This paper presents the improved thickness estimation technique using Steady-state excitation Continuous-scanning Laser Doppler Vibrometery(SCLDV).
In this study, the wavenumber sensitivity with respect to the thickness variations of a structure, along with the information of wave modes, is utilized to find an optimal interrogation frequency band for SCLDV. In addition, the use of multi-frequency steady-state response is used to improve the accuracy of the thickness variation. By utilizing the wavenumber sensitivity along with the multi-frequency excitations, the proposed SCLDV shows the improved depth estimation, compared to the previous approaches which empirically select the interrogation frequency.
For validation of this technique, several experiments were performed on steel plates, which contain corrosion damage with various depth variations. The results showed that the proposed technique is very efficient in detecting and visualizing very small thickness variations of a structure at high speed.
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