abstract
- © 2022Operational Modal Analysis (OMA) or output-only modal analysis allows obtaining modal parameters in operational conditions, i.e., without external excitation. While being more challenging than traditional or Experimental Modal Analysis (EMA), OMA allows to monitor the structural health of a structure in cases where EMA is not practical or feasible. This article presents an introduction to an OMA technique based on Frequency Domain Decomposition (FDD) and its mathematical formalism, and demonstrates its potential for detecting damage in a cantilever beam. A transient dynamic Finite-Element Analysis (FEA) under white noise excitation has been performed in ANSYS Workbench to obtain the acceleration responses of the system. The numerical accelerometers signals along the beam are used for the OMA analysis and multiple cracks are analyzed at different positions along the beam. The technique used for damage detection is Curvature Mode Shape (CMS) analysis, using only the information of the damaged structure, making it a baseline-free method. The technique is shown to be capable of correctly detecting and locating the different damages analyzed.