Damage identification method based on correlation function of structural responses to operational excitation

Structural damage identification utilizing operational vibration measurements has been an attractive research area with regard to health monitoring. Dynamic modal parameters identification based on output-only modal analysis becomes the principal method to detect the damage and other hazards. The main idea of these methods focuses on distinctness between damaged and undamaged structural natural frequencies, model shapes and stiffness attribution. The technique proposed in this paper can avoid shortage of common vibration-based structural damage identification techniques, which usually need to extract vibration characteristics. It's a time domain method that directly works with response data, without the necessary to convert them to spectra. Comparing between damaged and undamaged structural response correlation function amplitudes of two neighbour test points, one can determinate the damaged segments or member parted by test points. Then refined damage location can be derived by correlation function time lag analysis, which is similar to wave transmission theory. The results of numerical study demonstrate the effective applicability of this method. The correlation-based approach has potential to be used as an easy technique in structural damage identification from operational vibration.