Advanced Materials Research Vol. 871

Abstract: Hydraulic excavator slewing system is an important component of the excavator and its core-component is the rotary motor. When the rotary hydraulic system starts, stops, and reciprocating works, dynamic characteristic of rotary motor anti-reverse valve has a great influence for working condition of the whole system. Through researching working principle of hydraulic system anti-reverse valve, establish dynamic mathematical model of anti-reverse valve, analyze dynamic response of the model, and get the theoretical foundation of the impact of anti-reverse valve middle chamber throttle opening on hydraulic system. According to the actual working condition of the excavator slewing hydraulic system, establish the system AMESim simulation model, take different parameters of the anti-reverse valve throttle opening, conduct simulation and analysis of the anti-reverse valve characteristics, and validate throttle opening has a great influence on dynamic characteristics of the hydraulic system.

Abstract: Variable nozzle turbine (VNT) has become a popular technology for diesel application. While one of the major challenges for VNT is resonant vibration due to the fluctuating pressure in unsteady flow. Both the leakage flow forms inside the nozzle clearances and the shock produces under small nozzle openings increase the flow unsteadiness inside downstream rotor tunnel. In this paper, the unsteady simulation of the turbine was conducted to investigate the effects of nozzle clearances and openings on the transient load fluctuation of the blades. Then a finite element model of turbine wheel was built and blade forced response was simulated with harmonic analysis. The results showed that the decrease of nozzle opening would intensify rotor vibration and increase the blade dynamic stress. The simulation of blade resonance showed that the 1st order resonance located at the blade trailing edge while the 2nd order resonance happened at the leading edge, which was consistent with the blade actual crack.

Abstract: Its hard to use traditional ways to set up a hydroelectric power plant model due to its complex, time-varying and nonlinear characteristics. This article uses the neural network autoregressive with exogenous input (NNARX) to identify and model hydro-turbine generating unit which is the key in the hydroelectric power plant modeling. The random guide vain signal is used to train NNARX in this paper and the other two working conditions are used to check its generalization ability. In order to improve identification accuracy, generalization performance and training speeds, an improved Levenberg-Marquardt algorithm is proposed in this article which is based on the L-M algorithm that widely used in artificial neural network weights adjustment. Simulation results indicate that NNARX model with improved L-M algorithm can reach high recognition accuracy and have good generalization ability. It can provide a good simulation model for intelligent controller design in the future.

Abstract: In order to meet the needs of 3D simulation training system, this paper proposed a three-dimensional simulation training system based on Web3D technology. 3Dmax,Balder3D and Silverlight5 are used to build 3D models, construct 3D scene and bear the 3D scene, respectively. Combining with the ASP.NET platform, we constructed a 3D training system platform, which could be applied to the hydropower plant simulation training system. The system includes whole process simulation, single-step simulation and dynamic simulation. Since its built on B/S structure, users have an easy access to the simulation system by using the browser. So the system will surely help the users to get a more intuitive and convenient knowledge of ship lift operation process.

Abstract: Micro In-Pipe Robots are strongly demanded in the application of micro pipe failure-detection in nuclear stations and actuation systems of ships. In this essay, a micro in-pipe robot based on 15mm diameter's pipe with new spiral driving system and cage structure was developed, and the mechanics model of the micro robot was built. By utilizing virtual modeling technology, the robot's structural parameters were analyzed and optimized, and a real model was manufactured using optimized parameters with maximum traction 21.49N, maximum moving speed over 10mm/s, which met the requirements of being micro in size and large in traction.

Abstract: The carbody structure of electric multiple unit (here in after EMU) shall be designed withstand the loading conditions without permanent deformation or any form of damage. And the carbody shall have a minimum design life of 25 years or more in Korea. Loading conditions have a longitudinal compressive force and a vertical load. Camber of the carbody is defined as its curved shape viewed in side elevation. Carbody camber shall be a smooth arc from end to end of the carbody and shall be measured from a datum line drawn between the intersections of the arc with the center lines of the carbody bolsters to a line tangent to the arc midway between bolsters. The carbody shall be built with positive camber such that camber shall remain positive with the carbody at maximum load and shall not bind due to deflection caused by variations of service load. To assess the strength and stiffness of the designed carbody, carbodys designer shall be demonstrated by a programme of finite element analysis and testing shall be carried out in accordance with Korean standard technical specifications. The carbody is manufactured by giving the slope of the deflection to be compensated strength and stiffness. The deflection is camber. So this study analyzes that how camber affects safety and durability of carbody according to the load conditions and revenue service on main-line. Methods and analytical model of carbody structure is introduced to demonstrate them.

Abstract: Marriage in Honey Bees Optimization (MBO) is a new swarm-intelligence method, but it has the shortcomings of low speed and complex computation process. By changing the structure of MBO and utilizing a linear method to perform the local characteristic, we propose a new optimization algorithm. The global convergence characteristic of the proposed algorithm is proved by using the Markov Chain theory. And then some simulations are done on Traveling Salesman Problem (TSP) and several public evaluation functions. By comparing the proposed algorithm with MBO and Genetic Algorithm, simulation results show that the proposed algorithm has better convergence performance.

Abstract: In this study, we generated the uniform diameter micro-bubbles using a piezo-vibration assisted capillary nozzle for apply the nano/micro bubbles device use. The capillary nozzle (diameter: 35 μm) was fabricated by FIB technique, and attached with piezo-device as micro bubbles generator. The fabricated piezo-nozzle showed inflective movement, whose displacement amount was about 3 μm. Micro bubbles were not able to generate from capillary nozzle without piezo-vibration, while micro bubbles, whose diameter was in the range of 20 μm to 21 μm, could be generated from the capillary nozzle with piezo-vibration.

Abstract: The coil is the important part of a motor. The traditional monitoring system of the coil can only act when a fault was found. A new fault diagnosis system in motor coil is discussed in the paper. We had built coil fault knowledge base by using data fusion. We had predicted and diagnosed the causes of coil fault quickly by inference rules.

Abstract: A lecture on the method to compute the the stress of V-tooth coupling under the actual operating conditions. the finite element analysis model of V-tooth coupling under the preload, axial load and torsion was established by used of the software ABAQUS,and the distribution of the bending stress at the root was obtained. The analytical method to compute the bending stress of V-tooth disk is deduced based on the basic principle of material mechanics, and the relative error within 10% compared with the results of finite element analysis.The paper work provide the reference for the precision design of V-tooth coupling.