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Acoustic Emission as a Method for Analyzing Changes and Detecting Damage in Composite Materials During Loading

Panasiuk Katarzyna, Dudzik Krzysztof, Hajdukiewicz Grzegorz

Archives of Acoustics

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2021

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Vol. 46, No. 3

399--407

EN

Thanks to their excellent strength and durability, composite materials are used to manufacture many important structural elements. In the face of their extensive use, it is crucial to seek suitable methods for monitoring damages and locating their origins. The purpose of the article was to verify the possibility of applying the acoustic emissions (AE) method in the detection of damages in the structures of composite materials. The experimental part comprised static tensile tests carried out on various sandwich composites, including simultaneous registration of elastic waves with increasing loads, carried out with the use of an acoustic-electrical sensor connected. The signal obtained from the sensor was then further processed and used to draw up diagrams of the AE hits, amplitude, root mean square of the AE source signal (RMS) and duration in the function of time. These diagrams were then applied on their corresponding stretching curves, the obtained charts were analysed. The results obtained point to a conclusion that the acoustic emissions method can be successfully used to detect and locate composite material damages.

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Modeling of a three-point bend test of a beam made of AW 5083 alloy

Żuk Daria, Hajdukiewicz Grzegorz

Scientific Journal of Gdynia Maritime University

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2020

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nr 116

100--111

EN

The paper describes the modeling of a three-point bend test carried out on a beam made of the AW 5083 aluminium alloy performed using the finite element method. The three-point bend test was carried out experimentally in accordance with the current standard PN-EN ISO 7438:2016-0. During the test, the values of the beam material constants, such as Poisson number and Kirchoff modulus which were necessary for the modeling were determined. The results obtained in the test allowed for modelling using software based on the finite element method, such as MSC Patran and Abaqus software. The test modelling in the software was performed taking into account the beam geometry, the material properties, the boundary conditions, and the load. In order to verify the model, a comparative analysis was performed of the values of the bend of the beam’s central axis obtained from the experiment and the values obtained after the FEM modeling and those obtained by the analytical method.

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The impact of polyester-glass recyclate on the hardness and structure of composites

Panasiuk Katarzyna, Kyzioł Lesław, Abramczyk Norbert, Hajdukiewicz Grzegorz

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2019

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nr 59 (131)

22--26

EN

The attractive characteristics of polyester-glass composites have led to their use in many industries, but using them as structural elements requires knowing their mechanical properties. This paper presents processing methods of polyester and glass scrap and their use in the production of new composites. This scrap, called the recyclate, was pre-crushed, ground, and then passed through sieves to obtain the desired fractions. Composite materials with added recyclate were made by hand lamination. Composites were made and then used to conduct appropriate tests to determine the degree of cure of the resin, and to determine the effect of the polyester-glass recyclate content on the hardness of composites. For this purpose, rectangular panels with a thickness of g = 8 mm were produced by manual lamination. Each plate contained 0% glass mat, 10% resin, and 20% recyclate with granulation ≤ 1.2 mm and ≤ 3 mm. Then, test samples were formed from each plate. Hardness measurements were performed using the ball-pressing method. In addition, structural studies were carried out to determine the correlation between the structural and mechanical properties of the discussed materials. The obtained test results showed that the recyclate content and its granulation clearly affected the mechanical properties of the tested composite materials.

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Analysis of the cracking process of layered composites with polyester-glass recyclate using dynamic tests

Panasiuk Katarzyna, Kyzioł Lesław, Hajdukiewicz Grzegorz

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2019

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nr 57 (129)

73--78

EN

Layered composites are materials that are widely used in industry due to their low manufacturing costs. They are used, among others, as a construction material for the construction of light aircraft, cars, wind turbine blades and the hulls of vessels. The universality of their use has contributed to the formation of a large amount of post-production and post-use waste from these composites. Layered composites, using recycled polyester and glass, or recycled composite waste, may be materials that could be used in the economy. The polyester-glass waste used in the composite was created by crushing and then grinding and sieving to obtain the appropriate granulation. Materials with a waste content of 0%, 10%, 20% and with granulation of this waste of ≤ 1.2 mm were made using the hand lamination method. Test specimens were prepared from the material plates that were obtained in accordance with the PN-EN ISO 179-1: 2010E standard (Plastics – Charpy Impact Assessment – Part 1: Non-instrumental impact test). Impact tests of samples were carried out according to the above-mentioned standards using a Zwick Roell RKP450 swinging hammer. Test bench instrumentation and software enabled the bending forces to be recorded, as well as the deflection of the samples for short time intervals and displacement, so a detailed force-deflection graph could be obtained. During the analysis, the results of the research were focused on describing the kinetics of the process where the samples were destroyed (fracture mechanics), this allowed for the initial determination of the material’s resistance to dynamic loads. The results obtained showed that the increase of the recycled content in the produced composite contributed to the lowering of the destructive force threshold in the impact tests, as well as the simultaneous increase of the plasticity of the material. The increase of the sample’s deflection with the occurrence of the maximum force resulted in the energy of the elastic state being increased (Ue).

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Effect of the recyclate on a deflection of composites in bending

Panasiuk Katarzyna, Kyzioł Lesław, Hajdukiewicz Grzegorz

Journal of KONES

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2019

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Vol. 26, No. 4

197--203

EN

The aim of the research was to determine the effect of polyester-glass recyclate on the deflection of composite samples subjected to three-point bending. The polyester-glass recyclate was obtained from the part of the ship’s hull made of polyester-glass composite, constituting scrap metal. The pieces of scrap were pre-fragmented and then processed into a prepared stand for this purpose. Such a fragmented recycling will be used to make composites with different scrap / recycled content. For this purpose, research materials were made using the vacuum bag method with the percentage of 0%, 10% and 20% recyclate) as well as various granulation (i.e. 1.2 mm and 3.0 mm). The research material consisted of rectangular plates with a thickness corresponding to the thickness of the samples. The samples for testing were made by water cutting. The tests were carried out on a suitably prepared stand, which was made of a universal Zwick Roell testing machine and three-point bending handles and a dial indicator. The spacing of the supports has been determined in accordance with the binding standard for three-point bending. Obtained results from tests, i.e. strain, stress, deflection, deformation allowed analysing the impact of recyclate on bending strength and defining the deflection arrow. Based on the results obtained from three-point bending, it can be concluded that the polyester-glass recycling has an influence on the decrease of strength, stress and deflections of the tested composites.

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Application of the Kolmogorov-Sinai entropy in determining the yield point, as exemplified by the EN AW-7020 alloy

Kyzioł Lesław, Hajdukiewicz Grzegorz

Journal of KONBiN

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2019

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Vol. 49, iss. 3

241--269

EN

The article presents a method of determining the yield point, applying calculations based on the Kolmogorov-Sinai (K-S) metric entropy model. Data used in metric entropy calculations was obtained during a static tensile test of the AW-7020 aluminium alloy. The methodology of K-S entropy calculations was presented and illustrated by a selected example from a data collection. Analyzing the results obtained, the values of an arbitrary yield point were compared for R02 selected samples with the values of the yield point obtained using the metric entropy method ReK-S.

PL

W artykule przedstawiono sposób wyznaczania granicy plastyczności wykorzystując obliczenia oparte na entropii metrycznej Kołmogorow-Sinai (K-S). Dane do obliczeń entropii metrycznej uzyskano w czasie wykonania statycznej próby rozciągania stopu aluminium AW-7020. Opisano dokładnie metodologię obliczeń entropii K-S ilustrując ją wybranym przykładem ze zbioru danych. Analizując uzyskane wyniki porównano wartości umownej granicy plastyczności R R02 wybranych próbek z wartościami granicy plastyczności uzyskanymi metodą obliczenia entropii metrycznej ReK-S.