岩石声发射信号能量分布特征的EMD分析

冲击荷载作用下岩石声发射信号具有瞬态性和多样性的特点，属于典型的非平稳信号。利用EMD方法对岩石声发射信号进行分解，得到一系列具有不同特征时间尺度的IMF分量，对每一个平稳的IMF分量提取能量特征。分析结果表明：冲击荷载作用下岩石声发射信号能量主要分布在前4个IMF分量内，且分布不均匀；岩石声发射信号各IMF分量的频谱与原始信号的频谱基本一致；随着岩石的密度、纵波波速、弹性模量的降低，冲击荷载作用下岩石声发射信号的优势频率越来越集中，且其优势频率有往低频发展的趋势；相比小波包分析，EMD分析法对于非平稳信号而言更具适应性。

Energy distribution characteristics of rock acoustic emission signals with EMD analysis

Rock acoustic emission signals have transient property and diversity under impact loading,which belong to a typical non-stationary signal.EMD method was used to decompose a rock acoustic emission signal into a number of IMF components with different characteristic time scales and then the energy characteristic of each stationary IMF component was extracted.The test results showed that the energy of a rock acoustic emission signal mainly distributes in the first four IMF components,and distributes unevenly;the frequency spectrum of each IMF component agrees well with the original signal frequency spectrum;if density of rock,speed of longitudinal wave and its elastic modulus decrease,the dominant frequencies of the rock acoustic emission signal under impact loading become more concentrated and tend to be lower;compared with wavelet packet analysis,EMD analysis is more suitable for non-stationary signals.