Damage localization in plate structures from uniform load surface curvature

Although a large number of methods exist for detecting damage in a structure using measured modal parameters, many of them require a correlated finite element model, or at least, modal data of the structure for the intact state as baseline. For one-dimensional beam-like structures, curvature techniques, e.g., mode shape curvature and flexibility curvature, have been applied to localize damage. In this paper a damage localization method based on changes in uniform load surface (ULS) curvature is developed for two-dimensional plate structures. A new approach to compute the ULS curvature is proposed based on the Chebyshev polynomial approximation, instead of the central difference method. The proposed method requires only the frequencies and mode shapes of the first few modes of the plate before and after damage, or only the eigenpairs for the damaged state if a gapped-smoothing technique is applied. Numerical simulations considering different supported conditions, measurement noise, mode truncation, and sensor sparsity are studied to evaluate the effectiveness of the proposed method. It is found that the ULS curvature is sensitive to the presence of local damages, even with truncated, incomplete, and noisy measurements. (C) 2003 Published by Elsevier Ltd.