The Experts below are selected from a list of 15837 Experts worldwide ranked by ideXlab platform
Jianguo Lin - One of the best experts on this subject based on the ideXlab platform.
-
a controlled poisson voronoi Tessellation for grain and cohesive boundary generation applied to crystal plasticity analysis
Computational Materials Science, 2012Co-Authors: P. Zhang, D.s. Balint, Jianguo Lin, Morad Karimpour, D C J FarrugiaAbstract:Abstract A novel computational framework is presented for the representation of virtual polycrystalline grain structures with cohesive boundaries for large-scale crystal plasticity finite element (CPFE) analyses. This framework consists of a grain structure generation model and cohesive zone (CZ) representation and junction partitioning scheme. The controlled Poisson Voronoi Tessellation (CPVT) model is employed to generate virtual grain structures that are statistically equivalent to metallographic measurements in terms of grain size distribution. In the CPVT model, physical parameters including the mean grain size, a small grain size, a large grain size and the percentage of grains within this range are used to determine the grain size distribution. To study inter-granular crack initiation and evolution using the cohesive zone model, a novel grain boundary representation scheme is proposed for producing cohesive interfaces for Voronoi Tessellations and automatically partitioning multiple junctions. The proposed virtual grain structure generation model and cohesive boundary generation method is demonstrated in a crystal plasticity simulation of polycrystal tension. The features of inter-granular crack initiation and propagation are presented and the mechanical response is discussed.
-
controlled poisson voronoi Tessellation for virtual grain structure generation a statistical evaluation
Philosophical Magazine, 2011Co-Authors: P. Zhang, Daniel S Balint, Jianguo LinAbstract:A controlled Poisson Voronoi Tessellation (CPVT) model has been developed for producing two-dimensional virtual grain structures that are statistically equivalent to metallographic observations of polycrystalline materials in terms of the Tessellation's regularity and grain size distribution. The descriptive fitting model, which is critical to link the grain size distribution parameter to the regularity parameter, has been improved in this work; previously, the descriptive model was poor for large values of the distribution parameter c. A set of four physical parameters is involved in uniquely determining the grain size distribution properties and configuring the CPVT system. Emphasis is devoted to examining the effectiveness and robustness of the CPVT system in generating virtual grain structures with specified properties. Two series of statistical tests are performed to validate the agreement between the prescribed regularity and that of the resultant Tessellations, and to investigate the details of the...
-
An integrated scheme for crystal plasticity analysis: Virtual grain structure generation
Computational Materials Science, 2011Co-Authors: P. Zhang, D.s. Balint, Jianguo LinAbstract:Abstract An integrated scheme is developed based on the controlled Poisson Voronoi Tessellation (CPVT) model to generate the polycrystalline grain structure for micromechanics simulations. The proposed model of CPVT involves a single control parameter that is used to produce the grain structure with regularity control, by which the yielded Tessellation varies from the purely random Voronoi Tessellation to the regular hexagonal Tessellation. The system extends the standard CPVT model by the addition of two features: a one-parameter gamma distribution and a mapping from a set of quantitative metallographic measurements to the distribution parameter. Based on this scheme, a grain structure can be constructed such that the virtual Tessellation is statistically equivalent to the expected grain size distribution. To validate the modules that utilise the physical parameters that dictate the regularity, a series of theoretical investigations is performed. Efforts are devoted to proving the uniqueness of the mapping from the physical parameters to the distribution parameter and the regularity parameter. An efficient numerical algorithm is provided to facilitate the mapping solution process. A software system (VGRAIN) is developed implementing the proposed CPVT model to generate the grain structure for crystal plasticity finite element (CPFE) analysis. To demonstrate the proposed scheme and the VGRAIN system, a plane strain CPFE analysis is conducted. Two microstructures are generated with different regularities, and the deformation under uniaxial tension is simulated.
P. Zhang - One of the best experts on this subject based on the ideXlab platform.
-
a controlled poisson voronoi Tessellation for grain and cohesive boundary generation applied to crystal plasticity analysis
Computational Materials Science, 2012Co-Authors: P. Zhang, D.s. Balint, Jianguo Lin, Morad Karimpour, D C J FarrugiaAbstract:Abstract A novel computational framework is presented for the representation of virtual polycrystalline grain structures with cohesive boundaries for large-scale crystal plasticity finite element (CPFE) analyses. This framework consists of a grain structure generation model and cohesive zone (CZ) representation and junction partitioning scheme. The controlled Poisson Voronoi Tessellation (CPVT) model is employed to generate virtual grain structures that are statistically equivalent to metallographic measurements in terms of grain size distribution. In the CPVT model, physical parameters including the mean grain size, a small grain size, a large grain size and the percentage of grains within this range are used to determine the grain size distribution. To study inter-granular crack initiation and evolution using the cohesive zone model, a novel grain boundary representation scheme is proposed for producing cohesive interfaces for Voronoi Tessellations and automatically partitioning multiple junctions. The proposed virtual grain structure generation model and cohesive boundary generation method is demonstrated in a crystal plasticity simulation of polycrystal tension. The features of inter-granular crack initiation and propagation are presented and the mechanical response is discussed.
-
controlled poisson voronoi Tessellation for virtual grain structure generation a statistical evaluation
Philosophical Magazine, 2011Co-Authors: P. Zhang, Daniel S Balint, Jianguo LinAbstract:A controlled Poisson Voronoi Tessellation (CPVT) model has been developed for producing two-dimensional virtual grain structures that are statistically equivalent to metallographic observations of polycrystalline materials in terms of the Tessellation's regularity and grain size distribution. The descriptive fitting model, which is critical to link the grain size distribution parameter to the regularity parameter, has been improved in this work; previously, the descriptive model was poor for large values of the distribution parameter c. A set of four physical parameters is involved in uniquely determining the grain size distribution properties and configuring the CPVT system. Emphasis is devoted to examining the effectiveness and robustness of the CPVT system in generating virtual grain structures with specified properties. Two series of statistical tests are performed to validate the agreement between the prescribed regularity and that of the resultant Tessellations, and to investigate the details of the...
-
An integrated scheme for crystal plasticity analysis: Virtual grain structure generation
Computational Materials Science, 2011Co-Authors: P. Zhang, D.s. Balint, Jianguo LinAbstract:Abstract An integrated scheme is developed based on the controlled Poisson Voronoi Tessellation (CPVT) model to generate the polycrystalline grain structure for micromechanics simulations. The proposed model of CPVT involves a single control parameter that is used to produce the grain structure with regularity control, by which the yielded Tessellation varies from the purely random Voronoi Tessellation to the regular hexagonal Tessellation. The system extends the standard CPVT model by the addition of two features: a one-parameter gamma distribution and a mapping from a set of quantitative metallographic measurements to the distribution parameter. Based on this scheme, a grain structure can be constructed such that the virtual Tessellation is statistically equivalent to the expected grain size distribution. To validate the modules that utilise the physical parameters that dictate the regularity, a series of theoretical investigations is performed. Efforts are devoted to proving the uniqueness of the mapping from the physical parameters to the distribution parameter and the regularity parameter. An efficient numerical algorithm is provided to facilitate the mapping solution process. A software system (VGRAIN) is developed implementing the proposed CPVT model to generate the grain structure for crystal plasticity finite element (CPFE) analysis. To demonstrate the proposed scheme and the VGRAIN system, a plane strain CPFE analysis is conducted. Two microstructures are generated with different regularities, and the deformation under uniaxial tension is simulated.
D.s. Balint - One of the best experts on this subject based on the ideXlab platform.
-
a controlled poisson voronoi Tessellation for grain and cohesive boundary generation applied to crystal plasticity analysis
Computational Materials Science, 2012Co-Authors: P. Zhang, D.s. Balint, Jianguo Lin, Morad Karimpour, D C J FarrugiaAbstract:Abstract A novel computational framework is presented for the representation of virtual polycrystalline grain structures with cohesive boundaries for large-scale crystal plasticity finite element (CPFE) analyses. This framework consists of a grain structure generation model and cohesive zone (CZ) representation and junction partitioning scheme. The controlled Poisson Voronoi Tessellation (CPVT) model is employed to generate virtual grain structures that are statistically equivalent to metallographic measurements in terms of grain size distribution. In the CPVT model, physical parameters including the mean grain size, a small grain size, a large grain size and the percentage of grains within this range are used to determine the grain size distribution. To study inter-granular crack initiation and evolution using the cohesive zone model, a novel grain boundary representation scheme is proposed for producing cohesive interfaces for Voronoi Tessellations and automatically partitioning multiple junctions. The proposed virtual grain structure generation model and cohesive boundary generation method is demonstrated in a crystal plasticity simulation of polycrystal tension. The features of inter-granular crack initiation and propagation are presented and the mechanical response is discussed.
-
An integrated scheme for crystal plasticity analysis: Virtual grain structure generation
Computational Materials Science, 2011Co-Authors: P. Zhang, D.s. Balint, Jianguo LinAbstract:Abstract An integrated scheme is developed based on the controlled Poisson Voronoi Tessellation (CPVT) model to generate the polycrystalline grain structure for micromechanics simulations. The proposed model of CPVT involves a single control parameter that is used to produce the grain structure with regularity control, by which the yielded Tessellation varies from the purely random Voronoi Tessellation to the regular hexagonal Tessellation. The system extends the standard CPVT model by the addition of two features: a one-parameter gamma distribution and a mapping from a set of quantitative metallographic measurements to the distribution parameter. Based on this scheme, a grain structure can be constructed such that the virtual Tessellation is statistically equivalent to the expected grain size distribution. To validate the modules that utilise the physical parameters that dictate the regularity, a series of theoretical investigations is performed. Efforts are devoted to proving the uniqueness of the mapping from the physical parameters to the distribution parameter and the regularity parameter. An efficient numerical algorithm is provided to facilitate the mapping solution process. A software system (VGRAIN) is developed implementing the proposed CPVT model to generate the grain structure for crystal plasticity finite element (CPFE) analysis. To demonstrate the proposed scheme and the VGRAIN system, a plane strain CPFE analysis is conducted. Two microstructures are generated with different regularities, and the deformation under uniaxial tension is simulated.
D C J Farrugia - One of the best experts on this subject based on the ideXlab platform.
-
a controlled poisson voronoi Tessellation for grain and cohesive boundary generation applied to crystal plasticity analysis
Computational Materials Science, 2012Co-Authors: P. Zhang, D.s. Balint, Jianguo Lin, Morad Karimpour, D C J FarrugiaAbstract:Abstract A novel computational framework is presented for the representation of virtual polycrystalline grain structures with cohesive boundaries for large-scale crystal plasticity finite element (CPFE) analyses. This framework consists of a grain structure generation model and cohesive zone (CZ) representation and junction partitioning scheme. The controlled Poisson Voronoi Tessellation (CPVT) model is employed to generate virtual grain structures that are statistically equivalent to metallographic measurements in terms of grain size distribution. In the CPVT model, physical parameters including the mean grain size, a small grain size, a large grain size and the percentage of grains within this range are used to determine the grain size distribution. To study inter-granular crack initiation and evolution using the cohesive zone model, a novel grain boundary representation scheme is proposed for producing cohesive interfaces for Voronoi Tessellations and automatically partitioning multiple junctions. The proposed virtual grain structure generation model and cohesive boundary generation method is demonstrated in a crystal plasticity simulation of polycrystal tension. The features of inter-granular crack initiation and propagation are presented and the mechanical response is discussed.
Taiji Sakamoto - One of the best experts on this subject based on the ideXlab platform.
-
location of Tessellations in ocular fundus and their associations with optic disc tilt optic disc area and axial length in young healthy eyes
PLOS ONE, 2016Co-Authors: Hiroto Terasaki, Takehiro Yamashita, Naoya Yoshihara, Yuya Kii, Minoru Tanaka, Kumiko Nakao, Taiji SakamotoAbstract:Tessellated fundus is found as common and early-phase characteristic of myopic eyes and their locations are varied among patients. However, the relationship between their locations and morphological parameters of the eyes is still unknown. The purpose is this study is to determine the locations of the Tessellations in the ocular fundus of young healthy eyes, and to determine relationships between their locations and morphological parameters of the eyes. This is a prospective observational cross sectional study of 126 eyes of 126 healthy volunteers (mean age 26.0±4.1 years). The eyes were classified into eight groups based on the location of the Tessellations; no Tessellation, temporal, infra-temporal, inferior, nasal, peripapillary, whole retina, and unclassified Tessellations. The degree of optic disc tilt was quantified using a sine curve fitting program on the optical coherence tomographic circle scan images. The correlations between each Tessellation location and the axial length, area of the optic disc plus conus (AOC), and optic disc tilt were determined. Forty-four eyes were place in the no Tessellation group, 12 eyes in the temporal, 21 eyes in the infra-temporal, 9 eyes in the inferior, 8 eyes in the nasal, 15 eyes in the peripapillary, 11 eyes in the whole, and 6 eyes in the unclassified groups. The differences in the axial lengths between the no Tessellation group and the infra-temporal groups were significant. A significant difference was found in the AOC between the no Tessellation and the inferior, infra-temporal, and peripapilalry groups. A significant difference was found in the optic disc tilt between the no Tessellation and infra-temporal groups (P<0.05). The Tessellations are located at specific sites in the fundus of young healthy eyes with the infra-temporal location most frequent. It was correlated with some parameters associated with myopia.
