【摘要】 根据定量地震学中的矩张量理论,建立了裂缝扩展声发射源的力学模型及有限元模型,通过有限元计算得到裂缝扩展声发射的波形信号。利用小波变换对不同裂缝深度的声发射波形信号进行时频分析,得到不同裂缝深度的声发射波形信号的时频特征。通过研究声发射信号中零阶反对称模式成分(A0)和零阶对称模式成分(S0)的能量比,发现声发射信号的能量比EA 0/ES 0随裂缝深度变化具有一定规律性,能够通过能量比判断裂缝扩展的深度。更多还原

【Abstract】 The mechanical model and the finite element model of acoustic emission source are established according to the moment tensor theory in quantitative seismology,and the waveform signals of acoustic emission due to crack growth are calculated by finite element method.A time-frequency analysis based on the wavelet transform is employed to investigate the acoustic emission waveform signals in different depths,and the time-frequency characters of acoustic emission waveform signals in different depths are obtained.Specifically,a ratio of fundamental anti-symmetric mode energy to fundamental symmetric mode energy is studied for source depth identification.The energy ratios of acoustic emission signals have certain regularity with the crack depth variation.The crack depth can be estimated from the energy ratio.更多还原