Study On Identifying The Modal Parameter And The Dynamic Response Of The Structure Based On The Ambient Excitation

The outlet structure was struck all the while by the high-speed flow, so it is very easy to damage injuries. If we don’t handle it carefully, it will influence the project benefits and threat the people’s life. In many Water Conservancy and Hydropower Engineering at home and abroad, The water cushion pond bottom was often damaged. And the reason and the extent of the damage is usually similar. The most of the damage is belong to the slab which was washed away by the high-speed flow, few of them was damaged by the sundries in the water. Therefore, to establish the real time monitoring system of plunge pool floor vibration, which can accurate and timely diagnose the structure of water plunge pool risks and diseases is necessary. The study of this paper mainly include the following aspects:(1) This paper introduced the wavelet analysis method into the plunge pool floor vibration analysis. we introduce the basic principles of wavelet analysis, and use the wavelet analysis of vibration signals to achieve the decomposition on different frequency bands. Through analysing the different frequency bands, different scales of the signal, we can get the plunge pool on the vibration signal energy in different frequency bands and the bottom of the distribution of vibration characteristics.(2)According to the signal noise, using the universal threshold, the threshold which was got from Birge-Massart strategy, the threshold which was got from penalty strategy,and the threshold was got from the sample estimate reduces the noise of the signal. And get the best methord.(3)This article analyses the the measured signal of the spillway plunge pool floor vibration response. And gets the strength, the amplitude characteristics, the frequency domain, the correlation, the coefficient of partial peak and the amplitude ratio coefficient of the signal. At last we can access the plunge pool floor’s vibration laws in different conditions.(4)This paper introduced the basic principles of RTD and STD method. And using the STD method togethers with ordering systems’s determination by singular entropy to identification modal parameters of the plunge pool floor.