Advanced Materials Research Vols. 690-693

Abstract: Cogging torque is one of the main reasons which cause ripple in motor's speed and torque. So the reduction of cogging torque must be considered in the design of permanent magnet machines. This paper presents a new method for cogging torque minimization by optimizing pole-arcs combined with varying the thickness in magnets. With the combination of different pole-arcs of each PM slice to achieve the minimum cogging torque while without being harmful to the average torque. Thus, optimize the offset value which varies the thickness of magnets to further reduce the amplitude of cogging torque. In this paper, it used genetic algorithm (GA) to optimize pole-arcs and magnet offset on the basis of Finite Element Method (FEM).

Abstract: The structure and properties simulation of Cu under vacuum were studied by ab initio molecular dynamics simulation. The calculation results were characterized in terms of radial distribution function (RDF), coordination number (CN) and partial density of states (PDOS). The results show that the average distance between atoms increased with the temperature, while CN decreased, which indicated an obvious improvement of the thermal motion between atoms. The simulation datas showed that the liquid phase appeared in the system when the temperature arrived 1373K,which close to the melting point(1357K) of copper.

Abstract: The interactive orthogonal design was employed to investigate the aerodynamic drag coefficient (CD) of hatchback car by using CFD methods. And the effects of back windshield angle, diffuser angle, front windshield angle, hood angle, side windshield angle and tail length were discussed. The results indicates that back windshield angle, diffuser angle and their interaction, hood angle and front windshield angle have notable effect on the CD of the model, while other parameters and interactions have no notable effect. The best CD conditions are: back windshield angle 20°/60°, diffuser angle 12°, front windshield angle 30°, hood angle 15° and tail length 4300mm.

Abstract: The paper deals with the application of Reverse Engineering (RE) in the process of redesigning and manufacturing of a printer spare part. The paper presents the devices for transfer of a damaged printer part into a digital model by non-contact three-dimensional (3D) digitization. The paper discusses the 3D computer-aided designing (CAD) of a model with CAD software based on a digitized real part. The paper presents two proposals for spare part manufacturing: a) manufacturing by computer numerical control (CNC) milling, which is projected and programmed in computer-aided manufacturing (CAM) software with regard to production potential of selected CNC machine tools; b) manufacturing by Rapid Prototyping (RP) technology. The article concludes with a comparison of the proposed methods of manufacturing of printer spare part in term of production time.

Abstract: A FANCU computerized numerical control(CNC) machining carving method in the hemisphere surface parts by MasterCAM is recommended in the article, including CAD modeling of carving text & setting processing parameters according to the machining process , transmitting the G code of fool path to the FANUC , to realize the actual processing of the surface text carving . The method solves the problem of manual programming limitations, avoids the tedious calculation and program panel inputting, and improves the processing quality and efficiency of carving machining.

Abstract: A pillar spiral three floors staircase with no need additional be needed for construction in engineering. Based on this project profiles and steel stairs design standards, the appearance and the form of structure of the stairs be designed. And the spiral staircase’s overall modeling set. Calculated on the strength and deformation be analyzed by finite element analysis software. Provide a reference for other similar projects.

Abstract: Study on flow field of civil transport upswept aft-body is of much value as the drag coursed by aft-body contributes to about 10 percent of total drag. Currently researches were mostly concerned on clean fuselage, while little emphasis was put on fuse-tail configuration. With interests to exploiting the effect of design parameters on fuselage with empennage, computational fluid dynamics (CFD) was used to simulate the flow field of fuselages with different parameters. Based on studying the aerodynamic performance of clean fuselages, emphases were placed on fuse-tail configurations. Although fairing at root of stabilizer is good for reducing pressure drag, influence on friction drag should be taken into consideration when determine the design of fairing. With stabilizer mounted, drag of axial symmetric fuselage is not the minimum, while the one with some angle upswept is drag optimal.

Abstract: Railway ballast tamping operations is employed in order to restore the geometry of railway track distorted by train traffics. The selection of tamping parameter is usually dependent on field trials and practical experience, for lack of theoretical basis. This paper creates discrete element analysis model of railway ballast using the discrete element method, the numerical simulations are carried out to study the mesomechanics of railway ballast during tamping process. We focus on the change of railway ballast compactness and stone ballast interaction force during tamping process. The present study can be helpful for the analysis of the internal mechanism of ballast compaction during tamping process.

Abstract: Railway ballast tamping operations is employed in order to restore the geometry of railway track distorted by train traffics. The main goal is to compact the stone ballast under the sleepers supporting the railway squeezing and vibrations. The ballast compactness is the most direct index for evaluating the effect of tamping operation. This paper presents an experimental method used to detect the railway ballast compactness before and after tamping operation based on water-filling method, and creates a discrete element analysis model of railway ballast which analyzes the change of ballast compactness before and after tamping operation based on discrete element method. The simulation results are very similar with experimental results, which verify that the discrete element method is an effective method to evaluate the change of railway ballast compactness during tamping process.

Abstract: Frame of the van is the basis for mounting of the other assemblies, by sustaining the various kinds of force and load from the road and the weight, so the strength and stiffness of the frame is the very important on the overall design of the van. This thesis does an analysis and research in accordance with ANSYS, discussing the frames static strength of the warp working status and the torsion working status, and doing an analysis of stiffness. The result of analysis shows that the frames ultimate stress is lower than the ultimate strength of material, satisfy the design demand. But the strength of material is overall higher, so the economic efficiency is low. This thesis is also provided the parameter for the nest step design of stress centralization areas and unreasonable design structure.