Structural damage assessment with incomplete and noisy modal data using model reduction technique and LAPO algorithm

The present article proposes an efficient method for damage assessment of structures with incomplete and noisy modal data using model reduction method and Lightning Attachment Procedure Optimisation (LAPO) algorithm. The damage identification problem is formulated as an optimisation problem, in which the extent of damaged elements and a combination of both natural frequencies and modal flexibility changes are considered as the continuous design variables and a hybrid objective function, respectively. The LAPO algorithm, a recently developed algorithm, is for the first time extended to solve the formulated optimisation problem. In addition, due to incomplete modal data, an iterated improved reduction system (IIRS) technique is adopted to condense structural physical properties. The efficiency and robustness of the proposed method are investigated using three types of structures and the results are compared with those obtained by other well-known optimisation algorithms. It is shown that regardless of the effect of incomplete and noisy modal data, the proposed method not only successfully determines the location and extent of single and multiple damage cases in the structures, but also has lower computational cost than the other optimisers.