Output-only Based Identification of Modal Parameters of Linear and Nonlinear Structures by Wavelet Transform
Keywords:Wavelet Transform, Structural health monitoring, modal parameters identification, Time-Frequency Analysis, signal processing
In recent years, the methods of integrity monitoring of civil structures and mechanical ones, such as damage detection, fatigue analysis and risk-based management structures, have been receiving considerable interest from various fields of science and engineering. This work uses a mathematical tool for calculation and for a relatively new signal processing, in which uses a time-frequency analysis that provides more detailed information about non-stationary signals. We are talking about the Wavelet Transform. First, the Continuous Wavelet Transform is used to identify the modal parameters such as natural frequencies and damping rates, of a linear structure with four degrees of freedom. After that, this method is tested on a non-linear structure that represents a 20 floor building, proposed in the literature. A theoretical explanation of the methodology and an example of a simple application are also presented in order to understand the efficiency of the technique in the identification of modal parameters of structures.