Research Of Methods On Extracting Characteristic Signals Of Acoustic Emission Based On Time-Frequency Energy Analysis

In receiving the external force, the internal force or under the temperature influence, the internal energy of the material structure gathers to the certain degree when acoustic emission (AE) with complex components is produced. The AE signals contain the important characteristics of the AE source. In the project application, the situation of producing and developing of the material flaw can be obtained through gaining and analyzing the characteristics of AE signals. This is helpful in monitoring the stressed parts of a machine dynamically. The AE detecting technology has a significant realistic value on aspect of equipment running status monitoring and production safety early warning. But, as a result of the AE signals itself complex characteristics, extracting the signals which possess the most capability to represent the AE source has difficulties, these difficulties have once limited the development of this detecting technology. Therefore, in engineering application and fundamental research of AE technology, the AE signal processing technology research is always a key problem.This article narrated the developing situation of AE technology in domestic and overseas. The forming mechanism of AE has been discussed from mechanics, internal structure and movement of internal energy. Using energy rearrangement technology to rearrange the quadratic time-frequency representation, smooth the cross terms, and simulate the processing result. The corresponding relations between frequency and energy have been established. Use ENYI information computational method to calculate the component number of the AE signals. Partition the AE signals according to its component number, then calculate the proportions between every section signals' energy and the whole signals energy. According to energy of the AE signals, the characteristic signals can be extracted, and also the low frequency noises can be filtered out.The wavelet analysis and wavelet packet analysis theories have been introduced.