Sensor Measurements Only With Transmissibility Operators for Fault Detection in Flexible Beams

In this work, we extend transmissibility-based fault detection to flexible structures and then use transmissibilities to estimate the system’s total number of independent excitations. Transmissibilities are mathematical representations of the relationship between the outputs of an underlying system. The input and output of transmissibility are both outputs of the underlying system. The article then examines a class of flexible structures for which neither the excitation signal nor the structural dynamics are known. We begin by examining a simulation model for testing a class of faults that are notoriously difficult to replicate experimentally, such as fatigue cracks. Following that, we will examine an experimental setup comprised of a flexible cantilever beam and multiple accelerometers. To illustrate the proposed algorithm, we consider a flexible beam with a change-of-stiffness fault. The transmissibility operators between the accelerometers are identified under normal beam conditions and then used for fault detection and estimating the number of excitation signals.