 250 mm, 300 × 300 mm in Cross Section and 300 mm in Diameter, and 3,600 mm in Length

https://research.thinkwood.com/en/permalink/catalogue1508
Year of Publication
2011
Topic
Moisture
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Author
Lee, Nam-Ho
Zhao, Xue-Feng
Shin, Ik-Hyun
Park, Moon-Jae
Park, Jung-Hwan
Park, Joo-Saeng
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2011
Format
Journal Article
Material
Solid-sawn Heavy Timber
Application
Wood Building Systems
Topic
Moisture
Keywords
Radio-Frequency/Vacuum Drying
Moisture Gradient
Shrinkage
Case Hardening
Surface Checks
Compressive Load
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
This study examined the characteristics of radio-frequency/vacuum dried Korean red pine (Pinus densoflora heavy timbers with 250 × 250 mm (S), 300 × 300 mm (L) in cross section and 300 mm in diameter, and 3,600 mm in length, which were subjected to compressive loading after a kerf pretreatment. The following results were obtained : The drying time was short and the drying rate was high in spite of the large cross section of specimens. The moisture gradient inall specimens was gentle in both longitudinal and transverse directions owing to dielectric heating. The shrinkage of the width in the direction perpendicular to was 21 percent ~ 76 percent of that of the thickness of square timbers in the direction parallel to the mechanical pressure. The casehardening for all specimens was very slight because of significantly reduced ratio of the tangential to radial shrinkage of specimens and kerfing. The surface checks somewhat severely occurred although the occurrence extent of the surface checks on the kerfed specimens was slight compared withthat on the control specimen.
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Effect of Reserve Air-Drying of Korean Pine Heavy Timbers on High-Temperature and Low-Humidity Drying Characteristics

https://research.thinkwood.com/en/permalink/catalogue1506
Year of Publication
2014
Topic
Moisture
Material
Solid-sawn Heavy Timber
Author
Lee, Chang-Jin
Lee, Nam-Ho
Park, Moon-Jae
Park, Joo-Saeng
Eom, Chang-Deuk
Publisher
The Korean Society of Wood Science Technology
Year of Publication
2014
Format
Journal Article
Material
Solid-sawn Heavy Timber
Topic
Moisture
Keywords
Moisture Content
Temperature
Humidity
Pine
Air Drying
Shrinkage
Internal Checks
Twist
Case Hardening
Research Status
Complete
Series
Journal of the Korean Wood Science and Technology
Summary
The pre-air-drying of Korean pine before the high-temperature and low-humidity drying was shown to be effective in uniform moisture content distribution and prevention of surface check. Our results suggest that initial moisture content of the timber also plays important role in high-temperature and low-humidity drying method. The pre-air-drying also helps in the reduction of surface checks in Korean pine when compared to the Korean pine dried by only high-temperature and low-humidity. End-coating was not effective in the prevention of twist, shrinkage, case hardening and internal checks. The pre-air-drying reduces the internal tension stresses which occur during high-temperature and low-humidity drying thus decreasing case hardening and also preventing internal checks. The pre-air-drying decreases the moisture content and causes shrinkage which leads to increased twist in the Korean pine.
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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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Evaluate Bearing Stress of Glulam Using Digital Image Correlation

https://research.thinkwood.com/en/permalink/catalogue687
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Jeong, Gi-Young
Park, Moon-Jae
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Digital Image Correlation
Drift Pins
Bearing Stress
Strain Distribution
Fracture Behaviour
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
The goal of this study is to evaluate the effect of different sizes of drift pins (12mm, 16mm, 20mm, 30mm) and six orientations of glulam associated with pin positions (RL, TL, LR, TR, LT, RT) on bearing stress and strain distributions of glulam using digital image correlation (DIC). Different bearing stresses, strain distributions, and fracture behaviours associated with the orientation of the glulam and pin sizes were observed. As the diameter of drift pins increased, the bearing strength increased regardless of the orientation. However, the trends of failure behaviours did not change by the pin size.
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Moment Resistance of Post-And-Beam Joints with Concealed Metallic Connectors

https://research.thinkwood.com/en/permalink/catalogue621
Year of Publication
2014
Topic
Connections
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Humbert, Jérôme
Lee, Sang-Joon
Park, Joo-Saeng
Park, Moon-Jae
Year of Publication
2014
Format
Conference Paper
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Connections
Mechanical Properties
Keywords
Moment Resistance
Post and Beam
Joints
Metallic Connectors
Monotonic
Reverse Cyclic Loading
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 10-14, 2014, Quebec City, Canada
Summary
This paper presents a study on the moment resistance of post-and-beam joints with concealed metallic connectors aimed at replacing in a more modern design the wood-wood joints of traditional Korean Hanok timber houses. Several variations of the design of the connectors are investigated to optimize the moment resistance of the joints. Experimental tests are conducted under monotonic and reversed cyclic loading. The performance of the joint is evaluated in terms of peak moment resistance, as well as ductility and energy dissipation. Results show that optimization in the design can improve the moment resistance of the joint while preventing the brittle wood fracture and favoring a more ductile plasticizing of the connector, for the benefit of safety.
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Prediction of Shear Performance on Cross Laminated Timber Wall with Wall to Wall Connections

https://research.thinkwood.com/en/permalink/catalogue1781
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Author
Oh, Jung-Kwon
Hong, Jung-Pyo
Kim, Chul-Ki
Pang, Sung-Jun
Lee, Hyeon-Jeong
Jang, Sung-Il
Park, Moon-Jae
Lee, Jun-Jae
Year of Publication
2016
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Shear Walls
Topic
Mechanical Properties
Keywords
Shear Performance
Failure Mode
Displacement
Peak Load
Model
Conference
World Conference on Timber Engineering
Research Status
Complete
Notes
August 22-25, 2016, Vienna, Austria p. 5503-5510
Summary
A cross-laminated timber (CLT) wall plays a role of resisting shear stress induced by lateral forces as well as resisting vertical load. Due to the press size, CLT panels have a limitation in its size. To minimize the initial investment, some glulam manufactures wanted to make a shear wall element with small-size CLT panels and panel-to-panel...
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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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7 records – page 1 of 1.