Acoustic Emission from Composite Materials at Low Temperatures

The study of metals in impact bending and indentation is considered. A bench is developed for assessing the character of failure on the example of 45 steel at low temperatures using the classification of acoustic emission signal pulses and a trained artificial neural network. The results of fractographic studies of samples on impact bending correlate well with the results of pulse recognition in the acoustic emission signal. Keywords acoustic emission, classification, artificial neural network, low temperature, character of failure, hardness. [email protected]

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

Sensors ◽

10.3390/s21010145 ◽

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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Aspects of Strain Rate Effects on Some Composite Materials

10.1115/imece2000-1639 ◽

2000 ◽

Author(s):

Emmanuel O. Ayorinde

Keyword(s):

Acoustic Emission ◽

Composite Materials ◽

Strain Rate ◽

Matrix Cracking ◽

Epoxy Composites ◽

Fiber Architecture ◽

Strain Rate Effects ◽

Rate Effects ◽

General Strain ◽

Ultrasonic Images

Abstract Effects of moderate straining speed on the material and damage characteristics of beam samples of graphite/epoxy and E-glass/epoxy composites were investigated. The basic fiber architecture utilized was unidirectional, axial layup, but data was also obtained for the 45-degree orientation. Ultrasonic and acoustic emission (AE) inspections were utilized. The acoustic emission records show matrix cracking. The ultrasonic images revealed the regions of failure. The results show that in general, strain rate notably affects material and damage properties.

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Investigation of the Staging of Damage Accumulation in Polymer Composite Materials during Bending and Tensile Tests

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.887.116 ◽

2021 ◽

Vol 887 ◽

pp. 116-122

Author(s):

A.A. Bryansky ◽

O.V. Bashkov ◽

Daria P. Malysheva ◽

Denis B. Solovev

Keyword(s):

Acoustic Emission ◽

Composite Materials ◽

Polymer Composite ◽

Loading Rate ◽

Tensile Tests ◽

Mechanical Tests ◽

Rate Effect ◽

Polymer Composite Materials ◽

Static Tension ◽

Point Bend

The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.

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Application and evaluation of the technical condition of composite materials in aircraft and unmanned aerial vehicles by acoustic emission method of nondestructive testing

Advanced Engineering Research ◽

10.23947/2687-1653-2021-21-4-328-336 ◽

2022 ◽

Vol 21 (4) ◽

pp. 328-336

Author(s):

A. V. Popov ◽

A. O. Samuylov ◽

I. S. Cherepanov

Keyword(s):

Acoustic Emission ◽

Composite Materials ◽

Nondestructive Testing ◽

Unmanned Aerial Vehicles ◽

Technical Condition ◽

Acoustic Emission Method ◽

Emission Method ◽

Software Complex ◽

Aerial Vehicles ◽

Aerial Vehicle

Introduction. The paper analyzes the application of composite materials as the main determining method of reducing the mass of the airframe and an unmanned aerial vehicle. Advanced nondestructive testing methods provide assessing the technical condition of these materials, as well as determining stress concentrators on the airframe and an unmanned aerial vehicle with high accuracy in order to make a decision on the further operation of this object under control. The objective of the work was to increase the accuracy and efficiency of the assessment of crack resistance of composite materials through the acoustic emission control.Materials and Methods. This paper presents the nomenclature of composite materials used in the construction of various aircraft, including unmanned aerial vehicles. The most possible probable defects of these materials due to the influence of operational factors are presented. The applied methods of nondestructive testing of composite material and selection of the most suitable one according to specific advantages were compared. An experiment was carried out to determine the strength limits of carbon fiber using a hardware and software complex by acoustic emission method. The research results are presented in the form of drawings projected by the hardware and software complex.Results. The application of the acoustic-emission method of composite material control is described.Discussion and Conclusions. The results obtained experimentally can be used in the process of determining the strength limits of various composite materials by the acoustic emission method of nondestructive testing to assess the technical condition in mechanical engineering, shipbuilding, and aircraft construction. The paper is recommended to researchers involved in the design of aircraft and unmanned aerial vehicles.

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