A novel and efficient method for damage detection in beam-like structures solely based on damaged structure data and using mode shape curvature estimation

Abstract

Dynamic-based methods for detecting the location of damage in structures are generally based on changes caused by damage in the dynamic properties of structures such as modal frequencies and mode shapes. Mode shape curvature damage detection method is one of these techniques in which the difference in mode shape curvatures between undamaged and damaged structures is used to identify the location of damage. In this paper, a new damage detection method for beam-like structures is presented in which obtaining data from the analytical model of the undamaged structure is not required. The proposed method introduces the difference between mode shape curvature and mode shape curvature estimation of damaged structure as an indicator of identifying the damage location. Mode shape curvature estimation is solely done by using the displacement mode shape of the damaged structure. Hence, in the proposed method there is no need for the undamaged structure data. The curvature estimation can be easily and quickly done using simple mathematical relations. The efficacy of the proposed method in detecting the location of damage is evaluated using the finite element model of various damaged beams with different boundary conditions as well as experimental validation. Moreover, the classical relations of mode shape curvature estimation are presented for the first mode of single-span uniform beams with minor damage. The results indicate that the introduced index in magnifying the location of damage is as capable and efficient as the classical mode shape curvature method.