Investigation of propagation characteristics of acoustic emission waves in composite heterogeneous structures
[Objective]This paper aims to investigates the impacts of acoustic emission(AE)signals on the propagation characteristics of composite hetero-structures.[Methods]First,the calculation procedure of the dispersion curves is developed on the basis of the semi-analytical finite element method in order to calculate the group velocity dispersion curves of AE waves in composite panels.Next,ABAQUS is used to establish a finite element model and analyze the dispersion and attenuation characteristics of AE signals in the composite structure.Finally,the time-frequency characteristics and mode conversion of AE signals in a T-section com-posite hetero-structure are analyzed in combination with wavelet transform and modal acoustic emission the-ory.[Results]The attenuation of AE signals is related to the propagation distance and direction of signals,in which a signal is significantly attenuated when passing through the hetero-structure interface.The interac-tion between AE signals and the hetero-structure will produce complex propagation phenomena including T-shaped transformation and modal conversion.The signal strength of the reflected signal is strongest in the T-shaped transformation of the AE signal,and the signal strengths of the transmitted signals across the structure and the transmitted signals through the 90° corner of the structure are comparable.[Conclusion]This paper quantifies the scattering characteristics of AE signals using reflection and transmission coefficients,thereby providing theoretical references for the application of AE technology in the health monitoring of marine struc-tures.
composite structuresacoustic emissionsacoustic wave propagationwavelet transformsmodal conversionstructural health monitoring
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