检索结果-南通市图书馆

METHOD TO SOLVE ELASTIC CONJUGATE SURFACES IN MULTI-TEETH MESHING

第三届国际仪器科学技术学术研讨会

作者： YANG Lian-gen a WANG Sheng-huai a SHEN Bang-xing a XIE Tie-bang b aSchool of mechanical engineering Hubei Polytechnic University Wuhan 430068 china bschool of mechanical science and engineering Huazhong University of science and Technology Wuhan 430074 china

Motif method is a new important assessing method of surface topography. Firstly,the basic concept, basic characterization parameters, essential combination conditions, and elementary calculation proce

关键词： surface roughness surface waviness Motif parameter symbol bit combination algorithm

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2002年第4期15卷 348-352页

作者： Yi ChuanyunSchool of mechanical science and engineering, Huazhong University of science and Technology,Wuhan 430074, china School of mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074

A method to solve the elastic conjugate surfaces in multi-teeth meshing ispresented. In mechanical manufacturing and design, there exist a lot of problems relating toconjugate surfaces, such as three-dimensional engagement, steel rolling and workpiece machining,which cause great effects on the quality of machining and performances of transmission. This methoddescribes relation between conjugate motion and elastic deformation in the process of mesh-in andmesh-out, and can be used to determine the profile of gear tooth by a certain given load sharing.

关键词： multi-teeth meshing elastic conjugate surfaces

Prediction and Control of both Wrinkle Limit and Fracture Limiton Cylindrical Cup Deep-drawing(Ⅱ)

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 201-204页

作者： Junxiang Lei Yonglin Kang(Department of mechanical engineering, Yantai University, Yantai 264005, china)(Material science and engineering School, University of science and Technology Beijing, Beijing 100083, china) Department of mechanical engineering Yantai University Yantai 264005 China Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

The prediction and control criterion of both the wrinkle limit and fracture limit on the cylindrical cup deep-drawing are given, and the prediction and control diagram of both the wrinkle limit and fracture limit are also given. The results show that it is suitable for no-flange cylindrical cup deep-drawing, narrow-flange cylindrical cup deep-drawing, wide-flange cylindrical cup deep-drawing/expanding compound forming and rigid punch expanding forming.

关键词： cylindrical cup wrinkle limit fracture limit deep-drawing expanding forming compound forming

A New Genetic Algorithm Based on Niche Technique and Local Search Method

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and Technology Beijing 2001年第1期8卷 63-68页

作者： Jinwu Xu, Jiwen Liu mechanical engineering School, University of science and Technology Beijing, Beijing 100083, china mechanical engineering School Univ. of Sci. and Technology Beijing Beijing 100083 China

The genetic algorithm has been widely used in many fields as an easy robust global search and optimization method. In this paper, a new generic algorithm based on niche technique and local search method is presented under the consideration of inadequacies of the simple genetic algorithm. In order to prove the adaptability and validity of the improved genetic algorithm, optimization problems of multimodal functions with equal peaks, unequal peaks and complicated peak distribution are discussed. The simulation results show that compared to other niching methods, this improved genetic algorithm has obvious potential on many respects, such as convergence speed, solution accuracy, ability of global optimization, etc.

关键词： genetic algorithm (GA) niche technique local search method

INTEGRATED APPROACH TO GENERATION OF PRECEDENCE RELATIONS AND PRECEDENCE GRAPHS FOR ASSEMBLY SEQUENCE PLANNING

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2002年第3期15卷 193-198页

作者： Niu Xinwen Ding Han Xiong YoulunSchool of mechanical science and engineering, Huazhong University of science and TechnologyWuhan 430074, china School of mechanical science and engineering Huazhong Univerisy of science and Technology Wuhan 430074

An integrated approach to generation of precedence relations and precedencegraphs for assembly sequence planning is presented, which contains more assembly flexibility. Theapproach involves two stages. Based on the assembly model, the components in the assembly can bedivided into partially constrained components and completely con-strained components in the firststage, and then geometric precedence relation for every component is generated *** to the result of the first stage, the second stage determines and constructs allprecedence graphs. The algorithms of these two stages proposed are verified by two assemblyexamples.

关键词： Assembly sequence planning Assembly flexibility Precedence relations Precedence graphs

PROFILE TOLERANCE EVALUATION OF PARAMETRIC CURVES AND SURFACES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of mechanical engineering 2002年第2期15卷 121-125页

作者： Huang Xiaoping Xiong YoulunSchool of mechanical science and engineering, Huazhong University of science and Technology,Wuhan 430074, china School of mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074

The profile error evaluation of complex curves and surfaces expressed inparametric form is considered. The linear error model is established on the base of two hypothesesfirstly. Then the profile error evaluation is converted into one of these optimal formulations:MINIMAX, MAXMIN and MINIDEX problems, which are easier to be solved than the initial form. To eachone of them, geometric condition and algebraic condition are presented to arbitrate whether theideal element reaches to the optimal position. Exchange algorithm is proven highly effective insearching for solutions to these optimization problems. At last some key problems in tolerance offreeform surfaces and curves in B spline method are discussed.

关键词： Parametric form Profile tolerance Linear error model Exchangealgorithm

Change Laws of Flake's Temperature during Making a Diamond Film by DC-PJ

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 97-102页

作者： Xuhong Chen Lihe Zhao Fanxiu Lu(mechanical engineering School, University of science and Technology Beijing, Beijing 100083, china) mechanical engineering School University of Science and Technology Beijing Beijing 100083 China

When making a diamond film by direct current plasma jet, a kind piece of flake is used as a base body Which the film can beattached to. The flake's temperature is unstable. Therefore, some experiments and constructed mathematical models, which were solvedby computer, were done. The results show that the flake's temperature is influenced by many factors and the mains are plasma jet powerand vacuum pressure. Through adjusting the two parameters, the flake's temperature can be accurately controlled, furthermore, diamondfilms' quality would be improved. Lowering sediment platform's temperature has a little effect to the flake's temperature at present technology conditions.

关键词： CVD (Chemical Vapor Deposition) plasma, impact heat transfer

Effect of Process Factors on Microstructure of Semisolid Continuous Casting Billets

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 242-245页

作者： Shuming Xing, Qijie Zhai, Hanqi Hu ( Department of mechanical engineering, Tsinghua University, Beijing 100084, china School of Material science and engineering, Shanghai University, Shanghai 200072, china Material science and engineering School, Univer Department of mechanical engineering Tsinghua University Beijing 100084 China School of Material science and engineering Shanghai University Shanghai 200072 China Material science and engineering School University of Science and Technology Beijing Beijing 100083 China

Semisolid continuous casting (SSCC) is a new technology to produce billets for semisolid metal forming (SSMF). The effect of process factors, such as pouring temperature, stirring rate, preheating temperature and thermal conductivity of stirring chamber, on the microstructure of SSCC billets was studied by means of the factorial experimental method. The results show that the microstructure of SSCC billets can be controlled by the above-mentioned four process factors. In order to obtain fine and rounded granular grains in an SSCC billet, the pouring temperature, preheating temperature and stirring rate should be kept in a moderate range, and the thermal conductivity of stirring chamber should be high. The regression equations with the process factors connecting the microstructure was also set up based on experimental data.

关键词： semisolid metal continuous casting process factors microstructure Metallurgy

Nonequilibrium Thermodynamic and Dissipative Structure Mechanism of Fluidized Beds

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 90-93页

作者： Maozhan Qi Li Wang Xuezi Ni (mechanical engineering School, University of science and Technology Beijing, Beijing 100083, china) mechanical engineering School University of Science and Technology Beijing Beijing 100083 China

Fluidized beds are nonlinear dynamic systems that exchange mass and energy with outside. They are governed not only byfluid dynamics, but by thermodynamics, especially the second law of thermodynamics as well. According to Prigogine's dissipative structure theory, the following have been concluded: (l) a fixed bed is on thermodynamic blanch, and bubbling, turbulent and fast beds areon the dissipatve structure branches. (2) Entropy in fluidized beds is divided into tWo parts: entropy production and entropy flux. The latter increases with gas velocity and decreases with pressure of the systems. That means the entropy of a system may reduce and the systemwith higher gas velocity behaves as dissipative structure characteristics. (3) For a giVen velocity, a fluidized bed operates stably on thewhole, but it is unstable to local gas-solid phases. The unstable phases are described by fluid dynamic equations, While the minimum ofsystem energy function assures whole stability of the system. (4) A transition criterion of a bubbling bed is derived from Prigogine's stability theory.

关键词： fluidized bed nonequilibrium thermodynamics dissipative structure energy extremum