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Deformation Uniformity of Cold-Rolled Q2.5 Steel Rebar by FEM in Bending and Rolling Processes

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Journal of Iron and Steel Research International 2012年第8期19卷 37-42页

作者： SUI Feng-li1, CHEN Qi-wei1, ZHU Guo-hui1, LIU Bao-dong2.(1. Anhui Key Laboratory of Materials and Processing, school of Materials Science and engineering, Anhui {2. of Technology, Maanshan 2.3002. Anhui, china 2. Dongyang Steel Making Co Ltd, shenyang 11002., liaoning, china) [a] Anhui Key Laboratory of Materials and Processing School of Materials Science and Engineering Anhui University of Technology Maanshan 243002 Anhui China [b] Dongyang Steel Making Co Ltd Shenyang 110026 Liaoning China

An analytic model based on ANSYS/LS-DYNA has been developed on the cold rolling process for Q2.5 steel rebar with 12.mm in diameter. The elastic-plastic finite element method (FEM) and the cold deformation resistance model of Q2.5 steel were adopted in this model. Deformation uniformity of the final product has been analyzed using this model. The results indicate that the uniformity of the final product is obtained only as the centerline of the bending rolls is vertical to the centerline of the driven roll and parallel to the centerline of the drive roll in the whole rolling process. Besides, the number of the bending rolls must even realize the continuous bending and reverse bending process. Also, the number of the bending rolls must match the deformation degree of the workpiece in the cold rolling process. The validity of this finite element model was verified by the size and distribution of grains from the billet to the rebar in a practical cold rolling process.

关键词： deformation uniformity Q2.5 steel rebar finite element method cold rolling mechanical descaling

Diffusion and Oxidation Wear of PCBN Tool based on Thermodynamics

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Journal of Wuhan university of Technology(Materials Science) 2010年第2期25卷 265-271页

作者：邵芳 Binzhou Vacational College school of mechanical {2. Shandong University

The rules of diffusion wear and oxidation wear for PCBN cutting tools were analyzed based on thermodynamics theory. Dissolution concentrations in typical normal workpice materials of PCBN tool material at different temperature were then calculated. Diffusion reaction rules in high temperature were developed and analyzed using the Gibbs free energy criterion. The machining tests were conducted using the PCBN tools at different cutting speeds of 50, 95,100 and 180 m/min, feed of 0.1, 0.2.and depth of cut of 0.1, 0.8, 1, and 1.5 mm respectively on a PUMA300LM numerically-controlled lathe. It was found that the theoretical results were uniform with the experimental data, and the results will provide useful references for tool material design and selection.

关键词： thermodynamics PCBN tool diffusion wear oxidation wear

TiC/Fe cermet coating by plasma cladding using asphalt as a carbonaceous precursor

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Progress in Natural Science:Materials International 2008年第4期18卷 447-454页

作者： Junbo Liu school of mechanical and Electronic {2., Weifang university, Weifang 2.1061, china school of mechanical and Electronic {2. Weifang University Weifang 261061 China

A new Ti-Fe-C compound powder for plasma cladding was prepared by heating a mixture powder of ferrotitanium and asphalt pyro-lyzed as a carbonaceous precursor. The carbon by the pyrolysis of the asphalt acts as a reactive constituent as well as a binder in the compound powder. The TiC/Fe cermet coatings were prepared by plasma cladding with the compound powder. Results show that the Ti-Fe-C compound powder has a very tight structure, which can avoid the problem of the reactive constituent particles being sep- arated during cladding. The TiC/Fe cermet coating presents a typical morphology of plasma cladding coatings with two different lam- inated layers:one is the composite layer in which the round fine TiC particles (2.3. The coating shows high hardness and excellent wear resistance. The surface hardness of the coating is 68 ± 5(HR30N). In the same fretting conditions, the wear area of Ni60 coating is about 11 times as much as the TiC/Fe cermet coating.

关键词： Plasma cladding TiC/Fe cermet coating Precursor Microstructure Wear resistance

Tribological Properties of PVA-H Composites Reinforced by Nano-HA Particles

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Journal of Wuhan university of Technology(Materials Science) 2007年第3期22卷 490-493页

作者：吴刚 school of mechanical {2. Shanghai Jiaotong University

The friction and wear behaviors of tribological mechanical components were studied on a four-ball tester under dry conditions, and the wear mechanism was analyzed by observed worn surface using a scanning electron microscope （SEM）. It was found that the friction and wear properties were improved by the addition ofnano HA particles. The composite containing 1 wt% nano HA had the optimum friction coefficient. It is also found that the addition of nano HA increases the wear resistance of oure PVA-H and PVA-H composites.

关键词： articular cartilage composites wear friction coefficient corrosion-abrasion

ANALYSIS OF DRAWING UNDER LUBRICATION OF NON-NEWTONIAN LUBRICATING MATERIALS

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中国有色金属学会会刊：英文版 1995年第4期5卷 173-176页

作者： Lei Zhanbo Wang Zhanxue Gao Youzhi(Department of mechanical engineering,Tsinghua {2.,Beijing 100084)(Department of Metal Processing, northeastern university,shenyang 110006) Tsinghua Univ Beijing China

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关键词： drawing force rheology upper-bound method non-Newtonian material tribology

Dimensional synthesis of a 3-DOF parallel manipulator based on dimensionally homogeneous Jacobian matrix

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Science china(Technological Sciences) 2010年第1期53卷 168-174页

作者： SUN Tao1,SONG YiMin1,LI YongGang2.& LIU LinShan1 1 school of mechanical {2.,Tianjin university,Tianjin 300072.china 2.school of mechanical {2.,Tianjin university of Technology and Education,Tianjin 3002.2.china 1. school of mechanical {2. Tianjin University Tianjin 300072 China2. School of Mechanical Engineering Tianjin University of Technology and Education Tianjin 300222 China

A study of dimensional synthesis of a 3-DOF parallel manipulator with coupling of translation and rotation is carried *** architecture of the manipulator is composed of a moving platform attached to a fixed base through three identical PRS(prismatic-revolute-spherical) serial limbs,whose unique topology leads to the physical unit inconsistency of the conventional Jacobian matrix and the emergence of the parasitic *** this paper introduces a kinetostatic performance index of the manipulator based on the condition of a dimensionally homogeneous Jacobian matrix,later,the workspace of the aforementioned manipulator is searched and the influence of the crucial design variables on the workspace is ***,a dimensional synthesis method of the manipulator is proposed,which may be regarded as a nonlinear programming problem with subject to the parasitic motion and other several engineering constraints.

关键词： PKMs(parallel kinematic machines) dimensional synthesis dimensionally homogeneous Jacobian 3-PRS manipulator workspace

STABILITY ANALYSIS OF DECENTRALIZED ADAPTIVE BACKSTEPPING CONTROL SYSTEMS WITH ACTUATOR FAILURES

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Journal of Systems Science & Complexity 2009年第1期22卷 109-121页

作者： Wei WANG Changyun WEN Guanghong YANG school of Electrical and Electronic engineering Nanyang Technological University Nanyang 639798 Singapore. College of Information Science and engineering Northeastern University Shenyang 110004 China.

In this paper,the authors analyze the stability of a class of interconnected systems withsubsystem unmodeled dynamics and dynamic interactions employing decentralized adaptive controllersdesigned by Wen,Zhou,and Wang (2.08) in the presence of actuator *** will be shown that theglobal stability of the remaining closed-loop system is still ensured and the outputs are also regulatedto zero when some subsystems break down.

关键词： Actuator failure adaptive control backstepping decentralized control stability analysis

Complex conforming Delaunay triangulation

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Science china(Information Sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1, LI JiGang 1, YANG Qin 1, CAI Qiang 2.& CHEN QiMing 3 1 NLSDE, school of Computer Science and engineering, BeiHang {2., Beijing 100083, china 2.school of Computer Sciences, Beijing Technology and Business {2., Beijing 100037, china 3 school of mechanical engineering and automation, BeiHang {2., Beijing 100083, china 1. NLSDE School of Computer Science and Engineering BeiHang University Beijing 100083 China2. School of Computer Sciences Beijing Technology and Business University Beijing 100037 China3. School of Mechanical Engineering and Automation BeiHang University Beijing 100083 China

A novel algorithm of conforming Delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled Delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation Delaunay triangulation conforming curved constraints tetrahedralization weight

Sol-gel-derived Hybrid Conductive Films for Electromagnetic Interference (EMI) Shielding

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Journal of Wuhan university of Technology(Materials Science) 2011年第2期26卷 217-222页

作者：解基源 school of Information and Comunication engineering North University or China

The conductive nano-sized zinc particles were embedded in an insulating amorphous silica matrix,and the hybrid films were obtained by a sol-gel *** stable hybrid sol solution was prepared by hydrolysis and condensation of Methyltrimethoxysilane （MTMS） with a one-step acidic catalyst *** films were dip-coated on silicon wafer and cured at 12.℃ for *** structural characterization of hybrid films were investigated by means of attenuated total reflection infrared （ATR-IR） spectroscopy and X-ray diffraction （XRD）.The electrical properties of the films were examined with four-point *** films showed to be relatively dense,uniform and defect *** conductivity of hybrid films was varied with the different contents of zinc nanoparticles and the thickness of the *** was observed that there was the percolation threshold for the film＇s electrical properties.

关键词： sol-gel hybrid films conductive EMI shielding