| 摘要 |
The proposed method uses records from the BTT device and further processes thereof. By means of the discrete Fourier transform, distorted amplitude spectra are created in the frequency bands (-fiN, +fin.). Subsequently, resonance zones of the distorted amplitude spectra are transferred upon respecting polarity in the reconstructed spectra of the separate moving blades within the interval (-fiR, +fiR), wherein fiR represents one half of the reconstructed spectrum sampling frequency. By means of the inverse Fourier transform, there occur reconstructed characteristics of the original signals of the moving blade oscillation in horizontal direction. The signal-reconstructed characteristics serve for determination of stress tensors and therefrom effective damaging stress. The effective damaging stress serves for the calculation of damage increments caused by sequences of the time lines extreme values of the damaging stresses decomposed by the method known under the name “rain running down”, whereupon these damage increments cumulate for each moving blade separately. After transfer of the resonance zones in the reconstructed Fourier spectrum, is possible to spread the rest of the distorted Fourier spectrum in the reconstructed Fourier spectrum. In case more sensing elements are used in the BTT device, the evaluation of records is carried out for each sensing element. Results of the sensing element with the greatest damage increment, serve for evaluation of the cumulated damages. |
