Applied Mechanics and Materials Vols. 313-314

Abstract: Bythe method of unioning thematrix-valued Lyapunov functional and comparison theorem,delay big system’sconnected Lyapunov stability is studied deeply.A series of new sufficientconditions are proposed.These results have not only theory meaning but alsopractical value.

Abstract: The acoustic radiation of submerged damped cylindrical shell is investigated by combining with thin shell theory and elasticity theory. The classical integral transform technique is used to derive the solutions of coupled equations. Numerical computations show the correctness of the proposed method, and also conclude the influence of thickness of inner shell and coated layer to acoustic radiation. The conclusions may be valuable to the application of damping material on noise and vibration control of underwater pipes.

Abstract: This paper presents an investigation into the active control of structural-acoustic coupled system of a rectangular enclosure involving two simply supported flexible plates. One of the two plates is driven by a point force. The locations of actuators are determined by considering contour plot of the optimal potential energy. The control mechanisms for this enclosure are analyzed when one, two and three actuators are applied on one of the plates. Results obtained demonstrate that the control mechanisms for Panel a are always modal restructuring; those for Panel b are dominantly modal suppression when a different number of actuators is applied to reduce the noise level.

Abstract: t is a great significance for power supply reliability and smart grid to locate feeder fault quickly and accurately for distribution network. A new ground fault traveling-wave signal time-frequency analysis method is proposed, which decomposes the aerial mode component and zero mode component of fault current based on EMD to get multi-stage stable intrinsic mode function (IMF). The first IMF contains high frequency components which can reflect the mutation of signal. Hilbert-Huang transformation is done for the first IMF to get the instantaneous frequency of signal. And then check the moment of traveling wave arrival by the instantaneous frequency in the figure of IMF time-frequency. The fault distance is computed based on the time difference between the moments of wave arrived of aerial mode component and zero mode components. Simulation shows that this method is able to accurately give the distance of fault without the influence of the random fault condition such as fault transition resistance and the moment of fault.

Abstract: The term “acoustic emission” means radiation processes of exertion waves which are produced by internal sources located in the thickness of material under investigation. Acoustic emission method is used as a means of analysis of materials, constructions, productions control and diagnosis during operating time. Energetic parameters as the acoustic emission energy itself may be obtained only based on the whole spectrum analysis. It is strictly contraindicated to measure signal energy in narrow band, naming such measures as “energetic parameters”. Energetic parameters as the acoustic emission energy itself may be obtained only based on the whole spectrum analysis.

Abstract: In this report givens descriptions of principle hardware-software complex. It was designed for generation signals special form on their frequency characteristics. Simulation of the signal occurs through the summation of harmonic components of the spectrum with user-defined step, and the registration system response reduces the measurement error value of the phase-frequency characteristic can be calculated by the algorithm to maximize the average signal power during the period of generation. Designed software and hardware system to reduce the quantity of necessary equipment for nondestructive testing by acoustic methods and to increases the flexibility of approaches to the study of a specific object.

Abstract: Based on a modified neural network with a new structure and a fast algorithm, an approach on adaptive predictive control is represented in this paper. Advantage of neural network modeling accuracy and good control performance of the optimal predictive control are combined. In the meantime, we can take the nonlinear network model output as a kind of measured disturbance, which is overcome in predictive feed-forward control. So the approach achieves satisfied control effectiveness.

Abstract: This paper introduces the particle swarm Optimization (PSO) algorithm and the ant colony optimization (ASO) algorithm to solve the optimal problem of distribution network restoration reconfiguration. In the solving process, propose a multi objective function which contains the minimize line losses and minimize number of switching operations. In the time, simplify distribution and received the feasible searching strategy improved the searching speed. Because parameters has an important influence on ACO algorithm, this method use the PSO optimizate the parameters α and β of ACO. Take the parameters as the position of PSO. This method overcomed the parameters on the influence of the ACO and improved the global searching capability. Simulation on a typical 33 node case is conducted, the results show this method has a good performance of global searching.

Abstract: Distribution automation development and research on system devices have been introduced in this paper. In terms of new issues appearing in distribution automation, such as distributed generation, electrical vehicles station, microgrid, electrical interaction, etc., applications and development prospects have been concluded, as well as the research on new power electronics technology, information technology, interactive strategy, etc. in smart grid.

Abstract: In order to obtain more rapid and effective communication, simplify the format information of the slave and the transmission logic under the appropriate project application requirements, and form the simplified scheme.