Cross modal strain energy–based structural damage detection in the presence of noise effects

Abstract

When conducting damage assessment by cross modal strain energy method, two very different approaches can be employed to solve cross modal strain energy equations. However, there are no performance comparison between these two approaches on their efficiency and effectiveness, especially under noise-polluted situations. In this article, cross modal strain energy method together with these two solving approaches, locality and wholeness approaches, is summarized, and their intrinsic features are extensively discussed. A new methodology for damage assessment is developed by combining these two approaches, in which the wholeness approach is first utilized for roughly localizing the potentially damaged members, and the final damage locations and associated extents are exactly estimated with the locality approach in the second step. To effectively investigate and compare the behavior of cross modal strain energy method, two factors, one measuring the recognition ability of damage location and the other measuring the precision of severity estimation, are introduced. A numerical simulation is conducted for a three-dimensional offshore platform structure. Both single- and multiple-damage cases, with and without noise effects, are considered. The numerical results indicate that the new methodology outperforms either approach in damage localization and severity estimation.