Applied Mechanics and Materials Vols. 236-237

Abstract: In order to make the levitation performance of the high temperature superconducting (HTS) magnetic levitation (Maglev) vehicle more stable and safer, in this paper, using a cryogenic measurement system, we measured the levitation forces of YBCO bulk above halbach-type permanent magnet guideway (Halbach PMG) in the temperature range from 77 K to 60 K, then in the condition of deep cryogenic, the levitation forces of YBCO bulk at different field cooling heights (FCHs) were also measured, according to which the levitation stiffness were calculated. The results show that the levitation stiffness of HTS/PMG Maglev system is better at lower temperature. Moreover, when the temperature of YBCO bulk decreases from 77 K to 73 K, the levitation stiffness largely increases in any FCHs. However, after the temperature of the bulk decreases to 73 K, the rate of the levitation stiffness increased gradually reduces. The results are helpful to HTS Maglev vehicle application.

Abstract: The paper provided a feasible method for selecting the scheme of arrangement of main shaft bearing. It presented the common arrangement of main shaft bearing. According to the characteristics of high stiffness CNC lathe, selecting the scheme of arrangement of main shaft bearing by means of AHP. And then, it has chosen the optimum matching scheme in the common arrangement of main shaft bearing.

Abstract: Nd-Fe-B permanent-magnet generator provides DC power for the electrical equipment of light vehicle and charges the battery. The rotor of this generator is constructed by several fastening segments of Nd-Fe-B permanent-magnet material onto the iron core through pole shoes by nonmagnetic bolts with adjacent magnet segments opposed to each other in polarity, i.e. N poles and S poles arrayed alternately. When the rotor rotation, hence the magnetic field rotates, the armature winding cuts the magnetic line and produces electromotive force. The developed five-phase half-controlled bridge commutation and stabilizing voltage adjuster combines both functions of voltage stabilization, commutation, and output direct current (DC) with stable voltage. The instability of output voltage was overcome when the permanent-magnet generator for light vehicle ran at wide range of speed and load.

Abstract: hree-dimensional aerodynamic performance of wind turbine impeller is one of the most important elements in the wind turbine design process; its accuracy directly impacts the efficiency and stability of wind turbine operation. As the current numerical simulation for three-dimensional aerodynamic performance of wind turbine impeller does not fully consider the impact of the rotation effect of the wind turbine and other factors, a relatively large calculation error can be resulted. In this paper, a 1.65MW Vestas wind turbine was taken as an model, and design process of wind turbine blade was made. Also, three-dimensional numerical simulation was made to get a comprehensive dynamic performance of the wind turbine, and the influence of wind turbine power and wind farm efficiency by the pitch angle and wind speed were made.

Abstract: Multi-bar linkage mechanism is one of the most important directions to the development of mechanical presses. But there are a large number of bars, so how to choose each bar size to ensure the best kinematical characteristic and to achieve longer drawing depth as soon as possible is a key to the design. This paper established kinematics mode of the eight-bar drawing mechanism by bar-group method, and deduced kinetics expressions of all bars, then developed application simulated system by Visual Basic, characterizing Windows universal interface. In addition, proposed two-objective optimization functions-drawing depth and drawing speed, and optimized the mechanism by genetic algorithm. The optimization results shows that its motion performance has been improved in a great degree.

Abstract: To establish more accurate and effective gun dynamics model, which considered fully the coupling influence of projectile and flexible barrel, by introducing the virtual substance into the barrel system, a modeling method for self-propelled guns was presented. Taking a tracked self-propelled gun for an example, combining Ansys and Recurdyn, a multi-body dynamics model was built up. The correlation curves between the experimental data and the simulation result under the same firing conditions were obtained. The results show that the model can describe accurately the dynamic response and the projectile movement, which can provide theoretical references for the further research on gun launch dynamics characteristics.

Abstract: This study summarizes the necessity of researching brake pedal in hybrid cars, analyzing the shortcomings in self-study algorithm of capacitive hybrid cars and puts forward the improved algorithm to brake pedal self-study, combined with capacitive hybrid cars. Braking effects with the self-study algorithm control software are proved through the experiment.

Abstract: The design scheme of electrical gear-type time grating sensor is presented for both dynamic measurement and static measurement. This sensor consists of upper layer, middle layer and lower layer. Symmetric three-phase windings are wound around gears of these three layers, respectively, and winds of each layer are staggered by 1/3 pitch. Inductance coils of sensor are embed in slots in another single layer of framework. This structure ensures that the number of pole pairs and probes is half the number of slots to realize high precision measurement with machining of low precision spatial division and low cost. Experiment results show that the accuracy of electrical gear-type sensor can achieve ±2″with multi-polygon autocollimator.

Abstract: This paper, based on Unigraphics NX6.0, made use of UG’s strong parametric modelling technology and secondary development module of UG/OPEN API, used the technology of ADO to achieve technical applications and databases interface, and integrated with database and MFC, to develop a gear CAD library system ,and achieve the aim of parameterization modelling and data management of gears.

Abstract: This paper presents a new design method of TUST dexterous hand. With cable based transmission scheme and implementation methods, and a new designed clutch device and finger cable-drive mechanism for second distribution of electrical power, the plan of using one motor to drive a robot hand with 21 Degrees of Freedom is fulfilled. Then the prototype is machined and manufactured, and the main design propose is verified.