Fault Detection in Flexible Beams Based on Output Only Measurements

Abstract

Transmissibilities are mathematical models that describe the relationship between outputs of an underlying system. This paper uses transmissibilities for fault detection and localization in a class of flexible structures. We assume that the dynamics of the beam and the excitation signal acting on it are unknown. We consider an experimental setup consisting of a flexible cantilever beam with multiple accelerometers attached to it. The dynamics of the beam and the excitation signal that acts on it are assumed to be unknown. Transmissibility operators between the accelerometers are identified under healthy conditions of the beam, and then used for online fault detection and localization in the flexible beam. We consider a change-of-stiffness fault in the flexible beam to demonstrate the proposed algorithm. In order to test the algorithm under different faults that can be difficult to implement experimentally, we develop a bond graph model of the beam. A simulation of the bond graph model is used to obtain the acceleration measurements at different locations on the beam, and the proposed algorithm is tested under fatigue faults.