Clustering of acoustic emission signals after evaluation via analog modulations of a hybrid neural network for the study of crack propagation

摘要

The acoustic emission (AE) technique is a non-destructive testing technique applied to pressurized rigid pipelines in order to identify metallurgical discontinuities. This study analyses the dynamic behavior of the propagation of discontinuities in cracks via AE, in the following propagation classes : no propagation (NP), stable propagation (SP), and unstable propagation (UP). The methodology involves applying the concept of modulation of analogue signals, which are used in signal transmission in telecommunications, for the development of a neural network in order to determine new parameters for the AE waveform. The classification of AE signals into propagation classes occurs, therefore, through the extraction of information related to the dynamics of AE signals, by means of the parameters of the analogue carriers of the modulations (in amplitude and in angle) that make up the AE signal. This set of parameters enables an efficient classification (average of 90%) through the identification of patterns from the AE signals in the classes for monitoring the state of the discontinuity, through the use of computational intelligence techniques (artificial neural networks and non-linear classification).