Analysis of energy characteristics of acoustic emission signals during uniaxial compression of geomaterial samples

Abstract

Acoustic emission (AE) signals were obtained during deformation by uniaxial compression of specimens of various geomaterials. Experiments on uniaxial compression were carried out on a low-noise lever setup with water leakage, where the maximum load on the sample does not exceed 250 kN. The received signals were digitized by an 8-channel USB 3000 ADC unit with a width of 14 bits and a maximum sampling rate of 3 MHz. The energy distribution functions of AE signals are considered. The maximum amplitude of the AE waveform was selected as the energy characteristic of the AE signal. The flow of AE events is considered from the viewpoint of nonequilibrium thermodynamics using the Tsallis statistics. To describe the energy distribution function of the AE signals, we used a modified model of a stick-slip earthquake source -”discontinuous sliding” of two plates over each other along a fault in the presence of friction and the principle of maximum entropy. The model is used to quantify long-range correlations arising in the flow of earthquakes. It is shown that the AE signal flow is a system with memory and longrange correlations. The analysis of the behavior of the Tsallis parameter was carried out throughout the experiment.

Micromechanics of impact damage of ductile (ZnS) and hard (MgAl2O4) ceramics

“…The AE technique is a widely used experimental method for studying micromechanics of the destructive processes in loaded heterogeneous materials, such as rocks, 19 building materials, 20,21 porous minerals, 22 ceramics, 23 etc. It is well established that the fracture process in non‐homogeneous materials exhibits the power law dependences of number of elementary events on event size (referred to a term of “scaling”) giving rise to fractal structures 21,24,25 .…”