Advanced Materials Research Vols. 971-973

Abstract: This paper deals with the aerodynamical problems of rigid flapping wing at low Reynolds numbers with emphasis on investigating the lift generation mechanism of simplified ornithopter. Theoretical analysis and Particle Image Velocimetry (PIV) were conducted to analyze and verify the lift generation conditions. The results revealed that the rigid flapping wing will generate lift under the conditions of both angle of attack α and free incoming flow velocity v were not zero. With the wings flapped periodically, there were votexes formed, developed and shedding alternately. The calculation of curl demonstrated that the greater of flapping speed, the greater of curl. The statistic of circulation suggested that the circulation generation of flapping down was greater than that of flapping up, the circulation difference contributed to the lift generation. The difference of circulation will increase along with the angle of attack α in the circumstances of free stream velocity v and flapping speed π and flapping amplitude Φ matched well.

Abstract: In this paper, the characteristics of four-axis NC (Numerical Control) machining are analyzed initially. Afterwards, in order to obtain a complex workpiece by use of four-axis NC machining, a combined method that can optimize the machining process is proposed, which includes: modeling and programming based on UG software; simulation of the machining process by applying VERICUT. Finally, the results indicate that the method combined with UG programming and VERICUT simulation has practicability and superiority in four-axis NC machining.

Abstract: This article uses the method of variables separation and generalized coordinates method to analyze the characteristics of the mine hoist wire rope tension, and the steel rope tension on-line monitoring system is designed, the experiments show that the system can reflect the hoist wire rope tension work state; result provides the basis for the optimal design of hoist.

Abstract: The subject comesfrom major national special project in Kunming Machine Tool Factory which oursupervisor is working on currently. This report is the analysis of overallstructure of magnetorheological dampers,main technical features andperformance. It also provides a brief introduction to the main features of MRFand rheological principle, as well as the calculation of magnetorheologicaldamper size design, and also constructs the magnetorheological damper simulationmodel based on the magneto-rheological dampers structural features. With theTHM65160 CNC machine structure, we designed specifically on the localapplication of magneto-rheological dampers for varying magnetic flux dampermounted machine made ​​dynamic performance test responses. Based on this,magnetorheological dampers combine structural and performance characteristics,simulating the motion by using ADMS.

Abstract: Complex operating environment makes excavator working device become the main wearing parts ,In this paper,builds three-dimensional models of the excavator working device using Pro/E. And selects the working device typical operating conditions which is in the maximum discharge height ,then imports it into the finite element analysis software ANSYS - Workbench module. For the purpose of acquiring its natural frequencies and mode shapes, it conducts the modal analysis by setting the material properties, meshing and boundary conditions,which provided foundation for the optimal design of hydraulic excavator overall vibration analysis and structural dynamic characteristics.

Abstract: Modern motor needs high speed, high efficiency, high power density and low pulsating torque, traditional rare earth permanent magnet motor manifests its limitation. Halbach motor is a novel permanent magnet motor. Analysis of Halbach motor based on ANSYS proves its merits: sinusoidal field, higher air gap flux and lower rotor yoke flux, which can reduce pulsating torque and improve power density, efficiency of the motor, these merits can improve its dynamic characteristics greatly.

Abstract: Abstract: The packer rubber stress in the bottom hole is more complex. Based on constitutive model of the packer rubber material, this paper determines such parameters as model constants, Poisson's ratio of rubber materials and elastic modulus by using experimental method, to build up the finite element model of center tube-rubber cylinder-casing for the purpose of stress analysis. Finally, the distribution regularity of rubber cylinder-casing contact stress and packer setting travel distance with varying loads is concluded. The results can provide the theoretical basis for further analysis of packer rubber sealing performance.

Abstract: The difference between the theoretical calculation and the actual volume of sound insulation which appears in the actual engineering of water pump system always exceed the standard of noise in the residential areas. It is difficult to meet the requirement even when the quality of the project gets improved. In this paper, ,the acoustical mode is obtained by finite element method and the distribution of noise after coming through the floor is calculated in different frequency based on the theory of sound and vibration coupling effect . The result points out that the neglect of the vibro-acoustic coupling effect is the main reason of imprecise. The solution to the problem is put forward and the direction of the noise reduction measures in the future is pointed out .

Abstract: CNC equipment as carriers of the advanced manufacturing technologies, to accelerate the rapid development of China's aviation industry has a pivotal role. In this article, the development of intelligent Aero-CNC machine tools is studied, the reliability improvement of domestic CNC machine tool is illustrated, the specific applications of domestic CNC machine tools is analyzed in the field of aviation, the development direction of China Aero-CNC machine tool is pointed out, it has a strategic significance for the revitalization of China's aviation industry.

Abstract: In units’ grid-related protection, loss of excitation protection and out-of-step protection are very important to ensure the stable running of grid. If both can realize the right coordination when unit occur a phenomenon of low excitation, it can improve the level of power source coordinated with grid. However, there is a problem in the coordination of both. Propose an idea to solve the problem based on power angle. Besides, out-of-step protection and out-of-step splitting exists a coordination relation according to the location of out-of-step oscillation center. In order to prevent the collapse of grid and protect units, it is necessary to cut off out-of-step lines and units correctly. Summarize the reasonable coordination relation between both by theory analysis and research.