Wyniki wyszukiwania - Biblioteka Nauki

1

Application of the Acoustic Emission Technique for Damage Identification in the Fiber Reinforced Polymer Composites

100%

Samborski S. , Korzec I.

Advances in Science and Technology. Research Journal

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2023

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tom Vol. 17, no 1

210--221

EN

A set of experiments having in target determination of fracture resistance was performed on the Fiber Reinforced Polymer (FRP) composites specimens with an additional monitoring of damage onset and evolution with a so-called Acoustic Emission (AE) technique. The AE technique is a non-destructive material testing method, which enables registering the phenomena usually not audible with a human ear - the frequency bands lay between 100 and 1000kHz. For the FRP composites this enables monitoring various damage phenomena - matrix cracking, delamination, fiber cracking etc. by acquisition and subsequent analysis of several AE parameters: number of hits, number of counts, amplitude or energy of the signal. In the paper advantages of a deeper analysis of the raw AE signal was presented with an application of the Fast Fourier Transform (FFT), leading to a more detailed damage identification along the whole loading procedure. The study proved the usability of the AE method in damage monitoring of the FRPs; a bundle of illustrative examples of chosen acoustic emission parameters’ evolution displayed on the background of the load applied to composite specimens was presented and interpreted.

2

A Study on Mechanical Strength and Failure of Fabric Reinforced Polymer Composites

80%

Korzec I. , Samborski S. , Łusiak T.

Advances in Science and Technology. Research Journal

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2022

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tom Vol. 16, no 2

120--130

EN

The paper presents a study on influence of different fabric weave and fabric orientation on strength properties of fiber reinforced polymer composites. The research concerns materials used in a new type of rotorcraft. Four series of laminates were fabricated with hand forming, using the MGS L285/H285 epoxy resin. Triple-kind experiments were performed: the Shore hardness measurements, tensile strength testing and fractographic analysis. The specimens of different series shown various strength and stiffness characteristics, depending on the type of weave and fabric layup. Three different failure schemes were observed. The Poisson coefficient was different among series, as well, but no understandable link to specimen morphology could be found so far. Fractographic observations suggested intralaminar delamination.

3

The application of composite materials in the aerospace industry

80%

Skoczylas J. , Samborski S. , Kłonica M.

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tom Vol. 5, nr 1

1--6

EN

The paper investigates the growing popularity of composite materials concentrating on explanation of their advantages, especially taking into consideration composite materials used in the aerospace industry such as polymer matrix composites, metal matrix composites, ceramic matrix composites and smart composite materials. Various types of matrices and fibers are described with special emphasis on nanotechnology and opportunities to improve the properties of composites. The paper also presents selected examples of applications in the aerospace industry.

4

Numerical Study of the Natural Oscillations of Perforated Vibrating Surfaces with Holes of Complex Geometry

80%

Kharchenko S. , Samborski S. , Kharchenko F. , Paśnik J.

Advances in Science and Technology. Research Journal

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2023

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tom Vol. 17, no 6

73--87

EN

The widespread use of perforated vibrating surfaces in various industries requires maximum productivity and construction reliability. The research task is to determine the significant factors and their degree of influence on the natural oscillations of vibrating surfaces with multiple holes of complex geometry. For this purpose, studies were carried out for three samples of plates: non-perforated, with basic round holes and holes of complex geometry in the form of a five-petal epicycloid. Studies of the natural oscillations of perforated vibrating surfaces have been conducted using the finite element method in Abaqus, which has proved sufficient accuracy of calculations. The dependencies of the natural oscillation frequency of perforated surface samples on their thickness, partition width between the holes, material type, and fixing method have been obtained. In addition, the analysis involved the study of eight modes of oscillation common in practice. The dependencies of the natural oscillation frequency of perforated surface on the relative parameters of ligament efficiency and stiffness coefficient have also been obtained. These parameters take into account the ratios of the partition width between the holes to the plate thickness and the dimensions of the holes. The research results allow to obtain levels of influence of the perforated vibrating surface parameters on their natural oscillations frequency. The obtained research results make it possible to further determine the absence of damage between the holes and predict the durability of perforated vibration surfaces in the presence of holes of complex geometry.

5

Determination of Hole Blocking Conditions for Perforated Sifting Surfaces

80%

Kharchenko S. , Samborski S. , Kharchenko F. , Kotliarevskyi I.

Advances in Science and Technology. Research Journal

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2024

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tom Vol. 18, no 5

342--360

EN

The efficiency of widespread technological processes of sieve sifting of loose materials depends on timely cleaning of holes from the blocked particles. The blocking of holes occurs under specific conditions related to mechanical-and-physical properties of loose material particles, constructive and technological parameters of perforated sifting surfaces and clean-up systems. We established the conditions that contribute to blocking of holes of sifting surfaces and identified all significant factors, namely size, mass, constant of friction and Young's modulus for loose material particles; form and size of hole, thickness of perforated surface; loose material layer thickness and velocity. Using analytical and experimental methods, we identified variation range of these factors for loose material particles of biological origin, such as buckwheat, wheat, peas, corn. As a result of this study, we received analytical equations for determination of force of adhesion of loose materials particles with the edge of holes of perforated surfaces. The numeric calculations allowed establishing the dependence of the force of adhesion on moisture and thickness of loose material layer, as well as thickness and shape of the holes of the perforated surfaces. We have also established the dependence of constant of friction, mass, Young's modulus from the moisture of particles of loose material. The obtained results make it possible to determine the force of adhesion and prediction the power necessary for unblocking this hole, created by the cleaning system elements, such as brushes and elastic impact cleaners. The use of this method will make it possible to justify the parameters of the system for cleaning holes of perforated sifting surfaces with different types of holes and when separating different types of loose materials.