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6 records – page 1 of 1.

A Hierarchical Approach for Solving an Integrated Packing and Sequence-Optimization Problem in Production of Glued Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue2580
Year of Publication
2020
Topic
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Author
Acermann, Heiner
Diessel, Erik
Publisher
Springer
Year of Publication
2020
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Application
Beams
Topic
Design and Systems
Keywords
Sawmills
Production
Packing
Optimization
Language
English
Research Status
Complete
Series
EURO Journal on Computational Optimization
Summary
Integrated packing and sequence-optimization problems appear in many industrial applications. As an example of this type of problem, we consider the production of glued laminated timber (glulam) in sawmills: Wood beams must be packed into a sequence of pressing steps subject to packing constraints of the press and subject to sequencing constraints. In this paper, we present a three-stage approach for solving this hard optimization problem: Firstly, we identify alternative packings for small parts of an instance. Secondly, we choose an optimal subset of these packings by solving a set cover problem. Finally, we apply a sequencing algorithm in order to find an optimal order of the selected subsequences. For every level of the hierarchy, we present tailored algorithms, analyze their performance and illustrate the efficiency of the overall approach by a comprehensive numerical study.
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Innovative Composite Steel-Timber Floors with Prefabricated Modular Components

https://research.thinkwood.com/en/permalink/catalogue1350
Year of Publication
2017
Topic
Connections
Design and Systems
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Author
Loss, Cristiano
Davison, Buick
Publisher
ScienceDirect
Year of Publication
2017
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Steel-Timber Composite
Application
Floors
Topic
Connections
Design and Systems
Mechanical Properties
Keywords
Prefabricated
Multi-Storey
Residential
Bearing Capacity
Stiffness
Construction
Mechanical Connectors
Epoxy
Modular
Bending Tests
Finite Element Model
Language
English
Research Status
Complete
Series
Engineering Structures
Summary
An innovative steel-timber composite floor for use in multi-storey residential buildings is presented. The research demonstrates the potential of these steel-timber composite systems in terms of bearing capacity, stiffness and method of construction. Such engineered solutions should prove to be sustainable since they combine recyclable materials in the most effective way. The floors consist of prefabricated ultralight modular components, with a Cross-Laminated Timber (CLT) slab, joined together and to the main structural system using only bolts and screws. Two novel floor solutions are presented, along with the results of experimental tests on the flexural behaviour of their modular components. Bending tests have been performed considering two different methods of loading and constraints. Each prefabricated modular component uses a special arrangement of steel-timber connections to join a CLT panel to two customized cold-formed steel beams. Specifically, the first proposed composite system is assembled using mechanical connectors whereas the second involves the use of epoxy-based resin. In the paper, a FEM model is provided in order to extend this study to other steel-timber composite floor solutions. In addition, the paper contains the design model to be used in dimensioning the developed systems according to the state of the art of composite structures.
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Parametric and Generative Design Techniques for Mass-Customization in Building Industry: A Case Study for Glued-Laminated Timber

https://research.thinkwood.com/en/permalink/catalogue1351
Year of Publication
2017
Topic
General Information
Design and Systems
Material
Glulam (Glue-Laminated Timber)
Author
Monizza, Gabriele
Rauch, Erwin
Matt, Dominik
Publisher
ScienceDirect
Year of Publication
2017
Country of Publication
Netherlands
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
General Information
Design and Systems
Keywords
Research
Building Industry
Mass-Customization
Production
Parametric Design
Generative Design
Language
English
Research Status
Complete
Series
Procedia CIRP
Summary
According to Wortmann classification, the Building Industry (BI) can be defined as engineer-to-order (ETO) industry: the engineering-process starts only when an order is acquired. This definition implies that every final product (building) is almost unique, and processes cannot be easily standardized or automated. For this reason, the Building Industry is one of the less efficient industries today, and the productivity gap with other industries is growing faster. Since the 1940s, prefabrication and standardization of entire buildings or of complex components are effective strategies to push BI from an ETO industry towards an assembly-to-order industry (ATO). Although, prefabrication and standardization strategies provide effective solutions to improve process efficiency, they are not widespread adopted. The reason for this poor success can be identified in limits of customization that afflicts prefabricated and standardized products, which do not satisfy completely the needs usually delivered by customers. This paper presents a research activity aiming at enhancing Mass-Customization capabilities in the BI through Parametric and Generative design techniques in frontend activities of the value-chain system. Referring to a case study for Glued-Laminated Timber (GLT) products, a parametric algorithm has been programmed in order to satisfy two specific design intents: reducing the usage of unneeded high-quality raw material in final products and facilitating the manufacturing process of complex products, such as doubled-curved ones. Crossing capabilities of the parametric algorithm in Digital Fabrication strategies and capabilities of a standard production system of GLT, authors discuss whether Parametric and Generative Design techniques may enhance Mass-Customization capabilities in the BI, pushing the whole production system towards more efficient processes.
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Bonding Strength Test Method Assessment for Cross-Laminated Timber Derived Stressed-Skin Panels (CLT SSP)

https://research.thinkwood.com/en/permalink/catalogue1404
Year of Publication
2017
Topic
Mechanical Properties
Material
CLT (Cross-Laminated Timber)
Author
Luengo, Emilio
Hermoso, Eva
Cabrero, Juan Carlos
Arriaga, Francisco
Publisher
Springer Netherlands
Year of Publication
2017
Country of Publication
Netherlands
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Topic
Mechanical Properties
Keywords
Stressed-Skin Panels
Shear Strength
Glue Lines
Shear Tests
Bending Tests
Bonding
Language
English
Research Status
Complete
Series
Materials and Structures
ISSN
1871-6873
Summary
Different methods, including bending tests and small and medium size shear tests, were used to assess the skin to stringer glue line shear strength of Radiata Pine Cross-Laminated Timber Derived Stressed-Skin Panels (CLT SSP). Bending test shear strengths were estimated using the mechanically jointed beam theory (gamma method) for CrossLaminated Timber (CLT) panels with modifications in the layers’ effective widths, and then compared with results from the small and medium size shear tests. Small and medium size shear tests proved to be possible methods for assessing bonding strength for factory production control. The small shear tests provided lower strength values and higher scatter results than those gathered from the medium size tests. The mean shear strength results obtained from bending tests were inferior to the values obtained from the small and medium size specimens. The bending tests proved necessary for assessing the mechanical behaviour of CLT SSP.
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Mechanical Behaviour of Finger Joints at Elevated Temperatures

https://research.thinkwood.com/en/permalink/catalogue612
Year of Publication
2012
Topic
Fire
Mechanical Properties
Material
Glulam (Glue-Laminated Timber)
Author
Frangi, Andrea
Bertocchi, Marco
Clauß, Sebastian
Niemz, Peter
Publisher
Springer-Verlag
Year of Publication
2012
Country of Publication
Germany
Format
Journal Article
Material
Glulam (Glue-Laminated Timber)
Topic
Fire
Mechanical Properties
Keywords
Fire Resistance
Tensile tests
Bending Tests
Finger Joints
Language
English
Research Status
Complete
Series
Wood Science and Technology
ISSN
1432-5225
Summary
Finger joints are commonly used to produce engineered wood products like glued laminated timber beams. Although comprehensive research has been conducted on the structural behaviour of finger joints at ambient temperature, there is very little information about the structural behaviour at elevated temperature. A comprehensive research project on the fire resistance of bonded timber elements is currently ongoing at the ETH Zurich. The aim of the research project is the development of simplified design models for the fire resistance of bonded structural timber elements taking into account the behaviour of the adhesive used at elevated temperature. The paper presents the results of a first series of tensile and bending tests on specimens with finger joints pre-heated in an oven. The tests were carried out with different adhesives that fulfil current approval criteria for the use in loadbearing timber components. The results showed substantial differences in temperature dependant strength reduction and failure between the different adhesives tested. Thus, the structural behaviour of finger joints at elevated temperature is strongly influenced by the behaviour of the adhesive used for bonding and may govern the fire design of engineered wood products like glued laminated timber beams.
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Experimental Behavior of a Continuous Metal Connector for a Wood-Concrete Composite System

https://research.thinkwood.com/en/permalink/catalogue730
Year of Publication
2004
Topic
Connections
Design and Systems
Mechanical Properties
Material
Timber-Concrete Composite
PSL (Parallel Strand Lumber)
Application
Floors
Author
Clouston, Peggi
Civjan, Scott
Bathon, Leander
Publisher
Forest Products Society
Year of Publication
2004
Country of Publication
United States
Format
Journal Article
Material
Timber-Concrete Composite
PSL (Parallel Strand Lumber)
Application
Floors
Topic
Connections
Design and Systems
Mechanical Properties
Keywords
Pine
US
Continuous Steel Mesh
Steel Connectors
Push-Out Tests
Shear Strength
Stiffness
Bending Tests
Language
English
Research Status
Complete
Series
Forest Products Journal
Summary
The benefits of using shear connectors to join wood beams to a concrete slab in a composite floor or deck system are many. Studies throughout the world have demonstrated significantly improved strength, stiffness, and ductility properties from such connection systems as well as citing practical building advantages such as durability, sound insulation, and fire resistance. In this study, one relatively new shear connector system that originated in Germany has been experimentally investigated for use with U.S. manufactured products. The connector system consists of a continuous steel mesh of which one half is glued into a southern pine Parallam® Parallel Strand Lumber beam and the other half embedded into a concrete slab to provide minimal interlayer slip. A variety of commercial epoxies were tested for shear strength and stiffness in standard shear or “push out” tests. The various epoxies resulted in a variety of shear constitutive behaviors; however, for two glue types,shear failure occurred in the steel connector resulting in relatively high initial stiffness and ductility as well as good repeatability. Slip moduli and ultimate strength values are presented and discussed. Full-scale bending tests, using the best performing adhesive as determined from the shear tests, were also conducted. Results indicate consistent, near-full composite action system behavior
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6 records – page 1 of 1.