Advanced Materials Research Vols. 542-543

Abstract: By using Solidworks, a three-dimensional solid model of the wind turbine gearbox is established. Use Spring element in ANSYS joins transmission system and case structure system, the whole gearbox coupling dynamic model is built up and the first 20-order bound mode of the gearbox is calculated. Through modal analysis and experimental test show that the structure of wind turbine gearbox is reasonable, and resonance wouldn’t occur during the operational process, ensure the reliability of the unit operation and that for the wind turbine gearbox structure design to provide the theoretical basis.

Abstract: This paper presents a novel system for detecting concentration of the CH₄ and CO gases, which exist widely in the coal industry. The system applies micro blazed grating to split the collimated light and may get the infrared absorption light with certain wavelength and bandwidth for the gases detection. The schematic diagram, calculation, signal processing, and setup were described in details. Experimental results indicate that the detection system has the ability to detect methane and carbon monoxide with maximum error of 0.169% and 58.3ppm, stability of 0.76% and 0.22%, respectively.

Abstract: The pulsating flow is an important factor affecting the performance of the rotor-seal system. From the point of view of pulsating flow induced vibration, the nonlinear models of the rotor-seal system with the pulsating fluid flow are established. Based on the numerical simulations by Matlab/Simulink, the characteristics of pulsating flow induced vibration with the flow velocity in a form of sine wave or/and a constant have been quantitatively analyzed. The investigation also demonstrates that the proposed models, from the point of view of pulsating flow induced vibration, can be effectively applied to the analysis of the rotor-seal system.

Abstract: Absorption heat pump (AHP) heating in power plants in winter is an effective way to recover waste heat and make full use of energy. In this paper, quantitative calculation is taken to analyze the energy saving and economy efficiency of AHP heating in a power plant. The rate of energy utilization ηtp, the coal and water saving amount and the increased income of AHP heating are calculated. Results show AHP heating in power plants is superior to steam extraction heating both in energy saving and economy.

Abstract: The incompatible data information between the various types of ventilation management software and the coal mine safety monitoring system has become a major obstacle to the mine ventilation and safety management informatization. This paper studies the synchronizing integration of the heterogeneous data between the coal mine three-dimensional visualization ventilation system and the security monitoring system, which divides the mine ventilation information into the basic information and the security monitoring real-time information, analyses the transmission characteristics of the real-time monitoring data, explores the conversion of heterogeneous data online communication, and achieves the integration of geometric parameters and various dynamic parameters for the coal mine ventilation system.

Abstract: Considering the limitation and production costs, the selective assembly is often used to enhance the precision of assembly of complex products. This paper presents an imporved grouping method based on MOPSO( Multi-Objective Particle Swarm Optimization) for selective assembly with multiple characteristics. The properties and quality criteria of selective assembly of components with multi-quality characteristics were analyzed to establish a mathematical model. The objective function of this model is to minimize the clearance variation in selective assembly. Fitness sharing strategy and dynamic archiving strategy are introduced to improve the solving performance of MOPSO. The method is applied to the optimization in a piston-cylinder selective assembly problem. The results show that the presented method can effectively reduce the clearance variation of of the product assembly

Abstract: Through the data acquisition system of drop impact test impact excitation pulse and in response to a pulse, to reduce or eliminate the experimental process generated interference signal brought influence, the excitation and response signals are Fourier transform (FFT), get the cushing material power spectrum and cross spectrum density value, the time domain signal into frequency domain signal, realize the effective filtering, the frequency domain signal in each frequency through the transfer rate calculation formula of cushing packaging material transient vibration transmitting rate, the transmission rate of the way the process of obtaining description and theoretical analysis.

Abstract: Objective method of image quality evaluating is necessary for the research of ultrasonic imaging quality of different ultrasonic testing method, and deterministic calculation method is essential for the defect analyzing of ultrasonic image. Defect analyzing method of ultrasonic image is researched by threshold segmentation, noise point rejecting and area filling. Experiment results indicated that the defect position and size can be adjudged by the ultrasonic image.

Abstract: As an example for the test of built monitoring system, the experimentation was carried out to monitor the condition of tool wear, which related with the machining process closely. In pattern recognition, using the nonlinear mapping function of neural network, a three-layer BP artificial neural network was selected to carry out the mapping between the processing status and related signal features. In this way, the monitoring of machining processing was implemented. The Matlab Script node of LabVIEW software was used to call the neural network package of Matlab, which reduced the program development cycle and increased the reliability of the program. According to the cutting experimentation of the finger milling cutter, it is verified that BP artificial neural network can effectively recognize the tool condition and accomplish the wear prediction.

Abstract: Nowadays solar photovoltaic energy has become an important alternative energy sources. This paper focuses on single-phase PV grid-connected system, a reference frame which used for three-phase inverter has been used in this single-phase grid-connected inverter. The in-quadrature signal is generated used T/4 transport delay technique. This single-phase grid-connected inverter uses space vector pulse width modulation(SVPWM) method. Finally, the 3KW small power single-phase photovoltaic inverter system model is built to verify the presented control strategy by using the Matlab/Simulink.