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12 records – page 1 of 2.

Acoustic emission monitoring of wood materials and timber structures: A critical review

https://research.thinkwood.com/en/permalink/catalogue3187
Year of Publication
2022
Topic
Acoustics and Vibration
Author
Nasir, Vahid
Ayanleye, Samuel
Kazemirad, Siavash
Sassani, Farrokh
Adamopoulos, Stergios
Organization
The University of British Columbia
Mississippi State University
Iran University of Science and Technology
Swedish University of Agricultural Sciences
Publisher
Elsevier
Year of Publication
2022
Format
Journal Article
Topic
Acoustics and Vibration
Keywords
Non-Destructive Evaluation
Acoustic Emission
Structural Health Monitoring
Wood Machining
Kiln Drying
Termite Detection
Thermally Modified Timber
Wood Fracture
Damage Detection
Research Status
Complete
Series
Construction and Building Materials
Summary
The growing interest in timber construction and using more wood for civil engineering applications has given highlighted importance of developing non-destructive evaluation (NDE) methods for structural health monitoring and quality control of wooden construction. This study, critically reviews the acoustic emission (AE) method and its applications in the wood and timber industry. Various other NDE methods for wood monitoring such as infrared spectroscopy, stress wave, guided wave propagation, X-ray computed tomography and thermography are also included. The concept and experimentation of AE are explained, and the impact of wood properties on AE signal velocity and energy attenuation is discussed. The state-of-the-art AE monitoring of wood and timber structures is organized into six applications: (1) wood machining monitoring; (2) wood drying; (3) wood fracture; (4) timber structural health monitoring; (5) termite infestation monitoring; and (6) quality control. For each application, the opportunities that the AE method offers for in-situ monitoring or smart assessment of wood-based materials are discussed, and the challenges and direction for future research are critically outlined. Overall, compared with structural health monitoring of other materials, less attention has been paid to data-driven methods and machine learning applied to AE monitoring of wood and timber. In addition, most studies have focused on extracting simple time-domain features, whereas there is a gap in using sophisticated signal processing and feature engineering techniques. Future research should explore the sensor fusion for monitoring full-scale timber buildings and structures and focus on applying AE to large-size structures containing defects. Moreover, the effectiveness of AE methods used for wood composites and mass timber structures should be further studied.
Online Access
Free
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Advanced Quality and In-Service Condition Assessment Procedures for Mass Timber and Cross-Laminated Timber Products

https://research.thinkwood.com/en/permalink/catalogue2558
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Non-Destructive Evaluation
Bond Performance
Monitoring Techniques
Serviceability
Quality Assurance
Research Status
In Progress
Notes
Project contacts are Frederico França at Mississippi State University and Robert J. Ross at the Forest Products Laboratory
Summary
With the rapid development of CLT manufacturing capacity around the world and the increasing architectural acceptance and adoption, there is a current and pressing need regarding adhesive bond quality assurance in manufacturing. As with other engineered glued composites, adhesive bondline performance is critically important. Bondline assessment requires technology in the form of sensors, ultrasonics, load cells, or other means of reliable machine evaluation. The objectives of this cooperative study are to develop quality assurance procedures for monitoring the quality of mass timber and CLT during and after manufacturing and to develop assessment techniques for CLT panels in-service.
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Analytical and experimental evaluation of the effect of knots on rolling shear properties of cross-laminated timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue1942
Year of Publication
2019
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Cao, Yawei
Organization
Mississippi State University
Year of Publication
2019
Format
Thesis
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Rolling Shear
Southern Pine
Center Point Bending Test
Two-Plate Shear Test
Knots
Strength
Failure Mechanism
Research Status
Complete
Summary
Knots are usually regarded as defects when grading lumber. In order to evaluate a member under out-of-plane loading, shear strength is one of the major mechanical properties, specifically, rolling shear (RS) strength is one of the critical mechanical properties of Cross-Laminated Timber (CLT), which determines the flexural strength of CLT under short-span bending loads. Lower grade lumber with a higher percentage of knots is recommended to be utilized for the cross-layer laminations which are mainly responsible for resisting shear stresses. Firstly, shear tests were performed in order to evaluate the effect of knots on longitudinal shear strength using shear blocks. After that, the effect of knots on the RS strength of 3-ply southern yellow pine CLT were investigated by experimental tests and an analytical model. Center-point bending tests with a span-to-depth ratio of 6 and two-plate shear tests with a loading angle of 14° were conducted on six CLT configurations composed of different types of cross layer laminations: clear flatsawn lumber with/without pith, lumber with sound knots with/without pith, and lumber with decayed knots with/without pith. The shear analogy method was implemented to evaluate the RS strength values from the bending test results, which were also compared against the results from the two-plate shear tests. It was found that: (1) The shear blocks containing sound knots had higher shear strength than matched clear shear blocks, the shear blocks containing unsound knots had lower shear strength than the matched clear shear blocks. (2) CLT specimens with cross-layer laminations with either sound knots or decayed knots had higher RS strength. (3) In general, the shear analogy method underestimated the RS strength of CLT specimens containing knots and pith.
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Free
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Cross-Laminated Timber (CLT) Resistance to Infestation by Subterranean Termites

https://research.thinkwood.com/en/permalink/catalogue2265
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Mississippi State University, USDA Forest Service Forest Products Laboratory
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Biodegradation
Research Status
In Progress
Notes
Contact: C. Elizabeth Stokes, Mississippi State University, Juliet Tang, Forest Products Laboratory
Summary
Outcomes anticipated from the results of this project are biodegradation information for CLT products and an improved understanding of biodegradation differences between CLT products and comparable laminated and solid wood products. Results will benefit the emerging CLT industry and provide valuable information for market expansion into areas with high termite pressure.
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Development of a modified standard termite test for mass timber products

https://research.thinkwood.com/en/permalink/catalogue3252
Year of Publication
2022
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Franca, Tamara S.F.A.
Stokes, Elizabeth C.
Tang, Juliet D.
Organization
Mississippi State University
Forest Products Laboratory
Year of Publication
2022
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Keywords
Subterranean Termites
Laboratory Assay
Wood Durability
Research Status
Complete
Series
Wood and Fiber Science
Summary
US manufacturers are looking to expand the use of cross-laminated timber (CLT) panels into the North American market, including states located in the southeast where termites are important pests. However, there is no current assessment method for determining CLT vulnerability to the highly destructive native termites found in many states across the United States. The impact of damage by these termites is of particularly high interest in areas with suitable climate to their proliferation, such as the southeastern United States. This study evaluated durability of CLT panels and developed a laboratory assay to test susceptibility of this product to termites. Untreated CLT suffered mass losses of up to 5.8% in testing with an average visual rating of 7.2, indicating a moderate to severe attack with 10-30% of the cross section of the product affected by termite intrusion. Recommendations were developed for the inclusion of modifications presented in standardized testing protocols and will be presented to standards organizations. The proposed method may also be applied to evaluate termite resistance of other mass lumber products such as laminated veneer lumber and Glulam.
Online Access
Free
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Development of Preservative-treated Southern Pine Cross-laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2566
Topic
Moisture
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Application
Industrial Application
Organization
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Application
Industrial Application
Topic
Moisture
Mechanical Properties
Keywords
Industrial Mats
Preservative Treatment
Weathering
Durability
Research Status
In Progress
Notes
Project contact is Hyungsuk Lim at Mississippi State University
Summary
This project aims to develop the preservative-treatment procedures for industrial cross-laminated timber (CLT) mats composed of southern yellow pine (SYP) lumber. The feasibility of pre- and post-treating CLT panels with an environment-friendly preservative system for ground-contact applications at an industrial scale will be evaluated from adhesion, mechanical, and durability performance aspects. As for the pre-treatment method, CLT panels will be consolidated with preservative-treated lumber adopting industrial CLT manufacturing parameters, including glue-type and clamping pressure. Alternatively, conventional CLT panels will be pressure treated with the same preservative system and dried afterward. As one of the primary focuses of the research, drying schedules which would not damage wood or adhesive layers will be determined. Also, penetration and retention of the preservatives throughout the post-treated panels will be analyzed. Adhesion and mechanical performance of the treated panels will be evaluated according to industry-accepted standards. Durability performance of the treated panels will be examined through laboratory weathering and on-site field tests.
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Effect of Notches on the Performance of Cross-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2559
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory
Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Notches
Notched Connections
Bending Properties
Flexural Properties
Research Status
In Progress
Notes
Project contacts are Robert J. Ross at the Forest Products Laboratory and Rubin Shmulsky at Mississippi State University
Summary
Notches, particularly when incorporated on the tensile face, influence the ultimate capacity of members, such as beams and floor panels. Understanding and quantification of failure modes, ductility, and strength of notched CLT floor panels can allow the safe application of notches on building construction. Despite wood’s ductility, notches are known areas of stress concentration. The 2018 International Residential Code for one- and two-family dwellings (International Code Council 2017) restricts the use of notches on engineered wood products by requiring structural calculations instead of elucidating the ways notches might be used. To employ CLT to its maximum potential, there is a current and pressing need for better knowledge regarding the influence of notches on flexural performance. This research seeks to review the literature regarding notches in solid and engineered beams, review typical CLT design details that employ or utilized notched panels, and conduct pilot-scale testing of notched CLT panels.
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Evaluating Decay Resistance of Mass Timber

https://research.thinkwood.com/en/permalink/catalogue718
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Organization
Forest Products Laboratory Mississippi State University
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Keywords
Funghi
Decay
Research Status
In Progress
Notes
Project contacts are Grant Kirker (Forest Products Laboratory), Katie Ohno (Forest Products Laboratory) and C. Elizabeth Stokes (Mississippi State University)
Summary
Mass timber, as a renewable prefabricated structural panel material, is seen as highly desirable in the “green” building movement and has excellent thermal insulation, sound insulation, and fire restriction qualities. CLT is one of the more recent additions to the mass timber market worldwide, and although the product has undergone structural property testing in several laboratories, degradation testing of this non-preservative-treated product has only recently been initiated. Preliminary testing with exposure to Oligoporus placenta and Antrodia xantha indicated that untreated CLT is susceptible to the spread of mold and decay fungi, while treatment with boron somewhat reduced the extent of the decay fungus spread. These panels are easily handled on-site and have a much higher strength-to-weight ratio than their precast concrete competitors, which make them ideal for rapid construction of modular buildings, including apartment/condominium structures. However, installations using CLT as a primary structural component in humid/damp climates, such as the southeastern United States, may be heavily affected by molds and decay fungi, and effects on CLT strength should be determined prior to widespread use of the product in these areas.
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Life Cycle Analysis of Cross Laminated Timber: Increasing Awareness and Utilization of Wood Products in the Building Community

https://research.thinkwood.com/en/permalink/catalogue3177
Year of Publication
2022
Topic
Environmental Impact
Material
CLT (Cross-Laminated Timber)
Organization
Mississippi State University
Year of Publication
2022
Material
CLT (Cross-Laminated Timber)
Topic
Environmental Impact
Keywords
Life Cycle Analysis
Building Integrity
Research Status
In Progress
Notes
Forest Service/USDA Wood Innovations Grants Recipient Point of Contact: Frederico Franca Location: Mississippi State
Summary
Cross-laminated timber (CLT) is part of a wood composite category called mass(ive) timber, and has desirable environmental attributes, and it fits right in as a “green” or “eco-friendly” product. CLT is able to help the building industry to reduce carbon emissions and becomes an important player in the solution for climate change. However, the number one barrier preventing the utilization of CLT is lack of knowledge, more specifically in its attributes and capabilities. There is a need for accurate and technical information on performance, integrity, and health of CLT buildings. This project seeks to increase the awareness and confidence levels of architects, engineers, and builders to adopt CLT buildings. This project will develop protocols for onsite inspections and datasets based on field tests that will enhance safety and reliable methods to assess CLT building integrity. With sound and readily applicable protocols, higher adoption rates of CLT inside the building community is expected and consequently, an increase in wood consumption and increase of competitiveness of wood products with other products such as concrete and steel, and consequently promoting economic and environmental health of communities. The technical knowledge developed in this project will be transferred to the building community and CLT industries.
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Non-Destructive Lumber and Engineered Pine Products Research in the Gulf South U.S. 2005–2020

https://research.thinkwood.com/en/permalink/catalogue3070
Year of Publication
2021
Topic
General Information
Author
Seale, R. Dan
Shmulsky, Rubin
Franca, Frederico Jose Nistal
Organization
Mississippi State University
Publisher
MDPI
Year of Publication
2021
Format
Journal Article
Topic
General Information
Keywords
Nondestructive Evaluation
Pine Lumber
Modulus of Rupture
Modulus of Elasticity
Mass Timber
Acoustic Velocity
Transverse Vibration
Structural Lumber
Engineered Wood Products
Research Status
Complete
Series
Forests
Summary
This review primarily describes nondestructive evaluation (NDE) work at Mississippi State University during the 2005–2020 time interval. Overall, NDE is becoming increasingly important as a mean of maximizing and optimizing the value (economic, engineering, utilitarian, etc.) of every tree that comes from the forest. For the most part, it focuses on southern pine structural lumber, but other species such as red pine, spruce, Douglas fir, red oak, and white oak and other products such as engineered composites, mass timber, non-structural lumber, and others are included where appropriate. Much of the work has been completed in conjunction with the U.S. Department of Agriculture, Forest Service, Forest Products Laboratory as well as the Agricultural Research Service with the overall intent of improving lumber and wood products standards and valuation. To increase the future impacts and adoption of this NDE-related work, wherever possible graduate students have contributed to the research. As such, a stream of trained professionals is a secondary output of these works though it is not specifically detailed herein.
Online Access
Free
Resource Link
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12 records – page 1 of 2.