Applied Mechanics and Materials Vols. 284-287

Abstract: Portal axle unit is a gearbox unit installed on every end axles of the vehicle. It is installed to the vehicle to give higher ground clearance to enable vehicle to go over large obstacle when driving in off-road conditions. Shafts must be exceptionally tough and lightweight to improve the overall performance of the portal axle unit. In this paper, the shaft is analyzed in three-dimensional model and the stress of the shaft model is analyzed using finite element analysis (FEA). The FEA result is compared with experimental results.

Abstract: This paper describes the Transient Simulation Method (TSM) which predicts the steady state and performance of autorotation in forward flight. Flapping and rotational equations of motion are integrated from an arbitrary initial rotor speed, and the steady state of autorotation is obtained as a periodic solution through a transient process. The induced velocity field update method and the average thrust, lift, and drag computations during the transition are described in detail. TSM is then applied to the model rotor to validate the feasibility. High speed autorotation is simulated using an aerodynamic data set that is analyzed by the two-dimensional compressible Navier-Stokes Solver. Rotor speed variation for increases in airspeed at low shaft angle is presented and discussed. When TSM is used with sophisticated aerodynamic data analyzed as functions of the blade angle of attack, the Reynolds number, and the Mach number, the autorotation range for the collective pitch, velocity, and shaft angle can be reasonably explored.

Abstract: The computational results of the scattered electromagnetic (EM) fields from a rotating circular dielectric cylinder were presented in this paper. The method of characteristics (MOC) was applied in a two dimensional modified O-type grid system to the solutions of the time-dependent Maxwell equations. To accurately model the rotating cylinder under the illumination of EM pulse, the passing center swing back grids (PCSBG) technique is employed in cooperation with MOC to overcome the difficulty of grid distortion due to the rotational movement of the cylinder. A number of electric and magnetic field distributions over the whole computational space were demonstrated in a side-by-side fashion for the comparison of the scattered EM fields from rotating circular dielectric cylinder with those from the stationary one. The numerical results exhibit feasible trends.

Abstract: Planetary gear trains produce several advantages, including high speed reduction, compactness, greater load sharing and higher torque to weight ratio, which are used widely in wind turbine, automobiles, robot and other applications. In some important transmission applications, the noise and vibration are key concerns in design. In this paper, a 3D dynamic contact and impact analysis model of planetary gear trains has been proposed. Tooth surface friction, backlash, tolerance of peg hole, and time-varying stiffness were considered in this dynamic model. The ANSYS / LS-DYNA were utilized to analyze the dynamic responses of gear transmission of the planetary gears. The vibration behavior of an actual gear set under dynamic loading was simulated in the dynamic model. The stiffness and elastic deformation of gear teeth are calculated using the finite element method with actual geometry and positions of the gears. The time-varying position of the carrier defined as the vibration and noise source. After impact analysis, the numerical results of vibration of carrier involved with the transient and steady states. Through the Fast Fourier Transform (FFT) methods, frequency spectrums of the transient and steady states of the calculated vibration of planet carrier are obtained for the gearbox designer to avoid the resonance zone.

Abstract: Coal anode baking temperature system is a MIMO control system which is nonlinear and has cross-coupling and time-delay. The thermal model and flue model before are usually created based on hydrodynamics and heat transfer theory which take long to do the calculation or have ill conditions sometimes. The PID control systems based on the two mechanism models do not yield satisfactory results. In order to control the baking temperature accurately, an intelligent control model based on GA-NN with the aim of improving control precision of baking temperature of carbon anode is established by gathering the real data from anode baking furnace used for initial predictive models. A new GA-NN predictive control system is thus realized for the control of anode baking temperature of which the simulation and real control results showed that the system is efficient and effective with better control precision and robust properties than tradition PID control systems.

Abstract: Electrical Discharge Machining is a controlled process where pulsed electrical discharge is used to erode metal in a workpiece. A number of EDM power supplies utilizing different topologies have been widely developed for various applications. Nowadays, EDM process has been given a significant amount of research focus in manufacturing micro components with new low power topologies being utilized. Recently, a demand in micro machining has also extended into biomedical applications. In this paper a current mode flyback converter is implemented for micro machining biomedical component. A MATLAB/SIMULINK modeling technique of flyback converter is presented and the effectiveness of the flyback converter topology is evaluated through the simulation results obtained by varying the value of primary inductance

Abstract: There are relatively insufficient quality specialized modeling tools for power engineering. Regardless there are few possibilities how to simulate main elements of electric network and systems consisting of them. Beside most used specialized tool EMTP-ATP there is MATLAB with its Simulink library SimPowerSystems and newly also DYNAST with its own growing library of power engineering elements. There are also many other general simulation tools with libraries of elements suitable for power engineering. Therefore there seems to be opportunity to compare quality of mentioned tools in accuracy, reliability, speed and flexibility in high demanding problems. Branch “Power engineering” is very specific, because there is necessary in most cases to simulate multiple technical disciplines. Not only electrical network is to solve, but also connection with mechanical equipment and other devices of power engineering. One of the most powerful tools that meet all these requirements is Dynast. Now new library for electric components was developed to make creation of model easy and fast.

Abstract: This study works on the efficiency analysis of a compressed air wind energy system which is composed of a windmill, a continuous variable planetary (CVP) transmission, a flywheel, a clutch, a reciprocating compressor, and an air tank. To make the system operate at its best performance, the subsystem characteristic must be fully understood. In this study, we examine three main subsystems of the wind energy system: windmill, CVP transmission and reciprocating compressor thoroughly by experiments. The characteristic of these subsystems are discovered based on the different operating conditions. The performance characteristics of these subsystems offer a reference for the operation design of compressed air wind energy system.

Abstract: This investigation intends to establish an experimental test platform for a small vertical-axis wind turbine (VAWT), which is installed on the rooftop of a building. The experiment platform designed here is flexible and suitable for executing the systematic performance evaluation on different types of VAWT. By utilizing the data acquisition system (DAQ), all environmental information and power data from sensors and generator on the platform are recorded and transferred to the computer automatically. Later, these analogy signals are transformed to digital format for transmitting into computer. Also, with the aids of a visual software programming within the framework of Labview, the real-time monitoring on the input/output parameters of generator and wind condition on the rooftop can be accomplished simultaneously. Afterwards, the data processing and in-depth analysis on the experimental outcomes are carried out via the established computer program. Consequently, the on-site performance of the wind turbine generator system is attained in an automatic and systematic manner. Moreover, to ensure for providing sufficient data and its accuracy, statistic concept is enforced to judge whether the test data are qualified or not in the data-processing procedure. In summary, together with the data-acquisition software programmed under the framework of Labview, this experimental system can provide the capability for monitoring, recording, and filtering these test data in an rigor manner, and is appropriate for executing the R&D and performance evaluation on different VAWTs.

Abstract: Tesla engine converts the fluid energy into the rotating energy by using the viscosity of moving fluid. Because this machine has high rotating speed but low torque, the application of this engine is still under discussion. However, due to environmental problem, a lot of researches focus on green energy, the air engine becomes an important research issue. The main power source of Tesla engine is compressed air. Because only the mechanical energy transformation occurs inside the engine, there is no by-product produced by the engine. In this study, this device was considered to extract power from wind energy. The viscous stress is relatively small when it is compared to drag force or pressure. Therefore, this study is to discover the possibility of this application through the experiment. The unique inlet was constructed to guide the wind into the engine’s casing. The disk spacing was also changed to discover the optimum disk spacing. The main purpose is to test the engine’s output for its application on the wind energy capture.