Energy Spectrum of Acoustic Emission Signals in Coupled Continuous Media

Authors V.V. Marasanov1, A.V. Sharko2, A.A. Sharko1

1 Kherson National Technical University, 24, Berislav Shosse St., 73008 Kherson, Ukraine

2 Kherson State Maritime Academy, 20, Ushakov Ave., 73009 Kherson, Ukraine

Issue Volume 11, Year 2019, Number 3
Dates Received 22 January 2019; revised manuscript received 13 June 2019; published online 25 June 2019
Citation V.V. Marasanov, A.V. Sharko, A.A. Sharko, J. Nano- Electron. Phys. 11 No 3, 03028 (2019)
PACS Number(s) 43.25.Ed, 06.60.Ei
Keywords Acoustic emission, Signals, Spectrum (13) , Coupled continuous media, Eigenvalues, Eigenfunctions, Second-kind Fredholm equation, Fourier transform.

The regularities for the existence of elastic energy of initiating AE signals operators establishment is one of the unsolved problems of nanostructure modeling and the physics of nanosystems. The propagation of acoustic emission signals with the coupling of two continuous media is considered. The main variables in the equations of motion for particles are the force that determines the occurrence of acoustic emission and the displacement of particles of the medium, which determines the elastic wave propagation. A methodo-logical basis for determining the energy spectrum of acoustic emission signals in coupled media using the Green function and Fourier transforms is presented. The conditions for the existence of an elastic energy operator for initiating acoustic emission signals are substantiated. The first basic condition that the elastic energy operator must satisfy is the invariance of the particles of the material structure relative to the translation. The second main condition for the existence of the elastic energy operator is its hermiticity The third basic condition, which the elastic energy operator must satisfy, is its homogeneity, which is based in its invariance with respect to the shift. The unequivocal correspondence between the characteristics of the discrete structure of materials and parameters of propagation of AE signals in conjugate media is established. Based on a comparison of the calculated characteristic numbers of the spectrum and the load diagram for discontinuous tests, it was shown that the energy spectrum of acoustic emission signals in coupled continuous media is completely determined by the material power constants and the forces initiating the appearance of acoustic emission signals. Presented energy spectrum of acoustic emission signals in conjugated continuous media models allows to associate them with the formation of metal crystal lattice defects and can be used to predict the stage of material destruction. The experimental verification of the main theoretical models of the energy spectrum of AE signals in a medium with a developing defect, at different stages of the load diagram, showed their consistency and satisfactory agreement in the basic details of the energy spectrum structure.

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