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INTERVAL PARAMETER PERTURBATION METHOD FOR EVALUATING THE BOUNDS ON NATURAL FREQUENCIES OF STRUCTURES WITH INTERVAL PARAMETERS

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Acta mechanica Solida Sinica 1998年第1期11卷 56-62页

作者： Qiu Zhiping Gu Yuanxian Beijing Univ Aeronaut & Astronaut Inst Solid Mech Beijing 100083 Peoples R China Dalian Univ Technol Res Inst Engn Mech Dalian 116023 Peoples R China

For structural parameters with uncertainties, interval mathematicscan , in the case where the probabilistic distribution density ofuncertain variables is unavailable, deal with the influ- ence ofuncertainties in structural parameters on the response of *** order to evaluate the re- gion containing natural frequencies ofstructures with interval parameters, the interval parameter per-turbation method is presented in this paper. The advantage of thepresent method is its computational efficiency in evaluating theregion containing natural frequencies. A numerical example is used toil- lustrate the efficiency of the method proposed.

关键词： region containing natural freuqency interval mathematics intervalparameter perturbation method

Characterization of Electroless Ni-P Deposits on Surface of AZ91D Magnesium Alloy

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稀有金属材料与工程 2012年第S1期41卷 183-186页

作者： Li Jiansan Guo Yanting Liu Junquan S China Univ Technol Sch Mech & Automot Engn Inst Corros Control & Surface Engn Guangzhou 510640 Guangdong Peoples R China

Characterization of electroless nickel deposits on magnesium alloys was investigated by X-ray diffraction(XRD),scanning electron microscope(SEM),energy dispersive spectrometer(EDS)and electrochemical potentiodynamic polarization *** result of XRD showed that the electroless nickel deposits on magnesium alloys were composed mostly of amorphous Ni-P and partially of microcrystalline *** phosphorus content in the Ni-P deposits was 10.8%by the calculation of *** micrographs showed that morphology of electroless nickel deposits on magnesium alloys was a typical cellular structure,and the growth of cellular structure was influenced by surface condition of *** layer between substrate and electroless nickel deposits was not found by the results of SEM and EDS,which indicated that the zinc layer on the surface of magnesium alloy was very thin,and the zinc would dissolved while being immersed in electroless nickel plating *** thin zinc layer was almost dissolved completely before Ni-P *** result of electrochemical potentiodynamic polarization analysis showed that the corrosion potential Ecorr of electroless nickel deposits in 3.5%NaCl solution was about-0.53 V,which was 1 V higher than that of magnesium alloys *** corrosion current density of Ni-P deposits in 3.5%NaCl solution was much smaller than that of magnesium alloys substrate at the same potential value,which indicated that corrosion resistance of electroless Ni-P deposits was *** time of concentrated nitric acid test for electroless nickel deposits on magnesium alloys was 445 s,which also indicated excellent corrosion resistance.

关键词： magnesium alloy electroless nickel plating corrosion resistance structure

High Manganese Steel Alloying Process and Its Influence on Microstructure and Properties of the Steel

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Journal of Materials Science & Technology 1995年第2期11卷 102-108页

作者： SHI, ZL GU, MY LIU, JY YIN, YS HEBEI inst mech ELECT DEPT MAT SCI & ENGNSHIJIAZHUANGPEOPLES R CHINA DALIAN UNIV TECHNOL DEPT MAT SCI & ENGNDALIAN 116023PEOPLES R CHINA

The influence of two kinds of alloying processes, adding Nb (or Ti) and N-Mn alloy as well as adding Nb (or Ti) and spraying Nz, on microstructures and properties of a high manganese steel has been studied. It has been found that adding Nb(or Ti), accompanying with N-Mn alloy, is unfavourable to microstructure compactness of the high manganese steel, but adding Nb (or Ti) and spraying N-2 into the melt is good for refining austenitic grain, forming a lot of hard particles and improving microstructure compactness. The mechanical properties of the high manganese steel have relation to the content of elements Nb or Ti. Its fracture mode will turn ductile fracture into brittle cleavage fracture gradually By X-ray and TEM analysis, it is proved that the austenite can be transformed to deformation-induced cr martensite after adding a certain amount of element Nb (or Ti). The microstructure transformation of alloying high manganese steels through deformation is one of methods for strengthening austenite matrix acid increasing the work-hardening rate as well as improving antiwear property.

关键词： Alloying

EFFECT　OF　Mn　CONTENT　ON　KINETIC　PARAMETER　DURING　PHASE　TRANSFORMATION　IN　CuZnAlMnNi　SHAPE　MEMORY　ALLOYS

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中国有色金属学会会刊：英文版 1996年第3期6卷 150-152页

作者： Geng, GL Bai, YJ SHANDONG UNIV TECHNOL INST MAT ENGNJINAN 250061PEOPLES R CHINA SHANDONG inst MIN & TECHNOL DEPT MECHJINAN 250031PEOPLES R CHINA

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关键词： Mn content CuZnAlMnNi shape memory alloy phase transformation kinetic parameter

Semi-solid characteristics and thixoforming of hypereutectic Al-Si alloy

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中国有色金属学会会刊：英文版 2000年第3期10卷 309-313页

作者： LIU Chang ming(刘昌明) HE Nai jun(何乃军) LI Hua ji(李华基) Chongqing Univ Sch Mech Engn State Key Lab Mech Transmiss Chongqing 400044 Peoples R China

Effects of processing parameters on microstructure evolutions by mechanical stirring, procedures for obtaining thixotropy in semi solid slurries, and procedure for thixoforging component, were investigated in hypereutectic Al Si alloy. It is shown that 605 ℃ was the proper temperature for stirring treatment of this alloy, at which the coarse and plate primary Si crystals were effectively changed to globular crystals with a mean diameter of 200 μm after 50 min stirring, that billets with excellent thixotropy were obtained after 50 min remelting at 575 ℃, in which solid fraction of matrix and primary Si crystals was about 60%, and that a perfect near net shape component of disc casting was obtained by thixoforging.

关键词： hypereutectic Al Si alloy primary Si crystals thixoforming

Effect of wrinkles on formability in hydroforming a double-diameter aluminum alloy tubular part

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Rare Metals 2007年第S1期26卷 220-225页

作者： WANG Xiaosong1),YUAN Shijian1),YAO Yingxue2),and Wang Z.R.1)1) School of Material Science and Engineering,Harbin institute of Technology 2) School of mechatronics Engineering,Harbin institute of Technology,Harbin 150001,China Harbin inst Technol Sch Mat Sci & Engn Harbin 150001 Peoples R China Harbin inst Technol Sch Mech Engn Harbin 150001 Peoples R China

An experiment was conducted on hydroforming a double-diameter aluminum alloy tubular *** influence of loading paths,*** relation between internal pressure and axial feeding,on the forming results was emphasized with fixed total axial feeding *** loading paths were analyzed together with the corresponding diagram of stress and *** kinds of bursting phenomenon occurred in the *** part can be formed whether there are wrinkles or *** is indicated by the experiment results that the loading path has great effect on the distribution of material during axial *** thickness distribution is more even for the part formed with wrinkles than that without wrinkles.

关键词： internal high pressure forming double-diameter part wrinkle thickness distribution

NEUROCOMPUTING THEORY AND NUMERICAL SIMULATION ON ELASTICITY

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Acta mechanica Solida Sinica 1999年第3期12卷 269-278页

作者： Sun, DH Sun, XF Hi, Q Xu, H Xiamen Univ Dept Electromech Engn Xiamen 361005 Peoples R China Sw Jiaotong Univ Dept Appl Mech & Engn Chengdu 610031 Peoples R China NE Univ Technol Inst Engn Mech Shenyang 110006 Peoples R China

A new finite element analysis principle based on neural networks is proposed. It can realize the finite element analysis in real time. The neural computation of a simple structure was simulated on digital computer, the effect of input parameters on convergent speed and precision was analyzed. Before solving a certain FE problem, the linking weight matrix of the neural net, i.e., the global stiffness matrix of the structure analyzed, must be defined. In this paper, a method which uses the BP net to compute the element stiffness matrix in real time is proposed.

关键词： neural networks elasticity finite element real-time computation

On the Methods of Beam Direction and MisorientationAngle/Axis Determination by Systematic Tilt

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Journal of Materials Science & Technology 1999年第5期15卷 410-414页

作者： Rong, YH He, G Chen, SP Hu, GX Gao, M Wei, RP Shanghai Jiao Tong Univ Sch Mat Sci & Engn Shanghai 200030 Peoples R China Lehigh Univ Dept Mech Engn & Mech Bethlehem PA 18015 USA

The methods for determining electron beam direction and misorientation angle/axis of grain boundaries are described in this paper. The present methods are based on a series of diffraction spot patterns obtained by systematic tilt of the crystal, combined with simple mathematical calculations. instead of the use of Kikuchi patterns, the limitations resulting from the visibility or sharpness of Kikuchi lines and the number of Kikuchi pole(s) existed are avoided and a sufficient accuracy of determination has been achieved.

关键词： Transmission electron microscopy

Study of Solidification Shrinkage of Ductile Iron in Dry Sand Molds

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Journal of Materials Science & Technology 1999年第3期15卷 245-250页

作者： Li, JR Liu, BC Beijing inst Aeronaut mat Beijing 100095 Peoples R China Tsing Hua Univ Dept Engn Mech Beijing 100084 Peoples R China

The effects of metallurgical and processing parameters on the formation of solidification shrinkage in ductile iron have been studied, considering the parameters of carbon equivalent, inoculation, casting modulus and pouring temperature within specific ranges of these variables. Based on the orthogonal experiments, the metallurgical and processing parameters of the minimum casting shrinkage and the maximum casting shrinkage were obtained, and the effects of metallurgical and processing parameters on the formation of shrinkage cavities and porosities in ductile iron castings were discussed. A regression equation relating these variables to the formation of shrinkage was derived based upon the orthogonal experiments conducted.

关键词： Nodular iron