Identifying damage using local flow variation method

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In this paper, a damage identification method called local flow variation is introduced. It is a practical implementation of a phase space warping concept. A hierarchical dynamical system is considered where a slow-time damage process causes drifts in the parameters of a fast-time system describing the measurable response of a structure. The method is based on a hypothesis that the probability distribution function of the fast-time trajectory in its phase space is a function of a damage state. In this method, an ensemble of estimated expectations of a trajectory in different locations of the reconstructed phase space is used as a damage feature vector. Using these feature vectors, damage identification is realized by a smooth orthogonal decomposition. An experiment is conducted to validate the method. A two-dimensional slow-time damage process is identified from experimental fast-time data. Although damage identification results from the local flow variation are not as accurate as those from the direct application of phase space warping tracking functions, the required computation time is about two orders of magnitude shorter. © IOP Publishing Ltd.

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Smart Materials and Structures