Physica B-Condensed Matter
Rayleigh identity based on a multipole expansion theory is extended to analyze the forces between particles in electrorheological system. The shear modulus for chains of particles arrayed on a square lattice is calculated. It is found that the modulus increases linearly with the ratio of dielectric constants of dispersed particles to the continuous phase, as the ratio becomes large, contrary to expectations from a simple dipole approximation where it would saturate. In the case of conducting particle, the modulus varies with the frequency of applied held. A limiting case of infinitely conducting particles conductivity is considered. It is found that the particle-particle forces are extremely sensitive to their separation. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
electrorheological fluids;permittivity;conductivity;shear stress;shear modulus
Composites Science and Technology
By incorporating the dislocation punched zone model, the Taylor-based nonlocal theory of plasticity, and the cohesive zone model into the axisymmetric unit cell model, an enhanced FEM model is proposed in this paper to investigate the particle size dependent flow strengthening and interface damage in the particle reinforced metal matrix composites. The dislocation punched zone around a particle in the composite matrix is defined to consider the effect of geometrically necessary dislocations developed through a mismatch in the coefficients of the thermal expansion. The Taylor-based nonlocal theory of plasticity is applied to account for the effect of plastic strain gradient which produces geometrically necessary dislocations due to the geometrical mismatch between the matrix and the particle. The cohesive zone model is used to consider the effect of interfacial debonding. Lloyd's experimental data are used to verify this enhanced FEM model. In order to demonstrate flow strengthening mechanisms of the present model, we present the computational results of other different models and evaluate the strengthening effects of those models by comparison. Finally, the limitations of present model are pointed out for further development. (C) 2010 Elsevier Ltd. All rights reserved.
关键词:
Particle-reinforced composites;Debonding;Strength;Modeling;strain-gradient plasticity;conventional theory;behavior;deformation;aluminum;mechanisms
Chinese Physics
The Rayleigh identity, based on a multipole expansion theory, is extended to analyse the forces between particles in an electrorheological system. The shear modulus for chains of particles arrayed on a square lattice is calculated. It is found that the modulus increases linearly with the ratio of dielectric constants of the dispersed particles to that of the continuous phase; as the ratio becomes larger, contrary to the expectations from a simple dipole approximation, the modulus would saturate. In the case of conducting particles, the modulus varies with the frequency of the applied field. In a limiting case of perfectly conducting particles, the conductivity is also considered. It is found that the particle-particle forces are extremely sensitive to their separations from each other.
关键词:
electrorheological fluids;permittivity;conductivity;shear stress
Xiaohong YAN
,
Jianwen DING
,
Qibin YANG
,
Bruno Iochum
材料科学技术（英）
We present a new series of two-dimensional decagonal tilings which are connected with each in five transformation rules. In this case, a real-space renormalization group scheme is developed to study physical properties of the decagonal systems in terms of Green's function theory.
关键词:
Powder Diffraction
Ternary Al-Cu-W alloys were investigated. The previously reported Al(3)Ti-type phase (space group 14/mmm) with the average composition Al(67)Cu(11.5)W(21.5) was found to have a=3.7296(4) angstrom and c=8.3797(10) angstrom. The ternary phase forming around Al(67)Cu(21)W(12) has a hexagonal structure with a=8.6594(13) angstrom and c=15.2677(21) angstrom. (C) 2011 International Centre for Diffraction Data. [DOI: 10.1154/1.3549770]
关键词:
Al-Cu-W;powder X-ray diffraction;system
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金属学报(英文版)
Silver nanoparticles with average particles sizes ranging from 2 to 131nm were manipulatively synthesized starting from silver nitrate using different functional group-containing organic modifiers at room temperature. The effects of the organic modifiers on the morphology of the resulting silver nanoparticles were strongly dependent on the intrinsic properties of the functional groups and the reducibility of the reductant. Numerous ether bonds (-O-) present in polyethylene glycol and Tween-80 were beneficial to the formation of silver nanoparticles with particle sizes of several nanometers in a narrow size distribution in both weak and strong reducing environments. Cetyltrimethylammonium bromide induced the formation of nanosized silver triangle plates in a weak reducing environment. The crystal growth of the silver nanoparticles with particle sizes of more than 10nm was postulated through an adhesion process of small-sized particles followed by a subsequent coalescence process under the present reaction conditions.
关键词:
silver nanoparticle
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R Escribano
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R Lostado
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F J Martínez-de-Pisón
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A Pernía
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E Vergara
钢铁研究学报(英文版)
An experience is presented using the finite element method (FEM) and data mining (DM) techniques to develop models that can be used to optimize the skin-pass rolling process based on its operating conditions. A FE model based on a real skin-pass process is built and validated. Based on this model, a group of FE models is simulated with different adjustment parameters and with different materials for the sheet; both variables are chosen from pre-set ranges. From all FE model simulations, a database is generated; this database is made up of the above mentioned adjustment parameters, sheet properties and the variables of the process arising from the simulation of the model. Various types of data mining algorithms are used to develop predictive models for each of the variables of the process. The best predictive models can be used to predict experimentally hard-to-measure variables (internal stresses, internal strains, etc) which are useful in the optimal design of the process or to be applied in real time control systems of a skin-pass process in-plant.
关键词:
skin-pass rolling
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predictive model
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finite element method
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data mining
