In this contribution, we study the applicability of non-contact vibration analysis for flaw detection on the example of a ceramic electrolyte cup. These components are key parts in a prospective power cells design. First, extensive numerical modal analysis was performed using finite element modelling (FEM). Beside the complete mode spectrum of the freefloating perfect component, the influence of the suspension as well as deviations from the ideal geometry to the eigenmodes were studied. Additionally, the impact of different defect parameters, such as shape, location, and size, on the eigenmodes was investigated. For experimental investigation a soft suspension, impact excitation pendulum and near-surface microphone array rack were designed and built. Initially the samples with reference geometry and no defects have been measured. Eigenfrequencies, damping ratios and mode shapes have been extracted from the microphone array records using the operational modal analysis (OMA) algorithms, as the impact excitation signal was not traced. Experimental and numerical data have shown the good agreement. Further, the samples with reference defects, induced by laser cuts of different length and position, as well as laser drilled holes were studied. Depending on their type, size and position, the defects lead to a decrease of some eigenfrequencies and to a splitting of formerly degenerate modes. Same effects for a real crack are shown. Based on these results, preliminary application boundaries and potential development patterns for non-contact modal testing using a microphone array for defect detection are discussed.
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