Structural Damage Diagnosis Using an Improved Eigenvalue Perturbation Method

This paper presents an improved method to identify structural damages only by changes of natural frequencies. The underlying principle of the proposed technique is to measure the natural frequencies of the damaged system, and then use this set of data as well as the original test data of undamaged system to identify structural damages with the help of eigenvalue perturbation method. In this contribution, a simple accelerated formula is developed to improve the accuracy of the eigenvalue perturbation method. With the introduction of the accelerated formula, the proposed method is able to achieve more accurate results than that obtained by the original eigenvalue perturbation method without any high-order analysis or multi-iterations. The effectiveness of the proposed method is illustrated using simulated data on a published numerical example. From the numerical results, it can be conclued that the proposed approach is simple to implement and can identify structural damages very accurately only by the first few natural frequencies.