Applied Mechanics and Materials Vols. 599-601

Abstract: Dynamic and static frequency of the rotor about diameter of 1.4m small horizontal axis wind turbine was tested by using PULSE16.1 structural vibration analysis system., through combining the data of static frequency to identify rotor Dynamic frequency using spectrum analysis method. The conclusions found that, at a yaw condition of constant rotor speed, vibration acceleration of axial movement, disc effect and first order vibration of rotor increased with the increase of the yaw angle. The reason was that yaw exciting force which generated by the yaw behavior increased with the increase of yaw angle. At a constant load yaw, vibration acceleration of axial float, disc effect increased with the increase of the yaw angle. At the yaw condition of constant load R=82Ω、R=118Ω and the yaw angle 25°,30°,the acceleration value sharp increased and occurred the machine resonance phenomenon due to the tower instability. First order symmetric and anti symmetric vibration acceleration of rotor decreased with the increase of the yaw angle. The reason was that after the wind turbine yaw, the speed decreased of rotor caused the centrifugal force of the blades decreased, the impact of the centrifugal load changed was far greater than yaw exciting force for the first order vibration acceleration. The study also found that vibration acceleration values of rotor first order anti symmetric was ​​greater than axial movement, disc effect and first order symmetric vibration acceleration values, which shows that stress concentration in root of blade was large and the blade fatigue damage was more serious. This paper related research results can provided a new analytical thinking for rotor fatigue damage or breakage occurred frequently in wind turbine operation process, and may provide a reference for the vibration characteristics of rotor in the process of yaw.

Abstract: In order to select the band-pass filter parameters reasonably, a new method of rolling bearing feature extraction based on wavelet filtering with optimal combination bands is proposed. Filter banks with different number of filter/octave are constructed by Morlet wavelet, which are used to filter the signal. The filters with the optimal frequency-band are selected according to the kurtosis of the filtered signal. Then, the optimal band filters in each filter bank are combined to filter the signals and the feature extraction is available. Through simulation and experimental verification, results show that the proposed method is more effective than the common one.

Abstract: In this paper, we construct a second-order two-scale (SOTS) asymptotic expansions for thermopiezoelectric problems in periodic structure by means of construction way. A set of numerical results are demonstrated for predicting the temperature, mechanical displacement and electric potential in periodic structures. It shows that SOTS's asymptotic expansions can capture the 3-D local behaviors caused by 3-D micro-structures well.

Abstract: In this paper, a portable underwater acoustic transducer sensitivity test device is designed to overcome the disadvantages of traditional test methods, such as the bigger size of anechoic pool, and single function of the vibrating column of liquid method. This new design has the advantage of small size, easy to carry and implement. A model of this device is constructed based on the finite element analyse software COMSOL Multiphysics. By calculating the sound field distribution of the test device model, the optimization size of the piezoelectric ceramic can be determined. Also the effect of some other key parameters, such as the material of vessel and thickness, are considered. All these results can provide the theoretical basement of the design of portable underwater acoustic transducer in practice.

Abstract: The coupling simulation model of a gasoline engine’s working process and muffler is established by GT-Power software, and related data are obtained by simulation calculation. It is found that the calculating results are consistent with the actual data, which validates the correctness of this simulation model. Through the analysis processing of the coupling simulation model, it is put forward an improved case for the exhaust muffler in this paper. Based on a local optimization, the simulation results show that the insertion loss of muffler has improved markedly, the exhaust noise values decreased and indicated power engine remain basically unchanged.

Abstract: An engine cooling system of heavy vehicle was used as a research object in this thesis. Engine system model was designed with KULI software according to wind tunnel testing data of heat exchanger provided by supplier. Simulation calculation provides optimization program based on the results. The result is that it can simulate calculation with KULI software, in the early design on a cooling system of heavy vehicle engine. The study provides a theoretical basis for the design of a cooling system of heavy vehicle engine, improve the efficiency and save the cost.

Abstract: Gantry cranes are used throughout the materials handling industry. But conventional methods of power transfer to the cranes such as trolley conductor and wire directly connected have remained less than ideal, that is until the recent development of a novel wireless power transfer (WPT) system that is clean and spark-free, is robust to dust and water, and has very low maintenance. A 10kw WPT simulation system applied to gantry crane has been developed. The best compensation topology and the parameter have been studied in order to get high efficiency of the system. The study has been focused in showing the parameter design. Finally, the simulation has proved the validation of the proposed parameter design method.

Abstract: A Magneto-rheological Fluid Clutch (MRC for short) which has a novel and simple structure is designed; the research on the magnetic field distribution is based on the finite element simulation software which is named Ansoft; In order to test the work performance, the electronic torsion testing machine is used for the torque transmission capability and controllability test. The experimental results reveal that the MRC could meet the torque transmission demand of high power machine and response quickly and reliably.

Abstract: Based on low utilization rate of energy and high fuel consumption, a parallel hydraulic & electric configuration for hybrid excavator was proposed according to the capacitor and motor. The mathematical model of key components such as engine, electric motor, and capacitor were established. For the hybrid power system based on SUNWARD 20T hybrid excavator, the paper established simulation model and analyzed the energy saving effect of hybrid system by simulation based on the actual load spectrum of hydraulic excavator as input signal. The results indicate that adopting the parallel hybrid system are helpful to improve the energy saving effect of hydraulic excavator, and the energy saving efficiency is about 23.6%.

Abstract: Taking the drilling bed of Z8016 deep hole drilling machine as the research object, a modal analysis of drilling bed structure is performed by ANSYS software. Assuming that the low-order natural frequencies basically remain unchanged, the structure of the drilling bed is analyzed and modified so as to decrease its weight. The bed structure is selected based on ANSYS, that is to say, the structural parameters of the drilling bed are optimized in the condition of fundamental frequency constraints, which takes wall thickness, ribbed plate thickness and the diameter of ribbed plate holes of the drilling bed as design variables. Compared with the original one, the optimal drilling bed has better dynamic stiffness, reduces material consumption, lowers the cost of the drilling bed and achieves the optimal goal.