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Novel Blasting-Like Lubricating Process for Cold Extrusion

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Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 322-329页

作者：陈海棠胡成亮龚爱军施卫兵赵震 institute of Forming Technology&Equipment School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200030China National Engineering research Center of Die and Mold CAD Shanghai Jiao Tong UniversityShanghai 200030China Jiangsu Sunway Precision forging Co. Ltd.Yancheng 224100JiangsuChina

A blasting-like lubricating process(combination of shot blasting and lubricating processes)is *** this process,the specimens to be treated,alloy shots,and solid lubricating powder are rotated together in a *** surface pockets formed due to the impact by the shots can store lubricants,and the lubricant can also adhere to the specimen surface by *** effects of process parameters,including rolling time,rotational speed,mass of alloy shots,and the diameter of shots,on the surface topography of the steel specimen are investigated using 13 experimental *** distribution ratio and average depth of surface pockets on the defined areas of the specimen are quantitatively *** selected schemes with the MoS_(2) solid lubricating powder are further carried out to lubricate the cylindrical billets,and the lubricating effect is evaluated using the steady combined forward and backward extrusion *** indicated friction factor of the novel blasting-like process is smaller than that of the conventional phosphate-soap coating process.

关键词： blasting-like process lubricating surface pocket friction factor cold extrusion

Numerical simulation on the process of multi-point forming for tube

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Journal of Harbin institute of Technology(New Series) 2010年第6期17卷 858-862页

作者：刘启骞付文智李明哲陈志红 roll-forging research institute Jilin University

To apply the multi-point forming technology to the field of tube processing,the process of multi-point forming for tube is *** simulation for the process of multi-point forming for tube is achieved by using elastic-plastic FEM in *** simulation,reasonable coefficient of mass scaling and friction model of penalty function are *** influence of several major technological parameters on the process is *** the tube diameter is 60 mm and the forming curvature radius is 1000 mm,the distortion rate of cross-section and the absolute forming error gradually decrease with the increasing of tube wall thickness;However,when the tube wall thickness is constant,the smaller the curvature radius,the larger the distortion rate of cross-section,but as to forming part,its absolute forming error becomes smaller.

关键词： tube-bending multi-point forming numerical simulation technological parameter

Design and Experimental Verification of a roll Control Strategy for Large Wingspan Flapping-Wing Aerial Vehicle

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Journal of Bionic Engineering 2024年第4期21卷 1644-1661页

作者： Rui Meng Bifeng Song Jianlin Xuan Xiaojun Yang Dong Xue School of Aeronautics Northwestern Polytechnical UniversityXi’an710072China research and Development institute of Northwestern Polytechnical University in Shenzhen Shenzhen518057China Yangtze River Delta research institute of Northwestern Polytechnical University Taicang215400China

Most flapping-wing aircraft wings use a single degree of freedom to generate lift and thrust by flapping up and down,while relying on the tail control surfaces to manage ***,these aircraft have certain limitations,such as poor accuracy in attitude control and inadequate roll control *** paper presents a design for an active torsional mechanism at the wing's trailing edge,which enables differential variations in the pitch angle of the left and right wings during *** simple mechanical form significantly enhances the aircraft's roll control *** experimental verification of this mechanism was conducted in a wind tunnel using the RoboEagle flapping-wing aerial vehicle that we *** study investigated the effects of the control strategy on lift,thrust,and roll moment during flapping ***,the impact of roll control on roll moment was examined under various wind speeds,flapping frequencies,angles of attack,and wing ***,several rolling maneuver flight tests were performed to evaluate the agility of RoboEagle,utilizing both the elevon control strategy and the new roll control *** results demonstrated that the new roll control strategy effectively enhances the roll control capability,thereby improving the attitude control capabilities of the flapping-wing aircraft in complex wind field *** conclusion is supported by a comparison of the control time,maximum roll angle,average roll angular velocity,and other relevant parameters between the two control strategies under identical roll control input.

关键词： roll control Bio-inspired roll moment Flapping wing aerial vehicle

Influence of deformation path on the forming effect in a multistep flexible rolling process

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International Journal of Minerals,Metallurgy and Materials 2018年第10期25卷 1173-1180页

作者： Ying Li Wen-zhi Fu Ming-zhe Li Xiao-dong Liu Shuo Sun Zhuo Yi roll forging institute Jilin University College of materials science and engineering Jilin University

The flexible rolling process(FRP) is a novel three-dimensional(3 D) forming process that combines the multipoint and traditional rolling forming. The principle of FRP is based on thickness thinning, so the deformation path significantly impacts the forming effect. In this study, the multistep forming process with different deformation paths was introduced to improve the forming effect of FRP. For instance, with the convex surface part, three finite element models of multistep FRP(MSFRP) were established. The corresponding numerical simulations and forming experiments performed among different deformation paths showed the surface part with a longer effective forming region was obtained and the forming regions with more steps in MSFRP were smoother. Thus, the sheet-metal utilization rate was greatly improved. Moreover, the MSFRP can improve the longitudinal bending effect dramatically and thereby endowing the forming part with a better forming effect. Therefore, MSFRP is a prospective method for broad applications.

关键词： 3D surface forming multistep flexible rolling numerical simulation deformation path forming effect

Flow characteristics and hot workability of a typical low-alloy high-strength steel during multi-pass deformation

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 323-336页

作者： Mingjie Zhao Lihong Jiang Changmin Li Liang Huang Chaoyuan Sun Jianjun Li Zhenghua Guo School of Aeronautical Manufacturing Engineering Nanchang Hangkong UniversityNanchang 330063China Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components Nanchang Hangkong UniversityNanchang 330063China State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China China National Erzhong Group Deyang Wanhang Die forging Co.LTD. Deyang 618000China Hubei Huangshi Mold Industrial Technology research institute Huangshi 435007China

Heavy components of low-alloy high-strength(LAHS) steels are generally formed by multi-pass forging. It is necessary to explore the flow characteristics and hot workability of LAHS steels during the multi-pass forging process, which is beneficial to the formulation of actual processing parameters. In the study, the multi-pass hot compression experiments of a typical LAHS steel are carried out at a wide range of deformation temperatures and strain rates. It is found that the work hardening rate of the experimental material depends on deformation parameters and deformation passes, which is ascribed to the impacts of static and dynamic softening behaviors. A new model is established to describe the flow characteristics at various deformation passes. Compared to the classical Arrhenius model and modified Zerilli and Armstrong model, the newly proposed model shows higher prediction accuracy with a confidence level of 0.98565. Furthermore, the connection between power dissipation efficiency(PDE) and deformation parameters is revealed by analyzing the microstructures. The PDE cannot be utilized to reflect the efficiency of energy dissipation for microstructure evolution during the entire deformation process, but only to assess the efficiency of energy dissipation for microstructure evolution in a specific deformation parameter *** a result, an integrated processing map is proposed to better study the hot workability of the LAHS steel, which considers the effects of instability factor(IF), PDE, and distribution and size of grains. The optimized processing parameters for the multi-pass deformation process are the deformation parameters of 1223–1318 K and 0.01–0.08 s^(-1). Complete dynamic recrystallization occurs within the optimized processing parameters with an average grain size of 18.36–42.3 μm. This study will guide the optimization of the forging process of heavy components.

关键词： low-alloy high-strength steel work hardening rate constitutive model hot workability multi-pass deformation

NUMERICAL METHOD FOR PREDICTION OF NET-SHAPED BLANK IN MULTI-POINT FORMING OF SHEET METAL

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 314-318页

作者： Cai Zhongyi Li Mingzhe Cui Xiangji roll forging institute, Jilin University, Changchun 130025, China roll forging institute Jilin University Changchun 130025 China

A new numerical method to predict the initial blank geometry from the desiredobjective shape of parts is presented. Based on the conditions that the deformations in materialare most evenly distributed and that the volume remains constant, a positive definite functional forblank design is constructed. The functional is minimized by an iterative scheme of finite element,and then the optimal initial configuration is obtained. The method is easy and expedient to use. Theresults of numerical simulation of forming process and multi-point forming experiments for sheetmetal demonstrate that good precision is achieved by the proposed method.

关键词： sheet metal blank design finite element

Filling Rules of Bevel Gears in the Closed-die Cold forging

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Journal of Materials Science & Technology 2005年第6期21卷 925-928页

作者： Huamin LIU Liangju HUANG Shenhua YANG Shihong ZHANG institute of roll forging Technology Jilin University Changchun 130025 China institute of Metal research Chinese Academy of Sciences Shenyang 110016 China

The closed-died cold forging technology of the bevel gears used in Jada car was investigated. With the analysis of the strain field and velocity field of the plastic deformation and the endured forces of the dies, the filling rules for the metal were analyzed by the elastic-plastic finite element method （FEM）. The results show that there is a great difference among closed-die cold forging, extrusion and forging, as far as the metal flowing is concerned. The outer addendum cannot be filled completely in the closed-die cold forging of the bevel gears, and the round angle will be formed. But it does not influence the application of the bevel gears. At the beginning, the rigid area is formed in the cavity of the lower die. And then it will move upwards to supply the metal for the gear filling. For the closed-die cold forging of the bevel gears, the force acting on the upper die and the lower die is significantly different.

关键词： Bevel gear Closed-die cold forging FEM Filling rule

Multi-Physics Coupled Acoustic-Mechanics Analysis and Synergetic Optimization for a Twin-Fluid Atomization Nozzle

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 204-223页

作者： Wenying Li Yanying Li Yingjie Lu Jinhuan Xu Bo Chen Li Zhang Yanbiao Li College of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China School of Materials Science and Engineering Northwestern Polytechnical UniversityXian 710072China Guizhou Anda Aviation forging Co. Ltd.Anshun 561005China

Fine particulate matter produced during the rapid industrialization over the past decades can cause significant harm to human ***-fluid atomization technology is an effective means of controlling fine particulate matter *** this paper,the influences of the main parameters on the droplet size,effective atomization range and sound pressure level(SPL)of a twin-fluid nozzle(TFN)are investigated,and in order to improve the atomization performance,a multi-objective synergetic optimization algorithm is presented.A multi-physics coupled acousticmechanics model based on the discrete phase model(DPM),large eddy simulation(LES)model,and Ffowcs Williams-Hawkings(FW-H)model is established,and the numerical simulation results of the multi-physics coupled acoustic-mechanics method are verified via experimental *** on the analysis of the multi-physics coupled acoustic-mechanics numerical simulation results,the effects of the water flow on the characteristics of the atomization flow distribution were obtained.A multi-physics coupled acoustic-mechanics numerical simulation result was employed to establish an orthogonal test database,and a multi-objective synergetic optimization algorithm was adopted to optimize the key parameters of the *** optimal parameters are as follows:A gas flow of 0.94 m^(3)/h,water flow of 0.0237 m^(3)/h,orifice diameter of the self-excited vibrating cavity(SVC)of 1.19 mm,SVC orifice depth of 0.53 mm,distance between SVC and the outlet of nozzle of 5.11 mm,and a nozzle outlet diameter of 3.15 *** droplet particle size in the atomization flow field was significantly reduced,the spray distance improved by 71.56%,and the SPL data at each corresponding measurement point decreased by an average of 38.96%.The conclusions of this study offer a references for future TFN research.

关键词： Twin-fluid nozzle BP neural network Multi-objective optimization Multi-physics coupled Acousticmechanics analysis Genetic algorithm

Numerical simulation of wrinkle phenomenon during multi-point forming process of shallow rectangle cup

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Journal of Harbin institute of Technology(New Series) 2004年第3期11卷 300-304页

作者：裴永生李明哲李雪隋振 roll forging Technology institute Jilin University Changchun 130025 China

In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.

关键词： multi-point forming wrinkle numerical simulation shallow rectangle cup