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DETERMINATION　OF　THRESHOLD　PRESSURE　FOR　INFILTRATION　OF　LIQUID　ALUMINIUM　INTO　SHORT　ALUMINA　FIBER　PREFORM

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中国有色金属学会会刊：英文版 1996年第4期6卷 133-137页

作者： Hu Lianxi Luo Shoujing Huo Wencan(School of Materials Science and Engineering,harbin institute of technology,harbin 150001) School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

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关键词： liquid infiltration effective capillary tube radius threshold infiltration pressure metal matrix composite

The nonlocal solution of two parallel cracks in functionally graded materials subjected to harmonic anti-plane shear waves

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Acta Mechanica Sinica 2007年第4期23卷 427-435页

作者： Jun Liang Shiping Wu Shanyi Du Center for Composite Materials and Structure,harbin institute of technology,harbin 150001,China Center for Composite Materials and Structure Harbin Institute of Technology

In this paper, the dynamic interaction of two parallel cracks in functionally graded materials （FGMs） is investigated by means of the non-local theory. To make the analysis tractable, the shear modulus and the material density are assumed to vary exponentially with the coordinate vertical to the crack. To reduce mathematical difficulties, a one-dimensional non-local kernel is used instead of a twodimensional one for the dynamic problem to obtain stress fields near the crack tips. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations, in which the unknown variables are the jumps of displacements across the crack surfaces. To solve the dual integral equations, the jumps of displacements across the crack surfaces are expanded in a series of Jacobi polynomials. Unlike the classical elasticity solutions, it is found that no stress singularity is present at the crack tips. The non-local elastic solutions yield a finite hoop stress at the crack tips. The present result provides theoretical references helpful for evaluating relevant strength and preventing material failure of FGMs with initial cracks. The magnitude of the finite stress field depends on relevant parameters, such as the crack length, the distance between two parallel cracks, the parameter describing the FGMs, the frequency of the incident waves and the lattice parameter of materials.

关键词： Crack The non-local theory Stress waves Functionally graded materials

Research on the influence of machining introduced sub-surface defects and residue stress upon the mechanical properties of single crystal copper

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Science China(Technological Sciences) 2010年第12期53卷 3161-3167页

作者： CHEN MingJun, XIAO GaoBo, CHEN JiaXuan & WU ChunYa harbin institute of technology, harbin 150001, China harbin institute of technology

Large scale molecular dynamics simulations of nanomachining and stretching of single crystal copper are performed to analyze the machining process’ influence on the material’s mechanical properties. The simulation results show that the machining process will introduce interfacial defects inside the specimen and enhance the compressive stress beneath the surface. Gener- ally speaking, interfacial defects lead to the decrease of the strength limit, while residue compressive stress can enhance the elastic limit and even the strength limit. Various machining parameters are adopted to investigate their influence on the me- chanical behavior of machined specimen. Lower cutting speed and smaller cutting depth lead to less defects and greater residue compressive stress, which brings about better mechanical properties. The elastic limit increases by 36.8% under the cutting depth of 0.73 nm and decreases by 21.1% under the cutting depth of 1.46 nm. The strength limit increases by 7.7% under the cutting speed of 100 m/s and decreases by 28.2% under the cutting speed of 300 m/s.

关键词： nanomachining deformation residue stress molecular dynamics dislocations

Deformation Processed Cu-15 wt pct Cr Composite Synthesized by Hot Hydrostatic Extrusion of Mechanical Milled Powders

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Journal of Materials Science & technology 2003年第5期19卷 507-508页

作者： Jinglei LIU, Zuyan LIU and Erde WANGSchool of Materials Science and Engineering, harbin institute of technology, harbin 150001, China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

A novel technique was developed for the preparation of Cu-15 wt pct Cr composite with high strength and conductivity. The composite powders with refined microstructure and curly lamellae strengthening phase was first prepared by mechanical milling in favorite milling time and then were hot hydrostatic extruded after pre-densification with sintering or hot pressing. It was shown that the extrusion densified the composite powders well and at the same time the chaos curled strengthening phase was aligned into lines and further deformed as strengthening ribbons. The deformation processed Cu-15 wt pct Cr composite prepared by this technique is of superior conductivity, strength and thermal stability.

关键词： Mechanical milling Hydrostatic extrusion Deformation processed composite Copper-base composite

Numerical Simulation and Assessment of Self-induced Tensile Stresses in Steel Ring Restrained Concrete

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Journal of Wuhan University of technology(Materials Science) 2010年第3期25卷 530-533页

作者：马新伟 Department of Civil Engineering Harbin Institute of Technology

For a better understanding of the strains and stresses,numerical simulation was conducted by using ANSYS under the assumption of absolute bond between the steel and *** results show that the stresses and strains in such concrete and steel rings are uneven;the curves of strains and stresses change gradually around the *** ease numerical computation,the mechanical system was simplified under the assumptions of synchronous deformation and uniform strains and *** results of the numerical simulation and simplified stress calculation can match almost *** means that the simplified mechanical model can be used in stress and visco-elastic behavior quantification.

关键词： restrained shrinkage numerical simulation model simplification

EFFECT　OF　MILLING　INTENSITY　ON　STRUCTURAL　CHANGES　OF　MIXED　Al－Fe－Ni　POWDERS　IN　MECHANICAL　ALLOYING　PROCESS

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中国有色金属学会会刊：英文版 1996年第3期6卷 143-145,149页

作者： Liu Zuyan Liang Guoxian Wang Erde(School of Materials Science and Engineering,harbin institute of technology, harbin 150001) School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

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关键词： Al-Fe-Ni powder structural change milling intensity mechanical alloying

Experimental study on a transpiration cooling thermal protection system

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Science China(Technological Sciences) 2010年第10期53卷 2765-2771页

作者： LIU Shuang & ZHANG BoMing Center for Composite Materials and Structure, harbin institute of technology, harbin 150080, China Center for Composite Materials and Structure Harbin Institute of Technology

Transpiration cooling thermal protection systems (TPS) are investigated for potential applications in hypersonic and re-entry vehicles,which are subjected to the severe aerodynamic heating environment. In this paper a transpiration cooling thermal protection system was designed and manufactured,and an experiment platform with radiant heating at the bottom as heat source was developed. The cooling capacity of the transpiration cooling TPS was experimentally investigated. By combining transpiration cooling method with traditional TPS,the heat load capability of the TPS can be improved. The structure temperature with active cooling applied was much lower than that without active cooling applied under the same heat load as well as the heat load increased with active cooling than the one without active cooling for the same structure temperature. The experimental results showed that at 5800 s,the temperature of inner structure was 100°C with active cooling applied compared to 500°C without active cooling applied,then the temperature increased and reached to 360°C at 8300 s. Heat load of this transpiration cooling TPS can be increased by over 70% as compared to the passion one and the cooling capability of the transpiration TPS was about 1700 kJ/kg. The results can provide fundamental data for developing the transpiration cooling TPS.

关键词： thermal protection metallic thermal protection system active cooling transpiration cooling cooling capacity

EUTECTIC GROWTH OF CAST IRON UNDER RAPID SOLIDIFICATION

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Acta Metallurgica Sinica(English Letters) 1992年第3期5卷 199-202页

作者： GUO Jingjie JIA Jun LI Qingchun LI Bangsheng harbin institute of technology,harbin,China harbin Inst of technology Harbin China

The eutectic growth of cast iron during rapid solidification has been studied with laser remelt- ing and deep etching technology.A new mode of mushroom eutectic growth was observed oth- er than the usual honeycomb and... 详细信息

关键词： cast iron eutectic growth rapid solidification

Singular analysis of two-dimensional bifurcation system

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Science China(Technological Sciences) 2010年第3期53卷 608-611页

作者： CHEN YuShu& QIN ZhaoHong School of Astronautics,harbin institute of technology,harbin 150001,China School of Astronautics Harbin Institute of Technology

Bifurcation properties of two-dimensional bifurcation system are studied in this *** unfolding and transition sets of the bifurcation equations are *** whole parametric plane is divided into several different persistent regions according to the type of motion,and the different qualitative bifurcation diagrams in different persistent regions are *** bifurcation properties of the two-dimensional bifurcation system are compared with its reduced one-dimensional *** is found that the system which is reduced to one dimension has lost many bifurcation properties.

关键词： two-dimensional bifurcation system bifurcation singular analysis