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Yang L.,Beijing Institute of Technology | Nie J.,Beijing Institute of Technology | Jiao Q.,Beijing Institute of Technology | Li J.,Beijing Institute of Technology | Ren M.,Chongqing Hongyu Precision Industrial CO.
IEEE Transactions on Plasma Science | Year: 2015

Based on the fact that the double-deck rail demonstrates excellent performance in preventing rails melting and gouging during electromagnetic launch tests, theory and simulation research studies were carried out on the lateral vibration of the double-deck rail and contact properties between the armature and the rail in this paper. We deduced the lateral vibration contact equations of the double-deck rail by simplifying the electromagnetic rail launcher as Bernoulli-Euler model based on the elastic foundation. A finite-element code was used to help us model the launch progress. The influence of the double-deck rail scheme has been analyzed. Both the characteristics of the contact surface between the rail and the armature and the displacement of the rail were considered. The results show that the double-deck rail can inhibit the propagation of bending waves and efficiently reduce rail gouging. Besides, the connection method of the two decks has much influence on this effect. © 2015 IEEE. Source

Xu G.Y.,Chongqing University of Technology | Xu G.Y.,China University of Petroleum - Beijing | Wang J.B.,Chongqing Hongyu Precision Industrial CO. | Guo L.P.,Northeast Petroleum University | Sun G.G.,China University of Petroleum - Beijing
Advanced Materials Research | Year: 2014

TG analysis was used to investigate the thermal decomposition of switchgrass, which is a potential gasification feedstock. 10 mg switchgrass sample with the particles between 0.45 and 0.70 mm was linearly heated to 873 K at heating rates of 10, 20, 30 K/min, respectively, under high-purity nitrogen. The Kissinger method and three isoconversional methods including Friedman, Flynn-wall-Ozawa, Vyazovkin and Lenikeocink methods were used to estimate the apparent activation energy of switchgrass. With the three isoconversional methods, it can be concluded that the activation energy increases with increasing conversion. The four model free methods reveal activation energies in the range of 70-460 kJ/mol. These activation energy values provide the basic data for the thermo-chemical utilization of the switchgrass. © (2014) Trans Tech Publications, Switzerland. Source

She Z.,Hunan University | She Z.,Researches Power Electronic and Electrified Transmission | Liu J.,Hunan University | Zhang B.,Chongqing Hongyu Precision Industrial CO. | And 2 more authors.
Proceedings of 2010 International Conference on Intelligent Control and Information Processing, ICICIP 2010 | Year: 2010

Soft starters have been widely used in fans and pumps drives. It is difficult to start high-power heavy-duty induction motor for traditional soft starter. To solve the problem of soft starter for large power and heavy load in conventional soft starters, the soft starter based the theory of discrete frequency is studied in this paper, which can make motor start with high torque and little current. Using discrete frequency makes the start frequency of motor from 5.25Hz to 50Hz step by step, which can make start torque larger. This paper presents a method of the calculation of optimal triggering angle which can make the torque be the biggest and positive was produced. The simulation waveform by MATLAB is similar to the real waveform by experiment. Control hardware circuit is simple and dependable. The experiment of the high torque soft starter which has a DSP as microcomputer is completed. The experimental results show that discrete frequency soft starter can start motor smoothly with high starting torque and small starting current. The advantages of discrete frequency soft starting proposed in this paper are stable start process, simple structure, low starting current and high starting torque. The result of load test is identical that conforms the theory is correct and valid. © 2010 IEEE. Source

Yang L.,Beijing Institute of Technology | Nie J.,Beijing Institute of Technology | Ren M.,Chongqing Hongyu Precision Industrial CO. | Zhang L.,Beijing Institute of Technology | Jin Z.,Xian Electronic Engineering Research Institute
Gaodianya Jishu/High Voltage Engineering | Year: 2014

In order to further improve the performance of rail electromagnetic launchers (railguns), we studied the contact between rail and armature during launch processes by a finite element model of railgun established with LS-DYNA code. We designed three C-shaped armatures, which have concave surface trailing edges of different curvature radius, to match rails with curvatures, and calculated the dynamic mechanical response of these armature/rail pairs. The simulation results show that the contact force, for all the three armatures, quickly increases during 0~0.1 ms, fluctuates with relatively small amplitude during from 0.1 ms to approximately 0.74 ms, starts to fluctuate with larger amplitude at about 0.74 ms when the armature reaches its critical velocity, and eventually changes obviously and reaches a local minimum value at 0.755 ms. Meanwhile, the three armatures have pressure distribution similar to their contact surfaces. As for the rails in the three matches, their deflection curves are similar, and the contour maps of the rail deflection passed by armatures are hardly different. It is concluded that the sharp downward fluctuation of armature/rail contact force marks an armature reaching its critical velocity, and the distribution of contact pressure becomes unsteady afterwards. Additionally, different matches between rail and armature interface show little impact on the dynamic mechanical response of both armature and rail. Source

Wang W.-L.,Yantai Naval Aeronautical and Astronautical University | Li Y.-S.,Yantai Naval Aeronautical and Astronautical University | Tian C.-Y.,Chongqing Hongyu Precision Industrial CO.
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2011

In order to verify the feasibility of installing annular shaped charge on the front of active missile s warhead, the numerical simulation is used to optimize the design of annular cutter, and the range cut test is used to preliminary investigate the damage effect. The results show that the cut effect on thick target is significant for the optimized annular cutter, and the cut effect is strong for 40mm targets at 30° attack angle. The conclusion provides reference for the newly tandem warhead design. Source

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