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10 records – page 1 of 1.

Analysis of Mechanical Properties of Cross-Laminated Timber (CLT) with Plywood using Korean Larch

https://research.thinkwood.com/en/permalink/catalogue1806
Year of Publication
2018
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)

Effects of the Width and Lay-Up of Sugi Cross-Laminated Timber (CLT) on its Dynamic and Static Elastic Moduli, and Tensile Strength

https://research.thinkwood.com/en/permalink/catalogue521
Year of Publication
2016
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Ido, Hirofumi
Nagao, Hirofumi
Harada, Masaki
Kato, Hideo
Ogiso, Junko
Miyatake, Atsushi
Publisher
Springer Japan
Year of Publication
2016
Country of Publication
Japan
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Modulus of Elasticity
Tensile Strength
Language
English
Research Status
Complete
Series
Journal of Wood Science
Summary
Cross-laminated timber (CLT) has recently emerged as a new wood product that utilizes a large quantity of domestic lumber. This study aims to analyze the effects of width and lay-ups on the tensile strength of CLT. To this end, the elastic modulus of sugi CLT with different lay-ups was measured by dynamic and static methods. Moreover, tensile tests were conducted for different widths and lay-ups of CLT. Results indicate that the apparent bending Young’s modulus, as calculated using the dynamic method, is directly proportional to the measured Young’s modulus in static method for each lay-up. Furthermore, there was no significant effect of width on the tensile strength in the range of 150, 300, and 600 mm. However, the variations in lay-ups affected the tensile strength as follows: CLT with larger ratio of the major strength direction lamina along the cross-section and with higher grade of lamina in the major strength direction showed higher tensile strength. The estimated tensile strength of CLT, as calculated using the Young’s modulus of the lamina of each layer, and the tensile strength of lamina as simple substance was found to be in good agreement with the measured tensile strength of CLT.
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Estimation of the Internal Shear Strength Distribution of the Element for Laminated Veneer Lumber by Nonlinear Least-Squares Method

https://research.thinkwood.com/en/permalink/catalogue1461
Year of Publication
2018
Topic
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Koseki, Makoto
Nakamura, Noboru
Naoi, Shinichiro
Publisher
Springer Japan
Year of Publication
2018
Country of Publication
Japan
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Mechanical Properties
Keywords
Nonlinear Least-Squares Method
Shear Strength
Modulus of Elasticity
Modulus of Rupture
Tensile Strength
Compression Strength
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
Until now we developed an estimation method for strength distributions of laminated veneer lumber (LVL) element by nonlinear least-squares method (NLM). Estimated strengths by this method were modulus of elasticity (MOE) and modulus of rupture (MOR) in the horizontal use direction and the vertical use direction, tensile strength and compression strength. But to use LVL for structural members, shear strength was also needed. Therefore, we tried to estimate the shear strength distribution of LVL element by NLM same as MOE and MOR in the horizontal use direction and the vertical use direction, the tensile strength of LVL and the compression strength of LVL in the previous reports. We conducted shear strength test for LVL and estimated element shear strength distribution by LVL strength data in the horizontal and vertical use direction. Next, we simulated LVL shear strength distribution using element shear strength distribution and compared with experimental ones in each use direction. They were overlapped in both use direction. Therefore, we could validate NLM for estimating element shear strength distribution.
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Influence of Strand Size, Board Density, and Adhesive Type on Characteristics of Oriented Strand Lumber Boards Manufactured from Pine Strands

https://research.thinkwood.com/en/permalink/catalogue2511
Year of Publication
2019
Topic
Design and Systems
Mechanical Properties
Material
OSL (Oriented Strand Lumber)
Application
Beams

Makerjoint, a New Concept for Joining Members in Timber Engineering – Strength Test and Failure Analyses

https://research.thinkwood.com/en/permalink/catalogue260
Year of Publication
2015
Topic
Connections
Mechanical Properties
Material
LVL (Laminated Veneer Lumber)
Author
Rebstock, Florian
Bomark, Peter
Sandberg, Dick
Year of Publication
2015
Country of Publication
Romania
Format
Journal Article
Material
LVL (Laminated Veneer Lumber)
Topic
Connections
Mechanical Properties
Keywords
CNC
Prefabrication
Failure Modes
Tensile Strength
Compressive Strength
Joints
Language
English
Research Status
Complete
Series
Pro Ligno
ISSN
2069-7430
Summary
The wood construction industries are becoming more focused on climate change and resource depletion, and individual and industrial consumption must reflect a greater degree of concern for the climate and environmental wellbeing. This paper presents a new concept for timber engineering, the purpose being to acquire information about the failure modes and the tensile and compressive strengths of two types of joint, the Simple Gooseneck and Thick Gooseneck, that can be used in a new concept for joining members in timber structures. This Makerjoint concept uses laminated veneer lumber (LVL) as nodes in regions with a pronounced non-uniform stress distribution and sawn timber in regions with a more uniform stress distribution. No metal fasteners or adhesives are used in the joint between timber and LVL. The concept is intended for joints using 3-axis CNC machinery and to be a system for on-site- and pre-fabrication of e.g. small houses, emergency shelters and exhibition stands. The joints have a higher compressive than tensile strength. The joints exhibited brittle failure in tension (beam and/or node failure) and buckling occurred in compression around the thinnest cross section of the beams. Suggestions are made for how the mechanical properties of the joints can be improved.
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Matching Tests of Brittle Failure of Bottom Rail Versus Tensile Strength Perpendicular to the Grain and Fracture Energy in RT and TR Plane

https://research.thinkwood.com/en/permalink/catalogue380
Year of Publication
2014
Topic
Mechanical Properties
Material
Solid-sawn Heavy Timber
Application
Shear Walls
Author
Caprolu, Giuseppe
Organization
Luleå University of Technology
Year of Publication
2014
Country of Publication
Sweden
Format
Report
Material
Solid-sawn Heavy Timber
Application
Shear Walls
Topic
Mechanical Properties
Keywords
Tensile Strength
Fracture Energy
Language
English
Research Status
Complete
Summary
A research study on a new plastic design method for timber frame shear walls partially anchored is under development in Sweden [1]. In this research an important focus has been put on the problem of the possible splitting of the bottom rail. In partially anchored timber frame shear walls there are not hold downs taking the vertical loads so the corresponding forces can be replaced by vertical loads from upper storeys, the roof or connection between shear wall and transversal wall. In this case the bottom row of rail transmits the vertical forces in the sheathing to the bottom rail (instead of the vertical stud) where the anchor bolts will further transmit the forces into the foundation. The bottom rail is then subjected to tensile load perpendicular to the grain, which can be often causes a splitting failure The aim of this report is to present the results of three experimental studies: tensile strength perpendicular to the grain in radial and tangential direction, fracture energy with TR and RT orientations and bottom rail. The experimental programs have been conducted at two different periods and places: bottom rail tests at Umeå University in October 2012 and tensile strength perpendicular to grain and fracture energy at SP in Stockholm in June 2013.
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Moisture Induced Stresses in Glulam: Effect of Cross Section Geometry and Screw Reinforcement

https://research.thinkwood.com/en/permalink/catalogue176
Year of Publication
2012
Topic
Mechanical Properties
Moisture
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Angst-Nicollier, Vanessa
Organization
Norwegian University of Science and Technology
Year of Publication
2012
Country of Publication
Norway
Format
Thesis
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Moisture
Keywords
Moisture Induced Stress
Mechanosorption
Numerical model
Tensile Strength
Tensile Stress
Load Bearing Capacity
Self-Tapping Screws
Climate
Language
English
Research Status
Complete
Summary
This thesis presents a state of the art on moisture induced stresses in glulam, complemented with own findings. These are covered in detail in the appended papers. The first objective was to find a suitable model to describe moisture induced stresses, in particular with respect to mechanosorption. A review of existing models led to the conclusion that the selection of correct material parameters is more critical to obtain reliable results than the formulation of the mechanosorption model. A series of laboratory tests was thus performed in order to determine the parameters required for the model and to experimentally measure moisture induced stresses in glulam subjected to one dimensional wetting/drying. Special attention was paid to using glulam from the same batch for all the experimental measurements in order to calibrate the numerical model reliably. The results of the experiments confirmed that moisture induced stresses are larger during wetting than during drying, and that the tensile stresses could clearly exceed the characteristic tensile strength perpendicular to grain.
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Performance of Wood Adhesive for Cross Laminated Timber Under Elevated Temperatures

https://research.thinkwood.com/en/permalink/catalogue1831
Year of Publication
2018
Topic
Mechanical Properties
Fire
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems

Stochastic Model for Predicting the Bending Strength of Glued-Laminated Timber Based on the Knot Area Ratio and Localized MOE in Lamina

https://research.thinkwood.com/en/permalink/catalogue1379
Year of Publication
2018
Topic
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Pang, Sung-Jun
Oh, Jung-Kwon
Hong, Jung-Pyo
Lee, Sang-Joon
Lee, Jun-Jae
Publisher
Springer Japan
Year of Publication
2018
Country of Publication
Japan
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Mechanical Properties
Keywords
Stochastic Model
Bending Strength
Modulus of Elasticity
Tensile Strength
Knot Area Ratios
Language
English
Research Status
Complete
Series
Journal of Wood Science
ISSN
1611-4663
Summary
The aim of this study was to develop a stochastic model for predicting the bending strength distribution of glued-laminated timber (GLT). The developed model required the localized modulus of elasticity (MOE) and tensile strengths of laminae as input properties. The tensile strength was estimated using a regression model based on the localized MOEs and knot area ratios (KAR) which were experimentally measured for lamina grades samples. The localized MOE was obtained using a machine stress-rated grader, and the localized KAR was determined using an image-processing system. The bending strength distributions in four types of GLTs were simulated using the developed GLT beam model; these four types included: (1) GLT beams without finger joints; (2) GLT beams with finger joints; (3) GLT beams with different lamina sizes; and (4) GLT beams with different combinations of lamina grades. The simulated bending strength distributions were compared with actual test data of 2.4 and 4.8 m-long GLTs. The Kolmogorov–Smirnov goodness-of-fit tests showed that all of the simulated bending strength distributions agreed well with the test data. Especially, good agreement was shown in the fifth percentile point estimate of bending strength with the difference of approximately 1%.
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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
Country of Publication
Korea
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Connections
Mechanical Properties
Keywords
Larch
Dovetail Joints
Tensile Strength
Language
Korean
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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10 records – page 1 of 1.