Processing And Research Of Acoustic Emission Signal Based On Wavelet Analysis And Moment Tensor Decomposition

As a new dynamic detection method,acoustic emission technology has been widely used in various fields.In recent years,firstly,with the widening of the detection range,the detection objects are more complex,so higher requirements are also proposed for acoustic emission detection system and signal processing technology,such as high noise signal filtering ability,signal classification ability and pattern recognition ability.Using conventional simplified waveform parameter method can not satisfy the above requirement.Secondly with the application of real-time waveform signal acquisition and storage technology in multi-channel digital acoustic emission detection instrument success,acoustic emission signal analysis based on waveform has become a new research direction and research focus of acoustic emission detection technology.Therefore,in this paper,the acoustic emission signal collected by rock fracture is the background,and the intelligent algorithm is used to process and study.The specific research work and research achievements of the project include the following aspects:1.In this paper,the acoustic emission signal of rock fracture is obtained through the experiment of indoor rock fracturing,using load equipment and signal acquisition and analysis integration software.Based on this experiment,data is provided for the processing and analysis of the following signals.2.The rock failure acoustic emission signal is analyzed by wavelet transform and it is also denoised by wavelet transform.The most suitable wavelet basis,threshold and threshold functions for dealing with rock signals were selected by comparing the signal-to-noise ratio(SNR)of the noise reduction signal and the root mean square errors.And it provided the basis for the wavelet packet decomposition.3.The process of rock fracture can be expressed by the characteristics of acoustic emission signals.Wavelet packet analysis technique can be used to study and deal with acoustic emission signals.And the characteristics of rock fracture can be gotten by this.The acoustic emission signal was decomposed in four layers by sym wavelet base.And the acoustic emission signal energy value in different frequency band can be gotten.By analyzing its energy distribution,it can be seen: The energy characteristics of acoustic emission signals under the influence of rocks are widely distributed in the frequency domain.And the main frequency of the AE signal energy distribution is mostly below 750 k Hz.It is shown that the wavelet packet decomposition method can effectively decompose the acoustic emission signal.4.The mode of propagation of acoustic emission signals in rock mass was studied,and combined with the theory of moment tensor analysis,a method for determining the fracture type of rock mass based on the moment tensor was given.This paper combines acoustic emission signal acquisition parameters,using method of 3-d jet lag to locate the acoustic emission source of rock fracture.5.By using the method of moment tensor decomposition,it can be known from the M.hostu test that when the rock breaks,its fracture type includes shear,tension,and its mixed type.By using the mathematical model function and the moment tensor calculation function,the three dimensional distribution diagram of the rupture type event and the proportion of each rupture type are obtained.