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Rheological behavior of continuous roll casting process of aluminum alloy

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Journal of central south university of Technology 2005年第6期12卷 629-634页

作者：湛利华钟掘李晓谦黄明辉 School of mechanical and electrical engineering Central South University Changsha 410083China

The rheological behavior of aluminum alloy and its influencing factors in physical simulation of continuous roll casting process were studied by using a Gleeble-1500 thermal-mechanical simulation tester with a set of special clamp system. The relationships between the flow stress and the strain rate in the deformation process of simulating roll casting experiment were obtained. The results show that four different characteristic stages exist in the temperature range of the whole rheological process. The first occurs when the temperature is higher than 600 ℃, which belongs to the creep deformation stage; the second occurs when the temperature lies in the range of 500600 ℃, and it can be regarded as the high temperature and low stress level deformation stage; the third occurs when the temperature decreases to the range of 300500 ℃, it is considered to be the middle stress level deformation stage; the last occurs when the temperature is less than 300 ℃ and the strain rate is less than 1.00 s -1, it belongs to middle stress level deformation stage. But when the strain rate is larger than 1.00 s -1,it belongs to the high stress level deformation stage. And the relative constitutive models suitable for the four different stages of continuous roll casting process were established through multivariate linear regression analysis of the experimental data.

关键词： aluminum alloy continuous roll casting simulation rheological behavior constitutive relation

Numerical simulation and analysis of solid-liquid two-phase threedimensional unsteady flow in centrifugal slurry pump

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Journal of central south university 2015年第8期22卷 3008-3016页

作者：吴波汪西力 LIU Hui 徐海良 School of mechanical and electrical engineering Central South University Department of Computer Science Missouri State University

Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.

关键词： slurry pump solid-liquid two-phase flow unsteady flow 3-D full passage numerical simulation

Design of a New Type of Distribution Valve for Hydraulic Breaker and Analysis of Energy Consumption

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Journal of China university of Mining and Technology 2006年第1期16卷 46-49页

作者： ZHAO Hong-qiang college of mechanical and electrical engineering Central South University Changsha Hunan 410083 China

Energy consumed by distribution valves causes an energy loss for the output energy of hydraulic breakers, which has a significant influence on its efficiency. A new type of distribution valve used for hydraulic breakers, de- signed to reduce energy consumption, is analyzed on the basis of the operating principle and energy loss of the current distribution valve. The new distribution valve adopts a cone valve and the optimization technique of unequal open de- gree for the valve port. Theoretical calculations and analyses have proven that the new distribution valve can reduce en- ergy loss by 9.0127J, or energy consumption by 31%, during an impact cycle and the efficiency of the hydraulic breaker can be raised by 4.5%. It has the following characteristics: little leakage, little pressure loss and low energy consump- tion.

关键词： hydraulic breaker distribution valve energy loss

Analysis of electromechanical coupling facts of complicated electromechanical system

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中国有色金属学会会刊：英文版 2002年第2期12卷 301-304页

作者：贺建军喻寿益钟掘 college of Information Science and engineering Central South UniversityChangsha 410083China college of mechanical and electrical engineering Central South UniversityChangsha 410083China

From aspect of electromechanical coupling,the probable conditions that cause rolling mill chatter to lead to periodic thickness error or bring about light and shade streaks on the surface of steel strip were studied. CM04 temper mill, a typical complicated electromechanical system, was taken as object of study to explore electromechanical coupling facts in complicated electromechanical system. Four modes of electromechanical coupling and their acting principle and law were expounded. Some suggests and measures were put forward for designing of a class of complicated electromechanical system.

关键词：复杂机电系统机电一体化电磁力矩谐波转矩微控制器

High-precision simulation and experimental verification of residual stress and surface topography of cylindrical surface shot peening

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Chinese Journal of Aeronautics 2024年第9期37卷 535-559页

作者： Jiuyue ZHAO Jinyuan TANG Huaming LIU Huiyun ZHANG Xin LI Han DING State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China college of mechanical and electrical engineering Central South UniversityChangsha 410083China

Shot peening is commonly employed for surface deformation strengthening of cylindrical surface ***,it is critical to understand the effects of shot peening on residual stress and surface *** to flat surface,cylindrical surface shot peening has two significant features:(i)the curvature of the cylindrical surface and the scattering of the shot stream cause dis-tributed impact velocities;(i)the rotation of the part results in a periodic variation of the impact velocity ***,it is a challenge to quickly and accurately predict the shot peening residual stress and surface topography of cylindrical *** paper developed a high-precision model which considers the more realistic shot peening ***,a kinematic analysis model was developed to simulate the relative movement of numerous shots and cylindrical ***,the spatial distribution and time-varying impact information was ***,the impact information was used for finite element modeling to predict residual stress and surface *** proposed kinematic analysis method was validated by comparison with the dis-crete element ***,9310 high strength steel rollers shot peening test verified the effectiveness of the model in predicting the residual stress and surface *** addition,the effects of air pressure and attack angle on the residual stress and surface topography were *** work could provide a functional package for efficient prediction of the surface integrity and guide industrial application in cylindrical surface shot peening.

关键词： Shot peening Cylindrical surface 9310 high strength steel High-precision modeling Residual stress Surface topography

2D SnOx/SnS2的异质结构的忆阻器用于神经形态计算（英文）

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Science China Materials 2025年

作者：吴扬武李思凡季云翁正进邢厚英 Lester Arauz Travis Hu 洪金华 Kah-Wee Ang 刘松 State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering Hunan University Department of electrical and Computer engineering National University of Singapore Joint International Research Laboratory of Information Display and Visualization School of Electronic Science and Engineering Southeast University Department of mechanical engineering California State University Los Angeles 5151 State University Dr college of Materials Science and engineering Hunan University Shenzhen Research Institute Hunan University

层状金属二硫化物（LMDs）神经形态忆阻器为解决传统冯·诺依曼架构在速度和能效上的限制,提供了一个有前景的替代方案.然而由于环境稳定性,晶体LMDs忆阻器的阻变行为和操作电压仍面临挑战,这阻碍了神经网络硬件的开发.在此,我们通过臭...

层状金属二硫化物（LMDs）神经形态忆阻器为解决传统冯·诺依曼架构在速度和能效上的限制,提供了一个有前景的替代方案.然而由于环境稳定性,晶体LMDs忆阻器的阻变行为和操作电压仍面临挑战,这阻碍了神经网络硬件的开发.在此,我们通过臭氧处理控制氧化制备了SnOx/SnS2阻变层,优化了其阻变操作特性.该忆阻器表现出低的开关电压（～1 V）、快的开关速度（～20 ns）、高的开关比（10～2）,并具备模拟突触权重可塑性的能力.通过截面透射电子显微镜和X射线光谱等手段的分析,探测到了阻变开关层中的缺陷和Ti导电丝,这有助于实现均匀开关并减少操作可变性.此外,SnOx/SnS2忆阻器在MNIST手写识别中实现了90%的准确率,并成功地实现了基于忆阻器的图像卷积,展示了SnOx/SnS2忆阻器在神经形态应用中的潜力.

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Forming process and numerical simulation of making upset on oil drill pipe

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Acta Metallurgica Sinica(English Letters) 2010年第1期23卷 72-80页

作者： Huaping TANG Changqian HAO Yongzheng JIANG Lei DU School of mechanical and electrical engineering Central South University Changsha 410083 China School of mechanical engineering Nantong University Nantong 226007 China

The flow stress behavior of grade G-105 steel （API standard） for oil drill pipe in hot compressive deformation was studied by isothermal compression tests on Gleeble- 1500 thermal-mechanical machine. Referring to established empirical formulas, the constitutive equation of the flow stress for G-105 steel was obtained. For the grade G- 105 oil drill pipe （φ114.3× 10.92 mm）, through proper design of the die and applying suitable process parameters, and using coupled rigid viscoplastic thermo-mechanical finite element method, the forming process of making upset on oil drill pipe was numerically simulated. The simulation results show that the internal transition section of the oil drill pipe is not only continuous and smooth but also long （up to about 220-250 mm）.

关键词： Oil drill pipe Constitutive equation End upsetting Numerical simulation

Micro scale design and experimental research of rolling interface

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中国有色金属学会会刊：英文版 2002年第1期12卷 21-25页

作者：钟掘王艾伦吴运新段吉安 college of mechanical and Electronic engineering Central South UniversityChangsha 410083 China

Aimed at some central issues of general interest and odd phenomena, an experimental research analysis and simulation of rolling interface was presented. Some root causes or originations of these issues were found. It is shown clearly that, surface roughness of working roll, a certain vibration mode of roll gap, material types of roll sleeve and lubrication state of rolling interface are the key factors determining rolling material quality and are sensitive to dynamic stability of rolling interface.

关键词：动态稳定温度场微刻度设计轧制接触面

Heat transfer analysis for the roller shell under the condition of periodic thermal shock

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Journal of university of Science and Technology Beijing 2003年第6期10卷 44-47页

作者： Lihua Zhan and Xiaoqian Licollege of Electro-mechanical engineering, central south university, Changsha 410083, China college of Electro-mechanical engineering Central South University Changsha 410083 China

According to the actual working conditions of roller shell in the process ofcontinuous roll casting, the Fourier heat transfer law is used to conduct the simulating analysisfor the temperature distribution of the roller shell under the condition of periodic thermal *** temperature variation law inside the roller shell is studied during the process of continuousroll casting, and the steady temperature distributions of the roller shell at different castingvelocities have been obtained when the thermal contact conductance between the roller shell and thecasting strip is considered.

关键词： roller shell thermal contact conductance (TCC) periodic thermal shock