Occurence of damage in a structure leads to changes in the system and modal parameters. Recently, finding relationships between the extent and location of damage in a structure has received considerable attention. Many of the proposed damage detection/location methods exploiting changes in the modal parameters adopt sensitivity approach and utilize only natural frequency changes. A major disadvantage of sensitivity based methods is the significant amount of computation required especially for large and complex structures. In addition, frequency changes alone may not be sufficient to locate the damage position since similar defects at different positions may cause the same amount of frequency change. In contrast, vibration mode shapes can be heavily influenced by local damage. The greatest change (in mode shapes) occur around the defect, thus offering the possibility of locating damage. In this paper, the performance of some procedures for locating damage using mode shapes are evaluated. The procedures do not require extensive computation or any theoretical damage model. Simulated data using the finite element method were used to compare the effectiveness of the methods in the absence of measurement errors. To test the practical applicability of the methods, experimental data obtained from a beam structure were also used. Varying degrees of success were obtained. Results from the investigations are presented and discussed.
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