Acoustic Emission Signal Characterisation of Failure Mechanisms in CFRP Composites Using Dual-Sensor Approach and Spectral Clustering Technique

Abstract

The characterisation of failure mechanisms in carbon fibre-reinforced polymer (CFRP) materials using the acoustic emission (AE) technique has been the topic of a number of publications. However, it is often challenging to obtain comprehensive and reliable information about individual failure mechanisms. This situation was the impetus for elaborating a comprehensive overview that covers all failure mechanisms within the framework of CFRP materials. Thus, we performed tensile and compact tension tests on specimens with various stacking sequences to induce specific failure modes and mechanisms. The AE activity was monitored using two different wideband AE sensors and further analysed using a hybrid AE hit detection process. The datasets received from both sensors were separately subjected to clustering analysis using the spectral clustering technique, which incorporated an unsupervised k-means clustering algorithm. The failure mechanism analysis also included a proposed filtering process based on the power distribution across the considered frequency range, with which it was possible to distinguish between the fibre pull-out and fibre breakage mechanisms. This functionality was particularly useful in cases where it was evident that the above-mentioned damage mechanisms exhibited very similar parametric characteristics. The results of the clustering analysis were compared to those of the scanning electron microscopy analysis, which confirmed the conclusions of the AE data analysis.

Acoustic Emission and K-S Metric Entropy as Methods to Analyze the Influence of Gamma-Aluminum Oxide Nanopowder on the Destruction Process of GFRP Composite Materials

“…It enables the study of deformation in the elastic or plastic range [23][24][25]. It allows for the monitoring and identification of damage, from the microscopic level to macroscopic changes, including the total destruction of the tested material [26][27][28]. The use of mechanical tests and acoustic emission allows for the detection and identification of individual destruction processes of composite materials, such as fiber breakage, matrix-reinforcement interface cracking and the cracking of the matrix.…”

Thermally Activated Crack Growth and Fracture Toughness Evaluation of Pipeline Steels Using Acoustic Emission

“…Traditional destructive methods of damage monitoring based on the study of the number of microfractures, such as transmission and scanning microscopy, X-ray scattering, and precision density measurement, due to their nature and complexity, have limitations in application to real objects [51]. The acoustic emission method, which is a direct passive method of monitoring the accumulation of damage, is based on the registration of elastic waves emitted by the source of the change of the continuity of the body [52][53][54]. To solve the problem of thermally activated crack growth, each act of AE should be considered as containing information about a collective act of destruction, where time is the main parameter [25,55].…”

Reduction in the Sensor Effect on Acoustic Emission Data to Create a Generalizable Library by Data Merging

“…A challenge in AE monitoring is to establish a clear link between the recorded AE signals and the corresponding source. The possibility of identifying the signatures of damage mechanisms is a well-established field [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Most of the time, the analysis of AE data is established through empirical correlations between the damage mechanism and the recorded signal.…”

“…These approaches use classification algorithms to gather signals into classes depending on their descriptor values. For the unsupervised clustering [ 12 ], each class is then associated with a specific damage mechanism. The attribution of each class to a specific damage mechanism is mainly based on empirical approaches, and the validation of this labeling remains difficult and is still a challenge.…”