Study on waveform duration characteristics of acoustic and electrical signals of coal damage under load

Abstract

In order to explore the rule of the duration of the acoustic electric signal when the coal sample is damaged by loading, the full waveform synchronous acquisition of the acoustic electric signal during the uniaxial loading failure process of the coal sample under different loading rates is carried out, the time sequence characteristics of the acoustic electric signal during the coal sample failure process are compared and analyzed, and the waveform characteristics and duration of the acoustic emission and electromagnetic radiation in the complete failure stage are emphatically analyzed. The results show that: in the process of uniaxial loading failure of coal samples, the response of acoustic and electrical signals has a good synergy, the higher the loading rate is, the denser and stronger the acoustic and electrical signals are generated during the main failure; the results show that the AE signal changes with the loading stage, and there is no obvious AE signal in the compaction and elastic stage; in the accelerated failure stage, the AE signal is gradually enriched and the amplitude increases; in the complete failure stage, the amplitude of the AE signal reaches the maximum when the main failure occurs, and decays synchronously after the peak; under different loading rates, the duration of AE signal is in millisecond level, and the duration of AE is 2 to 3 times longer than that of electromagnetic radiation. With the increase of loading rate, the duration of AE signal and electromagnetic radiation increase significantly, and the multiple increases with the increase of loading rate.

Keywords

• coal failure under load
• uniaxial compression
• acoustic emission
• electromagnetic radiation
• waveform duration