A Simple Correlation Factor as an Effective Tool for Detecting Damage

In previous works [1–3] the authors proposed the generalization of some well-known methods from mode shapes to operational deflection shapes, and their respective spatial derivatives. Such a generalization and necessary normalization of the maximum occurrences proved to be effective in the task of locating the damage with the additional advantage of avoiding the modal identification process. In previous papers [4, 5] the authors proposed a new method, the Detection and Relative damage Quantification indicator, DRQ, based upon a simplified form of the Frequency Domain Assurance Criterion [6–8], the Response Vector Assurance Criterion [9]. This method aims at detecting damage, not locating it, simply identifying its existence. The advantage is that is very simple, just using the measured frequency response functions without any need for identification of natural frequencies or mode shapes. In this paper new assessments are made concerning the ability of the indicator to detect and relatively quantify damage. Numerical and experimental work is presented to illustrate the effectiveness of the indicator.