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A TWO-ORDER AND TWO-SCALE COMPUTATION MODEL FOR THE DAMAGE OF COMPOSITE MATERIALS

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A TWO-ORDER AND TWO-SCALE COMPUTATION MODEL FOR THE DAMAGE O...

A two-scale method for identifying mechanical parameters of composite materials with periodic configuration

庆祝中国力学学会成立50周年暨中国力学学会学术大会’2007

作者： SU Fang cui j.z. (Academy of Mathematics and System Science,Chinese Academy of Sciences,Beijing 100080,China)

The damage of composite materials occurs through different mechanisms usually in-volve the interaction between *** the past two decades,a number of models have been developed to simulate the damage and failure process of composite materials,among which the damage mechanics approach is particularly attractive in the sense,which provides a feasible framework for the description of distributed damage in-cluding material stiffness degradation,initiation,growth and coalescence of micro-cracks and voids.

关键词： homogenization quasi-periodic elastic structure composite material

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Acta Mechanica Sinica 2006年第6期22卷 581-594页

作者： j.z. cui X.G. Yu Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 10080 China

In this paper, a two-scale method （TSM） is presented for identifying the mechanics parameters such as stiffness and strength of composite materials with small periodic configuration. Firstly, a formulation is briefly given for two-scale analysis （TSA） of the composite materials. And then a two-scale computation formulation of strains and stresses is developed by displacement solution with orthotropic material coefficients for three kinds of such composites structures, i.e., the tension column with a square cross section, the bending cantilever with a rectangular cross section and the torsion column with a circle cross section. The strength formulas for the three kinds of structures are derived and the TSM procedure is discussed. Finally the numerical results of stiffness and strength are presented and compared with experimental data. It shows that the TSM method in this paper is feasible and valid for predicting both the stiffness and the strength of the composite materials with periodic configuration.

关键词： Two-scale method Stiffness Strength Composite materials Small periodic configuration

MODELING AND EXPERIMENTAL RESEARCH OF FOUR-STRAND LOW-FREQUENCY ELECTROMAGNETIC CASTING ALUMINUM ALLOY

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Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 157-166页

作者： j.C. Li B.F. Wang j.z. cui School of Materials ＆ Metallurgy Inner Mongolia University of Science and Technology Baotou 014010 China The Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China

With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density in the aluminum melt and magnetic field interaction of four coils applied with same currents were investigated. Calculating results showed that magnetic flux density in the aluminum melt was greatly improved and the magnetic field interaction among different coils was decreased when external part of mould is made of soft magnetic material. Based on the finding, a four-strand low-frequency electromagnetic casting 6063 aluminum alloy experiment was carried out in the laboratory . The experiment showed that the surface of the billet was smooth and had no exudations and cold shuts, the as-cast microstructures were fine, uniform, equiaxed, net-globular or globular under low-frequency electromagnetic field. The microstructure becomes finer with increased current value.

关键词： low-frequency electromagnetic casting finite element method aluminum alloy mould

MICROSTRUCTURE AND PROPERTIES OF zL201 ALLOY OBTAINED BY NEAR-LIQUIDUS ELECTROMAGNETIC CASTING

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 653-658页

作者： P. Wang L.F. Shi G.M. Lu j.z. cui The Key Laboratory of Electromagnetic Processing of Material Ministry of Education Northeastern University Shenyang 110004 China

The microstructures of zL201 alloy slurry prepared by near-liquidus electromagnetic casting （NLEMC）, electromagnetic casting（EMC）, and near-liquidus casting（NLC） were investigated by means of electron microscopy and image analysis. Mechanical properties of as-cast alloys were determined. The results show that the NLEMC induces a fine, uniform, and equiaxed grain structure with a mean equal-area-circle grain diameter of 32.8μm. The as-cast aUoy has a hardness of HV122.8 and a tensite strength of 368MPa. Both of them are betterthan those of the alloys prepared by EMC and by NLC. The mechanism of grain refinement in the NLEMC alloy slurry was discussed.

关键词： near-liquidus casting electromagnetic casting rheocasting,microstructure property

EFFECT OF LOW-FREQUENCY ELECTROMAGNETIC FIELD ON THE AS-CASTING MICROSTRUCTURES AND MECHANICAL PROPERTIES OF HDC 2024 ALUMINUM ALLOY

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 205-210页

作者： Q.F. zhu z.H. zhao j.z. cui Y.B. zuo F. Qu Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern Univer- sity Shenyang 110004 China

The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field.

关键词： Horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy Microstructures Macrosegregation

Synergistic promotion strategy of “dual-site” and “dual-path” to enhance the C–C coupling between CO2 and HCHO driven by photoelectrocatalysis

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journal of Energy Chemistry 2025年第1期100卷 39-49页

作者： Hongqiang Yang jianfeng zheng Guoyu Wang Yifei Gao Yatao Yang jia Li Xiaojin Han Yan cui zhanggen Huang National Key Laboratory of High Efficiency and Low Carbon Utilization of Coal Institute of Coal Chemistry Chinese Academy of Science University of Chinese Academy of Science Shenyang University of Chemical Technology

Photoelectrocatalytic coupling CO2and volatile organic compounds （VOCs） is a promising green strategy for the synergistic conversion of the two carbon-containing resources to *** catalytic efficiency is always at the mercy of chemical inertness of CO2and the competitive hydrogen evolution of ***,a modified g-C3N4/znAl-LDH z-scheme heterojunction catalyst with dual reaction site was rationally designed and precisely *** Faraday efficiency of ethanol reached 68.67%with a corresponding formation rate of 227.3μmol *** revealed by in-situ characterizations and density functional theory calculations,CO2and HCHO were absorbed at zn site and N site,***,*CO generated from CO2and HCHO was converted to*CH3O and*CHO on the dual-active-site *** detailed reaction mechanism experiments indicated that C–C coupling only occurred between*CO and*CH3O in electrocatalysis *** from the“*CO+*CH3O”path,another“*CO+*CHO”coupling path was also detected in photoelectrocatalytic *** selectivity of ethanol was significantly enhanced due to the synthesis of dual-site catalyst and the dual-path coupling path between CO2and HCHO simultaneously driven by light and electricity.

关键词： Ethanol

A DUAL COUPLED METHOD FOR BOUNDARY VALUE PROBLEMS OF PDE WITH COEFFICIENTS OF SMALL PERIOD

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journal of Computational Mathematics 1996年第2期14卷 159-174页

作者： j.z. cui H.Y. Yang(Institute of Computational Mathematics and Scientific/Engineering Computing,Chinese Academy of Sciences, Beijing, China) 中科院计算数学与科学工程计算所北京

In this paper the homogenization method is improved to develop one kind of dual coupled approximate method, which reflects both the macro-scope properties of whole structure and its loadings, and micro-scope configuration properties of composite materials. The boundary value problem of woven membrane is considered, the dual asymptotic expression of the exact solution is given, and its approximation and error estimation are discussed. Finally the numerical example shows the effectiveness of this dual coupled method.

关键词： PDE A DUAL COUPLED METHOD FOR BOUNDARY VALUE PROBLEMS OF PDE WITH COEFFICIENTS OF SMALL PERIOD

THE APPLICATION OF ARTIFICIAL NEURAL NETWORKS TO INVESTIGATION ON THE THICKNESS OF INTERMETALLIC LAYER UNDER SOLID-LIQUID PRESSURE BONDING OF STEEL AND ALUMINIUM

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Acta Metallurgica Sinica(English Letters) 1997年第6期10卷 523-526页

作者： P. zhang j.z. cui Y.H. Du and Q.z. zhang(Department of Metal Forming, Northeastern University, Shenyang 110006, China)(Department of Mining, Northeastern University, Shenyang 110006, China) Northeastern Univ Shenyang China

Artificial neural networks (ANN), being a sophisticated type of information processing system by imitating the neural system of human brain, can be used to investigate the effects of concentration of flux solution, temperature of liquid aluminium, temperture of tools and pressure on thickness of the intermetallic layer at the interface between steel and aluminium under solid-liquid pressure bonding of steel and aluminium perfectly. The optimum thickness has been determined according to the value of the optimum shearing strength.

关键词： artificial neural network thickness of the intermetallic layer,solid-liquid pressure bonding

SEMI-SOLID MICROSTRUCTURE AND ITS EVOLUTION OF WROUGHT ALUMINUM ALLOY BY DIRECTLYHEATING-ISOTHERMAL TREATMENT

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 856-861页

作者： X.T.Liu j.z.cui TheKeyLaboratoryofElectromagneticProcessingofMaterials MinistryofEducationNortheasternUniversityShenyang110004China

Microstructure evolution of wrought aluminum alloy extruded rods and the mechanism of liquid phase formation during reheating were investigated. And the relation between the volume fraction of liquid phase and the recrystallization microstructure was proposed. The results show that increase in reheating temperature and time can augment the volume fraction of liquid phase and accelerate the grain spheroidization, as a result of which the requirement of semi-solid forming can be satisfied. Due to the higher aberration energy of grain boundary, the melting point is lowered as a result of the easy diffusion of atoms. At higher reheating temperature the grain boundary melts, the growth of the recrystallized grain is inhibited and the grain is refined. The composition of the low melt-point phase along the recrystallized grains was determined using EDS. It can be seen from the experimental results that when the extrusion rod of the wrought aluminum alloy is reheated at 610℃ for 20min, perfect fine equiaxial grains can be obtained, the average grain size is about 66.34μm and the volume fraction of solid phase is about 68%.

关键词： wrought aluminum alloy hot extrusion reheating mechanism of micro- structual evolution spheroidization volume fraction of solid phase