Modeling the Propagation of Elastic Ultrasonic Waves in Isotropic and Anisotropic Materials when Excited by Various Sources

Abstract

This work is devoted to the investigation of the characteristics of acoustic emission waves to establish their relations with the parameters of the fracture of the structure of the material. The paper presents the results of the analysis of acoustic emission signals recorded during the propagation of ultrasonic waves in metal sheet materials using piezoelectric sensors. The specimen was a rectangular aluminum plate. The piezoelectric sensor recorded acoustic emission signals generated by the Hsu-Nielsen source. The piezoelectric sensor is located in the center of the aluminum plate. Then sources are generated with different hardness to model various kinds of cracks at each specific location. To determine the informative component of a useful acoustic emission signal, the Morlet wavelet transformation was used. When excited by a fracture pencils of different hardness, the magnitude of the wavelet differ in the energy and intensity of the spectrogram.