Abstract
Damage identification based on modal parameters is an important approach in structural health monitoring (SHM). Generally, traditional objective functions used for damage identification minimize the mismatch between measured modal parameters and the parameters obtained from the finite element (FE) model. However, during the optimization process, the repetitive calculation of structural modes is usually time-consuming and inefficient, especially for large-scale structures. In this paper, an improved objective function is proposed based on certain characteristics of the peaks of the frequency response function (FRF). Traditional objective functions contain terms that quantify modal shapes and/or natural frequencies. Here, it is proposed to replace them by the FRF of the FE model, which allows the repeated full modal analysis to be avoided and thus increases the computational efficiency. Moreover, the efficiency is further enhanced by employing the substructural virtual distortion method (SVDM), which allows the frequency response of the FE model of the damaged structure to be quickly computed without the costly re-analysis of the entire damaged structure. Finally, the effectiveness of the proposed method is verified using an eight-story frame structure model under several damage cases. The damage location and extent of each substructure can be identified accurately with 5% white Gaussian noise, and the optimization efficiency is greatly improved compared with the method using a traditional objective function.
Highlights
Structural damage identification plays an important role in structural health monitoring (SHM), which provides a reliable theoretical foundation for monitoring, early warning and safety assessment of large-scale structures [1].In recent years, many effective methods for SHM [2,3,4,5,6,7] and structural damage identification [8,9,10,11,12,13]have been presented
Damage identification using structural modal parameters is an important approach for SHM
Table that the results identified using the improved and damage case 2, multiple smaller damages are considered, and the damage identification results are traditional objective function are very close, which verifies the accuracy of the proposed method
Summary
Structural damage identification plays an important role in SHM, which provides a reliable theoretical foundation for monitoring, early warning and safety assessment of large-scale structures [1].In recent years, many effective methods for SHM [2,3,4,5,6,7] and structural damage identification [8,9,10,11,12,13]have been presented. Structural damage identification plays an important role in SHM, which provides a reliable theoretical foundation for monitoring, early warning and safety assessment of large-scale structures [1]. Many effective methods for SHM [2,3,4,5,6,7] and structural damage identification [8,9,10,11,12,13]. It is still difficult to identify the extent of structural damage accurately, and one of the reasons is a limited number of measurement points in large-scale structures. Damage identification using structural modal parameters is an important approach for SHM. The basic idea is that the damage location and extent can be determined by minimizing the difference between the damaged and undamaged state of the structure.
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