In this project, high-frequency vibrations are investigated in order to only resonate defects locally and thereby localize them. This non-destructive so-called Local Defect Resonance method is investigated experimentally and numerically for different composites with various defect types and sizes. Apart from the classical evaluation of out-of-plane characteristics, this research extends the evaluation towards in-plane vibrational characteristics. To further enhance the sensitivity of the technique, both linear and nonlinear approaches are analyzed.
Scanning laser Doppler vibrometry is employed to measure the defect resonances. In a later stage, it will also be investigated whether infra-red thermography could offer an alternative. Considering that thermography is a full-field method (comparable to digital photography, but in the infra-red spectrum) this would lead to a faster and more handy non-destructive evaluation technique.