Applied Mechanics and Materials Vol. 607

Abstract: Design method of hydraulic system of full hybrid transmission was analyzed. At first, oil volume flow and pressure requirement was confirmed according to the vehicle control strategy. Mechanical gear pump and electric pump were used to supply oil flow for all driving modes. Self-adapted pressure regulation circuit was designed to supply high pressure oil for brake engagement. Structure dimension of valves and cooling orifices was designed by theoretical calculation. Cooling flow can be distributed proportionally among electric motors and planetary gears.

Abstract: Performance of helicopters can be significantly influenced by rotor speed variation. A comprehensive model is built to exam the influences of rotating speed on performance and blade loads of a variable speed rotor. The results indicate that for a 2,200kg gross weight helicopter, power reduction is up to 30% at 100km/h by slowing the rotor properly. For lower gross weights, the reductions in rotor rotating speed and power savings are more apparent. The optimum rotating speed may cause a 20.5% increase in endurance and 8.5% in range by thoroughly consuming 400kg of fuel. Rotor RPM variation has an important effect on blade loads. For 100km/h and 2,200kg gross weight, amplitudes for most of the harmonic loads decrease with reduced rotor RPM.

Abstract: Micro stages have been used for various purposes on such as industry inspection, positioning technology, and manufacturing of semi-conductor etc. These micro stages have voice coil motor for actuator. The actuator has to be properly made in confined volume to generate enough force to thrust the stage. Therefore, the voice coil motor, which is actuator for the micro stage, should be optimally designed. In this paper, it is described how to design the voice coil motor in an optimal way.

Abstract: Vibration simulator is developed to excite the railway structure in one direction to measure the vibration and damage characteristics from the abnormal vibration in certain circumstances. The simulator consists of a base plate, a motor, several holders to fix the structure and a vibration controller. The vibration frequency can be controlled by an accurate frequency controller with 0.1Hz frequency step. The railway structure is located on the base plate which is integrated with an excitation motor. Frequency accuracy of vibration controller and amplitude level within the variable frequency range is demonstrated.

Abstract: Linear finite element analysis model of the typical rotor system is established by the finite element method. Considering the gyroscopic effect of the rotor, critical speed in the rotor system is solved. Then the effect of the rotor system by the unbalanced force on dynamic characteristic is analyzed by frequency response curve. The result shows that support damping coefficient has a great effect on critical speed in the rotor system. With the support from rigid support to elastic support, the critical speed greatly reduces. Because of the unbalance exciting force, maximum resonance amplitude of the disk is near the critical speed of the rotor.

Abstract: The radiation noise of motor shell vibration during operation is studied by finite element method. Firstly the finite element model is established to calculate the vibration frequency response characteristic. And on this basis the frequency response characteristic of the sound pressure under the work condition is calculated. The result shows that the vibration of the lateral wall and upper wall of the shell produces the radiation noise. And the radiation noise from the lateral wall makes a more significant contribution by comparison. While the method of adding the surrounded structure and stiffener to the shell can effectively reduce the vibration of the lateral wall and upper wall, which can finally reduce the vibration noise by 10dB.

Abstract: Ball bearing life test, once the failure specimen ball fatigue, if not timely shutdown, will lead to a series of chain reactions caused by the fault processing is not seasonable, serious word may also lead to the damage of equipment. Therefore the vibration test is very important to accurately determine the specimen failure, ball. In this paper, the vibration test for bearing fatigue testing machine, the test results to be real-time and accurate judgment sample ball failure.

Abstract: The dynamic excitation and the noise of meshing gears were analyzed quantitatively using the three-dimensional finite element contact analysis and the boundary element method. The distribution and variation roles of the gear mesh noise were obtained. The simulation result was verified by sound power measurement. The main excitation was determined additionally. It provides the theory basis for the control of the gearbox noise.

Abstract: with the increasing proportion of wind power in whole power system ,the influence between wind power system and grid become more and more seriously ,so it is great important to research how to keep the connection between the wind power system and grid when grid voltage drops .The paper presents a new method to realize the low voltage ride - through (LVRT) of DFIG by using dynamic voltage restorer (DVR). Once the grid voltage drops,DVR will be put into use and produce compensation voltage to keep the stator side voltage steady .And it also can stop operation after the fault resolution.The paper builds a simulation model of DFIG and gives simulation results on PSCAD/EMTDC platform .

Abstract: The design and manufacture of an innovative pump conceived based on vortex diffusion is described in this paper. The authors believe the pump has the potential of achieving higher efficiency gains than those currently available. A prototype was, therefore, manufactured for laboratory testing and eventual field trials and commercial manufacture. The success of the concept in achieving the goals, will pave the way towards significant savings in fuel expenditure through lower pumping costs.