Applied Mechanics and Materials Vol. 189

Abstract: Based on the disciplines theory such as the mechanics and electromagnetics, this paper presents three kinds of electromaglev linear feed unit, with the help of the 3D modeling software Solidworks and large general purpose finite element analysis software ANSYS. The statics analysis on workbenches of the three kinds of electromaglev linear feed unit are made by using of ANSYS, then the results are analyzed and compared. It can be identified as the conclusion that, the structural stiffness on workbenches of the three kinds of magnetic linear feed unit can basically meets the requirement, and all of them can be selected as the needed structural design. But the four-L separately suspended and oriented type electromaglev linear feed unit has the better structure stiffness, and take the weight, cost, load capacity and dynamic characteristics and other factors into account, we preferred to choose the workbench design of the four-L-pillar separately suspended and oriented type electromaglev linear feed unit.

Abstract: Vibration characteristics of the thin-walled cylindrical pipe are affected by the liquid within the pipe. The natural frequencies and vibration modes of the pipe without liquid are analyzed by the theory of beam bending vibration and finite element model, which is based on the Timoshenko beam model. The first three natural frequencies and vibration modes of the pipe with or without liquid are acquired by experiments. As shown in the experiment results, the natural frequencies of the containing liquid pipe are lower than the natural frequencies of the pipe without liquid.

Abstract: Stress concentration coefficient of welded joints has a crucial influence on mechanical properties of welded structures. Geometrical parameters of welded joints seriously affect the stress concentration coefficient. In order to increase the mechanical properties and safety of welded structures, it has great significance for reducing stress concentration coefficient and improving the mechanical properties of welded structures by researching and improving the geometry of welded joints. In this paper, the effect of stress concentration coefficient on the fatigue properties for welded cruciform joints of 16MnR steel was analyzed by using ABAQUS finite element and MSC.Fatigue programe, and the change rule of stress concentration coefficient with the variation of the parameter was studied and the fatigue life changed with the stress concentration coefficient was also researched. The calculation results indicate that reducing the weld tangent line angle θ can effectively decrease the stress concentration coefficient of welded cruciform joints, and the fatigue life of welded cruciform joints can be improved succesfully. In order to obtain the safety welded structures, the true weld tangent line angle θ should be controlled in the angle smaller than 20o.

Abstract: In mineral processing the high material volumes yield the fact that benefits of even small improvements in the production quality and product efficiency are remarkable. During the operation of the mineral material processing, the grinding circuit (GC) is the key unit and its product particle size and circulating load are two controlled indexes directly related to the quality and efficiency of the whole mineral material processing. Therefore, an appropriate control of GC is especially significant to improve the operation performance of the mineral material processing. Due to the GCs are essentially multivariable dynamic systems with high interaction among process variables. It is hard to improve the quality and efficiency in the mineral material processing by controlling the grinding system with the conventional methods. In this paper, a novel multivariable decoupling control scheme is adopted to handle such intricate process. Simulations have shown the proposed method can greatly improve the production quality and product efficiency of the mineral material processing.

Abstract: A BLDCM drive system based on Z-source converter is proposed in this paper, it can be integrated to control DC bus boost and BLDCM speed by Z-source transformation technology, which not only improve energy efficiency but also raise the system security. The algorithm of PWM is applied to control Z-source inverter, which is simulated by Matlab/Simulink, the results are shown to verify the features of the Z-source inverter for BLDCM drive system, and confirm that the method is correctly and availably.

Abstract: The magnetic suspension system is a strong nonlinear, uncertain and open-loop unstable system. All of these factors have increased the difficulty of maglev controller design. Considering the single freedom maglev system as the research object in this paper, structure analysis and modeling design are conducted for the system. By choosing new state variables, the system model is transformed. On the basis of that, we use back stepping design method to design the nonlinear suspension controller. Control performance of the controller can be observed by the Matlab/Simulink simulation.

Abstract: This paper focuses on an intelligent MPPT (maximum power point tracking) algorithm for permanent magnet vertical-axis direct-drive wind turbine systems. The relationship between generator speed and buck convert’s duty ratio is analyzed. then, the output and the speed of wind turbine are controlled by convert’s duty ratio. In this way an intelligent MPPT algorithm, the different step length is given in different directions, is used to this system. At last, the system is simulated by software, and the simulation results indicates that compared with the conventional MPPT strategy, the rapidity and the stability are increased by intelligent MPPT algorithm.

Abstract: Room-temperature ionic liquids are new emerging green material. They have good chemical and thermal stability, negligible vapor pressure, nonflammability, high ionic conductivity, transparence, and a wide electrochemical window. So the ionic liquid material strongly tempts many researchers. But ionic liquids are usually applied in chemistry and rarely applied in physics. In fact ionic liquids are good photoelectric medium material owing to its well ionic conductivity, transparence. However, in applications, the drive of ionic liquids is the key technic and is also a bottle-neck. Here a kind of electromagnetic drive way is presented, There are not any mechanical moving elements and the drive is bidirectional. Theory and experiments indicate the drive pressure and flow rate are distinct undering a few voltages and 0.5T magnetic flux density. So this drive way can be used as a low power liquid pump. Latency applications in Microfluidics, Optoelectronics and industry are given.

Abstract: The drop state of the ink-jet ink is an important factor that influences the ink-jet imaging quality, so the drop state under different voltage and frequency is researched in order to research the influence of the ink-jet condition to the drop state. The edible ink sample is printed with Spectra Polaris nozzle under different ink-jet condition including voltage and frequency, and the drop state is observed by drop observation. The result shows that while voltage increases, drop speed increases and drop volume increases first and decreases then. The duration time of drop necking state is the same under different voltage, but the tail length becomes longer if the voltage is up to 120V. The drop speed is stability under the frequency of 2KHz-4KHz, but when the frequency continues to increase, the speed shows a trend of decrease.

Abstract: The cotton recognition would become rather difficult during the application of the cotton harvesting robot (CHR) in the case where the cotton is sheltered or covered by other objects. In this paper, a novel approach of cotton detection based on the improved randomized Hough transform (IRHT) for this case is proposed. Based on the contour information from the boundary trace, the mathematic model-based IRHT is derived based on a modified circular detection technique. It yields a well agreement with the requirements of the precision and rating of CHR.