The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Christian Brischke - One of the best experts on this subject based on the ideXlab platform.
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Design and performance prediction of timber bridges based on a factorization approach
Wood Material Science & Engineering, 2018Co-Authors: Linda Meyer-veltrup, Christian Brischke, Jonas Niklewski, Eva Frühwald HanssonAbstract:Service life of timber bridges is predominantly affected by the site-specific climatic conditions in terms of moisture and temperature over time, the overall design, the design of details, and the choice of Materials. In recent years, a performance-based methodology has been developed to predict (1) the Material climatic conditions within timber components from macro climate data and comparison between design details, (2) decay intensity from Material climate data, and (3) the Material Resistance as a combined effect of wood-inherent properties and its moisture dynamics. Within the WoodWisdomNet project ‘Durable Timber Bridges’ we emphasized on utilizing exposure, decay, and Resistance models for a comprehensive guideline for the design of timber bridges. Therefore, a factorization approach is presented based on dose–response relationship between wood Material climate and responding fungal decay. The concept does also allow for quantifying the Material Resistance of untreated, modified, and preservative-treated wood using factors based on laboratory and field durability tests and short-term tests for capillary water uptake, adsorption, and desorption dynamics. The findings from the present study have the potential to serve as an instrument for design and service life prediction of timber structures and will be implemented in an engineering design guideline for timber bridges.
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Studies on the Material Resistance and moisture dynamics of Common juniper, English yew, Black cherry, and Rowan
Wood Material Science & Engineering, 2017Co-Authors: Christian Brischke, Carola Hesse, Linda Meyer-veltrup, Miha HumarAbstract:ABSTRACTThe overall aim of this study was to provide comprehensive durability characteristics of wood species underutilized but frequently occurring in Central and Northern Europe: Common juniper (Juniperus communis L.), Black cherry (Prunus serotina Ehrh.), English yew (Taxus baccata L.), and Rowan (Sorbus aucuparia L.). Decay Resistance was tested against white and brown rot causing basidiomycetes and soft rot causing micro-fungi in terrestrial microcosms. Their wetting ability was determined in terms of capillary water uptake at the end-grain, the liquid water uptake during submersion, the water vapor uptake at high humidity, and the water release during drying. All tests were performed with unleached and leached specimens. Durability classes were assigned based on results from the different tests. Juniper and Yew were classified very durable (Durability class DC 1); Black cherry and Rowan were found to be less durable (DC 3–5). Leaching did not affect the durability classification significantly. Durab...
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durability of oak timber bridges impact of inherent wood Resistance and environmental conditions
International Biodeterioration & Biodegradation, 2012Co-Authors: Christian Brischke, Christoph J Behnen, Marietherese Lenz, Karin Brandt, Eckhard MelcherAbstract:Abstract Premature failure of timber construction can have dramatic consequences, at worst threat to human life or physical condition. Timber components might perform unexpectedly poor due to insufficient protection by misuse, design, low work execution level, or due to low Resistance of the Material in use. However, information about the Material Resistance of prematurely failed structures is usually lacking. Therefore this study aimed on developing a method to display the relationship between damages occurring on structures in service and the Resistance against wood-destroying fungi of the Material used. Drilling cores taken from wooden structures were found to have the ability to serve as specimens in laboratory decay test when compared to standard specimens. Therefore, drilling cores were sampled from different components of six timber bridges in Hannover, Germany, made from English oak (Quercus robur L.). The cores were submitted to the white rot fungus Trametes versicolor and to soft rot fungi in terrestrial microcosms. The determined mass losses due to fungal decay were compared with the level of damage of the studied bridge components. The results indicated that the Material-inherent Resistance was responsible for damages rather than poor details of the construction. The methodological approach might be used to provide further knowledge about the relationship of timber in service and under ideal laboratory test conditions.
Eva Frühwald Hansson - One of the best experts on this subject based on the ideXlab platform.
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Design and performance prediction of timber bridges based on a factorization approach
Wood Material Science & Engineering, 2018Co-Authors: Linda Meyer-veltrup, Christian Brischke, Jonas Niklewski, Eva Frühwald HanssonAbstract:Service life of timber bridges is predominantly affected by the site-specific climatic conditions in terms of moisture and temperature over time, the overall design, the design of details, and the choice of Materials. In recent years, a performance-based methodology has been developed to predict (1) the Material climatic conditions within timber components from macro climate data and comparison between design details, (2) decay intensity from Material climate data, and (3) the Material Resistance as a combined effect of wood-inherent properties and its moisture dynamics. Within the WoodWisdomNet project ‘Durable Timber Bridges’ we emphasized on utilizing exposure, decay, and Resistance models for a comprehensive guideline for the design of timber bridges. Therefore, a factorization approach is presented based on dose–response relationship between wood Material climate and responding fungal decay. The concept does also allow for quantifying the Material Resistance of untreated, modified, and preservative-treated wood using factors based on laboratory and field durability tests and short-term tests for capillary water uptake, adsorption, and desorption dynamics. The findings from the present study have the potential to serve as an instrument for design and service life prediction of timber structures and will be implemented in an engineering design guideline for timber bridges.
Linda Meyer-veltrup - One of the best experts on this subject based on the ideXlab platform.
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Design and performance prediction of timber bridges based on a factorization approach
Wood Material Science & Engineering, 2018Co-Authors: Linda Meyer-veltrup, Christian Brischke, Jonas Niklewski, Eva Frühwald HanssonAbstract:Service life of timber bridges is predominantly affected by the site-specific climatic conditions in terms of moisture and temperature over time, the overall design, the design of details, and the choice of Materials. In recent years, a performance-based methodology has been developed to predict (1) the Material climatic conditions within timber components from macro climate data and comparison between design details, (2) decay intensity from Material climate data, and (3) the Material Resistance as a combined effect of wood-inherent properties and its moisture dynamics. Within the WoodWisdomNet project ‘Durable Timber Bridges’ we emphasized on utilizing exposure, decay, and Resistance models for a comprehensive guideline for the design of timber bridges. Therefore, a factorization approach is presented based on dose–response relationship between wood Material climate and responding fungal decay. The concept does also allow for quantifying the Material Resistance of untreated, modified, and preservative-treated wood using factors based on laboratory and field durability tests and short-term tests for capillary water uptake, adsorption, and desorption dynamics. The findings from the present study have the potential to serve as an instrument for design and service life prediction of timber structures and will be implemented in an engineering design guideline for timber bridges.
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Studies on the Material Resistance and moisture dynamics of Common juniper, English yew, Black cherry, and Rowan
Wood Material Science & Engineering, 2017Co-Authors: Christian Brischke, Carola Hesse, Linda Meyer-veltrup, Miha HumarAbstract:ABSTRACTThe overall aim of this study was to provide comprehensive durability characteristics of wood species underutilized but frequently occurring in Central and Northern Europe: Common juniper (Juniperus communis L.), Black cherry (Prunus serotina Ehrh.), English yew (Taxus baccata L.), and Rowan (Sorbus aucuparia L.). Decay Resistance was tested against white and brown rot causing basidiomycetes and soft rot causing micro-fungi in terrestrial microcosms. Their wetting ability was determined in terms of capillary water uptake at the end-grain, the liquid water uptake during submersion, the water vapor uptake at high humidity, and the water release during drying. All tests were performed with unleached and leached specimens. Durability classes were assigned based on results from the different tests. Juniper and Yew were classified very durable (Durability class DC 1); Black cherry and Rowan were found to be less durable (DC 3–5). Leaching did not affect the durability classification significantly. Durab...
Eckhard Melcher - One of the best experts on this subject based on the ideXlab platform.
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durability of oak timber bridges impact of inherent wood Resistance and environmental conditions
International Biodeterioration & Biodegradation, 2012Co-Authors: Christian Brischke, Christoph J Behnen, Marietherese Lenz, Karin Brandt, Eckhard MelcherAbstract:Abstract Premature failure of timber construction can have dramatic consequences, at worst threat to human life or physical condition. Timber components might perform unexpectedly poor due to insufficient protection by misuse, design, low work execution level, or due to low Resistance of the Material in use. However, information about the Material Resistance of prematurely failed structures is usually lacking. Therefore this study aimed on developing a method to display the relationship between damages occurring on structures in service and the Resistance against wood-destroying fungi of the Material used. Drilling cores taken from wooden structures were found to have the ability to serve as specimens in laboratory decay test when compared to standard specimens. Therefore, drilling cores were sampled from different components of six timber bridges in Hannover, Germany, made from English oak (Quercus robur L.). The cores were submitted to the white rot fungus Trametes versicolor and to soft rot fungi in terrestrial microcosms. The determined mass losses due to fungal decay were compared with the level of damage of the studied bridge components. The results indicated that the Material-inherent Resistance was responsible for damages rather than poor details of the construction. The methodological approach might be used to provide further knowledge about the relationship of timber in service and under ideal laboratory test conditions.
Guillaume Kermouche - One of the best experts on this subject based on the ideXlab platform.
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Assessment of mechanical property gradients after impact-based surface treatment: application to pure α-iron
Materials Science and Engineering: A, 2016Co-Authors: David Tumbajoy-spinel, Sylvie Descartes, Jean-michel Bergheau, Victor Lacaille, Gaylord Guillonneau, Johann Michler, Guillaume KermoucheAbstract:Mechanical surface treatments are known for their ability to improve Material Resistance to abrasive wear and local fatigue crack microstructure of the home-made crack propagation. These treatments are based on repeated contact loadings which create large plastic strains in the near-surface that can induce a local grain refinement. In this case, a significant increase in the near-surface local mechanical properties is thus usually observed. In this paper, nano-mechanical tests are used to quantify the mechanical property gradient in the near-surface of a purity-controlled α-iron after an impact-based treatment. A methodology based on the combination of two different techniques is proposed: nano-indentation and in-situ micro-pillar compression. The resulting in-depth mechanical properties gradient is compared to the average grain size measured by EBSD. A positive relationship with the well-known Hall-Petch effect is observed.
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Assessment of mechanical property gradients after impact-based surface treatment: application to pure alpha-iron
Materials Science and Engineering: A, 2016Co-Authors: David Tumbajoy-spinel, Sylvie Descartes, Jean-michel Bergheau, Victor Lacaille, Gaylord Guillonneau, Johann Michler, Guillaume KermoucheAbstract:Mechanical surface treatments are known for their ability to improve Material Resistance to abrasive wear and local fatigue crack microstructure of the home-made crack propagation. These treatments are based on repeated contact loadings which create large plastic strains in the near-surface that can induce a local grain refinement. In this case, a significant increase in the near-surface local mechanical properties is thus usually observed. In this paper, nano-mechanical tests are used to quantify the mechanical property gradient in the near-surface of a purity-controlled alpha-iron after an impact-based treatment. A methodology based on the combination of two different techniques is proposed: nano-indentation and in-situ micro-pillar compression. The resulting in-depth mechanical properties gradient is compared to the average grain size measured by EBSD. A positive relationship with the well-known Hall-Fetch effect is observed.
