Structural Damage Diagnosis Using Natural Frequency Changes

This paper presents a new method to identify structural damages only by changes of natural frequencies. The underlying principle of the proposed technique is to add known masses to the physical structure, measure the natural frequencies of this mass-modified system, and then use this set of new data as well as the original test data to identify structural damages with the help of eigenvalue perturbation method. The most significant advantage of the presented technique over the previous methods is that the proposed method can successfully identify structural damages even if only the first few natural frequencies are measured. A simply supported beam is analyzed as a numerical example to verify the presented method. Results show that the proposed approach is simple to implement and can identify structural damages very accurately only by the first few natural frequencies.