Defect detection by frequency analysis of flexural vibrations of free-free composite beam

  • 1 Sofia University “St.Kliment Ohridski”, Faculty of Physics, Sofia, Bulgaria; Institute of Mechanics at Bulgarian Academy of Sciences, Sofia, Bulgaria


This paper presents experimental investigations using a vibration method by impulse excitation of free flexural oscillations of composite beams. The purpose of the study is to establish the sensitivity of the method and technique used for defect detection and localization. To realize the objective, rectangular groove type defects were simulated at different distances and depths. The influence of the location and depth of the artificial cracks on the dynamic properties of the beams was investigated. The resonance frequencies were determined by frequency analysis. A decrease in the resonant frequencies of the flexural oscillations is observed. The experiments conducted show a change in the dynamic characteristics of the beam depending on the dimensions and location of the defects.



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