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2015 International Conference on Fluid Power and Mechatronics

作者： Wang Lihang Hu Shuwei Yang Lele Zhang Lijie Hebei Key Laboratory of Heavy Mechinery Fluid Power Transimission and Control Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan university)Yanshan university

The matching of the pilot valve and multi-way valve is a prerequisite for the pilot control in the engineering machinery. Based on hydraulic pilot control system of a certain bulldozer actuator and the principle of the pilot control system, we analyze the matching relationship between the pilot valve and multi-way valve. The parameters that influence the hydraulic pilot control system are summarized and the simulation model of pilot control system is built according to the actual parameters of components. The matching relationship of the hydraulic pilot control system is researched by experiments and simulation, which will provide theoretical guidance for the design of the pilot valve and multi-way valve that used in the engineering machinery.

关键词： pilot valve multi-way valve matching simulation

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Characteristics of Precipitation in an As-cast Nb-and V-containing High Nitrogen CrMn Austenitic Steel

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Journal of Iron and Steel Research International 2014年第10期21卷 945-950页

作者： Zhong-ping SHI Zhen-hua WANG Shu-hua SUN Ze-an ZHOU Ying-ping GUAN Wan-tang FU State Key Laboratory of Metastable Materials Science and Technology Yanshan University Key Laboratory of Advanced Forging and Stamping Technology and Science(Yanshan University) Ministry of Education of China

The phase diagram of an Nb- and V-containing 18Mnl8Cr0.5N steel was investigated using thermodynam ic calculation. The compositions and characteristics of precipitates were investigated by scanning electron microsco- py, energy dispersive spectrometry, X-ray diffraction, and differential scanning calorimetry. Under equilibrium con- ditions, MX precipitates at 1 350 ℃. MX is a substitutional solid solution of Nb4 N3.38, and its composition （at. %） is approximately.. Nb 40, N 40, V 8, and Fe, Cr, and Mn balance. The precipitates, with shapes including irregular bulk, rod, and ellipsoid, are primarily distributed at grain boundaries and triple junctions, and their size is approxi- mately 5 10 μm. Finally, the microalloying of high nitrogen CrMn austenite steels, control of precipitate size, and the effect of precipitate on hot formin~ were discussed.

关键词： high nitrogen steel microalloying precipitate

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The aligmnent technology in electrospinning and a novel method using variable magnetic fields

The aligmnent technology in electrospinning and a novel meth...

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第十一届全国再生医学(干细胞与组织工程)学术研讨会暨第七届全国组织工程与再生医学大会

作者： Kevin Firouzian Feng Lin Key Laboratory for Advanced Materials Processing Technology Ministry of Education of China Biomanufacturing and Rapid Forming Technology Key Laboratory of Beijing Rapid Forming Center Department of Mechanical Engineering Tsinghua University Beijing 100084 P.R.China

With the development of nanotechnology research, and increased interest in the unique properties of nanomaterials, electrospinning research has gained a lot of attention in the past *** is a very versatile technology and has application potential in several diverse *** include, but not limited to, tissue engineering, filtration, wound dressings, and *** nanofiber generation via electrospinning involves the use of an electrestatically driven jet of polymer *** features of the process include a chaotic oscillation of the electrospinning jet and fibers typically collected as non-woven *** nanofibers offer several advantages over conventional techniques such as high surface area to volume ratio, high porosity, and the ability to alter fiber composition in order to get required *** deposition and fiber alignment are key requirements for many applications such as tissue engineering ***, much of current research focuses on methods of alignment using mechanically-(rotary collectors), electrically-(parallel electrodes), and magnetically (parallel magnets on top of collector region)assisted ***, several methods have been suggested to stabilize the chaotic oscillating motion of the electrospun *** results have been achieved in beth alignment and stabilization, however there is still room for improvement.A novel jet stabilization and controlled fiber deposition method is proposed using a variable magnetic field that is expected to improve the flexibility of fiber ***, experimental results will be presented in this report to show the validation of this new method.

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Control over Mechanical Properties and Microstructure of BR1500HS Hot-stamped Parts

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Journal of Iron and Steel Research International 2014年第6期21卷 606-613页

作者： Bai-liang ZHUANG Zhong-de SHAN Chao JIANG Xin-ya LI State Key Laboratory of Advanced Forming Technology and Equipment of CAM Jiangsu Institute China Academy of Machinery Science and Technology

The hot stamping processing parameters are of critical importance in transforming ultra-high-strength steel （UHSS） into high-quality parts, which were studied by mechanical properties tests, metallographic observations and calculation analysis method based on hot stamping experiments and numerical simulation technology, the mechanical properties, thickness, dimensional accuracy, and microstructure of the hot formed parts are analyzed to determine the influence of different processing parameters for UHSS parts formed from BR1500HS. The results indicate that the quenching time had the most significant impact on the mechanical properties of the parts, and longer quenching time resulted in better mechanical properties. In addition, the pressing speed had a significant influence on the thick ness of the formed parts, and the part-opening temperature had the most significant effect on the dimensional accura cy of the parts. And to get hot stamped parts with excellent quality, the optimum process conditions should be set as heating temperature of 930 ℃, soaking time of 4 min, stamping force of 7 MPa, pressing speed of 75 mm/s, quench ing time of 15 s, and water-flow rate of 1.1 m/s.

关键词： hot forming processing parameter mechanical property microstructure

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Kinetostatics Analysis of a Novel 6-DOF Parallel Manipulator with Three Planar Limbs and Equipped with Three Fingers

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 919-927页

作者： LU Yi LI Xuepeng College of Mechanical Engineering Yanshan University Key Laboratory of Parallel Robot and Mechatronic System of Hebei Province Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of National Education

It is significant to develop a robot hand with high rigidity by a 6-DOF parallel manipulator（PM）.However,the existing6-DOF PMs include spherical joint which has less capability of pulling force bearing,less rotation range and lower precision under alternately heavy loads.A novel 6-DOF PM with three planar limbs and equipped with three fingers is proposed and its kinematics and statics are analyzed systematically.A 3-dimension simulation mechanism of the proposed manipulator is constructed and its structure characteristics is *** kinematics formulae for solving the displacement,velocity,acceleration of the platform,the active legs and the fingers are *** statics formulae are derived for solving the active forces of PM and the finger *** analytic example is given for solving the kinematics and statics of proposed manipulator and the analytic solved results are verified by the simulation *** is proved from the error analysis of analytic solutions and simulation solutions that the derived analytic formulae are correct and provide the theoretical and technical foundations for its manufacturing,control and application.

关键词： parallel manipulator planar limbs finger kinematics statics

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Fault Diagnosis Method for Hydraulic Pump Based on Order Tracking

Fault Diagnosis Method for Hydraulic Pump Based on Order Tra...

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2015 International Conference on Fluid Power and Mechatronics

作者： Wanlu Jiang Yong Zhu Meng Wang Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University)Ministry of Education of China

Aiming at the problem of extracting fault features from hydraulic pump under variable rotating speed, a fault diagnosis method based on order tracking was proposed. Firstly, the original signal was decomposed by ensemble empirical mode decomposition into a series of intrinsic mode function(IMF) components. Afterwards, the fault sensitive IMF was selected by combining energy spectrum and spectral kurtosis. Secondly, the selected IMF was processed by Hilbert demodulation and downsampling. Moreover, an appropriate frequency band was chosen and the signal was further processed by wavelet cluster-based bandpass filtering. Then, the fault sensitive envelope signal was obtained. Thirdly, the instantaneous frequency was extracted from the envelop signal by wavelet ridge tracking, and the time instant of phase discrimination was further calculated. Moreover, the even angle spaced resample was performed to the envelope signal. Then, the time domain non-stationary signal was transformed to the angular domain stationary signal. Finally, the stationary signal was analyzed by order tracking, and the fault diagnosis was executed according to the order spectrum. Furthermore, an application was performed to the vibration signals of hydraulic pump under variable rotating speed. The signals were respectively acquired in four typical states, which were normal, loose slipper, slipper wear and swash plate wear. Results indicate that the proposed method can effectively extract the fault features of hydraulic pump and further realize fault diagnosis.

关键词： hydraulic pump fault diagnosis order tracking variable rotating speed

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Research on Multi-fault Identification Method of Axial Piston Pump Based on Correlation Dimension

Research on Multi-fault Identification Method of Axial Pisto...

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2015 International Conference on Fluid Power and Mechatronics

作者： LIU Siyuan YANG Mengxue ZHANG Wenwen Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China Yanshan University

Aiming at the problem of multi-fault identification method of axial piston pump, a new method combining correlation dimension and support vector machine was ***, the envelope demodulation was performed to several typical fault vibration signals of pump by using wavelet packet decomposition and Hilbert transform method. Then, the useful signals corresponding to feature band were obtained. Secondly,using the embedded dimension as characteristic attribute, the correlation dimension feature information of the useful signals was extracted by correlation dimension analysis method. At the same time, the feature sample set consists of the correlation dimension feature information and the energy feature information was built. Finally, the feature sample set was utilized as input, and the multi-fault modes of the axial piston pump were identified by support vector machine. Moreover, the experiments were respectively performed to the pump including slipper wear, loose slipper failure and central spring failure. The results confirmed that the fault recognition accuracy of SVM can be improved, and the faults can be effectively identified.

关键词： multi-fault identification axial piston pump envelope demodulation correlation dimension support vector machine

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A+D Combined Pump-controlled System for the Regular forging Process of the forging Press

A+D Combined Pump-controlled System for the Regular Forging ...

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2015 International Conference on Fluid Power and Mechatronics

作者： Yao Jing Li Bin Cao Xiaoming Zhang Yang The Laboratory of Heavy Machinery Fluid Power Transmission and Control in Hebei Yanshan University National and Local Joint Engineering Center for Advanced Forging Press Forming Technology and Equipment Yanshan University Yanshan University

The regular forging process has been the primary technology for forging workpieces manufacturing because of its well-known adaptation and performance, and it usually needs thousands of input power. In this study, the energy consumption of the conventional valve-controlled system for 22 MN forging press was analyzed firstly, and depicted that the valve-controlled system had huge energy losses. Then in accordance with the digital pump concept, a novel proposal of A+D combined pump controlled system was given and conducted in 22 MN forging press. The simulation results proved that there was no overflow loss anymore and the useful work was improved considerably for the novel system. Additionally, the input work was decreased dramatically compared with the conventional valve-controlled system. However, the flow rate impact of the fixed displacement pump and the response of the variable displacement pump are still big challenges for this novel system to be applied into the industry.

关键词： forging presses pump controlled system regular forging process energy saving digital control

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Fatigue Analysis of the Cylinder in The Axial Piston Pump

Fatigue Analysis of the Cylinder in The Axial Piston Pump

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2015 International Conference on Fluid Power and Mechatronics

作者： Quan Ling-xiao Cao Yuan Luo Hong-liang Guo Rui Guo Haixin School of Mechanical Engineering Yanshan University The State Key Laboratory of Fluid Power Transmission and Control Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China

For the cylinder of the axial piston pump suffers complicated forces including hydraulic pressure force, mechanical forces and mutual coupling, which causes the cylinder fatigue damage with all forces whose fluctuation is caused by fluid striking on the cylinder of the pump cyclically, it is necessary to develop the fatigue analysis research. And the sensitive fatigue areas of the cylinder in the axial piston pump is presented through the nephogram of the fatigue life, the fatigue safety factor over the whole model and the curve of fatigue sensitivity, which can verify the theory of micro crack propagation and the transient dynamics analysis of the axial piston pump cylinder is simulated. All the results are produced by software, Solidworks is used to build the three-dimension assembling model containing seven pistons and ANSYS Workbench is used to manage the model through setting the parameters of different materials and constrains of the cylinder. It's promising to provide a theoretical basis when optimizing the design of the axial piston pump and to offer new ideas and methods for the study of reliability and fatigue durability on the axial piston pump.

关键词： Axial piston pump Cylinder Transient dynamics simulation Fatigue simulation

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Research on Parallel Energy-saving Reliability Test Method for Hydraulic Components

Research on Parallel Energy-saving Reliability Test Method f...

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2015 International Conference on Fluid Power and Mechatronics

作者： Liwang Wei Yi Zhang Rui Guo Jingyi Zhao School of Mechanical Engineering Yanshan University Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Key Laboratory of Advanced Forging & Stamping Technology and Science(Yanshan University) Ministry of Education of China

The traditional reliability test of hydraulic components is time-consuming and low efficiency with high energy consumption, so we propose a novel parallel energysaving reliability test method to improve the performance. By increasing the sample type and sample size of the single reliability test, the test time can be shortened and the energy can be recycled for many times. The design considerations of the parallel reliability test device are summarized at the end of the article. The experiment results indicate that the test time and the power loss of the parallel energy-saving reliability test device are greatly decreased, and it has large application value.

关键词： hydraulic components,parallel energy-saving,reliability test,recycle

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