ABSTRACT
This chapter presents the mathematical model of a dynamic civil structure in different coordinate systems. It introduces structural dynamic characteristics through a modal analysis in the modal coordinate system. The chapter shows modal identification methods in the frequency domain, time domain and frequency-time domain, and provides a brief introduction to force identification. It discusses the model updating methods, mainly the sensitivity-and-modal-based updating method. The chapter also provides the model updating of a multi-scale finite element (FE) model of a transmission tower. The initial FE model therefore needs to be finely tuned to match references to reduce modelling errors and produce a better FE model to represent the real one. Accurate FE models are frequently required in a large number of applications, such as optimisation design, damage identification, structural control and structural performance evaluation. The time–frequency character of wavelet transform allows the adaptation of both traditional time- and frequency-domain system identification approaches to examine non-stationary data and nonlinear structural parameters.
