Statistical Based Decision Making for Damage Localization with Influence Lines

Abstract

A theorem on damage localization from flexibility changes has been proven recently, where it has been shown that the image of the change in flexibility dF between damaged and reference states of a structure is a basis for the influence lines of stress resultants at the damaged locations. This damage localization approach can operate on output-only vibration measurements from damaged and reference states, and a finite element model of the structure in reference state is required. While the localization approach is based on purely mechanical principles, an estimate of the image of dF is required from the data that is subject to statistical uncertainty due to unknown noise excitation and finite data length. In this paper, this uncertainty is quantified from the measurements and a statistical framework is added for the decision about damaged elements. The combined approach is successfully applied to a numerical simulation and to a cantilever beam in a lab experiment.