WAVELET TRANSFORMS F OR SYSTEM IDENTIFICA TION AND ASSOCIATED PROCESSING CONCERNS

The time-frequency character of wavelet transforms allows increased flexibility – as both traditional time and frequency domain system identification approaches can be adapted to examine non-linear and non-stationary response data. However, a number of additional processing concerns must be understood to fully exploit the power of the multi-resolution, dual-domain transform, particularly for the popular Morlet wavelet. Unfortunately, in prior applications of wavelet transforms for system identification, the implications of the aforementioned c cerns were often negligible, as these studies considered mechanical systems characterized by higher frequency, broader-band signals. It was the subsequent analysis of Civil Engineering structures that highlighted the need to understand more fully these p ocessing concerns in order to insure the successful identification of dynamic system properties. This study identifies a number of these considerations that are a direct consequence of the wavelet’s multi-resolution character, including considerations for selection of wavelet central frequencies and strategies to resolve end effects errors. In total, this study serves as an overview of these processing considerations for Civil Engineering structures, helping to lessen the challenges associated with th transition into the time-frequency domain