Paolo Casini Fabrizio Vestroni Oliviero Giannini


The dynamic behavior of beam-like structures with fatigue cracks forced by harmonic excitation is
characterized by the appearance of sub and super-harmonics in the response even in presence of cracks with
small depth. Since the amplitude of these harmonics depends on the position and the depth of the crack, an
identification technique based on such a dependency can be pursued: the main advantage of this method relies
on the use of different modes of the structure, each sensitive to the damage position in its peculiar way. In this
study the identification method is detailed through numerical examples tested on structures of increasing
complexity to evaluate the applicability of the method to engineering applications. The amount of data to obtain
a unique solution and the optimal choice of the observed quantities are discussed. Finally, a robustness analysis
is carried out for each test case to assess the influence of measuring noise on the damage identification.