The application of POD curves to damage detection in civil engineering structures - a numerical and experimental study

摘要

The detection of structural damage by means of non-destructive testing has been a research topic for many years. For practical applications the reliability of any damage detection method is of high importance. Apart from the technical function of all components of a respective system reliability means in this context that a fault of a certain size can be detected by the respective system with a sufficiently high probability. This requirement can also be formulated in the way that one asks for the probability that a fault of a certain size will not be detected. Both formulations lead to the concept of Probability Of Detection (POD) that has been used for several year in aerospace and mechanical engineering applications of damage detection methods based on non-destructive testing. Classically, the POD curves are obtained from extensive experimental studies and applied to systems which are manufactured in series. In many cases only specific parts of a complex system are considered such that the tests can be performed with components independent from the whole system. A transformation of the concept of POD to civil engineering applications is connected with two major problems: a) the majority of structures are unique, b) experimental studies of damaged structures are cost prohibitive. Therefore, an alternative approach that is based on numerical simulations needs to be developed for civil engineering applications. The investigations presented in this contribution are concentrated on a simply supported beam that can be modified and tested under laboratory conditions. The study includes both experimental and numerical investigations, the application of vibration-based damage detection approaches and a comparison of the results obtained based on tests and simulations. For the evaluation of the used methodologies, specific model validation concepts are applied.