Abstract Due to limitation of traditional Lamb wave based structural damage monitoring methods, early micro damages which are smaller than the wavelength of the waves usually can hardly be detected and evaluated. In this paper, major efforts were focused on nonlinear Lamb wave, including its propagation characteristic and sensitivity to micro damages. The relationship between the nonlinear characteristic parameters of Lamb wave and the degree of damage is revealed by experimental study. The cumulative (S1, S2) symmetric mode Lamb wave were adopted in the research so that nonlinear second harmonic signals could be obtained to measure metallic structural material’s nonlinear changes quantitatively. In view of dispersion and multiple models characteristic that affect signal analysis, the time-frequency analysis method, STFT, was adopted to extract the fundamental Lamb wave mode and second harmonic mode respectively. Experimental results on T6061 aluminum plates shown that the nonlinear characteristic parameters were sensitive to the artificial fatigue damages. It can be also found that the nonlinear characteristic parameters were grown with the degree of the damages.
Research on Nonlinear Lamb Wave Based Structural Damage Monitoring
2017-01-01
11 pages
Article/Chapter (Book)
Electronic Resource
English
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