Based On Wavelet Analysis Of Cable-stayed Storm Vibration Measured Signal Non-stationary

The actual test and characteristic research about strong wind is an important basic and long-term work, it can provide reliable information for wind field simulation, the determination of the design wind load and some other follow-up study. Rain-wind induced vibration induced by the wind and rain in the common role, is very destructive fierce substantial vibration. As rain-wind induced vibration happens frequently and harmfully, it has become one of the world difficult and hot research spots. The existing analysis method of rain-wind assumes the measured speed is a stationary process. However, the wind speed measured in strong wind environment is usually nonstationary. At this time, still using a stationary speed assumption will lead to large analysis errors. So the nonstationary wind speed mode based on the theory of multi-scale analysis method is required.The contents of this paper is a part of the the National Natural Science Foundation project "Study on the law of damage accumulation and catastrophe evolution of long and huge bridge under strong wind"(Grant no.50808175). The process of field experimental tests of wind-rain induced stay cable vibration on Dongting Lake Bridge is briefly introduced, then, the wind characteristics and stay cables vibration acceleration sponse when wind-rain induced vibration happens are studied by using wavelet theory. The main work in this paper is concluded as follows:1. This paper expounds the parameters of wind characteristic, then introduces the traditional stationary wind speed model and the nonstionary wind speed model. These two models are compered with each other in the calculation of the wind parameters.2. The application of wavelet analysis in the extraction of time-varying mean wind speed is studied in this paper. All the results obtained by wavelets are more accurate than those by empirical mode decomposition (EMD). So the nonstationary wind speed model based on wavelet multi-resolution analysis is proposed. 3. By using the field measurements of wind speed of wind-rain induced vibration on the Dongting lake bridge, the wind field parameters of the bridge are obtained. The calculated results are compared with those provided by EMD and stationary model.4. In the paper, the relation between cable vibration acceleration and wind velocity, wind yawing anger, anger of attack are discussed. Nonstationarity in wind-rain induced response is studied, and the cause of this nonstationarity is discussed by using a wavelet approach.