scholarly journals Review of Existing Methods for Evaluating Adhesive Bonds in Timber Products

2021 ◽  
Author(s):  
Maryam Shirmohammadi ◽  
William Leggate
Keyword(s):  
Service Life ◽  
Service Condition ◽  
Wood Structure ◽  
Adhesive Bonds ◽  
Performance Effectiveness ◽  
Production Processes ◽  
As Species ◽  
Timber Products ◽  
Adhesive Application ◽  
Mass Timber

Gluing is an integral part of the majority of production processes in the timber industry. The effectiveness of adhesive application, glue bond development and glue penetration into the wood structure is becoming more and more important as more structural glued timber products are used in construction and other applications. The continued increase in utilisation of mass timber products (MTPs) such as CLT, glulam and LVL in tall timber buildings requires an accurate and in-depth understanding of adhesive roles and their performance effectiveness during the life span of any of those products in relation to the type of loading applied, environmental effects (e.g. RH and temperature) and in-service condition of elements (e.g. exposure to major wet events and degradation from decay). This review aims to provide a comprehensive summary of existing imaging and other visualisation methods used to assess the glue line properties and examine the performance of glue lines in relation to factors such as species, product type and environmental conditions during manufacture and in-service life.

scholarly journals Quasi-Static Tests of Hybrid Adhesive Bonds Based on Biological Reinforcement in the Form of Eggshell Microparticles

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1391 ◽  
Author(s):  
Viktor Kolář ◽  
Miroslav Müller ◽  
Rajesh Mishra ◽  
Anna Rudawska ◽  
Vladimír Šleger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cyclic Loading ◽  
Service Life ◽  
Adhesive Layer ◽  
Maximum Load ◽  
Adhesive Bonds ◽  
Static Tests ◽  
Static Test ◽  
The Matrix ◽  
Positive Effect

The paper is focused on the research of the cyclic loading of hybrid adhesive bonds based on eggshell microparticles in polymer composite. The aim of the research was to characterize the behavior of hybrid adhesive bonds with composite adhesive layer in quasi-static tests. An epoxy resin was used as the matrix and microparticles of eggshells were used as the filler. The adhesive bonds were exposed to cyclic loading and their service life and mechanical properties were evaluated. Testing was performed by 1000 cycles at 5–30% (165–989 N) and 5–70% (165–2307 N) of the maximum load of the filler-free bond in the static test. The results of the research show the importance of cyclic loading on the service life and mechanical properties of adhesive bonds. Quasi-static tests demonstrated significant differences between measured intervals of cyclic loading. All adhesive bonds resisted 1000 cycles of the quasi-static test with an interval loading 5–30%. The number of completed quasi-static tests with the interval loading 5–70% was significantly lower. The filler positively influenced the service life of adhesive bonds at a higher amount of quasi-static tests, i.e., the safety of adhesive bonds increased. The filler had a positive effect on adhesive bonds ABF2, where the strength significantly increased up to 20.26% at the loading of 5–30% against adhesive bonds ABF0. A viscoelasticity characteristic (creep) of the adhesive layer occurred at higher values of loading, i.e., between loading 5–70%. The viscoelasticity behavior did not occur at lower values of loading, i.e., between loading 5–30%.

Challenges in Circumferential Entry Blades for Structural Integrity of Closing Blade in Steam Turbines

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
A. S. SureshBabu ◽  
Jeevan Gowda G ◽  
M. V. Reddy
Keyword(s):  
Service Life ◽  
Structural Integrity ◽  
Weak Link ◽  
Kinematic Hardening ◽  
Research Work ◽  
Service Condition ◽  
Material Model ◽  
Steam Turbines ◽  
Mechanical Integrity ◽  
Locking Mechanism

The bladed disc of an LP last stage rotor assembly in a steam turbine often employs circumferential entry blades. The closing blade is fastened with the aid of a pin type locking mechanism, which locks the closing blade onto the disc. Radial entry blade root design demands for a groove in the disc through which blades are inserted and guided to their respective final positions which alters the stiffness in the disc. Closing blade is the most highly stressed weak link zone in the circumferential entry rotor disc achieving mechanical integrity for in-service condition is a challenge. Location of pin and its insertion is the key to achieve the desired in-service life with good material model. The present research work focus on emphasis of pin positioning to lock the T-root blade at operating range. Various material model configurations and pin positions are considered in both blade and disc to improve the reliability in design. Customized methodology is developed to address the elasto-plastic kinematic hardening in pin, disc and blade grove during in-service life. Finite element approach along with classical design equations followed by API 616 standards is employed to achieve the mechanical integrity in bladed disc assembly.

Connection Performance of Mass Plywood Panels

2020 ◽  
Vol 70 (1) ◽  
pp. 88-99
Author(s):  
Byrne T. Miyamoto ◽  
Arijit Sinha ◽  
Ian Morrell
Keyword(s):  
Large Scale ◽  
Seismic Analysis ◽  
Bearing Strength ◽  
Lateral Resistance ◽  
Component Test ◽  
Engineering Models ◽  
Timber Products ◽  
Wood Frame ◽  
American Society ◽  
Mass Timber

Abstract Tall wood buildings have become more prevalent in North America in the past 10 years. Tall wood-frame buildings implement both mass timber construction and products. Mass timber products are wood-based products that can withstand and hold large loads for long durations of time. Mass timber has allowed for large buildings, which consist mainly of wood, to be erected comprising multiple stories. One new mass timber product that has been fashioned is Mass Plywood Panels (MPP). MPP is a veneer-based engineered wood product, which is a massive, large-scale, structural composite lumber–based panel designed for use in building applications as both a vertical and horizontal element. For any new product to be used in the industry with confidence, a thorough investigation of its physical, mechanical, and connection properties is needed. A series of connection tests, such as fastener withdrawal resistance, dowel-bearing strength, lateral resistance, and a component test on a wall-to-floor system were conducted. The lateral resistance test indicated that the current European Yield Models can be used to calculate the yield loads and yield mode of the MPP by using the dowel-bearing strength of plywood. Three different connection configurations were tested in two distinct loading directions—shear and withdrawal. Their performances are evaluated and compared using two existing engineering models—namely, the American Society of Civil Engineers 41-13 tri-linear model and the seismic analysis of wood-frame structures 10-parameter connection model.

scholarly journals Increasing Mass Timber Consumption in the U.S. and Sustainable Timber Supply

2021 ◽  
Vol 14 (1) ◽  
pp. 381
Author(s):  
Jeff Comnick ◽  
Luke Rogers ◽  
Kent Wheiler
Keyword(s):  
Confidence Intervals ◽  
Forest Inventory ◽  
The United States ◽  
Timber Supply ◽  
Volume Estimate ◽  
Timber Products ◽  
Mass Timber ◽  
Timber Growth ◽  
The U.S ◽  
Timber Harvests

Mass timber products are growing in popularity as a substitute for steel and concrete, reducing embodied carbon in the built environment. This trend has raised questions about the sustainability of the U.S. timber supply. Our research addresses concerns that rising demand for mass timber products may result in unsustainable levels of harvesting in coniferous forests in the United States. Using U.S. Department of Agriculture U.S. Forest Service Forest Inventory and Analysis (FIA) data, incremental U.S. softwood (coniferous) timber harvests were projected to supply a high-volume estimate of mass timber and dimensional lumber consumption in 2035. Growth in reserve forests and riparian zones was excluded, and low confidence intervals were used for timber growth estimates, compared with high confidence intervals for harvest and consumption estimates. Results were considered for the U.S. in total and by three geographic regions (North, South, and West). In total, forest inventory growth in America exceeds timber harvests including incremental mass timber volumes. Even the most optimistic projections of mass timber growth will not exceed the lowest expected annual increases in the nation’s harvestable coniferous timber inventory.

scholarly journals Seismic performance of embedded steel beam connection in cross-laminated timber panels for tall-wood hybrid system

2017 ◽  
Vol 44 (8) ◽  
pp. 611-618 ◽  
Author(s):  
Xiaoyue Zhang ◽  
Md Riasat Azim ◽  
Pooja Bhat ◽  
Marjan Popovski ◽  
Thomas Tannert
Keyword(s):  
Hybrid System ◽  
Design Guidelines ◽  
Steel Beam ◽  
Test Results ◽  
Cyclic Tests ◽  
Building Systems ◽  
Recent Developments ◽  
Timber Products ◽  
Mass Timber ◽  
Reversed Cyclic

Recent developments in novel engineered mass timber products and connection systems have created the possibility to design and construct tall timber-based buildings. This research presents the experiments conducted on the steel-wood connection as main energy dissipating part of a novel steel–timber hybrid system labelled Finding the Forest Through the Trees (FFTT). The performance was investigated using quasi-static monotonic and reversed cyclic tests. The influence of different steel beam profiles (wide flange I-sections and hollow rectangular sections) and the embedment approaches (partial and full embedment) was investigated. The test results demonstrated that appropriate connection layouts can lead to the desired failure mechanism while avoiding excessive crushing of the mass timber panels. The research can serve as a precursor for developing design guidelines for the FFTT system as an option for tall wood-hybrid building systems in seismic regions.

Analysis of the service life of railway hydraulic dampers considering temperature and loading

2020 ◽  
Vol 235 (1) ◽  
pp. 3-11
Author(s):  
Zeyao Hu ◽  
Dongli Song ◽  
Yuanchen Zeng ◽  
Weihua Zhang
Keyword(s):  
Service Life ◽  
High Speed ◽  
Stable State ◽  
Service Condition ◽  
Performance Degradation ◽  
Load Test ◽  
Loading Test ◽  
Different Temperatures ◽  
Equivalent Method

Hydraulic dampers are mainly used to maintain high-speed trains in a stable state when running at high speed. In this paper, an equivalent method for the lifetime of dampers is proposed to establish the relationship between the long-term loading test and the mileage in service condition. The performance degradation of the damper at different temperatures is calculated using the long-term loading test carried out under the corresponding temperature conditions. Arrhenius model is applied to convert the degradation under different temperatures, and the sensitive parameter is selected for the conversion of the damper’s performance degradation under different temperatures. An energy method is proposed to solve the problem of the damper lifetime under different loads, so as to achieve the equivalent of the damper between the long-term load test and the mileage in service condition. Finally, taking the anti-yaw damper of a certain type of high-speed train in China as the research object, the lifetime equivalent method proposed in this paper is applied and the result showed that the anti-yaw damper had remaining service life after 2.4 million kilometers of service.

scholarly journals The Design of Mass Timber Panels as Heat-Exchangers (Dynamic Insulation)

2021 ◽  
Vol 6 ◽  
Author(s):  
Salmaan Craig ◽  
Anna Halepaska ◽  
Katherine Ferguson ◽  
Preston Rains ◽  
Jacob Elbrecht ◽  
...  
Keyword(s):  
Construction Industry ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Total Heat Transfer ◽  
Exterior Surface ◽  
Thermal Buoyancy ◽  
Forestry Management ◽  
Dynamic Insulation ◽  
Timber Products ◽  
Mass Timber

Mass timber products, together with careful forestry management, could help decarbonize the construction industry. These products must be long-lasting, to safely store atmospheric carbon for decades or centuries, and multi-functional, to displace materials and equipment that are emissions-intensive. This paper shows how to optimize mass timber panels as heat-exchangers, suggesting how to eliminate insulation while simplifying HVAC systems. Test panels measured the heat-exchange in steady and transient conditions, when the ventilation was driven by a fan or by thermal buoyancy. The total heat transfer was predicted accurately by theory in all cases. Further investigation is needed to understand the possible heat-recovery effects at the exterior surface.

scholarly journals Carbon Impacts of Engineered Wood Products in Construction

2021 ◽  
Author(s):  
Hongmei Gu ◽  
Prakash Nepal ◽  
Matthew Arvanitis ◽  
Delton Alderman
Keyword(s):  
Climate Change ◽  
Wood Products ◽  
Construction Sector ◽  
Topic Area ◽  
Engineered Wood Products ◽  
Engineered Wood ◽  
Timber Products ◽  
Mitigate Climate Change ◽  
Mass Timber ◽  
Building Designs

Buildings and the construction sector together account for about 39% of the global energy-related CO2 emissions. Recent building designs are introducing promising new mass timber products that have the capacity to partially replace concrete and steel in traditional buildings. The inherently lower environmental impacts of engineered wood products for construction are seen as one of the key strategies to mitigate climate change through their increased use in the construction sector. This chapter synthesizes the estimated carbon benefits of using engineered wood products and mass timber in the construction sector based on insights obtained from recent Life Cycle Assessment studies in the topic area of reduced carbon emissions and carbon sequestration/storage.

scholarly journals The merits of varying forms of mass timber products for offsite and modular construction

2018 ◽  
Author(s):  
Robert Hairstans ◽  
Ryan Smith ◽  
Peter Wilson
Keyword(s):  
Sustainable Use ◽  
Species Selection ◽  
Modular Construction ◽  
Moisture Movement ◽  
Technological Developments ◽  
Timber Products ◽  
Combination Of Methods ◽  
Management Approaches ◽  
The Uk ◽  
Mass Timber

Mass timber is a family of Solid Laminate Timber Systems (SLTS) formed from smaller sections of timber connected by glue, mechanical fixings, moisture movement or a combination of methods. These products, which include Structural Composite Lumber, GluLam, Cross Lam, Nail Lam and Dowel Lam (or Brettstapel), have over the past two decades seen an extraordinary upsurge in use internationally. This global phenomenon has been driven by a greater emphasis on the sustainable use of renewable resources and by significant technological developments in the manufacture of SLTS. This research paper considers the merits of each of these products, their manufacturing processes and the corresponding quality assurance requirements necessary for successful project delivery. The paper describes the advantages and barriers to the use of the mass timber and provides an overview of the various aspects to be considered during design for offsite and modular construction. The work presented also provides case studies of how these products have been researched and utilised into live projects in the UK utilising local resource resulting in the formation of new supply chain arrangements. The work further explains the advantages of the respective systems for the given application including information on species selection, connection systems employed and the necessary onsite and offsite management approaches deployed.

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