Effect of synchronization of continuous acoustic emission statistical properties during structurally heterogeneous materials deformation

In this paper, a correlation analysis of the statistical properties of continuous acoustic emission recorded in various parts of marble and glass fiber laminate samples during their quasi-static deformation is carried out. The spectral measure of coherence, which is a generalization of the square modulus of the coherence spectrum to the case of multidimensional series, is chosen as a correlation measure. The measure of coherence was estimated for the width of the multifractal spectrum and the spectrum carrier realizing its maximum, calculated in a sliding time window for acoustic emission signals. It is shown that the preparation of a macrofracture site is accompanied by synchronization of the statistical properties of acoustic emission in the selected frequency intervals. Based on the analysis of changes in the frequency-averaged measure of coherence for both types of materials, four characteristic stages are distinguished, the boundaries of which are individual for each of the materials. The onset of the fourth stage, which is characterized by a monotonic increase in the average measure of the coherence of the statistical properties of the AE, can be chosen as a possible criterion for the transition of the material to the limiting state.