Acoustic emission characteristics of rock under impact loading
来源期刊：中南大学学报(英文版)2015年第9期
论文作者：LIU Xi-ling LI Xi-bing HONG Liang YIN Tu-bing RAO Meng
文章页码：3571 - 3577
Key words：rock; acoustic emission (AE); split hopkinson pressure bar (SHPB); hit driven features; frequency characteristics; correlation analysis
Abstract: Acoustic emission tests were performed using a split hopkinson pressure bar system (SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is not well centralized around 50 dB, and that some hits with large amplitudes, usually larger than 70 dB, occur in the early stages of each test, which is different from the findings from static and low-loading-rate tests. Furthermore, the dominant frequency range of the recorded acoustic emission waveforms is between 300 kHz and 500 kHz, and frequency components higher than 500 kHz are not significant. The hit with the largest values of amplitude, counts, signal strength, and absolute energy in each test, displays a waveform with similar frequency characteristics and greater correlation with the waveform obtained from the elastic input bar of the split Hopkinson pressure bar system compared with the waveforms of the other hits. This indicates that the hit with the largest values of amplitude, counts, signal strength, and absolute energy is generated by elastic wave propagation instead of fracture within the rock specimen.
LIU Xi-ling(刘希灵)1, 2, LI Xi-bing(李夕兵)1, HONG Liang(洪亮)3, YIN Tu-bing(尹土兵)1, RAO Meng(饶蒙)1
(1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China;
2. Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Vancouver V6T1Z4, Canada;
3. School of Civil Engineering, Hunan City University, Yiyang 413049, China)
Abstract:Acoustic emission tests were performed using a split hopkinson pressure bar system (SHPB) on 50-mm-diameter bars of granite, limestone, sandstone and skarn. The results show that the amplitude distribution of hits is not well centralized around 50 dB, and that some hits with large amplitudes, usually larger than 70 dB, occur in the early stages of each test, which is different from the findings from static and low-loading-rate tests. Furthermore, the dominant frequency range of the recorded acoustic emission waveforms is between 300 kHz and 500 kHz, and frequency components higher than 500 kHz are not significant. The hit with the largest values of amplitude, counts, signal strength, and absolute energy in each test, displays a waveform with similar frequency characteristics and greater correlation with the waveform obtained from the elastic input bar of the split Hopkinson pressure bar system compared with the waveforms of the other hits. This indicates that the hit with the largest values of amplitude, counts, signal strength, and absolute energy is generated by elastic wave propagation instead of fracture within the rock specimen.
Key words:rock; acoustic emission (AE); split hopkinson pressure bar (SHPB); hit driven features; frequency characteristics; correlation analysis
