Abstract:By a standard split Hopkinson pressure bar(SHPB) dynamic test device and ZDKT–1 type transient magnetic vibration test system,the dynamic properties of coal and the characteristics of the transient magnetic nearby field in the process of coal impact damage are researched under impact velocity of 4.174–17.652 m/s. The one-dimensional stress wave theory and the signal analysis of Hilbert-Huang transform(HHT) method are used to analyze the strain signal and the transient magnetic signal,respectively. The results show that:(1) The dynamic response of coal transforms from hardening to softening within certain range of strain rate;(2) The magnetic field has varied obviously in 4 cm distance of coal sample area during coal dynamic impact process,and it shows that the duration is less than 2 s and the frequency is less than 40 Hz through the ensemble empirical mode decomposition(EEMD) analysis;(3) The characteristics of the signal curve of the transient magnetic changes in coal impact damage process is shown that the first performance straight up,then exponential decline,at the end of small oscillation;(4) The amplitudes of transient magnetic field changes in coal impact damage process rises with the impact velocity,average strain rate,the maximum strain rate and the limit value of fracture stress increasing,while it reduces with the failure strain increasing,but the data are of a larger dispersion.
李成武,解北京,杨 威,韦善阳. 煤冲击破坏过程中的近距离瞬变磁场变化特征研究[J]. 岩石力学与工程学报, 2012, 31(5): 973-981.
LI Chengwu,XIE Beijing,YANG Wei,WEI Shanyang. CHARACTERISTICS OF TRANSIENT MAGNETIC NEARBY FIELD IN PROCESS OF COAL IMPACT DAMAGE. , 2012, 31(5): 973-981.
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