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18 records – page 2 of 2.

Influence of Board Density on the Physical and Mechanical Properties of Bamboo Oriented Strand Lumber

https://research.thinkwood.com/en/permalink/catalogue2512
Year of Publication
2020
Topic
Design and Systems
Mechanical Properties
Material
OSL (Oriented Strand Lumber)
Other Materials
Application
Wood Building Systems
Author
Sun, Yuhui
Zhang, Yahui
Huang, Yuxiang
Wei, Xiaoxin
Yu, Wenji
Organization
Chinese Academy of Forestry
Publisher
MDPI
Year of Publication
2020
Format
Journal Article
Material
OSL (Oriented Strand Lumber)
Other Materials
Application
Wood Building Systems
Topic
Design and Systems
Mechanical Properties
Keywords
Bamboo
Density
Physical Properties
Microscale Morphology
BOSL
Research Status
Complete
Series
Forests
Summary
The process of bamboo-oriented strand lumber (BOSL) represents one of the best opportunities for automation, property control and consistency, and high utilization of material from abundant, fast-growing, and sustainable bamboo. In this study, BOSLs were prepared, with reference to the preparation process of bamboo scrimber, by compressing and densifying constituent units under the action of moisture-heat-force and resin polymerization, and then the effects of density variation on their physical and mechanical properties were investigated. The results revealed that the modulus of rupture, modulus of elasticity, compressive strength and shear strength of BOSL with density of 0.78–1.3 g/cm3 ranged from 124.42 to 163.2 MPa, 15,455 to 21,849 MPa, 65.02 to 111.63 MPa, and 9.88 to 18.35 MPa, respectively. The preparation of BOSL with bamboo as raw material could retain the good mechanical properties of natural bamboo, and produce bamboo-based structural products with different properties by controlling the density. The high strength of BOSL with high density was primarily due to the increased volume fraction of elementary fibers, the reduced porosity, and the enhanced gluing interface. The performance of BOSL can be comparable to, or surpass that of, wood or bamboo products. This study provided necessary basic research for the engineering design and application of BOSL.
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Influence of Wood Density to Fire Resistance of The Load-Bearing Member

https://research.thinkwood.com/en/permalink/catalogue1113
Year of Publication
2015
Topic
Fire
Material
Glulam (Glue-Laminated Timber)
Author
Ohashi, Hirokazu
Nagaoka, Tsutomu
Egasode, Hiroki
Yamamoto, Masato
Sugita, Keitaro
Hidemasa, Yusa
Omiya, Yoshifumi
Yamada, Makoto
Saito, Kiyoshi
Publisher
J-STAGE
Year of Publication
2015
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Keywords
Density
Fire Resistance
Load Bearing
Research Status
Complete
Series
Japan Architectural Institute Technical Report
Summary
Fire-resisting wood structural elements for building were developed. It is composed of three layers made of glued laminated timber, “a load-bearing part, a self-charring-stop and a surface layer”. Tree species of load-bearing part is limited to the only kind. In order to enable a species different, this research was carried out. Fire resistance test was performed to demonstrate the effect on fire resistance of the wood density. The relationship of fire resistance and wood density of the load-bearing part was clear. Usage of high wood density of the load-bearing part was obtained a conclusion that is advantageous to fire performance.
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In-Plane Permeability of Oriented Strand Lumber, Part I: The Effects of Mat Density and Flow Direction

https://research.thinkwood.com/en/permalink/catalogue1466
Year of Publication
2010
Topic
General Information
Material
OSL (Oriented Strand Lumber)
Author
Zhang, Chao
Smith, Gregory
Publisher
Society of Wood Science and Technology
Year of Publication
2010
Format
Journal Article
Material
OSL (Oriented Strand Lumber)
Topic
General Information
Keywords
Aspen
Permeability
Density
Research Status
Complete
Series
Wood and Fiber Science
Summary
The in-plane permeability was measured for thick, unidirectional oriented strand lumber made from aspen (Populus tremuloides) strands and pressed to five different densities. The press cycle was such that the vertical density profile of the panels was uniform. Specimens were cut from the boards and sealed inside a specially designed specimen holder; this jig was connected to a permeability measurement apparatus and in-plane permeability measured parallel, perpendicular, and 45° to the strand orientation. Permeability decreased markedly with increasing board density. The highest permeability was in the strand alignment direction and lowest perpendicular to it. The permeability in the 45° direction fell between those in parallel and perpendicular to strand alignment. A polynomial equation was fit to the results of each direction with r2 of 0.938 and 0.993. The in-plane distribution of permeability as a function of flow direction was obtained and its vector diagram was lenticular in shape.
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Performance of Glue-Laminated Beams from Malaysian Dark Red Meranti Timber

https://research.thinkwood.com/en/permalink/catalogue1822
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Ong, Chee Beng
Organization
University of Bath
Year of Publication
2018
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Malaysian Dark Red Meranti (DRM)
Production
Phenol-Resorcinol Formaldehyde
Fabrication
Bonding Performance
Carbon Fiber Reinforced Polymer
Tension Face
Unreinforced
Fire Test
Failure
Finger Joints
Softwood
Europe
Density
End Pressure
Cramping Pressure
Strength
Charring Rate
Fire Performance
Polyurethane
Bending Strength
Research Status
Complete
Summary
In this study, Malaysian Dark Red Meranti (DRM) was used to manufacture glulam beams, following closely the requirements of BS EN 14080:2013 so as to emulate commercial production. Phenol resorcinol formaldehyde (PRF), commonly used in structural glulam production, was used in the fabrication of finger joints and laminations of the glulam beams. Factors influencing the mechanical properties of finger joints and bonding performance of laminations were investigated. Full size glulam beams were manufactured and tested in bending with partial and complete carbon fibre reinforced polymer (CFRP) reinforcement on the tension face and compared with the performance of unreinforced beams. A bench-scale fire test was proposed to describe the behaviour of DRM finger joints in tension under fire condition, in order to simulate the failure of finger joints on the tension side of a glulam beam in a standard fire test. Overall, DRM finger joints exhibited better bending strength than Spruce finger joints which represented softwood used in European glulam. Wood density and end pressure were shown to affect the strength properties of the finger joints. Higher cramping pressure was needed to produce DRM laminations with higher shear strength. The glulam beam with CFRP reinforcement had a higher bending strength than the unreinforced glulam beams but partial reinforcement had an adverse effect on beam strength. In the bench-scale fire test, DRM finger-jointed specimens exhibited lower charring rate than Spruce. Furthermore, PRF finger-jointed specimens showed better fire performance than finger-jointed specimens bonded with polyurethane (PUR) adhesive. In conclusion, it is hoped that results from this research will motivate engineers and architects in Malaysia to design and build structures from less-utilised local timber, specifically in the form of glulam, encouraging the timber industry in Malaysia to produce them commercially.
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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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Process Optimization of Large-Size Bamboo Bundle Laminated Veneer Lumber (BLVL) by Box-Behnken Design

https://research.thinkwood.com/en/permalink/catalogue1807
Year of Publication
2018
Topic
Mechanical Properties
Material
Other Materials
LVL (Laminated Veneer Lumber)
Author
Niu, Xiaoyi
Pang, Jiuyin
Cai, Hanzhong
Li, Shan
Le, Lei
Wu, Junhua
Publisher
North Carolina State University
Year of Publication
2018
Format
Journal Article
Material
Other Materials
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Process Optimiazation
Box-Behnken Design
Lengthening Technology
Three-Factor
Lap-Joints
Board Density
Thickness
Optimum Pareto Solutions
Genetic Algorithma Method
Modulus of Rupture
Shearing Strength (SSI)
Elastic Modulus
Dimensional Stability
Bamboo
Research Status
Complete
Series
BioResources
Summary
This work focuses on optimization of the laminated lap-joint lengthening technology that is used to produce large-size bamboo bundle laminated veneer lumber (BLVL). A three-factor Box-Behnken design was developed in which lap-joint length (x1), board density (x2), and thickness of lap veneer (x3) were the three factors. Multi-objective optimization of response surface model was used to obtain 17 optimum Pareto solutions by a genetic algorithms method. The mechanical properties of BLVL predicted using the model had a strong correlation with the experimental values (R2 = 0.925 for the elastic modulus (MOE), R2 = 0.972 for the modulus of rupture (MOR), R2 = 0.973 for the shearing strength (SS)). The interaction of the x1 and x3 factors had a significant effect on MOE. The MOR and shearing SS were significantly influenced by the interaction of x2 and x3 factors. The optimum conditions for maximizing the mechanical properties of BLVL lap-joint lengthening process were established at x1 = 16.10 mm, x2 = 1.01 g/cm3, and x3 = 7.00 mm. A large-size of BLVL with a length of 14.1 m was produced with the above conditions. Strong mechanical properties and dimensional stability were observed.
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Shear Tests of Glulam at Elevated Temperatures

https://research.thinkwood.com/en/permalink/catalogue563
Year of Publication
2014
Topic
Fire
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Dhima, Dhionis
Audebert, Maxime
Racher, Patrick
Bouchaïr, Abdelhamid
Taazount, Mustapha
Publisher
Wiley Online Library
Year of Publication
2014
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Mechanical Properties
Keywords
Density
Shear Strength
Temperature
Thermal Gradient
Research Status
Complete
Series
Fire and Materials
Summary
Experimental investigations are conducted to characterize the evolution with temperature of the shear strength of glulam wood. To realize the tests, an original specimen with cylindrical shape has been developed and justified by a numerical study. The geometry allows obtaining thermal gradient within material to represent the real combustion of timber members, while keeping constant the temperature of sheared section. The experimental programs consider various parameters such as the presence or absence of moisture and the thermal gradient within the specimen. The experimental results are discussed and analyzed. They show the correlation between the density of the material and the reduction of its strength at high temperatures. The experimental failure loads are used to evaluate the reduction factors for wood strength depending on the temperature. These factors are compared with those given by EN1995-1-2 for the advanced calculations methods in fire situation. The comparisons show that the reduction factors given by EN1995-1-2 are conservative in comparison with the experimental results. Copyright © 2014 John Wiley & Sons, Ltd.
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Study the Influence of Perpendicular to Grain Compression and Creep in 4 to 8 Storey Lightweight Timber Framed Buildings

https://research.thinkwood.com/en/permalink/catalogue1925
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Organization
Timber Development Association
Publisher
Forest & Wood Products Australia
Year of Publication
2018
Format
Report
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Walls
Topic
Mechanical Properties
Keywords
Creep
Compression
Density
Deformation
Research Status
Complete
Summary
The aim of this project was to validate the assumption used within the Australian Standard AS1720.1 for calculating compression perpendicular to grain for common timber species and develop practical methods to reduce compression deformation. The project was successful in demonstrating that perpendicular to grain displacement of wall plates by studs can be reduced. It found that stud on stud connection was the best method as it removed the wall plates out of the load path altogether. The study also found where this is not possible, replacement of the wall plate with a stiffer timber such as a high density hardwood, softwood or cross laminated timber reduces this deformation. The investigation also found that the method used in AS1720.1 to assign perpendicular to grain bearing capacities for various timber species by “strength group” or stress grade over predicted low to medium density timber species whilst under predicting high density timber species. Accordingly, it is recommended that perpendicular to grain bearing capacity be assigned by the timber species’ density and that the characteristic values of commonly used timber species be re-established.
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18 records – page 2 of 2.