Abstract
A modal-based, simplified and practical algorithm to evaluate the local flexibility of structures is presented in this paper. Local flexibility indices for translational or rotational flexibility are adopted as damage metrics, and their approximate calculation scheme is proposed. Using the proposed algorithm, one can detect the extent of the local damages by using only the first few modes, whereas such damages cannot be detected by using the global feature such as natural frequencies. Furthermore, because the proposed damage index is evaluated from dynamically-identified mode shapes without calculating mass-normalization constant, this methodology can be realized in a decentralized form by installing a couple of sensors per one location of interest, not deploying many sensors throughout the structure. Experiments using a laboratory-scale test structure are carried out to show the potential advantage of the proposed algorithm when embedded in a wireless sensor network environment.
