| dc.description.abstract | This study uses Dynamic Vehicle Test to analyze the amplification characteristics of the bridge structure which is just completed. However, the bridge structure responses of vibration are often nonlinear and non-stationary. Fourier analysis using time invarint harmonic function as a basis function which is unable to meet the basic requirements of nonlinear and non-stationary signals. In order to carry out non-destructive testing of bridge damage, the Hilbert-Huang Transform (HHT), which is a time-frequency analysis technique without a prior basis functions and local adaptability, is often used for nonlinear and non-stationary signal analysis, it can show the energy distribution of the signal in the time domain and frequency domain and observe the dynamic characteristics of the object changing with time.
This study uses two analysis tools of the HHT SHM analysis method, the time-frequency amplification function (TFAF) and the modal time curve (MTVC). Converting the external force waveform into a wave-propagation characteristic, the dynamic characteristics of each phase of the structure will be exhibited on the TFAF, and the time-varying system vibration behavior will be found by observing the distribution of energy and instantaneous frequency on the frequency spectrum, and then the vibration mode characteristic in the TFAF spectrum is called MTVC. MTVC has a wealth of structural safety parameter information. It compares the external conditions of different tests, estimates structural traits and finds subtle differences in structural modal behavior. | en_US |