Applied Mechanics and Materials Vols. 397-400

Abstract: Based on statistical energy analysis method, the 32m z-propeller tug model was built by VA One software. The numerical simulation research of vibration and noise of 32m z-propeller tug cabin was carried out by VA One. In order to prove the numerical simulation validity, the simulation data was compared with that of the experiments, which shows that the vibration prediction error is lower than 15% and the noise prediction error is about 5 dB(A). Whats more, schemes of cabin noise reduction and the power plant vibration isolation were designed to make the vibration and noise levels meet the IMO and GB5980-2000 standards requirements. The sound absorption material was pasted on the bulkhead of cabins, and the average noise reduction level achieved to 7 dB(A). Then, the single-layer vibration isolation system was designed for the diesel engines, the average noise reduction level achieved to 5 dB(A). The simulations have some guiding values on the control of tug cabins vibration and noise.

Abstract: This article designed a kind of magnetorheological high-speed on-off valves and made optimized design based on the nature of the magnetorheological fluid(MRF). ANSYS software was used to analyze magnetic field of the two different structures and get the magnetic flux lines distribution and flux density map. The simulation analysis results show that: optimized high speed switching valve, can reduce the loss of the coil and the rise of temperature, improves the life of the valve body, it also can shorten the switching response time and improves the reliability of the valve.

Abstract: In this paper, firstly, a dynamic model of planetary gears involving the bearing wear and a model to calculation of the bearing wear capacity will be established. And then the basic flow for prediction on the wear life of bearings for planetary gears will be given by the proposed two models. Finally, the influences of the bearing wear on the bearing wear life will be studied and the methods to improve the bearing wear life will also be discussed. The simulation and analysis results show that with the increase of the limit wear capacity, the bearing wear will experience three periods, such as rapid increasing, steady increasing and constant, and there are also a significant impact of the bearing clearance and stiffness on the bearing wear life.

Abstract: Propeller thrust estimation method is convenient in selection of propellers. In this paper the Abbott formula method, Hamilton method and strip theory are introduced and then compared with the test value of propeller static thrust. The result shows that the three methods are all correct on the tendency of static thrust varies with revolution. Considered on the entire factor the Hamilton method is recommended.

Abstract: For wind turbine high-speed shaft vibration, this article proposes a hydraulic shock absorber design, and detailed describe the working principle and structure of the shock absorber. Use Amesim Software conduct vibration simulation ,confirm that the design is reasonable.

Abstract: The design in this paper is a rectangular piezoelectric vibrator driven Cantilever Beam Diaphragm Pump. By analyzing the working principle and characteristics of the piezoelectric cantilever beam pump, we developed the dynamics model and FEA model of the piezoelectric cantilever beam and optimized through tests the main factors that affect the output flow of the piezoelectric cantilever pump. Additionally, we designed the piezoelectric cantilever pump prototype, and by using an impedance analyzer, we measured the resonance frequencies of cantilever beams of different lengths; and we used the laser micrometer to test and measure the beams of different structures under loaded and unloaded condition. The maximum displacement of the output terminal of loaded cantilever beam is 50.5μm. Furthermore, through the experiments we tested the output flow and its corresponding variation under different diameters of transmission pistons and different excitation frequencies. Experimental tests show: when selecting the cantilever beam and the drive piston with optimal performance with the input voltage at 120V, and the frequency at 197Hz, the optimum output flow rate is 89ml/min.

Abstract: With the lengthen of the production time continuously, and the adjustment and implementation of development programs constantly, the situation of Jiangsu Oil field well casing will become worse, even damaged gradually, while corrosion is one of the main factors to cause casing leakage in Jiangsu Oil field. In order to study the corrosion mechanism and influencing factors, we developed downhole dynamic simulation experiment device. The device is mainly composed of the recycle loop system, temperature control system, pressure control system, the main riser, and the buffer vessel. It implements the control of factors impact on the oil casing corrosion such as temperature, partial pressure, flow rate etc and helps us study the corrosion behavior of downhole tubing and casing. The results of weightlessness and electron microscope scanning show that the flow velocity and flow pattern is the main factors of maximum casing corrosion near the oil pump suction rate, and the local corrosion by CO₂ is given priority to, this is consistent with the situation of field casing corrosion. It also shows that this experimental device has the advantages of reasonable structure, stable and reliable performance, easy operation, strong simulation and practicality.

Abstract: Based on the introduction of the control principle of path machining of NC machine tools, this paper studies and simulates the dynamic path error of machine tools. Simulation result shows that the dynamic path error is related to the path curvature and the feed speed of machine tools. In the case that the path curvature has been set, this paper proposes a variable feed speed strategy to optimize the dynamic path error of NC machine tools. The comparison simulation result shows that this strategy can decrease dynamic path error and improve the machining precision effectively.

Abstract: High-speed slotless permanent magnet brushless motor based on soft ferrite adopts a large effective air gap structure. For the large effective air-gap, the air-gap flux distribution becomes uneven and the end leakage flux significantly increases. Thus, the traditional analytical method of the phase EMF is inapplicable. This paper deduces the analytical expression of the phase EMF based on the analytical calculation of the air-gap field and analyzes the distribution of the end leakage flux by 3D finite elements methods. Then the end leakage flux is considered by a correction factor of the core length. Finally the analytical calculation method is proved to be feasible by the comparison between the finite elements results and the prototype test results.

Abstract: Based on the piezoelectric effect and magnetorheological technology, a parameter adaptive shock absorber was designed. Considering the practical working conditions of landing gear, mathematical model of the parameter adaptive shock absorber was built. Then on the basis of LMS Imagine.Lab AMESim software, the whole combined simulation model of self-adaptive control system was constructed and the drop dynamic simulation was conducted. Results showed that compared with passive control system, parameter adaptive shock absorber reduced the peak of axial force by 10.5% and increased the absorber efficiency by 5.6%.