Multi-damage localization in plate structure using frequency response function-based indices

Abstract

Abstract. Vibration signal and its derivative have shown some promise in structural damage detection in previous research. However, the theoretical and practical difficulties of multi-damage detection in plate structures based on dynamic responses remain. In this paper, an efficient damage localization index based on frequency response function (FRF) is presented.The imaginary part of FRF (IFRF) is extracted to derive the new localization index due to its relation to modal flexibility. For avoiding the finite element model error, two-dimensional gapped smoothing method (GSM) is employed without the need for baseline data from a presumably undamaged structure. Experimental studies on a steel plate with two localized defects in different boundary conditions are performed. The results are compared with some typical damage indices in the literature, such as mode shapes, uniform load surface and IFRF.In order to mitigate the inherent disadvantages of GSM in anti-noise ability, a simple statistical treatment based on Thompson outlier analysis is finally used for noise suppression. The effect of damage level and boundary condition on the detection results is also investigated.

Reference-Free Vibration-Based Damage Identification Techniques for Bridge Structural Health Monitoring—A Critical Review and Perspective

“…Ratcliffe and Bagaria [71] successfully employed the GSM to locate a manufactured delamination in a small-scale glass-reinforced epoxy beam. The GSM approach was extended to two-dimensional structures, such as plates [21,[74][75][76], using a cubic polynomial with two variables to represent curvature of the plate. Subtracting the fitted curvature of the undamaged state from the calculated curvature of the damaged state of plates resulted in peaks at the damaged locations.…”

“…Recognizing these limitations, Gao et al [75,76] proposed a non-modal damage localization technique utilizing frequency response functions (FRF) [83] combined with a two-dimensional GSM to detect and localize damage in plate-like structures. Unlike mode shapes and their derivatives that were based on natural frequencies, the FRF shapes and their derivatives were based on a wide range of frequencies; hence, provided more information on the location of damage.…”

“…-GSM [21,[70][71][72][73][74]78] -GFM [97] -GDM [87][88][89] -Regression [20,77] -FRF [75,76,83] -ODS [69,81,84,86] -FE models [22,[90][91][92] • Detecting perturbations in:…”