Investigation of damage mechanisms of composite materials: Multivariable analysis based on temporal and wavelet features extracted from acoustic emission signals

2009 ◽  
pp. 399-409 ◽  
Author(s):  
A. Marec ◽  
J. H. Thomas ◽  
R. El Guerjouma ◽  
R. Berbaoui
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Multivariable Analysis ◽  
Damage Mechanisms ◽  
Wavelet Features

Analysis of damage mechanisms in drilling of composite materials by acoustic emission

2015 ◽  
Vol 131 ◽  
pp. 107-114 ◽  
Author(s):  
Navid Zarif Karimi ◽  
Giangiacomo Minak ◽  
Parnian Kianfar
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Damage Mechanisms

Monitoring of damage mechanisms in sandwich composite materials using acoustic emission

2014 ◽  
Vol 24 (6) ◽  
pp. 787-804 ◽  
Author(s):  
Mustapha Assarar ◽  
Mourad Bentahar ◽  
Abderrahim El Mahi ◽  
Rachid El Guerjouma
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Sandwich Composite ◽  
Damage Mechanisms

scholarly journals Acoustic Emission-Based Diagnosis Using AlexNet: How Wave Propagation Effects Classification Performance

2021 ◽  
Keyword(s):  
Acoustic Emission ◽  
Wave Propagation ◽  
Composite Materials ◽  
Mechanical Damage ◽  
Classification Performance ◽  
Performance Estimation ◽  
Damage Mechanisms ◽  
Source Mechanisms ◽  
Propagation Paths ◽  
The Impact

Abstract. Composite materials are frequently used due to light weight and high stiffness. However, the use of composite materials is limited due to several micro-mechanical damage mechanisms, which are currently not well understood. Therefore, Acoustic Emission (AE) is frequently suggested for in-situ diagnosis of composite materials in Structural Health Monitoring. Elastic stress waves in the ultrasound regime are recorded using highly sensitive measurement equipment. Based on suitable analysis and interpretation of the waveform data, different micro-mechanical damage mechanisms such as delamination or fiber breakage can be distinguished. Frequently, data-driven approaches are suggested for classification of AE data. In literature, attenuation of AE due to wave propagation is currently the main limiting factor in AE-based diagnosis. In particular, AE is strongly attenuated in composite materials due to dispersion as dominant attenuation mechanism. Furthermore, depending on the source location, which is usually not known a-priori, different propagation paths are obtained in practice. Therefore, the effect of wave propagation on AE is important and can not be neglected to achieve reliable classification. However, the effect of different propagation paths on the classification performance is often not considered explicitly. Due to dependence of wave propagation behavior on waveform characteristics (e.g. frequency), it can be expected that the impact of wave propagation on AE classification performance depends also on the related source mechanism. Therefore, it is worth to study how classification performance of different source mechanisms is effected by wave propagation. In this paper, the dependence of the classification performance on different propagation distances is experimentally investigated in detail. To achieve highly reproducible AE measurements, different artificial AE sources are induced using surface mounted piezo elements. The corresponding waveforms are measured at two different locations. For classification, a convolutional neural network-based classification scheme is established. The pre-trained AlexNet architecture is fine-tuned using measurements obtained using different excitation signals. The classification performance is evaluated with particular focus on the impact of wave propagation. The variations in propagation distance have a strong impact on the classification performance. As main conclusion for AE-based SHM it can be stated that variations in the propagation path should be considered. Furthermore, the underlying source mechanisms should be taken into consideration for reliable performance estimation.

scholarly journals Damage mechanisms assessment of hybrid carbon/flax fibre composites using acoustic emission

2019 ◽  
Vol 283 ◽  
pp. 03003 ◽  
Author(s):  
Mariem Ben Ameur ◽  
Jean-Luc Rebiere ◽  
Abderrahim El Mahi ◽  
Moez Beyaoui ◽  
Moez Abdennadher ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Composite Laminates ◽  
Multivariable Analysis ◽  
Damage Mechanism ◽  
Tensile Tests ◽  
Flax Fibre ◽  
Acoustic Energy ◽  
Uniaxial Tensile ◽  
Damage Mechanisms ◽  
Hybrid Carbon

The purpose of the present experimental study is to describe the damage mechanisms occurring in epoxy matrix composites reinforced with hybrid carbon-flax fibres. The samples tested were consist of unidirectional carbon and flax fibre plies with different stacking sequences. Composite laminates were manufactured by hand lay-up process. The specimens were tested under uniaxial tensile loading. The tests carried out were monitored by the acoustic emission (AE) technique. The results obtained during the monotonic tensile tests were analyzed in order to identify the damage mechanisms evolutions. The recorded events were classified with the k-means algorithm which is a statistical multivariable analysis. In addition, it was an unsupervised classification according to temporal descriptors. The percentage of each damage mechanism to the global failure was evaluated by the hits number and the acoustic energy activity. The AE technique was correlated with scanning electron microscopy (SEM) observations to identify the typical damage mechanisms.

scholarly journals Acoustic Emission and K-S Metric Entropy as Methods for Determining Mechanical Properties of Composite Materials

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 145
Author(s):  
Lesław Kyzioł ◽  
Katarzyna Panasiuk ◽  
Grzegorz Hajdukiewicz ◽  
Krzysztof Dudzik
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Composite Material ◽  
Composite Materials ◽  
Testing Machine ◽  
Measurement Data ◽  
Entropy Method ◽  
Displacement Sensor ◽  
Metric Entropy ◽  
Plastic Phase

Due to the unique properties of polymer composites, these materials are used in many industries, including shipbuilding (hulls of boats, yachts, motorboats, cutters, ship and cooling doors, pontoons and floats, torpedo tubes and missiles, protective shields, antenna masts, radar shields, and antennas, etc.). Modern measurement methods and tools allow to determine the properties of the composite material, already during its design. The article presents the use of the method of acoustic emission and Kolmogorov-Sinai (K-S) metric entropy to determine the mechanical properties of composites. The tested materials were polyester-glass laminate without additives and with a 10% content of polyester-glass waste. The changes taking place in the composite material during loading were visualized using a piezoelectric sensor used in the acoustic emission method. Thanks to the analysis of the RMS parameter (root mean square of the acoustic emission signal), it is possible to determine the range of stresses at which significant changes occur in the material in terms of its use as a construction material. In the K-S entropy method, an important measuring tool is the extensometer, namely the displacement sensor built into it. The results obtained during the static tensile test with the use of an extensometer allow them to be used to calculate the K-S metric entropy. Many materials, including composite materials, do not have a yield point. In principle, there are no methods for determining the transition of a material from elastic to plastic phase. The authors showed that, with the use of a modern testing machine and very high-quality instrumentation to record measurement data using the Kolmogorov-Sinai (K-S) metric entropy method and the acoustic emission (AE) method, it is possible to determine the material transition from elastic to plastic phase. Determining the yield strength of composite materials is extremely important information when designing a structure.

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