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Lu Y.,Yanshan University | Lu Y.,CERI Yingkou Equipment Development and Manufacturing Co. | Ye N.,CERI Yingkou Equipment Development and Manufacturing Co. | Mao B.,Yanshan University | And 2 more authors.
Mechanism and Machine Theory | Year: 2012

Contracted graph (CG) is a basic and effective tool for deriving topology graphs which are widely used for type synthesis of closed mechanisms. This paper focuses on the derivation of valid CGs from simpler CGs by adding edge and the identification of their isomorphism. First, the concepts of CGs are explained, and the numbers of vertices and edges in CGs are determined. Second, many different CGs are constructed from associated linkages. Based on the numbers of different edges, many CGs corresponding to the same associated linkage are grouped and the isomorphic/invalid CGs are identified and deleted. Third, many complex valid CGs are derived from simpler valid CGs or virtual CGs by adding edge. Finally, two application examples of the CGs are illustrated for type synthesis of closed mechanisms. © 2012 Elsevier Ltd. All rights reserved. Source


Wang Z.,Taiyuan University of Technology | Wang T.,China Institute of Technology | Xie Y.,CERI Yingkou Equipment Development and Manufacturing Co. | He Z.,Taiyuan University of Technology | Tang B.,Taiyuan University of Technology
He Jishu/Nuclear Techniques | Year: 2011

Nb alloyed layer was prepared by plasma surface alloying technology on surface of stainless steel substrates. Microstructure morphology, depth profiling of the elemental composition and phase structure of the alloyed layer were analyzed. Corrosion performance of the Nb alloyed layer was investigated. The results show that the optimum parameters were: temperature, 1100°C; air pressure, 80 Pa, holding time 3 h, source voltage, 900-700 V; and cathode voltage, 600-450 V. The thickness of Nb alloyed layer was about 60 μm. The alloyed layer was mainly composed of NbC and Nb6C5, Cr2Nb and Fe2Nb. The surface Nb content was 50%, which decreased sharply in the first several microns of depths and then gradually in further depths. The Nb alloyed layer has improved resistance to intergranular corrosion and uniform corrosion. Source


Lu Y.,Yanshan University | Lu Y.,CERI Yingkou Equipment Development and Manufacturing Co. | Ye N.,CERI Yingkou Equipment Development and Manufacturing Co. | Wang P.,Yanshan University | Ho B.,Yanshan University
Journal of Mechanical Science and Technology | Year: 2012

It has been a significant and challenging issue to solve the inertial wrench of parallel manipulators (PMs) for their dynamics analysis and control. A CAD variation geometry approach is proposed for solving the inertial wrench of PMs. First, an initial simulation mechanism of PM, and a simulation mechanism of PM with linear/angular velocity and acceleration are created. Second, when modifying the driving dimension of the active legs, the simulation mechanisms are varied correspondingly, the position, linear/angular velocity and acceleration of moving platform and legs, and inertial wrench of moving platform and legs are solved automatically and visualized dynamically. Third, a 3-DoF PM is illustrated, and the displacement, linear/angular velocity and acceleration, and inertial wrenches of the moving platform and legs are solved using CAD variation geometry and are verified by the analytic solutions. Finally, inertial wrenches of the legs are transformed onto the moving platform. © 2012 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. Source


Lu Y.,Yanshan University | Lu Y.,CERI Yingkou Equipment Development and Manufacturing Co. | Ye N.,CERI Yingkou Equipment Development and Manufacturing Co. | Mao B.,Yanshan University | And 2 more authors.
Journal of Mechanical Science and Technology | Year: 2012

It has been a significant and challenging issue to derive the complex valid contracted graphs (CGs) with hexagonal links plus other links and identify their isomorphism for creating novel closed mechanisms. This paper focuses on the derivation of the valid CGs with hexagonal links plus other links using the characteristic strings (CSs). First, the concepts on the CGs and CSs are explained, and the numbers of vertices and edges in the CGs are solved. Second, the relative criterion are determined for representing/deriving CGs and identifying isomorphic/invalid CGs by CSs. Third, some simple CGs are derived from some associated linkages with hexagonal links plus more other links, are represented by CSs, and the isomorphic/invalid CGs are identified using the CSs and the isomorphic queues of the links. Fourth, some examples are given for illustrating their applications. Finally, many complex valid CGs with more hexagonal links plus other links are represented and derived using CSs, and their isomorphism are identified using CSs. © 2012 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg. Source


Lu Y.,Yanshan University | Ye N.,CERI Yingkou Equipment Development and Manufacturing Co. | Lu Y.,CERI Yingkou Equipment Development and Manufacturing Co. | Mao B.,Yanshan University | And 2 more authors.
Journal of Mechanical Design, Transactions of the ASME | Year: 2012

The relations among the associated linkages (ALs), the redundant constraints, the passive degree of freedom (DoF), and the degree of freedom are studied systematically for the type synthesis of the closed mechanisms in this paper. First, the kinematic pairs with multidegree of freedoms are formed by combination of the basic joints with single degree of freedom in series, and the formulae are derived for the calculation of the degree of freedoms of the associated linkages, the number of the basic joints, and the valid numbers of the basic links in the associated linkages. Second, many different associated linkages and the number of basic links are derived, and the relations among the associated linkages, the redundant constraints, the passive degree of freedom, and the degree of freedoms of the closed mechanisms are analyzed. Third, some topology graphs are derived and the relative closed mechanisms with the redundant constraints and the passive degree of freedom are synthesized. Finally, the redundant constraints and the degree of freedoms of the closed mechanisms are determined. © 2012 American Society of Mechanical Engineers. Source

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