Vibration and Wave Propagation Approaches Applied to Assess Damage Influence on the Behavior of Euler-Bernoulli Beams: Part II Inverse Problem

摘要

In a companion paper, the damage influence on the vibrational behavior and on the wave propagation issues of a slender Euler-Bernoulli beam was investigated. The theoretical formulation and the numerical implementation of the direct problem was taken into account. In the present work, one is concerned about the inverse problem of damage identification from the point of view of wave propagation approach. Different damage scenarios for a slender Euler-Bernoulli beam are considered. Time history responses, obtained from a pulse-echo experiment, are used to identify both damage position and shape. In order to account for noise corrupted data different levels of signal to noise ratio-varying from 30 to 0 dB-were introduced. In the identification process, different optimization methods were assessed: the deterministic Levenberg- Marquardt; the stochastic Particle Swarm Optimization; and a hybrid method combining the aforementioned ones. It is shown that the damage identification procedure built on the wave propagation approach succeeded, even for highly corrupted noisy data. Some comments on the advantages of deterministic and stochastic methods and their combination are reported.