Applied Mechanics and Materials Vols. 220-223

Abstract: The method of spectrum analysis is present to detect fault signals of main shaft and increasing gearbox of large-scale wind turbines, so as to prevent from huge loss and serious accidents. The real-time signals detected from wind turbines will be compared with those stored in the database to find whether the amplitude of the signals exceed the alarm threshold. Frequency spectrum is obtained based on both wavelet transform and frequency spectrum analysis of collected signals through the graphic programming language–LabVIEW. The method can judge accurate fault type and its position on wind turbines, which present evidence for fault diagnosis of the gearbox and main shaft. Experimental results indicate that the method is effective.

Abstract: On the base of converting the X6170ZC diesel engine into a diesel-LNG Hybrid Diesel Engines, intelligent control technology was used to improve the precision of fuel injection. Through the experimental analysis of the replacement rate changes, the test results show that the engine comprehensive replacement rate is higher and more economic.

Abstract: The paper presents the results of experiments in a circle drilling. Namely, the results of data processing load on the cutter (blade) moving in a certain radius, with step-checkboarded and sequential circuits of arrangement on the crown of ring bore. The paper presents the stresses of this incisor, with the two constellations, their relationship to each other. As a result, the conclusions brought under any scheme of arrangement of cutting elements are obtained by the least energy-intensive process.

Abstract: According to the induction motor operating characteristics, application of improved artificial fish swarm algorithm based on the simplex method to solve the equivalent circuit model parameters identification problem. Gives a detailed calculation steps and the curve of function expressions. Finally, the identification results and identification using genetic algorithm result is compared to prove that the accuracy of the identification results of the improved artificial fish swarm algorithm having higher precision.

Abstract: Based on analysis of press working characteristics, some of the main kinematics requirements for working mechanisms of servo mechanical presses were put forward: fast in empty stroke, slow and uniform in working stroke and big force gain. Crank link and knuckle-straight link are the most common working mechanisms in mechanical presses. To meet the requirement of servo mechanical presses, another mechanism, knuckle-triangle link, was designed. The kinematics simulations of the three mechanisms for a 1600kN press were conducted by dynamic software ADAMS. Knuckle-triangle link had the most uniform and lowest slide’s average velocity and biggest force gain within the working stroke. For the same nominal pressure of 1600kN, the required input torque of knuckle-triangle link was 9108Nm. In comparison with crank link and knuckle-straight link, the crank’s input torque was reduced by 84% and 76% respectively without considering the influence of friction and inertia. In conclusion, knuckle-triangle link mechanism is more suitable for large-tonnage servo presses.

Abstract: In this paper rear left side window buffeting characteristics of a production sedan under different yaw angles and different window opening sizes are investigated through full-scale aeroacoustic wind tunnel tests. By yaw angle -10 degree, as driver position on the lee side, the resonance peak SPL is much less than that by yaw angle 0 or +10 degree and the corresponding frequency is also some lower than that by yaw angle 0 or +10 degree. As window opening size turns small, the resonance peak SPL decreases. By side window with 25% opening size, the peak SPL is much less than that by side window with 50% or 100% opening size. In addition, the corresponding frequency is also some lower than that by side window with 50% or 100% opening size. Different test positions at the front row or back row show very similar buffeting characteristics.

Abstract: This paper investigates diagnostic methods and proposes modern service technologies for wood-processing equipment. The aim of this study is to ensure systematic, research-based wood-processing services and continuous, no-failure operation of facilities. We describe the working principle of a particular industrial, drum-type wood chipper and discuss the problems that occurred during operation, including potential excess engine load or construction imperfections. First experiments show that knife wear progresses even faster than previously expected. Cutting regime calculations are provided, along with a description of actual improvements and a comparison of cutting regimes before and after improvements. The intended result of this research is a monitoring unit with help of a few modifications, can be used on any drum-type wood processing equipment.

Abstract: In order to meter the wet gas without separation online, a novel measurement device composed of a long throat Venturi tube and a V-cone is proposed and a new metering method based on triple differential pressures. In this method, the ratios of the differential pressures are vital parameters used to establish the measurement correlations. The comparison of these correlations is also presented. In laboratory test, the measurement accuracy of the gas and liquid are 2.13% and 6.68% respectively.

Abstract: This paper researches fault feature extraction method based on singular value decomposition and the improved HHT method for non-stationary characteristics of wind turbine gearbox vibration signal. Firstly, through the signal phase space reconstruction, the singular value decomposition as a pre-filter, to preprocessing the signal, effectively weaken the random noise. Then using EEMD to improve the HHT method, decompose the denoising signal into a series of different time scales component of intrinsic mode functions. The fault characteristics of the signal are extracted by the Hilbert transform. Finally, simulating gearbox fault experiment to verify the effectively of the proposed method.

Abstract: To determine the purifying performance of filters to inhalable particles,an experimenal device to test purifying performance of the filters were developed based on GB12218-89 and EN779:2002. With the device,6 filters were taken as research objectives with a view to investigating the purifying performance to particles in ambient air,the influencing factors such as raw materials and structures on filters’ purifying performance were pointed out. The result shows that woven, knitted and general non-woven filters are not suitable for filtering the particles in the ambient air.With higher dust capacity ,higher filtration efficiency and lower resistance,PP acupuncture electret filters are suitable for purifying the inhalable particles in the ambient air.