A two-step interval structural damage identification approach based on model updating and set-membership technique

Abstract External conditions unavoidably cause deterioration to structures in service, and the degeneration in material property may accumulate and lead to huge accidents. Meanwhile, practical engineering includes a variety of uncertainties from responses, which can negatively influence the damage identification result. In this study, a two-step interval structural damage identification approach is proposed with consideration of response uncertainty. Deterministic damage identification strategy by which damage index can be solved is firstly introduced. Then, damage locations are identified as the first step based on model updating. For the second step, uncertain structural dynamic responses are viewed as interval variables. Then, the bounds of the damage extents of the identified elements are estimated using Chebyshev polynomial approximation and interval mathematics. For a tighter solution, set-membership technique is used to obtain the fusion interval damage index. Two numerical verifications and an experimental verification show the use of the presented two-step identification method. In addition, the Taylor expansion and interval combination methods are also analyzed for comparable purpose.