Damage detection by the curvature of POMs extracted from measured FRF data

Abstract

This study presents a damage detection method to determine damage in flexural beam structure by the curvature distribution of proper orthogonal modes (POMs). The POMs are extracted from measured frequency response function (FRF) data. The method doesn't require the information on input data and baseline data of intact structure unlike the FRF curvature method, mode shape curvature method etc. This work utilizes the POM data corresponding to the first proper orthogonal value (POV) for damage detection. It is observed that the POM curvature method and Ratcliffe's method should be sensitive to the FRF data corresponding to the considered frequency range for obtaining POMs. The proposed method is more effective in detecting damage than the FRF curvature method and is less sensitive to the noise than the Ratcliffe's method. Its superiority is illustrated in a numerical experiment and a beam test that consider external noise.