RESEARCH TOPICS
Damage detection in plate-like structures based on polarization of Lamb waves
 |
Interpretation of Lamb waves signals can rise serious difficulties due to their multi-modal nature. Different modes propagating with different velocities can be mislead with damage reflected components. As a solution to this problem a technique capable of modes separation based on a polarization filter can be used. |
| Simulated in-plane (H) and out-of-plane (V) signals of Lamb wavepropagating in an isotropic plate | For more details contact dr Lukasz Ambrozinski or prof. Tadeusz Stepnski |
Ultrasonic testing
 |
We perform ultrasonic scanning using broad-band high frequency transducers which allows for precise detection and localization of discontinuities. |
| C-scan image of a thin composite panel with a delaminated area. | For more details contact dr Lukasz Ambrozinski or prof. Tadeusz Stepnski |
Vibro-acoustic Modulation
 The principle of nonlinear vibro-acoustic wave modulation technique: schematic diagram illustrating the method (a); power spectrum of response signal for undamaged structure (b); power spectrum of response signal for damaged structure (c). |
The method utilises the combined vibro-acoustic modulation interaction of high-frequency ultrasonic wave and low-frequency vibration (modal) excitation. These two excitations are introduced to the structure simultaneously. When monitored structures are intact or undamaged, spectra of signal response exhibit only the two major frequency components corresponding to the propagating ultrasonic wave and the low frequency excitation. When monitored structures are damaged, spectra of response signals contain additionally sidebands around the main ultrasonic component. The number of sidebands and their amplitude depends on the intensity of modulation and strongly relates to damage severity. |
| For more details contact dr Andrzej Klepka or prof. Wiesław J. Staszewski |
Sidebands Imaging
 Damage imaging results for the proposed VAM based imaging technique at modulation sideband at frequency equal HF-LF=42539 Hz |
Based on vibro-acoustic modulation technique, damage localisation is also possible. In this case the sidbands amplitude is used for imaging |
| For more details contact dr Andrzej Klepka or prof. Wiesław J. Staszewski |