Добірка наукової літератури з теми "Granularity deformation"

This paper proposes a mesh deformation method being able to quickly exchange between different editing granularities. The method firstly simplifies the original model mesh to obtain an accuracy-specified control mesh while preserving user’s pre-configured control handle vertices, and then computes the original mesh vertices’ mean value coordinates on the control mesh. Next, uses the Laplacian deformation to deform the control mesh with user’s editing, and then computes the deforming result based on the new control mesh and the previous mean value coordinates. Users can quickly generate a different accuracy control mesh of the new mesh again for deforming with a different granularity. Users only need edit some control vertices, which contains user’s specified handles, so the manipulation is convenient. Experiments show that users can deform models with this method, while changing the granularity fluently and preserving mesh’s features.

In this work, the effects of the bimodal particle size distribution of fused silica on the properties of silica-based ceramic cores have been investigated. In order to simulate a casting process condition, the core specimens were sintered at 1220°C, tested at above 1500°C. Three point bending tests were carried out on all the prepared specimens. Phase evolution and microstructure were investigated by XRD and SEM respectively. The results showed that with the bimodal granularity distribution broaden and the content of coarse particles increasing, the contraction, flexural strength and creep deformation of ceramic cores decreased linearly, as the content of mineralizer was determined. Coarse particles served as the skeleton to relieve the contraction in ceramic matrix and avoided sharp decrease of flexural strength. The high temperature properties were largely determined by the combined effects of crystallization and skeleton network. The crystallization depended mostly on the fine particles, and the skeleton network was prerequisite to avoid creep deformation.

Huolinhe(HLH) Lignite was used for this experiment. Among the several factors that influence lignite briquetting, particle size distribution was investigated in detail. Rosin- Rammler- Bennet equation (RRB) was used to describe particle size distribution. Uniformity index n and characteristic feature size De were also calculated. Compaction curves of the lignite shows that the whole compaction process can be divided into the particle re-arrangement stage, the plastic deformation stage and the whole deformation stage. More reasonable uniformity of particle size distribution and characteristic feature size would have higher compact density. The granularity of lignite had a distinct effect on the briquette strength. In order to increase the mechanical stability of briquettes small particle size lignite should be used.

AbstractRoughness is an important property of wood surface and has a significant influence on the interface bonding strength and surface coating quality. However, there are no theoretical models for basswood-veneered medium-density fiberboard (MDF) by fine sanding from existing research work. In this paper, the basswood-veneered MDF was fine sanded with an air drum. Orthogonal experiment was implemented to study the effects of abrasive granularity, feed rate, belt speed, air drum deformation and air drum pressure on the surface roughness of basswood-veneered MDF. The simulation models of the parallel-grain roughness and the vertical-grain roughness of the sanded surface were conducted based on the BP (error back propagation) neural network, which was optimized by a genetic algorithm (GA) (GA-BP neural network), and these models were verified by extensive experimental data. The results showed that the influence of sanding parameters on parallel-grain roughness was similar to that on vertical-grain roughness. The order of influence was that: abrasive granularity > belt speed > feed speed > air drum deformation and air drum pressure. Based on the work, the parallel-grain roughness and vertical-grain roughness of basswood-veneered MDF could be well predicted by the GA-BP neural network. The average relative errors on parallel-grain roughness and vertical-grain roughness were 3.4% and 1.9%, respectively.

The compressive properties characterized as a function of the true stress-strain response of the ferritic oxide dispersion strengthened (ODS) alloys, fabricated by mechanical alloying, were examined at strain rates ranging from 0.01 to 0.5s-1. Based on the differential scanning calorimeter (DSC) analysis, the solidus temperature of the ferritic ODS alloys is 1446oC. Therefore, the compressive temperatures were chosen to be from 1050oC to 1300oC. Transmission electron microscopy (TEM) observation is indicative of the homogeneous distribution of the nano-yttria particles with the granularity of 100~200nm, which may exert a strong pinning effect on subgrains. The results indicate that flow stress of the ferritic ODS alloys enhances with decreasing compressive temperature and increasing strain rate. Investigation of the strain rate sensitivity exponent and apparent activation energy of the ferritic ODS alloys has been carried out in detail.

Equal channel angular pressing (ECAP) is a widespread severe plastic deformation (SPD) method to fabricate ultrafine-grained bulk materials. In the field of materials engineering, this method has already experienced rapid development over the past few decades. In this research, the authors sought to create a prediction of shortening and the material particle size after extrusion using ECAP. Behaviours of essential functions are analysed here on samples of pure copper Cu 99.9. It is the measurement and analytical processing of changes in the values of selected structural and mechanical parameters depending on the reduction of the structural granularity. Parameters such as deformation speed, deformation work and ECAP mechanical performance are also included in the results. The change in structure and mechanical parameters is also newly demonstrated by measuring the change in the velocity of the longitudinal ultrasound wave during the experimental passes. Based on the results obtained, new computational algorithms for Excel and Matlab were developed. The algorithms developed here contain many new findings, conclusions and derivations addressing the integrity of the surface with the inner structure of materials. Algorithms are very well-suited for obtaining results on different materials quickly, for predicting and checking measured values, and for designing optimal measurement technology parameters for the ECAP method.

The ability of metal plastic forming and the mechanism performance of the part are correlated with grain granularity of the metal. Grain growth is a prominent character of the microstructure evolution. It is very helpful for the design of process and die structure to study the mechanism of superpalstic deformation and microstructure evolution of superplastic forming. The microstructure evolution of material is impact directly the mechanic performance of the component in superplastic forming. It is necessary to optimize the complex process and to predict the microstructure evolution. A new simulation method that integration the finite element simulation and the microstructure simulation of superplastic forming is introduced in this paper. Monte Catlo method is an odds simulating technique and can simulate time course of microstructure evolution. Based on the studies of superplastic grain growth mechanism, the superplastic grain growth rate equation are derived in this paper by coupling static state anneal grain growth mechanism and deformation stimulated grain growth mechanism. The grain growth drive force of superplastic deformation includes mostly boundary energy and distortion energy. A new drive force model is derived based on energy model. The microstructure evolution is correlated with the stress and strain of the part, and the integration of superplastic forming FE simulation and microstructure evolution MC simulation is realized. Using the integrating simulation technique can predict not only the forming process but also presenting grain growth image of the part. Experimental studies of the part in forming process and microstructure evolution were performed.

On the basis of field experience, a bloom does not continue after treatment with modified clay (MC), even though the residual harmful algal bloom (HAB) biomass accounts for 20–30% of the initial cells. This interesting phenomenon indicates that, in addition to causing flocculation, MC can inhibit the growth of residual cells. Here, from a cell morphology perspective, Aureococcus anophagefferens was used as a model organism to explore this scientific issue and clarify the mechanism by which MC mitigates harmful algal blooms (HABs). The results showed that, at an ~70% removal efficiency, neutral clay (NC) could not effectively inhibit the growth of residual cells, although it caused various forms of damage to residual cells, such as cell deformation, cell breakage, decreased extracellular polysaccharides (EPS), increased cell membrane permeability, and increased cytoplasmic granularity, due to physical collisions. After modification, some physical and chemical properties of the clay particle surface were changed; for example, the surface electrical properties changed from negative to positive, lamellar spacing increased, hardness decreased, adhesion chains increased, adhesion improved, and the number of absorption sites increased, enhancing the occurrence of chemical and electrochemical effects and physical collisions with residual cells, leading to severe cell deformation and chemical cell breakage. Thus, MC effectively inhibited the growth of residual cells and controlled HABs.

The dynamic replacement method of soil strengthening consists in the constructing columns made of aggregate of various granularity. In order to form them, heavy pounders (weighing from 10 to 20 tonnes) are dropped from the height of 25 m. Considering the specificity of this technique, it is quite important to verify on site the assumptions of the project, such as diameter and length of columns, their compaction or stiffness. For that reason, a number of examinations are performed, including column excavations, various types of probing tests or trial loads. The latter consists in determining the “load-settlement” dependence - usually during initial and secondary loadings phase – and on their basis, indicating the value of deformation modulus. Therefore, a stiff plate is placed on the column head and the loading is realised using actuators leaning on the ballast. The diameter of the loading plate depends on diameter and length of column and on the predicted pressure under the plate. The diameter of the loading plate is often smaller than column's diameter. This paper tries to determine the influence of the diameter of the plate used in test loads on the result of the research presented as “load-settlement” dependence and on the values of deformation modulus determined on their basis. The calculations were performed using FEM on a spatial numerical model calibrated on the basis of column's bearing capacity tests. Two models were applied in calculations: elastic-ideally plastic and isotropic hardening elastoplastic.

Луценко, В.А. Наукові основи вдосконаленнятермомеханічної обробки катанки для сталевого дроту малого діаметру [Текст]: дис. … докт. техн. наук: 05.16.01 : захищена ....: затверджена…. /Луценко Владислав Анатолійович. – Запоріжжя, 2015. – 353 с.
UK: Дисертаційна робота присвячена підвищенню в процесі ТМО пластичних властивостей сталевої катанки. Отримана сталева катанка має структуру: високовуглецева – дисперсний перліт із відсутністю замкнутої цементитної сітки, мінімальний зневуглецьований шар, який рівномірно розподілений по периметру; низьковуглецева – рівномірну структуру фериту з мінімальною кількістю перліту; легована – наявність бейніто-мартенситних ділянок до 10% в змішаній структурі. Результати використані на дротових станах ВАТ «БМЗ» та ПАТ «АрселорМіттал Кривий Ріг». Підвищення пластичності катанки забезпечило виготовлення сталевого дроту малого діаметру без проміжної термічної обробки, що дозволило знизити видатковий коефіцієнт металу в середньому на 10%. EN: The dissertation is devoted of increasing in thermo-mechanical processing the plastic properties of steel wire rod. The obtained steel wire rod has the structure: high carbon – the dispersion of perlite without closed cementite net, the minimum depth of equable decarburized layer; low carbon – uniform structure of ferrite with a minimum of perlite; alloy – the occurrence of bainite-martensite areas up to 10% in the mixed structure. The results were used on the rod mills OJSC “Byelorussian steel works” and РJSC “ArcelorMittalKryvyiRih“. The increasing of plasticity provided the production of steel wire of small diameter without intermediate heat treatment, thus reducing the expenditure coefficient of metal by 10% in average. RU: В диссертационной работе решена актуальная научно-техническая проблема – повышение после высокотемпературной прокатки пластических свойств металла путем развития научных основ о влиянии процессов ТМО на структурообразование и качественные характеристики стальной катанки. Установленные закономерности позволили совершенствовать технологию ТМО катанки и при экономии материальных ресурсов обеспечить производство стальной проволоки малого диаметра для металлокорда (в том числе сверхвысокопрочного), высокопрочной бортовой, канатной, легированной сварочной и низкоуглеродистой. Изучена кинетика превращения аустенита непрерывнолитой стали 90 при непрерывном охлаждении и в изотермических условиях. Установлено, что выделения цементита по границам зерен подавляются и полностью отсутствуют при скоростях более 10°С/с и при изотермическом распаде. Определено, что величина эффекта рекалесценции в стали 90 зависит от времени превращения. Установлено, что при ТМО снижение температуры после горячей деформации с 1050…1100°С до 900…950°С в результате принудительного охлаждения при повышении дробности деформации (на 20%) приводит к увеличению пластических свойств высокоуглеродистой стали. Полученная катанка для стальной проволоки, в отличие от традиционной, имеет повышенные пластические свойства. Основу структуры катанки составляет: высокоуглеродистой – сорбитообразный перлит (более 70%) с отсутствием избыточных структур (замкнутой цементитной сетки), минимальный обезуглероженный слой равномерно распределен по периметру; низкоуглеродистой – равномерная структура феррита с минимальным количеством пластинчатого перлита; легированной – наличие бейнито-мартенситных участков до 10% в смешанной структуре. Повышены требования к микроструктуре и свойствам высокоуглеродистой катанки и проволоки, которые отражены в изменении №11 к ЗТУ 840-03-2006 «Катанка стальная сорбитизированная для металлокорда, бортовой проволоки и проволоки для рукавов высокого давления» и ТУ У 276.3-23365425-638.2008 «Проволока стальная термически обработанная». Результаты использованы на ПАО «АрселорМиттал Кривой Рог» при разработке СТИ 228-112-2008 «Производство катанки из легированных сталей для сварочной проволоки ответственного назначения», изменения №3 к режимам охлаждения проката в потоке проволочного стана 150-1 СПЦ-1. Разработаны и внедрены на ОАО «БМЗ» режимы ТМО стальной катанки, в том числе для сверхвысокопрочной проволоки и металлокордапо ЗТУ 840-03-2006 (Изменения к ТК 840-П13-01-2002 и ТК 840-П3-01-2007 на режимы двухстадийного охлаждения катанки различного марочного сортамента в потоке стана 150). Повышение пластичности после высокотемпературной прокатки обеспечило изготовление стальной проволоки малого диаметра различного назначения без промежуточной термической обработки с сохранением требуемых конечных характеристик. Катанка, изготовленная по новому режиму ТМО, переработанная на проволоку малого диаметра, имеет лучшую технологичность в сравнении с базовой. Так, при производстве высокопрочногометаллокорда обрывность снизилась на 34%, а сверхвысокопрочного – на 23%. Освоение усовершенствованных режимов ТМО позволило снизить расходный коэффициент металла в среднем на 10%. Общий фактический экономический эффект от внедренных новых технологических решений составляет 31,7 миллиона гривен, доля автора – 4,44 миллиона гривен.

L’évolution du champ de localisation des déformations plastiques des métaux ductiles a été suivie par interférométrie de granularité laser (ESPI) au cours d’une sollicitation de traction uniaxiale. Il a été montré que le modèle mathématique utilisé, croisement de deux bandes rectilignes, décrit bien l’évolution du champ de vitesse de déformation depuis la striction diffuse jusqu'à rupture. Les caractéristiques physiques de la localisation, telles que la largeur des bandes, leur orientation et leur vitesse de déformation maximale ont été identifiées quantitativement. Leur évolution a été suivie et analysée sous plusieurs facteurs d’influence, qui sont à la fois microscopiques, tels que la taille de grains et la structure cristalline, et macroscopiques, comme la géométrie de l’éprouvette et la direction de son prélèvement par rapport à la direction de laminage, et la vitesse de traction. Il a été trouvé que les bandes de localisation rétrécissent au cours de la striction et leur orientation évolue également. Ces évolutions, le mode de striction et le moment de transition entre la striction diffuse et localisée sont influencés différemment par ces facteurs
The evolution of the plastic strain localization field of ductile metals was followed by electronic speckle pattern interferometry (ESPI) during a uniaxial tensile test. It was shown that the mathematical model, a system of two crossing straight bands, describes accurately the evolution of the strain rate field from diffuse necking up to rupture. The physical characteristics of the localization, such as the width of the bands, their orientations and maximum strain rates were identified quantitatively. Their evolutions were followed and analyzed from several influencing factors, which are both microscopic, such as grain size and crystal structure, and macroscopic, like the geometry of the specimen and the direction in which the specimen were cut with respect to the rolling direction, and the pulling speed. It has been found that the bands narrow down during the necking process and their orientations were also changing. These evolutions, the necking mode and the transition between the diffuse and localized necking are influenced differently by these factors

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A two dimensional (2D) RNG k-ε sediment model including the effects of secondary currents is developed to simulate sediment transport and bed deformation in rivers with continuous bends. Nonuniform suspended and bedload sediment transports and variation of effective bed material size distribution are included in the model. A semi-coupled scheme for sediment model is proposed, which can be used for simulating both the long- and short-term sediment transport whenever riverbed changes. The model is applied to simulate the flow and sediment transport in the Shapotou reservoir in the upper reach of the Yellow River which is a typical natural river reach with continuous bends. River bed deformations caused by suspended and bedload sediment transport are investigated. Good agreement between the numerically simulated results and the field measurements is obtained, indicating that the model is capable of simulating the sediment transport and predicting the bed deformation of rivers having continuous bends with reasonable accuracy.
the Major Research Plan Project, National Natural Science Foundation of China(Grant No.: 91230111 and 51279071); National Key BasicResearch Development Program of China (973 Program, Grant No.: 2010CB429002);Project of Science and Technology of Colleges in Ningxia, China (Grant No.:NGY2012097)

Convolution learning on graphs draws increasing attention recently due to its potential applications to a large amount of irregular data. Most graph convolution methods leverage the plain summation/average aggregation to avoid the discrepancy of responses from isomorphic graphs. However, such an extreme collapsing way would result in a structural loss and signal entanglement of nodes, which further cause the degradation of the learning ability. In this paper, we propose a simple yet effective Graph Deformer Network (GDN) to fulfill anisotropic convolution filtering on graphs, analogous to the standard convolution operation on images. Local neighborhood subgraphs (acting like receptive fields) with different structures are deformed into a unified virtual space, coordinated by several anchor nodes. In the deformation process, we transfer components of nodes therein into affinitive anchors by learning their correlations, and build a multi-granularity feature space calibrated with anchors. Anisotropic convolutional kernels can be further performed over the anchor-coordinated space to well encode local variations of receptive fields. By parameterizing anchors and stacking coarsening layers, we build a graph deformer network in an end-to-end fashion. Theoretical analysis indicates its connection to previous work and shows the promising property of graph isomorphism testing. Extensive experiments on widely-used datasets validate the effectiveness of GDN in graph and node classifications.