Study On Dynamic Testing And Characteristics Of Three Gorges Left Powerhouse

The paper studies on the dynamic testing system of the Three Gorges left powerhouse by applying the theories of mathematics statistic, FEM, electricity and the dam engineering. The main contents are as follows:1. The frame and the main constituents of dynamic test system are studied. Principle of measuring point layout and parameter election are analyzed based on the structural characteristics and operating conditions of hydraulic structure. And it's also analyzed about how to select sensing device by sensor's character. The emphases are studied on the principles of signal transfer and matching between sensing device and measuring circuit and the generation and control of interference in test system.2. The time-frequency methods of random data processing and the differences among them are studied. The principles of Fourier analysis and wavelet analysis in removing and reducing signal noise are discussed and compared. Dynamic test signal is completely described, and by studying the methods of amplitude-domain, time-domain and frequency-domain, the various parameters of signal are determined.3. The time history of water hammer in pipeline in the condition of unit emergency load dump is calculated by characteristic line method. On the basis of FEM of structural dynamics, the dynamic response's solution method in the condition of water hammer load is discussed and the principle and process of Newmark method are mainly represented. What's more, frictional contact model is applied to the solution of dynamic response of pipe by considering contact nonlinear.4. The test system of the Three Gorges left powerhouse is studied using the theories and methods mentioned above. Field dynamic test signals are analyzed by the methods of amplitude-domain, time-domain and frequency-domain. The distribution regularities on dynamic response of pipe and factory building structure under the different behaviors are analyzed. On the same time, dynamic response of steel pipe is analyzed by FEA, and by comparing its results with measured value, the functional mode between steel and concrete is studied.