Acoustic emission

About: Acoustic emission is a research topic. Over the lifetime, 16293 publications have been published within this topic receiving 211456 citations.

The role of flaws on crack growth in rock-like material assessed by AE technique

Abstract: Experiments for the rectangular rock-like samples (made of high-strength gypsum and water–cement ratio is 1) with two parallel pre-existing flaws subjected to uniaxial compression were carried out to further investigate the influence of varying flaw geometries on mechanical properties and crack coalescence behaviors. According to the tests results, eight crack types were characterized on a basis of the mechanisms of crack nucleation, formation and propagation, and seven coalescence modes occurred through the ligament, including S-mode, M1-mode, M2-mode, M3-mode, T1-mode, T2-mode and T3-mode. The AE and photographic monitoring techniques were adopted to further clarify the procedure of the crack coalescence and failure during uniaxial compression tests and in consequence the whole process of crack emergence, growth, coalescence and failure was recorded in real time. The results of AE technique revealed that the characteristics of acoustic emission energy associate with crack coalescence modes, and AE location method can emphasize the moments of crack occurrences and follow the crack growth until final failure. This study put forward better understanding of the fracture and failure mechanism of underground rock engineering, like rock burst.

A first arrival identification system of acoustic emission (AE) signals by means of a high-order statistics approach

Abstract: One of the fundamental problems in non-destructive testing and geophysics is the precise determination of the first arrival of acoustic emission (AE) signals (or seismic signals) recorded by multi-channel systems. The knowledge of this time is very important, mainly in the case of automatic localization of individual AE events. Several approaches are routinely used in practice such as crossing of the threshold level, analysis of the LTA/STA (long-time average/short-time average), etc. In our paper, an approach based on high-order statistics (HOS) that is able to carry out precise arrival time determination without human intervention is presented. The approach was tested on real AE data recorded by an eight-channel recording system. This simple, accurate and quite fast method is predetermined to be used in automatic processing of transient waveform data from acoustic emission, seismic signals, ultrasonic sounding, etc.