摘要：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.
