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Study on Numerical Simulation of Mold Filling and Heat Transfer in Die Casting Process

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Journal of Materials Science & Technology 2000年第3期16卷 269-272页

作者： Liangrong JIA, Shoumei XIONG and Baicheng LIU (department of mechanical engineering, Tsinghua university, Beijing 100084, China) department of mechanical engineering Tsinghua University Beijing 100084 China

A 3-D mathematical model considering turbulence phenomena has been established based on a computational fluid dynamics technique, so called 3-D SOLA-VOF (Solution algorithm-Volume of Fluid), to simulate the fluid flow of mold filling process of die casting. In addition, the mathematical model for simulating the heat transfer in die casting process has also been established. The computation program has been developed by the authors with the finite difference method (FDM) recently. As verification, the mold filling process of a S-shaped die casting has been simulated and the simulation results coincide with that of the benchmark test. Finally, as a practical application, the gating design of a motorcycle component was modified by the mold filling simulation and the dies design of another motorcycle component was optimized by the heat transfer simulation. all the optimized designs were verified by the production practice.

关键词： Study on Numerical Simulation of Mold Filling and Heat Transfer in Die Casting Process Mold Simulation

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 university,Beijing 100084)(department of Metal Processing, Northeastern university,Shenyang 110006) Tsinghua Univ Beijing China

ＡＮＡＬＹＳＩＳＯＦＤＲＡＷＩＮＧＵＮＤＥＲＬＵＢＲＩＣＡＴＩＯＮＯＦＮＯＮ－ＮＥＷＴＯＮＩＡＮＬＵＢＲＩＣＡＴＩＮＧＭＡＴＥＲＩＡＬＳＬｅｉＺｈａｎｂｏ；ＷａｎｇＺｈａｎｘｕｅ；ＧａｏＹｏｕｚｈｉ（Ｄｅｐａｒｔｍｅ... 详细信息

ＡＮＡＬＹＳＩＳＯＦＤＲＡＷＩＮＧＵＮＤＥＲＬＵＢＲＩＣＡＴＩＯＮＯＦＮＯＮ－ＮＥＷＴＯＮＩＡＮＬＵＢＲＩＣＡＴＩＮＧＭＡＴＥＲＩＡＬＳＬｅｉＺｈａｎｂｏ；ＷａｎｇＺｈａｎｘｕｅ；ＧａｏＹｏｕｚｈｉ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇ...

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

THEORETICal　ANalYSIS　AND　DESIGN／CalCULATION　FORMULAE　FOR　HYDRAULIC　IMPACT　MECHANISM

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中国有色金属学会会刊：英文版 1995年第1期5卷 116-121页

作者： He Qinghua(department of mechanical engineering ,Central South university of Technology , Changsha 410083)

ＴＨＥＯＲＥＴＩＣＡＬＡＮＡＬＹＳＩＳＡＮＤＤＥＳＩＧＮ／ＣＡＬＣＵＬＡＴＩＯＮ　ＦＯＲＭＵＬＡＥＦＯＲ　ＨＹＤＲＡＵＬＩＣＩＭＰＡＣＴＭＥＣＨＡＮＩＳＭＨｅ；Ｑｉｎｇｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃ... 详细信息

ＴＨＥＯＲＥＴＩＣＡＬＡＮＡＬＹＳＩＳＡＮＤＤＥＳＩＧＮ／ＣＡＬＣＵＬＡＴＩＯＮ　ＦＯＲＭＵＬＡＥＦＯＲ　ＨＹＤＲＡＵＬＩＣＩＭＰＡＣＴＭＥＣＨＡＮＩＳＭＨｅ；Ｑｉｎｇｈｕａ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｃｅｎ...

关键词： hydraulic impact mechanism acceleration ratio unretrieved oil

Stress Field Analyses of Functionally Gradient Ceramic Tool by FEM

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Journal of Materials Science & Technology 2001年第4期17卷 466-468页

作者： Ning FAN , Xing AI and Jun ZHAO department of mechanical engineering, Shandong university,Jinan 250061, China Shandong Univ Dept Mech Engn Jinan 250061 Peoples R China

The cutting properties of the functionally gradient ceramic cutting tools relate closely to the gradient distribution. A cutting model of the functionally gradient ceramic tool is firstly designed in the present paper... 详细信息

关键词： Stress Field Analyses of Functionally Gradient Ceramic Tool by FEM Tool

LEVEL SET METHOD FOR TOPOLOGICal OPTIMIZATION APPLYING TO STRUCTURE, MECHANISM AND MATERIal DESIGNS

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Chinese Journal of mechanical engineering 2004年第2期17卷 200-209页

作者： Mei Yulin Wang Xiaoming department of mechanical engineering,Dalian university of Technology,Dalian 116024,China department of mechanical engineering Dalian University of Technology Dalian 116024 China

Based on a level set model, a topology optimization method has been suggestedrecently. It uses a level set to express the moving structural boundary, which can flexibly handlecomplex topological changes. By combining vector level set models with gradient projectiontechnology, the level set method for topological optimization is extended to a topologicaloptimization problem with multi-constraints, multi-materials and multi-load cases. Meanwhile, anappropriate nonlinear speed, mapping is established in the tangential space of the activeconstraints for a fast convergence. Then the method is applied to structure designs, mechanism andmaterial designs by a number of benchmark examples. Finally, in order to further improvecomputational efficiency and overcome the difficulty that the level set method cannot generate newmaterial interfaces during the optimization process, the topological derivative analysis isincorporated into the level set method for topological optimization, and a topological derivativeand level set algorithm for topological optimization is proposed.

关键词： Level set method Topology optimization Mean curvature flow Materialdesign Mechanism design Topological derivative

Semi-solid Processing of al-7Graghite Composite

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Journal of university of Science and Technology Beijing 2001年第3期8卷 203-206页

作者： Peng Zhang, Yunhui Du, Daben Zeng department of mechanical engineering, Tsinghua university, Beijing 100084, China Tsing Hua Univ Dept Engn Mech Beijing 100084 Peoples R China

al-7graphite composite was processed using al-7graphite mushy prepared by electromagnetic-mechanical stirring method, and the influence of solid fraction on the distributing of graphite particles in ingot was studied. The results shows that the relationship between solid fraction and stirring temperature of mushy is: f(s) = 591.5-0.897 t (where f(s) is the solid fraction, t is the stirring temperature). For al-7graphite composite, with the increasing of solid fraction, the aggregation extent of graphite particles reduced gradually, and when solid fraction was larger than 30%, graphite particles could distribute evenly in ingot.

关键词： al-7graphite composite electromagnetic-mechanical stirring method distributing of graphite particles solid fraction stirring temperature

EFFECT OF alUMINIUM AND BORON ON SURFACE MODIFICATION OF SOME MATERIalS

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中国有色金属学会会刊：英文版 1995年第1期5卷 101-106页

作者： Dai Zhongxing Yang Zixia(mechanical engineering department, Xiangtan university, Xiangtan 411105)

ＥＦＦＥＣＴＯＦＡＬＵＭＩＮＩＵＭＡＮＤＢＯＲＯＮＯＮＳＵＲＦＡＣＥＭＯＤＩＦＩＣＡＴＩＯＮＯＦＳＯＭＥＭＡＴＥＲＩＡＬＳＤａｉ；ＺｈｏｎｇｘｉｎｇＹａｎｇ；Ｚｉｘｉａ（ＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＤｅ... 详细信息

ＥＦＦＥＣＴＯＦＡＬＵＭＩＮＩＵＭＡＮＤＢＯＲＯＮＯＮＳＵＲＦＡＣＥＭＯＤＩＦＩＣＡＴＩＯＮＯＦＳＯＭＥＭＡＴＥＲＩＡＬＳＤａｉ；ＺｈｏｎｇｘｉｎｇＹａｎｇ；Ｚｉｘｉａ（ＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＤｅｐａｒｔｍｅｎｔ，Ｘｉａｎｇｔａｎ...

关键词： al-B co-diffusion microstructure co-diffusion layer surface modification

Simulation of Fracture Process of Lightweight Aggregate Concrete Based on Digital Image Processing Technology

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Computers, Materials & Continua 2024年第6期79卷 4169-4195页

作者： Safwan al-sayed Xi Wang Yijiang Peng Key Laboratory of Urban Security and Disaster engineering Ministry of EducationBeijing University of TechnologyBeijing100124China

The mechanical properties and failure mechanism of lightweight aggregate concrete(LWAC)is a hot topic in the engineering field,and the relationship between its microstructure and macroscopic mechanical properties is also a frontier research topic in the academic *** this study,the image processing technology is used to establish a micro-structure model of lightweight aggregate *** the information extraction and processing of the section image of actual light aggregate concrete specimens,the mesostructural model of light aggregate concrete with real aggregate characteristics is *** numerical simulation of uniaxial tensile test,uniaxial compression test and three-point bending test of lightweight aggregate concrete are carried out using a new finite element method-the base force element method ***,the image processing technology is used to produce beam specimens,uniaxial compression specimens and uniaxial tensile specimens of light aggregate concrete,which can better simulate the aggregate shape and random distribution of real light aggregate ***,the three-point bending test is numerically ***,the uniaxial compression specimen generated by image processing technology is numerically ***,the uniaxial tensile specimen generated by image processing technology is numerically *** mechanical behavior and damage mode of the specimen during loading were *** results of numerical simulation are compared and analyzed with those of relevant *** feasibility and correctness of the micromodel established in this study for analyzing the micromechanics of lightweight aggregate concrete materials are *** processing technology has a broad application prospect in the field of concrete mesoscopic damage analysis.

关键词： Digital image processing lightweight aggregate concrete mesoscopic model numerical simulation fracture analysis bending beams

CRITICal ISSUES OF POWDER METalLURGY TURBINE DISKS

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 467-471页

作者： K.M. Chang(department of mechanical and Aerospace engineering,West Virginia university, P.O. Box 6160, Morgantown,WV 26506, usa West Virginia Univ Morgantown United States

P/M superalloy disks obtain their final strength by appropriate heat treatments; the maximum attainable strength depends on the rapid cooling rate from the solution annealing. A rapid quench of a large disk forging can cause two problems, surface cracking and shape *** the past,many attempts employ the finite element code to model and to predict temperature evolution and induced stress distribution in a large turbine disk. The major difficulty was the correct description of alloy behavior; particularly the thermomechanical properties and the failure criteria of material during the cooling. High temperature fatigue resistance is always the key requirement for disk materials. New methodology of residual life management emphasizes the initiation as well as the propagation of the cracks developed under the service conditions. One of major challenges to P/M superalloys is the time-dependent behavior of fatigue cracking, which relates to the well-known SAGBO (stress-assisted grain boundary oxidation) phenomenon.A great effort has been done to understand the micro-mechanism of time-dependent fatigue crack propagation resulted in the second generation of P/M superalloys. Further improvement on temperature capability of disk alloys at rim area may lead to the idea of dual-property *** grain structures at different portions of a large disk are possible,as the property requirements for different locations are different. This goal is achievable if the thermal history at specific disk locations can be controlled to develop desirable microstructures and *** suggestions on the future direction of research efforts will be discused.

关键词： superalloy disk,powder metallurgy (P/M) quench cracking,fatigue crack propagation SAGBO (stress-assisted grain boundary oxidation),dual-property disk grain size