Genetic Algorithms and Modal Sensitivity for Damage Detection on Portal Frames

Abstract

The use of natural frequency as a diagnostic parameter in structural
damage detection and vibration monitoring, has been discussed in the
last decade for many authors in several works. The large use of
natural frequencies and mode shapes as sensitive indicators of
structural integrity is due to the fact of the ease in measuring these
modal parameters experimentally. Many types of methods are employed in
the state of art in damage detection and location using low frequency
data. There are two classes of methods that are investigated here: the
first is based on frequency sensitivity to the damage and the second
one is based on optimization techniques and parametric modeling. In
this work a genetic algorithm and a modal sensitivity method are used
to identify and evaluate damage cases in a numerical finite element
model of a portal frame. The results of the identification and the
evaluation of the damage in both methods were similar and could be
compared.