Some comparisons for damage detection on structures using genetic algorithms and modal sensitivity method

The last decade witnessed the development of a large number of non-destructive tests for structural integrity evaluation. This growth is due to attracted interest to reduce time and costs to perform damage monitoring and predictive maintenance. In this way, several methods intended to detect structural damage based on sensitivity and statistical methods were proposed. However, some of these methods present some practical problems in measuring structural dynamic characteristics such as dynamic mode shapes. Some methods based exclusively on structural responses show disadvantages in finding the damage position on structures. There are two methods that are investigated in this work: the first is based on frequency sensitivity to the damage and the second one is based on optimization techniques and finite element parametric modelling. In this paper a genetic algorithm and a modal sensitivity method are used to identify and evaluate damage cases in a parametric numerical finite element model. A real coded genetic algorithm is used as an optimization tool. The results for the identification and evaluation of the damage in both methods were similar and they are compared. Some numerical examples are presented for structural damage detection on multiple sites and levels. It is emphasized the advantages of this methodology due to the little amount of information necessary as well as robustness. (C) 2007 Elsevier Inc. All rights reserved.