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1

The application of composites based on recycled materials for electromagnetic field shielding

Jakubas Adam, Łada-Tondyra Ewa, Suchecki Łukasz

Przegląd Elektrotechniczny

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2023

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R. 99, nr 1

190--193

EN

This paper presents the possibilities of using polymer-metal composites as electromagnetic shields. Recycled materials such as iron scale and nanocrystalline tapes were used to build the composites. In the course of the work, research was carried out into the effectiveness of shielding electromagnetic fields in the range from 40 Hz to 15 GHz. The shielding effectiveness was shown to be competitive to that of other composite materials based on non-metallic fillers and comparable to that of layered composites containing e.g. aluminum.

PL

W artykule przedstawiono możliwości wykorzystania kompozytów polimerowo-metalowych jako ekranów elektromagnetycznych. Do budowy kompozytów wykorzystano materiały z recyklingu, takie jak zendra i taśmy nanokrystaliczne. W toku prac prowadzono badania nad skutecznością ekranowania pól elektromagnetycznych w zakresie od 40 Hz do 15 GHz. Wykazano, że skuteczność ekranowania jest konkurencyjna w stosunku do innych materiałów kompozytowych na bazie wypełniaczy niemetalicznych i porównywalna z kompozytami warstwowymi zawierającymi m.in. aluminium.

2

Właściwości mechaniczne betonów z dodatkiem makrowłókien poliolefinowych

Helbrych Paweł

Przegląd Budowlany

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2023

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R. 94, nr 11-12

54--57

PL

W artykule przedstawiono wyniki badań wpływu dwóch typów makrowłókien poliolefinowych na właściwości świeżego i stwardniałego betonu. Określono zawartość powietrza w mieszance betonowej, klasę konsystencji, wytrzymałość na ściskanie, wytrzymałość betonu na rozciąganie w próbie zginania oraz wytrzymałość na rozciąganie przy rozłupywaniu. Wykazano istotny wpływ rodzaju, kształtu i budowy włókien syntetycznych na właściwości mechaniczne betonu. Dodatek włókien poliolefinowych nie wpłynął negatywnie na wytrzymałość na ściskanie betonu, a serie badawcze z mniejszą ilością włókien fibrylowanych uzyskały podobne lub lepsze wyniki wytrzymałościowe niż serie z większą ilością foliowłókien. Wyniki te wskazują na potencjał wykorzystania makrowłókien polimerowych w konstrukcjach betonowych, co pozwoli na poprawę jego wytrzymałości i innych istotnych właściwości.

EN

The article presents the results of research on the influence of two types of polyolefinic macrofibers on the properties of fresh and hardened concrete. The content of air in the concrete mix, consistency class, compressive strength, tensile strength of concrete in flexural testing, and splitting tensile strength were determined. The significant impact of the type, shape, and structure of synthetic fibers on the mechanical properties of concrete has been demonstrated. The addition of polyolefin fibers did not have a negative effect on the compressive strength of concrete, and research series with a smaller amount of fibrillated fibers achieved similar or better strength results than series with a larger amount of film fibers. These results indicate the potential use of polymer macrofibers in concrete structures, which will allow for the improvement of its strength and other important properties.

3

Comparative Studies of GFRP Composites Using Pulsed Thermography and Transmission Terahertz Non-Destructive Testing Methods

Świderski Waldemar, Strąg Martyna

Pomiary Automatyka Robotyka

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2023

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R. 27, nr 3

33--37

EN

Composites are materials that have replaced traditional construction materials in numerous applications in various fields. Due to the possibility of creating the required material properties, fiber-reinforced composites are most often used. Despite competition from carbon and aramid fibers, the earliest glass fibers produced are used in many applications. One of the areas where glass fiber reinforced composites (GFRP) make a significant contribution to structural applications is aviation. Because both during production and operation, composites are exposed to damage, which often occurs in the internal structure of the composite, works are being carried out to develop the most effective method of non-destructive testing to detect such damage. The article presents a comparison of the results of non-destructive testing of glass fiber-reinforced composite samples. A comparison of the results of the possibility of detecting defects in the form of milled holes of different diameters and depths inside the samples was made. These damages are not optically visible on both surfaces of the samples. In non-destructive testing, infrared thermography and transmission terahertz methods were used. The obtained results indicate a great possibility of using terahertz radiation, especially in thicker structures of the GFRP composite, where thermographic methods are not as effective as in thin ones.

PL

Kompozyty to materiały, które zastąpiły tradycyjne materiały konstrukcyjne w licznych zastosowaniach w różnych dziedzinach. Ze względu na możliwość tworzenia wymaganych właściwości materiału, najczęściej stosuje się kompozyty wzmacniane włóknami. Pomimo konkurencji ze strony włókien węglowych i aramidowych, najwcześniej wyprodukowane włókna szklane są wykorzystywane w wielu zastosowaniach. Jednym z obszarów, w którym kompozyty wzmocnione włóknem szklanym (GFRP) wnoszą znaczący wkład w zastosowania konstrukcyjne, jest lotnictwo. Ponieważ zarówno w trakcie produkcji, jak i eksploatacji kompozyty narażone są na uszkodzenia, które często występują w strukturze wewnętrznej kompozytu, prowadzone są prace nad opracowaniem najskuteczniejszej metody badań nieniszczących pozwalających wykryć takie uszkodzenia. W artykule przedstawiono porównanie wyników badań nieniszczących próbek kompozytów wzmocnionych włóknem szklanym. Dokonano porównania wyników możliwości wykrywania defektów w postaci wyfrezowanych otworów o różnej średnicy i głębokości wewnątrz próbek. Uszkodzenia te nie są widoczne optycznie na obu powierzchniach próbek. W badaniach nieniszczących wykorzystano termografię w podczerwieni i transmisyjną metodę terahercową. Uzyskane wyniki wskazują na duże możliwości wykorzystania promieniowania terahercowego, zwłaszcza w grubszych strukturach kompozytu GFRP, gdzie metody termograficzne nie są tak skuteczne jak w strukturach cienkich.

4

Experimental research on the removal characteristics of simulated radioactive aerosols by a cloud-type radioactive aerosol elimination system

Zhang Jiqing, Jia Ying, Lv Xiaomeng, Xiong Tiedan, Huang Yuanzheng, Shen Keke

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 4

10--18

EN

Radioactive aerosols in the confined workplace are a major source of internal exposure hazards for workers. Cloud-type radioactive aerosol elimination system (CRAES) have great potential for radioactive aerosol capture due to their high adsorption capacity, lack of cartridges and less secondary contamination. A CRAES was designed and constructed, and a FeOOH/rGO composite was directly prepared by a hydro-thermal method to characterise and analyse its morphology, chemical structure and removal efficiency for simulated radioactive aerosols. The results show that the FeOOH/rGO composite works in synergy with the CRAES to effectively improve the removal efficiency of simulated radioactive aerosols. A 30-minute simulated radioactive aerosol removal rate of 94.52% was achieved when using the experimentally optimized composite inhibitor amount of 2 mg/L FeOOH/rGO with 0.2 g/L PVA as a surfactant. Therefore, the CRAES coupled with the composite inhibitor FeOOH/rGO has broad application potential for the synergistic treatment of radioactive aerosols.

5

Friction films analysis and tribological properties of composite antifriction self-lubricating material based on nickel alloy

Roszak Maciej Robert, Kurzawa Adam, Roik Tetiana, Gavrysh Oleg, Vitsiuk Iulia, Barsan Narcis, Pyka Dariusz, Bocian Mirosław, Krzysztof Jamroziak

Materials Science Poland

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2023

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Vol. 41, No. 3

1--17

EN

This article analyzes the composition and distribution of chemical elements in friction films and their effect on the tribological properties of the self-lubricating, high-temperature antifriction composite based on EP975 powder nickel alloy with CaF2 solid lubricant. Analysis of the chemical elements by energy-dispersive spectroscopy (EDS) showed their uniform distribution, on both the composite’s surface and the counterface’s surface. The alloying elements’ uniform distribution leads to a uniform distribution of the corresponding phases and structural elements in the antifriction film. This ensures high tribological properties at high temperatures. Analysis of the material’s tribological properties, by means of metallographic and micro-X-ray research confirmed the correctness of the technology for producing the composite. Solid lubricant CaF2, alloying elements, and their corresponding phases form the continuous antiscoring film. The film influences the antifriction properties formation during the friction process and provides a self-lubricating mode under the action of high temperature and oxygen. Antiscoring, self-lubricating CaF2 films minimize wear of the friction pairs and defend the contact surfaces against intensive wear. The dense antifriction films have smooth microtopography, which stabilizes the high-temperature friction unit operation. Thus, the self-lubrication mode is realized for a long exploitation time. Tribological properties analysis allowed us to determine the ranges of rational exploitation modes for the material being studied: a load up to 5.0 MPa, a slide speed from 0.3 to 1.0 m/s, a temperature up to 800°C, in the air. The results obtained opened the opportunity to control the antifriction film formation and the composite’s tribological properties by the choice of the initial ingredients while taking into account the operating conditions.

6

Development of lightweight geopolymer composites containing perlite and vermiculite

Korniejenko K., Pławecka K., Bulut A., Şahin B., Azizağaoğlu G., Figiela B.

Journal of Achievements in Materials and Manufacturing Engineering

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2023

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Vol. 117, nr 2

49--56

EN

Purpose The aim of this work was to prepare and characterise geopolymer composites containing lightweight aggregates - perlite and vermiculite. Design/methodology/approach The geopolymer matrix was prepared on the basis of fly ash, sand and a 6M sodium hydroxide solution with sodium silicate. The properties of the materials were tested 28 days after the preparation of the samples. The following research methods were used to characterise the composites: compressive and flexural strength tests, microstructural tests using a scanning electron microscope, and thermal conductivity were measured. Findings The results obtained showed a slight effect of the additives on the strength properties. Lightweight aggregates are characterised by good coherence with the matrix material. Their addition allowed to reduce the density and lowered the thermal conductivity of the materials. The results obtained indicate that the proposed additives can improve the properties of the geopolymer composite for use in the construction industry. Research limitations/implications Further research should focus on geopolymer composites with perlite and involve fire-resistant and water-absorption tests. Practical implications The production of lightweight building materials brings a number of benefits, such as reducing the density of building elements and, at the same time, the entire structure, which results in a reduction in their weight, as well as lower transport costs. Such elements have better thermal and acoustic insulation, reflected in the parameters of buildings. An additional advantage is the reduced environmental impact through better insulation properties, lower fuel consumption during transport, etc. Originality/value The density of the material can be reduced by using lightweight aggregates or obtaining porous material in the foamed process. In the case of geopolymer composites, a number of studies related to foamed materials have been provided, but there is only a few previous research connected with lightweight aggregates such as perlite and vermiculite.

7

Ocena wybranych normowych modeli przyczepności kompozytów FRP do wzmacniania betonu

Krzywoń Rafał

Inżynieria i Budownictwo

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2023

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R. 79, nr 9-10

533--537

PL

Przyczepność jest jednym z kluczowych czynników decydujących o efektywności zewnętrznego wzmocnienia kompozytowego konstrukcji betonowej. Wykorzystywane w projektowaniu normy stosują różne modele matematyczne do wyznaczania siły przyczepności taśm i mat FRP. Otrzymywane w obliczeniach wyniki mogą różnić się nawet ponad dwukrotnie. Artykuł przedstawia ocenę dokładności przewidywania siły przyczepności dla wybranych wytycznych projektowania w świetle badań przyczepności ponad 800 próbek. Wyniki analiz metodą Demerit wskazują, że najlepsze modele przyczepności proponują szwajcarska norma SIA 166 i włoska CNR-DT200.

EN

Bond is one of the key issues determining the effectiveness of external composite strengthening of a concrete structure. The standards used in designing use various mathematical models to predict the bond strength of FRP overlays. The results obtained in the calculations may differ even two times. The paper presents an assessment of the accuracy of bond force prediction for selected design guidelines. The results of over 800 samples taken from the literature were used for comparison. The results of analyses show that the best bond model is recomended by the Swiss standard SIA 166 and CNR-DT200.

8

Mechanical Properties of Textile-Reinforced Composites with a 3D Printed Core

Szary Jakub, Barburski Marcin, Świniarski Jacek

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 4

38--45

EN

The article discusses the mechanical properties of glass fiber epoxy composites with three types of textile structures. Braided, knitted and woven sleeves were placed on a 3D printed flat core and impregnated with resin using the vacuum bag method. The 3-point flexural and tensile tests were performed. The results were compared with those of 3D-printed flat bars and proved that woven textile structures increase the strength and modulus of elasticity, whereas braided and knitted structures only increase the moduli. The advantages, drawbacks and failure modes of each reinforcement structure are also discussed including the drapeability on the spatial core.

9

Effect of Pumice Powder on Mechanical, Thermal, and Water Absorption Properties of Fiberboard Composites

Koyuncu Menderes, Ulay Göksel, Şeker Ulvi

Fibres & Textiles in Eastern Europe

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2023

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Vol. 31, no. 3

30--36

EN

Composites were produced using medium-density fiberboard (MDF) flour with pumice powder which was mixed at various ratios by the hand lay-up technique. Mechanical properties, such as tensile and three-point bending strengths, were determined by ASTM D3039 and ASTM D790 respectively. The best three-point bending and tensile strength properties were maximum values obtained from composites containing 20wt% pumice powder (pp) and 50wt% pumice powder (pp) respectively. It is observed that the water absorption rate into the composites decreases with an increase in the pumice powder-to-ratio. The composite filled with 50wt%pumice powder absorbed the least amount of water compared to the other composites. All composites were characterized by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetry analysis (DSC). SEM images revealed a near-homogeneous surface partly free of defects and holes. However, lateral profile images showed the presence of MDF flour particles agglomerated and a considerable number of bubbles and cavities that could interfere with the mechanical properties of the composites. The results of the mechanical, and thermal properties suggested that pumice powder epoxy composites with MDF flour can increase their tensile, three-point-bending strength, and glass transition temperature for the pure MDF flour composite.

10

Methodology for the Composite Tire Numerical Simulation Based on the Frequency Response Analysis

Karpenko Mykola, Skačkauskas Paulius, Prentkovskis Olegas

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 2

art. no. 163289

EN

Reliability and maintenance analysis in transport focus on the main objective of accident and incident investigations that benefit to better understanding of the causes of accidents and prevention of them in the future. The conducted research presents theoretical and experimental research on composite pneumatic tire used in transport engineering. The approach of the numerical simulation sequence which is offered in this research facilitates engineers in efficient determination of the dynamic properties and behaviour of vehicle tire at design stage. The tire materials have been tested by employing piezoelectric micro-vibration tests and frequency analyses. The Finite Element Method used for numerical simulation in combination with experimental measurements based on optimization by material frequency response, was applied in modelling tire material behaviour avoiding problems of composite structure modelling. The obtained results indicate that the offered methodology can be used in numerical simulation of composite tire investigation and considering material viscos-elastic properties.

11

Utilization of Eco-Friendly Rice Husk Ash Waste as Reinforcement in LDPE Thermoplastics

Ginting Eva Marlina, Motlan, Sani Ridwan Abdulah, Bukit Nurdin, Bukit Bunga Fisikanta

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

240--246

EN

The topic of environmental contamination is currently regarded as one of the most urgent and significant challenges in contemporary society. Several strategies must be implemented to mitigate the environmental impact caused by waste materials, such as to rice husks ash, plastic, and other materials. Low-density polyethylene is widely recognized in academic circles for its distinctive property of having a low melting point and demonstrating inferior thermal stability. However, the utilization of RHA has promise for augmenting the thermal LDPE. The inclusion of silica inside rice husk ash functions as a flame retardant, hence augmenting the material’s capacity to resist combustion and thermal degradation. The objective of this study is to utilization of eco-friendly RHA waste as reinforcement in LDPE thermoplastics. RHA is produced by the coprecipitation process. Rheomixer is used to make thermoplastic composites by incorporate RHA into LDPE 0, 2, 4, 6, 8, and 10 wt.%. The micrograph of the failure surface of the composite material consisting of LDPE filled with reactive hot-melt adhesive RHA particles reveals significant variations in particle sizes. In adittion XRD graph showed a decrease in intensity when 6% wt and 8% wt RHA were added. The results of thermal analysis with DSC showed an increase in the melting point of the sample with RHA reinforcement from 108.96–109.21o C and 482.47–500.09oC. The incorporation of RHA as a reinforcement in LDPE holds promise for its utilization as a material possessing favorable thermal characteristics suitable for industrial applications such as pipes and protective coatings, which required enhanced thermal resistance. The utilization of rice husk ash (RHA) waste imposes both environmental and economic impacts. RHA has the potential to reduce environmental pollution caused by waste and decrease the costs involved in material production.

12

Mechanical properties of rotomolded parts with abaca fiber: effect of manufacturing with 1, 2 or 3 layers

Ortega Zaida, Suárez Luis, Kelly-Walley Jake, McCourt Mark

Composites Theory and Practice

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2023

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R. 23, nr 3

158--166

EN

The range of materials suitable for rotational molding is not as wide as for other polymer processing technologies. An option to reduce the carbon footprint of such materials is to introduce natural fibers, such as abaca. In this work, different loadings of abaca fibers (5 to 20 % by weight) were molded using one, two and three-layer constructions. A comparison of the mechanical behavior (tensile, flexural, and impact properties) with the fiber content, considering the method of obtaining the composite (1, 2 or 3 layers) was performed. The thermomechanical behavior of the matrix was not affected due to the introduction of the fibers; apart from a reduction in the storage modulus, especially at low temperature, the curves have a similar profile. In general terms, the tensile and flexural strength were not affected by the incorporation of the fibers, that is, the composites exhibit similar behavior to neat polyethylene. Significant improvements in the tensile modulus were obtained for the parts manufactured with 2 layers, with 10 wt.% fiber in the internal one. As expected, the impact strength was reduced for all the composites, although the layer of PE on the inner side that coats the fibers counteracts this reduction to a certain extent. An increase in the heating time was observed for all the composites made in different layers; although the incorporation of fibers slightly modifies the course of the curve, the heating time is only significantly increased for loadings over 10%. The higher energy consumption needed to obtain the part in the different layers would only then be justified by an increase in the composite properties, which is not the case of the parts obtained in this work.

13

Enhancing mechanical properties of composite polymer concrete with lanthanum oxide additive for potential use in anti-radiation applications

Jała Jakub, Nowacki Bartłomiej

Composites Theory and Practice

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2023

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R. 23, nr 2

104--109

EN

Polymer concretes constitute a commonly used group of materials with known and well-studied properties for construction applications. The following research is a preliminary investigation into the basic mechanical properties and structure of a proposed novel polymer concrete with a lanthanum oxide nanopowder additive. The composite material is made from epoxy resin binder with milled expanded clay filler and La2O3 nanopowder. The research samples were made by simple and scalable casting methods. The conducted mechanical testing included compression and flexural examinations typical for this group of materials, as well as Brinell hardness measurements. The microstructure of the manufactured samples was examined utilizing scanning electron microscopy supported by EDS analysis. The obtained results reveal acceptable mechanical properties for the investigated materials, with slight increases in the measured property values for increasing amounts of the nanoparticle addition. The SEM and EDS investigations show the dispersion of filler and nanopowder additive throughout the samples, which is advantageous for the macroscopic properties of the material. The slight agglomeration of the lanthanum oxide powder could be further decreased with the inclusion of another processing step, for example, resin mixture sonication. The mechanical properties of the investigated materials are adequate and further research is suggested to test the possibilities of developing the examined polymer concrete for anti-radiation and radiation shielding applications.

14

Effect of sintering temperature and isostatic pressure on selected properties of selected electrical contact materials manufactured by hot isostatic pressing

Kołacz Dariusz, Kulasa Joanna, Krukowski Karol, Hury Anna, Muzia Grzegorz, Osadnik Małgorzata, Kalabis Jarosław

Composites Theory and Practice

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2023

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R. 23, nr 2

67--75

EN

This paper presents the results of studies on the consolidation of metallic and composite powders by the hot isostaticpressing (HIP) process intended for electrical contact materials. Ag, Cu metallic powders, as well as AgW48Re2, AgRe1 and CuW47Re3 composite powders were used in the investigations. Green compacts for consolidation and hot sintering under pressure were prepared by double-sided axial pressing in steel dies. The density, electrical conductivity, and hardness were measured on the obtained sinters after the HIP process, and the microstructure was examined on selected ones. The research indicates that applying this technology allows good quality electrical material to be obtained, intended for electrical contact material.

15

Assessment of mechanical and thermomechanical properties of epoxy-basalt composites modified with halogen-free intumescent flame retardants

Barczewski Mateusz, Matykiewicz Danuta, Andrzejewski Jacek, Sałasińska Kamila, Paszkiewicz Sandra, Piasecki Adam, Aniśko Joanna, Hejna Aleksander, Przestacki Damian

Composites Theory and Practice

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2023

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R. 23, nr 4

239--246

EN

This study aims to examine the effect of flame retardants (FRs) on the mechanical and thermomechanical properties of epoxy composites reinforced with basalt fibers. To effectively modify fire behavior, it is usually necessary to introduce significant amounts of FRs, which raises many concerns due to the potential deterioration of other functional properties, including mechanical performance. In this work, 30 wt.% halogen-free FRs, including a two-component FR (ammonium polyphosphate with pentaerythritol) and melamine cyanurate, were introduced into the polymer matrix. The unmodified and intumescent FR-modified epoxy resin composites reinforced with basalt fibers were subjected to static flexural test and thermomechanical properties assessment. The research results were correlated with the analysis of changes in the chemical composition assessed using Fourier transform infrared spectroscopy. As a result, the saturation of the reinforcing fabrics by the modified epoxy resin was limited, which caused a different failure mechanism under static bending and impact test conditions. Both FR systems reduced the flammability of the modified epoxy laminates along with also acceptable deterioration of the mechanical properties. The most beneficial effects considering the combination of all the analyzed features were noted for the two-component FR system containing ammonium polyphosphate and pentaerythritol.

16

Aerospace 3D textile preform analysis: experimental and mesomodeling

Saboktakin Abbasali, Izmir Hossein Safaei

Composites Theory and Practice

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2023

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R. 23, nr 3

118--122

EN

For the purpose of predicting how textile preforms affect the quality of the composite material and its performance, the stitched textile preform must be characterized. Experimental compaction analysis and finite element analysis of textile preforms are the main subjects of this paper. The formability parameters of a preform can be changed by the stitching process, according to research on the mechanical properties of preforms conducted during compression testing. The loaddeformation response, which is depicted in detail, had the greatest influence on preform deformation. Less fiber bundle undulation in the plane direction and more stitching thread undulation in the thickness direction were observed during compression of the stitched preform, whereas the stitching thread improved the resistance of the preform to compression loading.

17

Wpływ infiltracji próżniowej na właściwości mechaniczne polimerobetonów wzmacnianych lekkimi kruszywami ceramicznymi

Smoleń Jakub, Pawlik Tomasz

Cement Wapno Beton

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2023

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R. 28, nr 1

56--64

PL

W niniejszej pracy opisano wpływ inflitracji próżniowej na właściwości polimerobetonów na bazie lekkich agregatów ceramicznych. W pierwszym etapie badań wytworzono ceramiczne granule o wysokiej porowatości otwartej, około 27%, w oparciu o wykorzystanie przemysłowych materiałów odpadowych. Ceramiczne agregaty, zwane dalej granulatami, o wielkości od 2 do 4 mm wytworzono z wykorzystaniem zanieczyszczonej stłuczki szklanej oraz łupków węglowych. Omówiono efektywność infiltracji granulatu żywicą epoksydową w produkcji polimerobetonu o wysokiej wytrzymałości mechanicznej i stosunkowo małej masie w porównaniu z tradycyjnym betonem. Wytrzymałość na ściskanie polimerobetonu w którym kruszywo infiltrowano próżniowo żywicą wynosi 87 MPa, a polimerobetonu w którym zastosowano infiltrację zanurzeniową wytrzymałość na ściskanie wynosi około 42 MPa. Powstały polimerobeton, ze względu na swoją gęstość, zaliczany jest do betonów lekkich o wysokiej wytrzymałości.

EN

In this paper, the influence of vacuum infiltration of lightweight ceramic aggregates as fillers in polymeric concretes was described. In the first stage of the investigation, a set of ceramic aggregates with a high open porosity of about 27% was produced on the basis of industrial wastes. Ceramic aggregates with a size of 2 to 4 mm, hereinafter referred to as granules, were produced using contaminated glass cullet waste and coal shale. The effectiveness of granule infiltration with epoxy resin in the production of polymer concrete with high mechanical strength and relatively low mass compared to traditional concrete was discussed. The compressive strength of polymer concrete, where the aggregates were infiltrated with resin, is 87 MPa, and the polymer concrete, in which the vacuum infiltration process was not used, reaches a compressive strength of approximately 42 MPa. The resulting concrete, due to its density, is classified as a lightweight high-strength concrete.

18

Use of reinforced ice as alternative building material in cold regions: an overview

Bosnjak Jelena, Bodrozic-Coko Natalia, Jurcevic Miso, Klarin Branko, Nizetic Sandro

Archives of Thermodynamics

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2023

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Vol. 44, no 3

269--300

EN

The design of suitable thermophysical properties of reinforced ice as well as employing the novel material in feasible ways represent key aspects towards alternative building sustainability. In this overview research studies dealing with reinforced ice structures have been presented with an emphasis on construction parameters and reinforcement materials of the structures. The main focus of the study is directed to the identification of the main issues related to the construction of reinforced ice structures as well as the environmental and economic impact of such structures. Obtained research data shows that the compressive, tensile, and bending strength of reinforced ice can be increased up to 6 times compared to plain ice. The application of reinforcement materials decreases creep rate, enhances ductility, and reduces brittle behaviour of ice. Assessed reinforced ice structures were mainly found to be environmentally friendly and economically viable. However, in most of the analysed studies construction parameters and physical properties were not defined precisely. The conducted overview indicates the necessity for more comprehensive and more accurate data regarding reinforced ice construction, applied methods, and processes, and preparation of ice composites in general.

19

Influence of a Directional Dependenceon Mechanical Properties of Composites Reinforced with Chopped Carbon Fibre Produced by Additive Manufacturing

Majko Jaroslav, Handrik Marian, Vaško Milan, Sága Milan, Kopas Peter, Dorčiak Filip, Sapietová Alžbeta

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

455--461

EN

Progress in the industry is accompanied by the development of new materials and more efficient technological production processes. At present, additive production is becoming very attractive in all industries (research, development, production), which brings a number of advantages compared to subtractive methods (customization, production speed, control of material properties by users, etc.). The main advantage of 3D printing is the controlled deposition of material in defined places. Instead of demanding manual labour, fully automated production via computers leads to the manufacturing of complex components from materials whose production in conventional ways would be problematic or even impossible. Because these are new technologies, the main direction of research at present is to identify the basic physical properties of these materials under different types of loading. The main goal of this article is to observe the dependence of the behaviour of the extruded material (thermoplastic reinforced with chopped carbon fibre) on the printing parameters (thickness of the lamina, the orientation of the fibres of the printed material, etc.). Based on published scientific works, it appears that these settings have a significant impact on the achieved physical properties. This is the reason why the authors decided to analyze the influence of these parameters on the basis of processed data from experimental measurements of mechanical properties in the MATLAB program. As this is FFF printing, an essential condition is to identify and specify the directional dependence of the behavior of the printed material. This physical phenomenon is a necessary condition for gradual knowledge for the purposes of a subsequent mathematical description of the material properties. According to the authors, for the purposes of modeling these materials in FEM-based programs, it is essential to define the directional dependence in the plane of the lamina.

20

Mechanical analysis of multilayer composite materials with duroplastic matrix after exposure to low temperatures

Krzak Anna, Nowak A. J.

Archives of Materials Science and Engineering

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2023

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Vol. 122, nr 2

49--57

EN

Purpose: Cryogenic engineering is gaining more and more interest in various industry sectors, which leads to an intensive search for effective solutions. The article presents the findings of mechanical testing conducted on glass-epoxy laminates at room temperature and after long- term contact with liquid nitrogen. Design/methodology/approach: To compare the impact properties and flexural strength, the samples were tested under cryogenic and room conditions, and then the fracture locations were identified using the Leica DVM6 microscope. The study brings value to the emerging field of cryogenic engineering by providing valuable information on the mechanical properties of glass-epoxy composites under cryogenic conditions. Findings: It has been found out that immersing the glass-epoxy composites into the Dewar had minimal influence on impact and flexural strength properties. The most noticeable changes were observed in the case of the EP_4_2 composite. The material consists of a solution of brominated epoxy resin in an organic solvent. It is used to produce laminates in electrical engineering and printed circuits in electronics, where it should exhibit excellent impact properties. Research limitations/implications: One of the prospective research directions is a thorough analysis of the mechanical properties of the developed composite materials during cryogenic cycles. Originality/value: The study aims to determine the effect of different compositions of glass fabric-reinforced resin with a weight of 205 g/m2 on the mechanical properties of the developed composite materials at both room temperature and after long-term exposure to liquid nitrogen. Those investigations serve as surveillance for developing of new material solutions directed towards cryogenic applications and are essential for subsequent stages of research.