Demodulation technique to identify nonlinear characteristics of vibro-acoustic NDT measurements

Publication date: Available online 15 October 2019Source: Journal of Sound and VibrationAuthor(s): A. Carcione, P. Blanloeuil, M. VeidtAbstractA novel approach for nonlinear ultrasonics is presented which uses the demodulated response of a nonlinear vibro-acoustic response signal. The demodulation process is similar to quadrature demodulation process used in telecommunications. It is shown that the demodulation method provides an alternative approach for the analysis of nonlinear behavior compared to the analysis of frequency spectra or other techniques. The proposed method suggests that a representative reconstruction of the time-domain nonlinearity behavior of the system can be obtained. The paper provides theoretical background to the technique as well as experimental validation. The proposed method is demonstrated for the analysis of four different types of contact acoustic nonlinear interfaces. It is shown that the demodulated waveforms are consistent with the expected mechanical behavior of different interfaces. The results suggest that this method can provide more insight into the nonlinear behavior of a system compared to conventional spectral amplitude analysis techniques.

Source: Journal of Sound and Vibration - October 16, 2019 Category: Physics Source Type: research