Analysis Of Dynamic Characteristics For Guyed Tower Based On Operational Modal Method

When TransmissionTowe structure in normal operation, the tower withstand avariety of environmental loads so that lead the structure vibration, even more make someseverely accidents such as Transmission Tower-line System collapse and damaged. Sothe research on tower structural dynamic analysis and vibration control method is specialsignificance. Compared with traditional mode analysis operational modal analysis doesnot use incentive facilities and affect equipment operation, which is not only safety butsaving labor costs,because operational modal analysis identify the structural’s modalparameters only bases on the response of structural inspired by the natural environment.Dynamic characteristics of guyed tower structure are analyzed by operational modalanalysis method. An analyzing program is also compiled with auto-cross power spectrummethod. Assuming ambient excitation is white noise，signal generator and vibrationexciter are utilized to generate random excitation for a model of cantilever beam. Thecorrectness of the method used in this paper is testified by comparing the theoretical andexperimental results. Combining with the practical projects, the dynamic characteristicsof guyed tower are studied. The experiments include modal tests, vibration tests byknocking, shaking tests in the nature wind condition on the guyed tower.Based onauto-cross power spectrum method, modal parameters of the guyed tower are identified,and the results are compared with ANSYS.It shows that the first natural frequencies and modes of bend of guyed tower are alittle difference in three methods. And get the inherent frequency of OMA methodincludes the results of the traditional mode analysis. The result shows that themeasurement error is in the extent permitted.Also, the paper analyzes the reasons ofdifferent results under hammer excitation ambient excitation and the resulting simulation.By comparing the results with this three modal analysis methods, it is shown that theAuto-cross Power Spectrum method is efficient.Operational modal analysis used inguyed tower modal is a valid attempt.