Crystal-Plasticity Simulation of the Evolution of the Matt Surface in Pack Rolling of Aluminium Foil

2014 ◽  
Vol 794-796 ◽  
pp. 553-558 ◽  
Author(s):  
Olaf Engler ◽  
Galyna Laptyeva ◽  
Holger Aretz ◽  
Gernot Nitzsche
Keyword(s):  
Crystal Plasticity ◽  
Large Scale ◽  
Rolling Texture ◽  
Spatial Arrangement ◽  
Alloy Sheet ◽  
Aluminium Foil ◽  
Strain Anisotropy ◽  
Recent Project ◽  
Final Rolling ◽  
Different Characteristics

Aluminium foil is rolled double-layered during the final rolling pass. When the sheets are later separated, the inside surface is dull and the outside surface is shiny. The matt inner side is characterized by significant surface corrugations which are believed to be a precursor for the initiation of fracture upon a subsequent forming operation. Therefore, understanding of the development of the matt side of Al foil will help to control and, eventually, improve the properties of Al foil. It was the goal of the present study to correlate the development of the matt side with the spatial arrangement of the crystallographic orientations of the foil rolling texture. This approach builds on a recent project to correlate the phenomenon of roping in AA 6xxx alloy sheet for car body applications to the occurrence of band-like clusters of grains with similar crystallographic orientation. Large-scale orientation maps obtained by electron back-scattered diffraction (EBSD) were input into a visco-plastic self-consistent crystal-plasticity model to analyse the strain anisotropy caused by the spatial distribution of the various rolling texture components. The new model is applied to several Al foils with different characteristics of the matt side.

Large-scale mapping of the catenas vegetation in Subarctic tundra

1995 ◽  
pp. 3-21
Author(s):  
S. S. Kholod
Keyword(s):  
Spatial Distribution ◽  
Vegetation Cover ◽  
Large Scale ◽  
Block Diagram ◽  
Abiotic Factors ◽  
Ecological Factors ◽  
Spatial Arrangement ◽  
Geological Time ◽  
Ecological Barriers ◽  
Functional Zones

One of the most difficult tasks in large-scale vegetation mapping is the clarification of mechanisms of the internal integration of vegetation cover territorial units. Traditional way of searching such mechanisms is the study of ecological factors controlling the space heterogeneity of vegetation cover. In essence, this is autecological analysis of vegetation. We propose another way of searching the mechanisms of territorial integration of vegetation. It is connected with intracoenotic interrelation, in particular, with the changing role of edificator synusium in a community along the altitudinal gradient. This way of searching is illustrated in the model-plot in subarctic tundra of Central Chukotka. Our further suggestion concerns the way of depicting these mechanisms on large-scale vegetation map. As a model object we chose the catena, that is the landscape formation including all geomorphjc positions of a slope, joint by the process of moving the material down the slope. The process of peneplanation of a mountain system for a long geological time favours to the levelling the lower (accumulative) parts of slopes. The colonization of these parts of the slope by the vegetation variants, corresponding to the lowest part of catena is the result of peneplanation. Vegetation of this part of catena makes a certain biogeocoenotic work which is the levelling of the small infralandscape limits and of the boundaries in vegetation cover. This process we name as the continualization on catena. In this process the variants of vegetation in the lower part of catena are being broken into separate synusiums. This is the process of decumbation of layers described by V. B. Sochava. Up to the slope the edificator power of the shrub synusiums sharply decreases. Moss and herb synusium have "to seek" the habitats similar to those under the shrub canopy. The competition between the synusium arises resulting in arrangement of a certain spatial assemblage of vegetation cover elements. In such assemblage the position of each element is determined by both biotic (interrelation with other coenotic elements) and abiotic (presence of appropriate habitats) factors. Taking into account the biogeocoenotic character of the process of continualization on catena we name such spatial assemblage an exolutionary-biogeocoenotic series. The space within each evolutionary-biogeocoenotic series is divided by ecological barriers into some functional zones. In each of the such zones the struggle between synusiums has its individual expression and direction. In the start zone of catena (extensive pediment) the interrelations of synusiums and layers control the mutual spatial arrangement of these elements at the largest extent. Here, as a rule, there predominate edificator synusiums of low and dwarfshrubs. In the first order limit zone (the bend of pediment to the above part of the slope) one-species herb and moss synusiums, oftenly substituting each other in similar habitats, get prevalence. In the zone of active colonization of slope (denudation slope) the coenotic factor has the least role in the spatial distribution of the vegetation cover elements. In particular, phytocoenotic interactions take place only within separate microcoenoses of herbs, mosses and lichens. In the zone of the attenuation of continualization process (the upper most parts of slope, crests) phytocoenotic interactions are almost absent and the spatial distribution of vegetation cover elements depends exclusively on the abiotic factors. The principal scheme of the distribution of vegetation cover elements and the disposition of functional zones on catena are shown on block-diagram (fig. 1).

scholarly journals Design and Validation of an Adjustable Large-Scale Solar Simulator

2021 ◽  
Vol 11 (4) ◽  
pp. 1964
Author(s):  
Daniele Colarossi ◽  
Eleonora Tagliolini ◽  
Paolo Principi ◽  
Roberto Fioretti
Keyword(s):  
Large Scale ◽  
Design Procedure ◽  
Spatial Arrangement ◽  
Luminous Flux ◽  
International Electrotechnical Commission ◽  
Solar Simulator ◽  
Class A ◽  
Pv Panel ◽  
Temporal Instability ◽  
Class B

This work presents an adjustable large-scale solar simulator based on metal halide lamps. The design procedure is described with regards to the construction and spatial arrangement of the lamps and the designed optical system. Rotation and translation of the lamp array allow setting the direction and the intensity of the luminous flux on the horizontal plane. To validate the built model, irradiance nonuniformity and temporal instability tests were carried out assigning Class A, B, or C for each test, according to the International Electrotechnical Commission (IEC) standards requirements. The simulator meets the Class C standards on a 200 × 90 cm test plane, Class B on 170 × 80 cm, and Class A on 80 × 40 cm. The temporal instability returns Class A results for all the measured points. Lastly, a PV panel is characterized by tracing the I–V curve under simulated radiation, under outdoor natural sunlight, and with a numerical method. The results show a good approximation.

A Study on Tensile Deformation Features of Ni-Based Super-Alloy Prepared by EB-PVD

2011 ◽  
Vol 55-57 ◽  
pp. 251-256
Author(s):  
Li Ma ◽  
Ting Zhang ◽  
Xiao Li ◽  
Zhao Hui Hu
Keyword(s):  
Physical Vapor Deposition ◽  
Large Scale ◽  
Tensile Deformation ◽  
Alloy Sheet ◽  
Dislocation Climb ◽  
Dislocation Glide ◽  
Double Phase ◽  
Transmission Electron ◽  
Deformation Features ◽  
Super Alloy

Large-scale Ni-based super-alloy sheet has been prepared by electron beam physical vapor deposition (EB-PVD). Microstructure and the dislocation structures in the γ-γ′ double phase alloy under different temperature after tensile strain are studied with Transmission electron microscopy (TEM). The results show that the dislocation glide in single slip system and shearing mechanics, the dislocation climb with part shearing, absolute dislocation climb and cross slip, dislocation round are a course of the interacting degree between dislocation and γ′ phase gradually weakened under the tensile temperature from room temperature to high temperature, so as to decrease materials strength and increase plasticity.

scholarly journals Control method for the stable operation of distributed inverters following the introduction of large-scale renewable energy to a remote island grid

Clean Energy ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 196-207
Author(s):  
Shoichi Sato ◽  
Yasuhiro Noro
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
Control Method ◽  
Synchronous Generator ◽  
Stable Operation ◽  
Battery Energy Storage Systems ◽  
Simulation Results ◽  
Battery Energy ◽  
Systems Simulation ◽  
Different Characteristics

Abstract The introduction of large-scale renewable energy requires a control system that can operate multiple distributed inverters in a stable way. This study proposes an inverter control method that uses information corresponding to the inertia of the synchronous generator to coordinate the operation of battery energy storage systems. Simulation results for a system with multiple inverters applying the control method are presented. Various faults such as line-to-line short circuits and three-phase line-to-ground faults were simulated. Two fault points with different characteristics were compared. The voltage, frequency and active power quickly returned to their steady-state values after the fault was eliminated. From the obtained simulation results, it was verified that our control method can be operated stably against various faults.

Improvement of Mechanical Properties and Corrosion Resistance by Deformation Induced Precipitation in Al-Zn-Mg-Cu Alloy

2017 ◽  
Vol 898 ◽  
pp. 179-190 ◽  
Author(s):  
Jin Rong Zuo ◽  
Long Gang Hou ◽  
Jin Tao Shi ◽  
Hua Cui ◽  
Lin Zhong Zhuang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Thermomechanical Treatment ◽  
High Strength ◽  
Alloy Sheet ◽  
Rolling Temperature ◽  
Al Alloy ◽  
Deformation Degree ◽  
Dynamic Aging ◽  
Final Rolling Temperature ◽  
Final Rolling

A final thermomechanical treatment (FTMT) including peak aging and subsequent dynamic aging was proposed to prepare 7055 Al alloy sheets. The optimization was based on nine well-planned orthogonal experiments. Three main processing conditions in the thermomechanical treatment for obtaining the optimum synthetic properties of 7055 (i.e. preheating temperature, final rolling temperature and deformation degree) were investigated. It was shown that the final rolling temperature is the most important factor among the three parameters, and the optimum properties (yield strength: 651 MPa, ultimate tensile strength: 660 MPa) of 7055 Al alloy sheet can be gained with preheating at 140oC and 40% deformation at 170oC. With dynamic aging, grain boundary precipitates became discontinuous without much coarsening of matrix precipitates, while they were continuously distributed after T6 aging. The present optimal FTMT process can improve the intergranular / exfoliation corrosion resistance without sacrificing the strength compared to T6 tempering. The present FTMT process as a good alternative can produce high-strength Al alloy sheets with high strength and good corrosion resistance efficiently and economically.

scholarly journals The spatial allocation of population: a review of large-scale gridded population data products and their fitness for use

2019 ◽  
Vol 11 (3) ◽  
pp. 1385-1409 ◽  
Author(s):  
Stefan Leyk ◽  
Andrea E. Gaughan ◽  
Susana B. Adamo ◽  
Alex de Sherbinin ◽  
Deborah Balk ◽  
...  
Keyword(s):  
Large Scale ◽  
Population Data ◽  
Disaster Risk ◽  
Spatial Allocation ◽  
Quality Aspects ◽  
Data Products ◽  
Methodological Approaches ◽  
Different Characteristics ◽  
Population Counts ◽  
Relative Quality

Abstract. Population data represent an essential component in studies focusing on human–nature interrelationships, disaster risk assessment and environmental health. Several recent efforts have produced global- and continental-extent gridded population data which are becoming increasingly popular among various research communities. However, these data products, which are of very different characteristics and based on different modeling assumptions, have never been systematically reviewed and compared, which may impede their appropriate use. This article fills this gap and presents, compares and discusses a set of large-scale (global and continental) gridded datasets representing population counts or densities. It focuses on data properties, methodological approaches and relative quality aspects that are important to fully understand the characteristics of the data with regard to the intended uses. Written by the data producers and members of the user community, through the lens of the “fitness for use” concept, the aim of this paper is to provide potential data users with the knowledge base needed to make informed decisions about the appropriateness of the data products available in relation to the target application and for critical analysis.

scholarly journals Natural Leaders: Some interlocutors elicit greater convergence across conversations and across characteristics

2020 ◽  
Author(s):  
Uriel Cohen Priva ◽  
Chelsea Sanker
Keyword(s):  
Individual Differences ◽  
Large Scale ◽  
Social Aspects ◽  
Large Collection ◽  
Human Communication ◽  
Large Scale Study ◽  
Different Characteristics

Are there natural followers in human communication, speakers who consistently converge more than others? Similarly, are there natural leaders, speakers with whom others converge more? Are such tendencies consistent across different linguistic characteristics? We use the Switchboard Corpus, a large collection of telephone conversations, to perform a large-scale study of convergence of speakers in multiple conversations with different interlocutors, across six linguistic characteristics. Having data from each speaker in several conversations makes it possible to investigate whether there are individual differences in likelihood to converge, among speakers (more or less likely to converge), and among interlocutors (more or less likely to elicit convergence). We only find evidence for individual differences by interlocutor, not by speaker; this shows that there are natural leaders, who elicit greater degrees of convergence than others, across different characteristics and different conversations. The absence of a similar finding for natural followers, speakers who converge more than others, suggests that the role of social aspects in mediating convergence is stronger than that of putative individual differences in propensity to converge, or that such propensities are characteristic-specific.

Experiments on mixing due to chaotic advection in a cavity

1989 ◽  
Vol 209 ◽  
pp. 463-499 ◽  
Author(s):  
C. W. Leong ◽  
J. M. Ottino
Keyword(s):  
Large Scale ◽  
Spatial Arrangement ◽  
Periodic Points ◽  
Chaotic Advection ◽  
Two Dimensional ◽  
Complex Behaviour ◽  
Chaotic Flows ◽  
Regular Time ◽  
Slow Flows ◽  
Time Periodic

Chaotic mixing of fluids in slow flows is ubiquitous but incompletely understood. However, relatively simple experiments provide a wealth of information regarding mixing mechanisms and indicate the need for complementary theoretical developments in dynamical systems. In this work we presnt a versatile cavity flow apparatus, capable of producing a variety of two-dimensional velocity fields, and use it to conduct a detailed experimental study of mixing in low-Reynolds-number flows. Since the goal is detailed understanding, only two time-periodic co-rotating flows induced by wall motions are considered: one continuous and the other discontinuous. Both types of flows produce exponential growth of intermaterial area, as expected from chaotic flows, and a mixture of islands and chaotic regions. A procedure for identifying periodic points and determining their movements is presented as well as how to make meaningful comparisons between periodic flows. We observe that periodic points move very much as a planetary system; planets (hyperbolic points) have moons (elliptic points) with twice the period of the planets; furthermore the spatial arrangement of periodic points becomes symmetric at regular time intervals. Detailed analyses reveal complex behaviour: birth, bifurcation, and collapse of islands; formation and periodic motion of coherent structures, such as islands and large-scale folds. However, the richness and complexity of the results obtained indicate that these two-dimensional time-periodic systems are far from completely understood and that other wall motions might deserve a similar level of scrutiny.

A Texture Evolution Study Using the Texture Component Crystal Plasticity FEM

2005 ◽  
Vol 495-497 ◽  
pp. 937-944 ◽  
Author(s):  
Franz Roters ◽  
Heyon S. Jeon-Haurand ◽  
Dierk Raabe
Keyword(s):  
Boundary Conditions ◽  
Crystal Plasticity ◽  
Texture Component ◽  
Hot Rolling ◽  
Texture Evolution ◽  
Texture Mapping ◽  
Rolling Texture ◽  
Fem Simulations ◽  
Evolution Study ◽  
Crystal Plasticity Fem

Crystal plasticity FEM simulations of plane strain compression were performed. The Texture Component Crystal Plasticity-FEM was used for the texture mapping. Two different starting textures (random and hot rolling texture) were studied using four different FE meshes and two different sets of boundary conditions. While for the random starting texture the evolution of the texture with deformation was found to be rather similar in all cases studied, the simulations using an experimental hot rolling texture as staring texture are much more sensitive to the boundary conditions and probably also to changes in the mesh geometry.

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