The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Nobuhisa Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Crack Geometry effect on stress strain fields for Crack under biaxial loading
Journal of Pressure Vessel Technology-transactions of The Asme, 2010Co-Authors: Fumiyoshi Minami, Mitsuru Ohata, Daisuke Watanabe, Takahiro Kubo, Nobuhisa SuzukiAbstract:With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness Crack; the near-Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near-Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.
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Crack Geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Mitsuru Ohata, Daisuke Watanabe, Takahiro Kubo, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
Magnus Ekh - One of the best experts on this subject based on the ideXlab platform.
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Crack propagation in rails under rolling contact fatigue loading conditions based on material forces
International Journal of Fatigue, 2012Co-Authors: Jim Brouzoulis, Magnus EkhAbstract:Tools for the prediction of Crack growth in rails are of vital importance for the railway industry. In this paper, numerical simulations of Crack growth in rails are presented. More specifically, the focus is on short surface head check like Cracks, often observed at the rail gauge corner. A fatigue Crack propagation model expressed in terms of a Crack driving force, derived from the concept of material forces, is presented. It is shown that only the component parallel to the Crack tip of the Crack driving force is a reliable quantity that can be used in numerical simulations of a Rolling Contact Fatigue (RCF) situation. In addition, it is shown that one term in the expression of the Crack driving force (Gsur) is dependent on the computational mesh. The propagation model has been used for parametric studies of Crack propagation to investigate key parameters such as loading and Crack Geometry. Results from these studies suggest that anisotropic effects from the highly deformed surface layer may need to be included in order to simulate head check growth in rails accurately.
Fumiyoshi Minami - One of the best experts on this subject based on the ideXlab platform.
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Crack Geometry effect on stress strain fields for Crack under biaxial loading
Journal of Pressure Vessel Technology-transactions of The Asme, 2010Co-Authors: Fumiyoshi Minami, Mitsuru Ohata, Daisuke Watanabe, Takahiro Kubo, Nobuhisa SuzukiAbstract:With increasing demand of high-strength and high-pressure pipelines in gas transmission industries, the fracture control design of pipelines has been a driving factor to ensure the integrity of the pipeline. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large-diameter pipe subjected to inner pressure coupled with axial loading. Attention is focused on the initiation of brittle fracture (stress controlled type) as well as ductile fracture (strain controlled type). Three-dimensional finite element-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness Crack; the near-Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near-Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.
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Crack Geometry effect on stress strain fields for Crack under biaxial loading
2008 7th International Pipeline Conference Volume 3, 2008Co-Authors: Fumiyoshi Minami, Mitsuru Ohata, Daisuke Watanabe, Takahiro Kubo, Nobuhisa SuzukiAbstract:With increasing demand of high strength and high pressure pipelines in gas transmission industries, the fracture control design of pipelines has been driven primarily. This paper addresses the stress and strain fields for a Crack in a wide plate component under biaxial loading, which simulates a large diameter pipe subjected to inner pressure coupled with axial loading. Three-dimensional FE-analyses are conducted. It was found that biaxial loading has a significant effect on the stress fields of through-thickness Crack; the near Crack-tip stress is elevated to a large extent by biaxial loading. By contrast, the stress field for a surface Crack is not sensitive to biaxial loading, while the near Crack-tip stress at the Crack corner is increased locally by biaxial loading. The Weibull stress criterion was applied to discuss the biaxial loading effect on the brittle fracture strength of the wide plate. Ductile Crack initiation properties are also discussed with two-parameter (plastic strain and stress triaxiality) diagram. The ductile damage is increased by biaxial loading for a through-thickness Crack, whereas a surface Crack has little effect of biaxial loading on the ductile damage.Copyright © 2008 by ASME
Christine Sarrazin-baudoux - One of the best experts on this subject based on the ideXlab platform.
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Some critical aspects of low rate fatigue Crack propagation in metallic materials
International Journal of Fatigue, 2010Co-Authors: Jean Petit, Christine Sarrazin-baudouxAbstract:This paper proposes an overview of some critical aspects of fatigue Crack propagation in metallic materials mainly concentrated on the near-threshold domain. The role of predominant influencing parameters including intrinsic parameters as alloy composition and microstructure, or extrinsic factors as loading condition, Crack Geometry, Crack closure, atmosphere environment is particularly discussed. The first section of the paper is devoted to basic mechanisms of fatigue Crack propagation after correction for Crack closure, with a modeling framework including the intrinsic propagation stages in high vacuum considered as a reference inert environment, and the environmentally-assisted Crack propagation regimes identified in gaseous atmosphere. The second section of the paper is dedicated to application of this basic framework to analyze three critical examples of Crack propagation including small Cracks, propagation at low temperature and ultra-slow Crack propagation at ultrasonic frequency. © 2009 Elsevier Ltd. All rights reserved.
J. D. Landes - One of the best experts on this subject based on the ideXlab platform.
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The load separation andη pl development in preCracked specimen test recordsdevelopment in preCracked specimen test records
International Journal of Fracture, 1993Co-Authors: M. H. Sharobeam, J. D. LandesAbstract:Load separation is the theoretical basis for the single specimenJ form and the incremental calculation ofJ-R andJM-R curves. It is based on the assumption that the load can be represented as a multiplication of two separate functions; a Crack Geometry function and a material deformation function. Until recently, the main experimental basis for such an assumption was the approximate agreement between the experimental results of the single specimenJ form and the energy rate interpretation ofJ in blunt notched bending geometries. The load separation assumption has been also implied in the growing Crack records in order to develop theR-curve analysis. Both the Crack Geometry and material deformation functions were assumed to maintain their forms as the Crack grows. Recently, an experimental study investigated the load separation in the test records of stationary Crack specimens of different Geometry, material, and constraint. The study showed that the load can be represented by a separable form for the entire plastic region except for a limited region at the early region of plastic behavior. Also, it was found that the load separation is not limited to a certain Geometry, material, or constraint but it is a dominant property in the ductile fracture behavior of stationary Crack specimens. The study also showed that the Crack Geometry function is a power law function. Henceηpl is a constant equal to the power law exponent of the Geometry function.
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The load separation and η pl
International Journal of Fracture, 1993Co-Authors: M. H. Sharobeam, J. D. LandesAbstract:Load separation is the theoretical basis for the single specimen J form and the incremental calculation of J-R and J M -R curves. It is based on the assumption that the load can be represented as a multiplication of two separate functions; a Crack Geometry function and a material deformation function. Until recently, the main experimental basis for such an assumption was the approximate agreement between the experimental results of the single specimen J form and the energy rate interpretation of J in blunt notched bending geometries. The load separation assumption has been also implied in the growing Crack records in order to develop the R-curve analysis. Both the Crack Geometry and material deformation functions were assumed to maintain their forms as the Crack grows. Recently, an experimental study investigated the load separation in the test records of stationary Crack specimens of different Geometry, material, and constraint. The study showed that the load can be represented by a separable form for the entire plastic region except for a limited region at the early region of plastic behavior. Also, it was found that the load separation is not limited to a certain Geometry, material, or constraint but it is a dominant property in the ductile fracture behavior of stationary Crack specimens. The study also showed that the Crack Geometry function is a power law function. Hence η pl is a constant equal to the power law exponent of the Geometry function.
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The load separation andη _ pl development in preCracked specimen test recordsdevelopment in preCracked specimen test records
International Journal of Fracture, 1993Co-Authors: M. H. Sharobeam, J. D. LandesAbstract:Load separation is the theoretical basis for the single specimen J form and the incremental calculation of J-R and J _ M -R curves. It is based on the assumption that the load can be represented as a multiplication of two separate functions; a Crack Geometry function and a material deformation function. Until recently, the main experimental basis for such an assumption was the approximate agreement between the experimental results of the single specimen J form and the energy rate interpretation of J in blunt notched bending geometries. The load separation assumption has been also implied in the growing Crack records in order to develop the R -curve analysis. Both the Crack Geometry and material deformation functions were assumed to maintain their forms as the Crack grows. Recently, an experimental study investigated the load separation in the test records of stationary Crack specimens of different Geometry, material, and constraint. The study showed that the load can be represented by a separable form for the entire plastic region except for a limited region at the early region of plastic behavior. Also, it was found that the load separation is not limited to a certain Geometry, material, or constraint but it is a dominant property in the ductile fracture behavior of stationary Crack specimens. The study also showed that the Crack Geometry function is a power law function. Hence η _ pl is a constant equal to the power law exponent of the Geometry function. The objective of this study is to investigate the extension of load separation to growing Crack records. Sets of test records from three different materials are used in this study. For each material three or four preCracked specimen test records and one blunt notched record are analyzed for the compact specimen Geometry. The study will discuss the main condition to have a separable behavior in a growing Crack test record. It will also construct the Geometry and deformation functions for the materials studied, these functions are compared with those obtained from stationary Crack records.
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The load separation and η_ pl
International Journal of Fracture, 1993Co-Authors: M. H. Sharobeam, J. D. LandesAbstract:Load separation is the theoretical basis for the single specimen J form and the incremental calculation of J-R and J _ M -R curves. It is based on the assumption that the load can be represented as a multiplication of two separate functions; a Crack Geometry function and a material deformation function. Until recently, the main experimental basis for such an assumption was the approximate agreement between the experimental results of the single specimen J form and the energy rate interpretation of J in blunt notched bending geometries. The load separation assumption has been also implied in the growing Crack records in order to develop the R -curve analysis. Both the Crack Geometry and material deformation functions were assumed to maintain their forms as the Crack grows. Recently, an experimental study investigated the load separation in the test records of stationary Crack specimens of different Geometry, material, and constraint. The study showed that the load can be represented by a separable form for the entire plastic region except for a limited region at the early region of plastic behavior. Also, it was found that the load separation is not limited to a certain Geometry, material, or constraint but it is a dominant property in the ductile fracture behavior of stationary Crack specimens. The study also showed that the Crack Geometry function is a power law function. Hence η_ pl is a constant equal to the power law exponent of the Geometry function. The objective of this study is to investigate the extension of load separation to growing Crack records. Sets of test records from three different materials are used in this study. For each material three or four preCracked specimen test records and one blunt notched record are analyzed for the compact specimen Geometry. The study will discuss the main condition to have a separable behavior in a growing Crack test record. It will also construct the Geometry and deformation functions for the materials studied, these functions are compared with those obtained from stationary Crack records.