Detection of multiple structural damage through modal analysis: an experimental and FE Approach

Abstract

This study investigates the effectiveness of modalbased damage detection techniques, specifically the Difference in Mode Shape Slope (DMSS) and Difference in Mode Shape Curvature (DMSC), in identifying and localizing both single and multiple damage in beam and framed structures. Experimental tests were performed on a scaled 7-storey steel framed structure using a shake table, while Finite Element (FE) models were developed in ABAQUS and validated against experimental results, showing minimal frequency deviations. Damage scenarios were simulated, and the resulting mode shapes were analyzed. The DMSS and DMSC indices were computed and normalized to evaluate their sensitivity to damage. Results demonstrated that while both DMSS and DMSC successfully localized single and multiple damage scenarios in beam model and single damage scenario in framed structure, only the DMSC method reliably identified multiple damage in the complex frame structure. This highlights the DMSC method’s superiority for advanced damage detection. The study confirms the feasibility of combining experimental and numerical modal analysis for reliable structural health monitoring and sets the foundation for future applications in irregular and asymmetric structures.