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1

Numerical analysis of the strength and stiffness of triggo light electric vehicle body

Stachowicz Łukasz, Boczkowska Anna, Budweil Rafał

Composites Theory and Practice

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2025

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R. 25, nr 1

38--48

EN

TRIGGO is one of the first vehicles to effectively combine the manoeuvrability and parking advantages of twowheelers with the safety and comfort features comparable to those of small passenger cars. It is intended for use in a short-term rental network and should be characterised by low energy consumption. To this end, it is reasonable to optimise the vehicle's design towards minimising weight. The use of composites in the TRIGGO body structure enabled a reduction in the ready-to-drive vehicle weight and optimal utilisation of the available space. This choice makes it possible to keep the body weight low while ensuring appropriate mechanical properties. The subject of this paper is numerical analyses of the strength and stiffness of the TRIGGO light vehicle body made of glass-epoxy composites. The scope of the work includes the construction of a computational model of the TRIGGO vehicle body made by the RTM method with a double skin and foam core, in addition to calculations of the stiffness and strength of the structure during body load tests. For this purpose, an FEM computational model was built based on the 3D body model. The body of the RTM version of the TRIGGO vehicle consists of 27 separate components, which are connected to each other by rigid bonded contacts. The composite structures with foam cores were modelled as single-layer shell elements including all the layers of the composite, and a foam spacer. Three design cases were developed: P1.1 - vertical-transverse body loading, P1.2 - vertical-longitudinal body loading, P1.3 - vertical-longitudinal body loading with a horizontal force component. The calculation cases were determined based on "Regulation (EU) No 168/2013 of the European Parliament and of the Council with regard to requirements for the functional safety of vehicles for the approval of two- or three-wheel vehicles and quadricycles", in particular Annex XI of this document. The calculations prove that the glass-epoxy body of the TRIGGO light vehicle meets the requirements for strength and stiffness.

2

Mechanical behaviour of filament-wound GFRP and BFRP composite tubes

Stabla Paweł, Kamiński Konrad, Wacławek Łukasz, Paczkowska Karolina, Pacholec Zuzanna, Barcikowski Michał, Błażejewski Wojciech

Composites Theory and Practice

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2025

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R. 25, nr 3

200--208

EN

Composite materials play a crucial role in the development of lightweight and innovative industry. For high-performance structures such as composite pressure vessels, tubes and pipelines, filament-winding technology is used as a highly automated and reliable manufacturing method. In this study, the mechanical investigation of composite tubes is performed. The analysis consists of a comparison of basalt and glass fibre reinforced plastics (BFRP and GFRP) under axial compression loading. The tubes were manufactured with one layer wound using a 55° winding angle and additional hoop reinforcement in the gripping area. During axial compression loading, the acoustic emission method was used to identify the damage modes occurring in the two groups of materials. Post-failure observations were conducted to assess the crack type and geometry. The results showed that GFRP exhibited superior performance over BFRP in terms of compressive strength (41% higher) and absorbed energy (20% higher).

3

Development of ultrasonic technique using phased array probes in type IV low-pressure tank

Kozera Paulina, Sarniak Łukasz, Dydek Kamil, Wolanin Andrzej, Boczkowska Anna

Composites Theory and Practice

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2025

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R. 25, nr 4

234--242

EN

The aim of this work is to develop an ultrasonic technique employing phased array probes to detect structural defects in type IV low-pressure tanks used for the storage of hazardous chemicals. Ultrasonic testing was performed by means of an OmniScan MX2 phased-array ultrasonic flaw detector with appropriate probes, and numerical simu lations were conducted utilizing CIVA software. Attenuation coefficients were measured for a composite layer excised from a two-layer low-pressure tank. Based on these results, a centre frequency of 5 MHz was selected as optimal. The determined parameters, such as the attenuation coefficient and the structural noise level, were implemented in the CIVA model. The detection criteria were established and color-coded: defects with a signal-to-noise ratio (SNR) < 0 dB were labelled white (undetectable); those 0-10 dB were labelled yellow (limited detectability); and those > 10 dB were labelled green (optimal detectability). The simulation results were validated by testing the composite samples with polytetrafluoroethylene (PTFE) inserts of varying sizes and depths. The defect detectability determined from the simulations was consistent with that obtained from testing reference samples.

4

Effect of environmental conditions on the characteristics of GFRP plates using non-destructive testing techniques

Boumehraz Mohammed-Amin, Goudjil Kamel, Baali Brahim, Mellas Mekki, Hamaidia Achref, Djeghader Djamel, Boucetta Farida

Budownictwo i Architektura

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2025

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Vol. 24, no. 2

207--217

EN

Glass fibre-reinforced polyester (GFRP) is widely used in industries such as aerospace, civil engineering and railway transportation due to its high specific strength, high specific modulus and excellent fatigue resistance. In civil engineering, GFRP is particularly employed for applications such as rebars, girders and other structural components. The objective of this research is to study the evolution of mechanical, physical and chemical properties of GFRP sheets using non-destructive testing methods, including the Barcol hardness test, water absorption test, infrared (IR) spectroscopy and scanning electron microscope (SEM) observation. These square-shaped GFRP sheets are manufactured through contact moulding and consist of isophthalic resins, glass fibres and additives such as catalysts and accelerators. These samples are exposed to three different environments: in the laboratory (control specimens), in potable water and in seawater. Laboratory tests are conducted on the GFRP samples at 30, 90, 180 and 365 days. The results indicate a significant decrease in hardness across all preserved samples. This reduction in GFRP rigidity can be attributed to water or moisture absorption, as evidenced by the obtained results. Furthermore, no changes in the chemical composition were observed on the surface of the tested samples. Finally, the matrix/glass fibre bond remains in good condition, despite this material being exposed to a humid and/or sulphate-rich environment for one year.

5

Experimental and numerical verification of the standard procedure for determining the load capacity of GFRP composite lighting columns

Broniewicz Mirosław, Broniewicz Filip, Broniewicz Elżbieta

Archives of Civil Engineering

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2025

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Vol. 71, nr 1

381--401

EN

The main objective of the research was to validate the method for determining the load capacity of GFRP composite lighting columns under horizontal loads according to the EN 40-3-3:2013 standard. The work involved developing a numerical model of GFRP composite columns with an inspection hole while accounting for the columns’ nonlinear behaviour before the failure phase. The model was verified by testing 11 GFRP lighting columns on a natural scale and material testing of the composite. A calculation method was used in accordance with the standards EN 40-3-3:2013 and EN-40-7:2002 to determine their bending resistance. It was discovered that the load capacity estimated experimentally is two to three times less than the load capacity estimated using the standard’s procedure. Also, the load capacity calculated based on the developed numerical model of the column is about 2.5 times lower than the characteristic load capacity calculated based on the currently applicable standard procedure. The analysis of the standard design procedure shows that the inspection opening is treated only as a local reduction of the cross-section, reducing the yield modulus. However, the possibility of buckling the walls in the inspection opening area is not taken into account. It means that the standard procedure for determining the bending resistance of composite columns has not been adapted to the actual behaviour of composite columns with inspection openings. Developed numerical model of a lighting pole with an unreinforced inspection opening accurately assesses the capacity of such poles for use in scientific and design practice.

PL

Głównym celem pracy była weryfikacja naukowa obliczeniowej procedury normowej, umożliwiającej projektowanie słupów GFRP o przekroju kołowym, wykonanych z tworzywa polimerowego wzmocnionego włóknem szklanym, poddanych obciążeniom poziomym. W celu osiągnięcia zamierzonego rezultatu opracowano model numeryczny słupów kompozytowych GFRP z otworem rewizyjnym uwzględniający nieliniowe zachowanie się słupów poprzedzające fazę zniszczenia. Weryfikację opracowanego modelu numerycznego dokonano poprzez realizację programu eksperymentalnego obejmującego badania doświadczalne 11 słupów oświetleniowych GFRP w skali naturalnej oraz badania materiałowe kompozytu. W pierwszej części pracy zastosowano procedurę normową obliczania nośności oświetleniowych słupów kompozytowych z otworem rewizyjnym według postanowień norm (PN-EN 40-3-3, 2013) oraz (PN-EN 40-7, 2004) do obliczeń projektowych badanych słupów, wyznaczając ich nośność na zginanie we wszystkich punktach krytycznych oraz wartość ugięcia wierzchołka słupa. Sprawdzono warunki stanu granicznego nośności porównując obliczone nośności z wartościami momentów zginających od obciążenia wiatrem wyznaczonych w przypadku słupów kompozytowych zgodnie z postanowieniami normy (PN-EN 40-3-1, 2014) oraz warunki stanu granicznego użytkowalności, porównując ugięcia poziome słupów w miejscu przyłączenia latarni z wartościami dopuszczalnymi. Stwierdzono, że wykorzystanie nośności badanych słupów w miejscu otworu rewizyjnego wynosi od 5% w przypadku słupów o wysokości 3,0 m do 55% w przypadku słupów o wysokości 9,0 m, natomiast przemieszczenie wierzchołka badanych słupów we wszystkich przypadkach jest mniejsze od wartości dopuszczalnych. Następnie przedstawiono badania doświadczalne słupów GFRP w skali naturalnej przeprowadzone zgodnie z normą (PN-EN 40-3-2, 2014), których celem było uzyskanie danych doświadczalnych dotyczących nośności i sztywności słupów kompozytowych GFRP poddanych obciążeniom statycznym oraz eksperymentalne zbadanie zjawiska utraty stateczności trzonu słupa w sąsiedztwie otworu rewizyjnego. Plan badań obejmował jedenaście słupów oświetleniowych o długościach od 3,0 m do 9,0 m. Analizowano cztery formy zniszczenia słupów: w obszarze otworu rewizyjnego, przy podstawie, w obszarze poza otworem rewizyjnym oraz utratę stateczności miejscowej w wyniku owalizacji przekroju. We wszystkich badanych słupach wystąpiła ta sama forma wyczerpania nośności słupa polegająca na zniszczeniu trzonu w obszarze otworu. Dokonano również porównania wartości nośności otrzymanych z badań doświadczalnych z wynikami uzyskanymi na podstawie obliczeń według normy przedmiotowej.

6

The influence of the matrix properties on mechanical properties of a glass fiber reinforced polymer made by the infusion method

Bieńczak Rafał, Janiszewski Jacek, Komorek Andrzej, Łusiak Tomasz, Krasuski Kamil, Wasilewski Szymon

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 4

206--219

EN

At every stage of the development of modern aerospace structures, engineers are keen to obtain the lightest possible product while maintaining high strength. In order to meet such requirements, composite materials are now widely used in the aerospace industry, with manufacturing methods constantly evolving. This thesis aims to investigate and analyze the influence of the matrix on the strength of a layered composite made using the infusion method. This method is currently among the most popular and effective ones. The technique makes it possible to produce a robust laminate using optimum labour and favourable costs. However, a number of rules must be followed during the production process to produce a satisfactory product. In relation to the objective of the thesis, three different composites were produced and tested, differing in the properties of the used resin composition. The matrixes were different in terms of the use of processes such as degassing and the ratio of epoxy resin to hardener. During the research, tensile strength, impact strength and bending tests were carried out. This work shows that on the basis of the results obtained from the strength tests and observations of the internal and external structure of the tested materials, it can be concluded that the ratio of resin and hardener has little effect on the strength properties of the material. The results also show that the specific conditions of composite production by the infusion method greatly affect the spontaneous degassing of the resin mixture.

7

The influence of temperature on the mechanical properties of a glass fiber reinforced polymer made by an infusion method

Janiszewski Jacek, Komorek Andrzej, Bieńczak Rafał, Łusiak Tomasz, Charkot Kacper

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 4

198--205

EN

Composite materials are increasingly used in the aerospace industry, among which laminates seem to be the most commonly used ones. They often replace conventional materials, such as metals due to their superior properties and performance. Composite materials help reduce fuel consumption and improve aircraft performance. It is important for the composites used in aircraft structures to have very high creep resistance and strength, due to high loads that they carry. Composites with the highest mechanical properties can be obtained using an infusion method. In the infusion process, the mould is prepared together with the reinforcement made of the material from which the composite is made, e.g. glass fibre. It is tightly closed in a vacuum bag, and the equipment supplying the previously mixed resin with hardener is connected to the injection points. This study describes the main issues related to composites. It characterizes in detail the infusion method and the laminate manufacturing process. Layered composites using an infusion method can be made at various temperatures. This work describes the effect of the applied different temperatures on the obtained mechanical properties from a composite reinforced with fibre glass. During the research, tensile strength, impact strength and bending tests were carried out. It turns out that the best strength properties of the material are obtained when it is manufactured at high temperature, while manufacturing at low temperature causes a significant decrease in strength and other material parameters. The authors also wanted to show the advantages of the infusion process with controlled (higher) temperature in the context of increasing strength factors of the composite.

8

Porównanie ugięcia betonowych belek zbrojonych prętami GFRP, BFRP i ze stali B500

Pytlowany Tomasz, Leń Dariusz, Piszczek Kazimierz, Zimka Roman

Przegląd Budowlany

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2024

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R. 95, nr 1-2

77--80

PL

Głównym celem badań było uzyskanie danych związanych z jakościową oceną sztywności belek betonowych zbrojonych prętami stalowymi EPSTAL B500SP oraz kompozytowymi prętami zbrojeniowymi GFRP i BFRP przy zachowaniu tego samego stopnia zbrojenia belek. Przyjęto schemat statyczny badanych elementów w postaci belki swobodnie podpartej o rozpiętości 1,5 m. Podstawowym opisem zachowania badanych elementów, zarejestrowanym podczas badań, była ścieżka równowagi statycznej opisana w układzie współrzędnych: siła obciążająca P i ugięcie belki u, rejestrowane za pomocą czujników, zarejestrowane zależności P-u. Podane na wykresach wartości ugięcia belek u są średnią arytmetyczną pomiarów z czujników przemieszczenia. W trakcie badań wykonano również pomiary odkształceń prętów zbrojeniowych w zależności od wartości przyłożonego obciążenia P. Wyniki tych pomiarów przedstawiono graficznie.

EN

The main purpose of the research was to obtain data related to the qualitative assessment of the stiffness of concrete beams reinforced with B500SP EPSTAL steel reinforcement bars and GFRP and BFRP composite reinforcing bars while maintaining the same degree of reinforcement of the beams. A static scheme of the tested elements was adopted in the form of a simply supported beam with a span of 1,5 m. The basic description of the behavior of the tested elements, recorded during the tests, was the static equilibrium path described in the coordinate system: loading force P and beam deflection u, recorded using sensors, the recorded P-u dependencies. The deflection values of the beams u given in the graphs are the arithmetic mean of the measurements from the displacement sensors. During the tests, measurements of reinforcing bars deformation were also carried out depending on the value of the applied load P. The results of these measurements are presented graphically.

9

Evaluation of tensile strength and flexural strength of GFRP composites in different types of matrix polymers

Sulistyo A. B., Wirawan W. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2024

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Vol. 123, nr 2

49--57

EN

Purpose: Resin selection has a crucial role in determining the properties and performance of GFRP composites; this study aims to investigate the effects of different resin types, specifically epoxy, bisphenol, ripoxy, and polyester, on the mechanical strength of GFRP composites. Design/methodology/approach: The composites were fabricated using the conventional method of hand lay-up technique with a fiber to matrix ratio of 60:40 wt%. The glass fibre laminate arrangement consists of 4 layers, two layers of Woven Roving Mat (WRM) fibres (0°/90°) and 2 layers on the outer side of the Chopped Strand Mat (CSM). The composite specimens were molded using the ASTM D-838 tensile test standard and ASTM D-790 for the bending test. Findings: The research results found that the maximum tensile strength was obtained by GFRP composite with ripoxy matrix type of 181.6 MPa, strain of 0.028%, and flexural strength of 1387 MPa. Composites using polyester matrices can generally be classified as splitting in multiple areas where failure occurs in various areas, but the composite has very high strength. Research limitations/implications: Material experiments conducted on a scientific laboratory scale may not fully reflect the behaviour of composites in actual conditions. Furthermore, aspects such as environmental influences, sustained stresses, or fatigue effects may need to be considered in further research. This evaluation also does not consider the effects of long-term exposures or ageing on the mechanical properties of GFRP composites. Investigating the behaviour of materials over long periods can provide important insights into their durability and reliability in practical applications. Practical implications: In GFRP composites, the application of resin to the fibres is critical. The performance and mechanical characteristics of GFRP composites are largely determined by the polymer matrix. Composites with epoxy, polyester, or bisphenol matrices can be compared to composites with the most equivalent tensile strength values, but composites with ripoxy matrices can be suggested. However, the GFRP composite with bisphenol matrix has an excellent bending strength value. As a result, numerous applications exist for implementing matrix selection in producing GFRP composites. Originality/value: The reliability of the tensile properties of GFRP composites was obtained using the ripoxy matrix type. Furthermore, the reliability of the flexural properties of the composites was obtained using the bisphenol matrix type.

10

Development of a method for producing composite parts of the TRIGGO electric car based on A.S.SET epoxy resin powder - feasibility study

Boczkowska Anna, Stachowicz Łukasz, Budweil Rafał

Composites Theory and Practice

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2024

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R. 24, nr 4

246--252

EN

Composite materials due to their outstanding mechanical properties and light weight are becoming increasingly im portant in the automotive industry, helping to develop lighter, more durable and environmentally friendly vehicles. It is espe cially important in the context of electric cars such as TRIGGO. It is an innovative electric vehicle (EV) designed with a focus on urban mobility. One of the unique features of this car is its compact design, aimed at providing a flexible solution for city driving. In this paper a method for manufacturing composite components of the TRIGGO electric car body by pressing tech nology, based on the innovative A.S.SET resin is described. It was confirmed experimentally that selected components of the TRIGGO vehicle body are feasible to be fabricated by pressing technologies using SemiNEMpreg pre-impregnated material based on A.S.SET epoxy resin. The studied technologies cover thermoset sheet forming using a membrane press or a hydrau lic press, also using a vacuum-assisted oven. These technologies were adapted to the requirements of manufacturing composite parts, with a special focus on the cost-effectiveness of the process. Owing to the use of the fast-crosslinking snap-cure epoxy resin with the trade name NEMresin (known as A.S.SET), it was possible to shorten the crosslinking process to 15 minutes. The studies made it possible to select the type of mold depending on the geometry of the component and the applied technolo gy. The studies led to the determination and matching of the type of component to the type of mold and predestined manufac turing technology, taking into account the most important factors affecting the start of mass production, such as the number of pieces, the surface quality of the component, i.e. roughness coefficient and surface finishing, mold cost, process time, pro cess cost, required repeatability, quality of the target component structure, as well as the cost of finishing. The developed technologies are innovative and allow the low-cost batch manufacture of composite parts for the automotive industry.

11

Assessment of the effectiveness of selected coatings for protection against UV radiation in glass fiber reinforced composites (GFRP)

Smoleń Jakub, Bechcińska Karolina, Smok Weronika, Olesik Piotr, Stępień Krzysztof

Composites Theory and Practice

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2024

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R. 24, nr 1

65--71

EN

The paper describes the effectiveness of selected protective coatings against ultraviolet radiation in glass fiber reinforced composites. Epoxy resin matrix GFRP composites with 1 mm thick coatings were produced. Four types of coatings were compared: pure epoxy resin, epoxy resin with the addition of a UV stabilizer from the benzophenone group, epoxy resin with an addition of graphite (screening function) and a commercial polyester gelcoat. The composites were irradiated for 1000 h with ultraviolet radiation from three separate radiation ranges: UVA, UVB, UVC. The changes in the surface appearance, flexural strength and chemical structure were described. The results shows that UV radiation caused changes in the surface condition for the reference samples (coating without additives), such as yellowing and matting. Also, a reduction in the flexural strength by over 10% and changes in the chemical structure, mainly caused by oxidation processes and the cracking of chemical bonds were observed. The most beneficial protection was found to be the UV stabilizer from the benzophenone group, the addition of which provides UV protection over the entire radiation range and protects the material against negative changes in the coating’s chemical structure. Also, similar results were obtained for the samples with the graphite coating.

PL

Opisano skuteczność wybranych powłok ochronnych przed promieniowaniem ultrafioletowym w kompozytach wzmacnianych włóknem szklanym. Wytworzono kompozyty GFRP z żywicą epoksydową i powłokami o grubości 1 mm. Porównano cztery rodzaje powłok: czysta żywica epoksydowa, żywica epoksydowa z dodatkiem stabilizatora UV z grupy benzofenonów, żywica epoksydowa z dodatkiem grafitu (funkcja ekranizowania) oraz komercyjny żelkot poliestrowy. Kompozyty poddawano działaniu promieniowania UV przez trzy różne zakresy promieniowania: UVA, UVB, UVC przez 1000 godzin. Opisano zmiany w wyglądzie powierzchni, wytrzymałości na zginanie i strukturze chemicznej. Wyniki pokazują, że promieniowanie UV spowodowało zmiany w stanie powierzchni dla próbek referencyjnych (powłoka bez dodatków), takie jak żółknięcie i matowienie. Zaobserwowano również redukcję wytrzymałości na zginanie o ponad 10% i zmiany w strukturze chemicznej, głównie spowodowane procesami utleniania i pękaniem wiązań chemicznych. Najkorzystniejszą ochroną okazał się stabilizator UV z grupy benzofenonów, dodatek którego zapewnia ochronę UV w całym zakresie promieniowania i chroni materiał przed negatywnymi zmianami w strukturze chemicznej powłoki. Podobne wyniki uzyskano także dla próbek z powłoką z dodatkiem grafitu.

12

Performance of GFRP-RC precast cap beam to column connections with epoxy-anchored reinforcement: a numerical study

El-Naqeeb Mohamed H., Hassanli Reza, Zhuge Yan, Ma Xing, Bazli Milad, Manalo Allan

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e131, 2024

EN

In this study, a detailed finite element investigation was conducted to evaluate the performance of glass fibre-reinforced polymer (GFRP) RC precast cap beam to column connections connected with epoxy-anchored reinforcement (epoxy duct connection). The developed model was initially validated against three experimental results with different anchored GFRP reinforcement considering the effect of reinforcement slippage. Different interaction models for slippage simulation were evaluated and discussed. The validated model was then utilized to investigate the effect of anchored length, bar diameters, anchored reinforcement amount, and the geometry of the connection. The results indicate that an optimum anchored length, equal to 25 times the bar's diameter, should be provided. It was also found that the precast beam-to-column element connection should be designed for a moment capacity at least 25% higher than that of the column section. Moreover, a minimum beam width, depth and beam overhanging length of 1.75, 1.6 and 0.25 times the column width respectively were recommended to be considered in design. The results from this study can provide direct guidelines for the design of precast GFRPRC cap beam to the column connection with epoxy anchored reinforcement, especially in applications where precast elements need to be erected quickly, a novel method that can accelerate the construction of jetties and bridges.

13

Assessment of Different Methods for Cutting Composites Used in Unmanned Air Vehicles

Szala Grzegorz, Andryszczyk Marek, Wirwicki Mateusz Szymon

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 5

EN

The goal of this study is to determine the effect of cutting methods on the edges of selected materials applied in structural elements and floor sheathing of unmanned air vehicles. Three cutting methods for MGS L285 epoxy resin composites used for production of unmanned air vehicles manufactured in one of the European companies have been presented. Composites reinforced by glass and aramid fibers are approved for certified production of air vehicle elements (AMC-20). Cutting was applied to each material using a different technology such as: milling, laser cutting and abrasive water jet cutting. The authors focus on the edge quality of the tested specimens cut by various methods. Quality assessment was based on electronic microscopic scanning images and measurement of the specimen maximum damage. In summary, the choice of an appropriate composite cutting method depends on the type of material and its parameters, and it is crucial for the quality of the machined product. The authors focus on determining the selection of parameters for chosen cutting methods and materials used in the military unmanned aerial vehicle industry. Among the conducted tests, the results indicate that better cutting effects are obtained for milling methods in the case of GFRP+L285 (0.143±0.073 µm) and CFRP+L285 (0.072±0.027 µm), and the worst for AFRP+L285 (0.831±0.269 µm). The water jet method gives the worst results in the cutting zone (results above 0.224 µm).

14

Analysis of the Surface Topography of Fractures Caused by Static and Impact Bending of Polypropylene and Polyamide PA6 Reinforced with Continuous Glass Fibers

Głowacka Karolina, Małecka Joanna, Smolnicki Tadeusz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no. 5

51--64

EN

The work analyzes the fracture topography of composite specimens subjected to three-point bending - static and impact. Scanning electron microscopy was used for this purpose. The tests were performed for two different materials - polypropylene and polyamide PA6, each reinforced with unidirectional glass fibers. In one case, the fibers were distributed evenly, and in the other, there were areas more and less reinforced with fibers. It was observed that in all cases the tension and compression parts could be clearly distinguished. However, for different materials and with different methods of destruction, different failure mechanisms were observed, noted based on the analysis of the fracture topography. It was observed that regardless of the loading method and material, in the tensile part there were visibly protruding fibers, and in the compressed part it was the matrix, not the fibers, that was destroyed. In the case of statically loaded samples, damage occurred at the macrostructural level, and in the case of dynamically loaded samples, at the microstructural level. Additionally, samples with uneven fiber distribution were more susceptible to delamination.

15

A comparative analysis of single-field concrete slabs reinforced with FRP bars

Piotr Lacki, Niemiro-Maźniak Judyta, Derlatka Anna, Gąćkowski Roman

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2023

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Z. 29 (179)

85--91

EN

Fibre-reinforced composite bars (FRP) are becoming an increasingly common alternative to steel reinforcement in civil structures. The paper presents a comparative analysis of single-field concrete slabs reinforced with steel bars and FRP bars. The tested models differed in the type of reinforcement material and the diameter of the reinforcement bars. The behaviour of slab reinforced with steel bars (SRB) and composite bars made of GFRP, CFRP, BFRP and AFRP were simulated. The numerical analysis was carried out in the ADINA System program, based on the Finite Element Method (FEM). The obtained distributions of displacements and the development of cracks in the tested elements made it possible to assess the serviceability limit states (SLS) the slabs. The smallest deflections were observed for slabs reinforced with AFRP bars.

PL

Pręty kompozytowe wzmacniane włóknami (FRP) stają się coraz częstszą alternatywą zbrojenia stalowego w konstrukcjach budowlanych. W pracy przedstawiono analizę porównawczą jednopolowych płyt betonowych zbrojonych prętami stalowymi oraz prętami FRP. Badane modele różniły się rodzajem materiału zbrojenia i średnicą prętów zbrojeniowych. Symulowano zachowanie płyt zbrojonych prętami stalowymi (SRB) i prętami kompozytowymi GFRP, CFRP, BFRP oraz AFRP. Analizę numeryczną przeprowadzono w programie ADINA System, opartym na metodzie elementów skończonych (MES). Uzyskane rozkłady przemieszczeń oraz rozwój zarysowań w badanych elementach pozwoliły na ocenę stanu granicznego użytkowalności płyt. Najmniejsze ugięcia zaobserwowano dla płyt zbrojonych prętami AFRP.

16

Charakterystyka przyczepności prętów GFRP i BFRP do betonu z dodatkiem zeolitu i metakaolinitu

Urbański Marek, Woyciechowski Piotr, Szmigiera Elżbieta, Adamczewski Grzegorz, Sosnowska Edyta

Przegląd Budowlany

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2023

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R. 94, nr 11-12

121--127

PL

Porównano zależności przyczepność-poślizg oraz mechanizmy zniszczenia dla betonu z dodatkami zeolitu i metakaolinitu w obecności prętów GFRP, BFRP i stalowych. Przyczepność prętów GFRP do betonu z dodatkiem metakaolinitu była o 50% większa niż do betonu zwykłego, natomiast przyczepność do betonu z zeolitem podobna. W przypadku prętów BFRP stwierdzono wzrost przyczepności o 7% dla betonu z metakaolinitem. Pręty BFRP miały większą przyczepność w stosunku do zbrojenia stalowego. Zmiana przyczepności prętów GFRP i BFRP była stopniowa, a poślizg był kilkukrotnie większy niż prętów stalowych.

EN

Bond stress-slip relationship and failure mechanisms for concrete with additions of zeolite and metakaolin in the presence of GFRP, BFRP and steel bars were compared. The bond strength of GFRP bars to concrete with the addition of metakaolin was 50% higher than to ordinary concrete, while the bond strength to concrete with zeolite was similar. In the case of BFRP bars, an increase in bond strength by 7% was found for concrete with metakaolin. BFRP bars had greater bond strength to steel reinforcement. The change in the bond stress of the GFRP and BFRP bars was gradual and the slip was several times greater than that of the steel bars.

17

Wpływ metakaolinitu i zeolitu na przyczepność prętów BFRP i GFRP do betonu

Krassowska Julita, Wolka Paweł

Materiały Budowlane

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2023

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nr 10

6--10

PL

Celem przeprowadzonych badań jest ustalenie, w jaki sposób obecność metakaolinitu i zeolitu wpływa na przyczepność prętów zbrojeniowych do betonu oraz na jego wybrane właściwości mechaniczne. Próbki do badań przygotowano zgodnie z obowiązującą procedurą testu belkowego wg [1]. Otrzymane wyniki pozwoliły na analizę porównawczą próbek referencyjnych oraz zawierających metakaolinit i zeolit. Badania wykazały, że wprowadzenie do betonu aktywnego dodatku pucolanowego w postaci metakaolinitu i zeolitu powoduje zwiększenie wartości naprężeń przyczepności o ok. 20% w przypadku prętów szklanych GFRP i 15% bazaltowych BFRP, przede wszystkim w fazie zniszczenia.

EN

The aim of the conducted research is to determine how the presence of metakaolinite and zeolite affects the adhesion of reinforcing bars to concrete and selected mechanical properties. Test samples were prepared in accordance with the applicable beam test procedure according to [1]. The obtained results allowed for a comparative analysis of the reference samples and those with metakaolinite and zeolite. The research showed that the introduction of an active pozzolanic additive in the form of metakaolinite and zeolite into concrete leads to an improvement in adhesion stress values of approximately 20% for GFRP glass bars and 15% for BFRP basalt bars, especially during the failure phase.

18

Selected energy aspects of GFRP drilling

Polasik Robert

Developments in Mechanical Engineering

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2023

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nr 19(11)

15--22

EN

Original research results of GFRP drilling, using HSS steel drill bit, process energy indicators were presented in the article. The research stand was a 5-axis DMU50 machining center, equipped with a Kistler force gauge with a signal amplifier and a DAQ data acquisition system. The obtained measurement data were processed using the force gauge manufacturer's software, a spreadsheet and the Statistica statistical data analysis package. As a result of the analysis, on the basis of technological parameters and measured and determined values of cutting force and torque, changes in the values of selected process status indicators were determined; total and specific energy (per unit of material volume removed) generated when making individual holes as a function of the number of holes made. Moreover, the empirical value of the specific cutting resistance kc was determined. As a result of the experimental work carried out and the analysis of available literature in the scope of the article, conclusions were formulated regarding the energy indicators of the process - total and specific energy generated during processing, as well as possible causes of thermal damage to the processed material were indicated.

19

Zbrojenie kompozytowe z włókien szklanych - potencjalne źródło problemów inżynierskich

Błyszko Jarosław

Inżynieria i Budownictwo

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2022

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R. 78, nr 3-4

128--131

PL

W artykule omówiono zastosowanie prętów kompozytowych z włókna szklanego jako alternatywnego sposobu zbrojenia elementów zginanych. Przedstawiono koncepcję zbrojenia minimalnego wyliczanego na podstawie układu sił w przekroju zginanym, a następnie porównano z wynikami badań. Wykazano, że w przypadku zbrojenia GFRP opieranie się jedynie na zależnościach statycznych może prowadzić do zaniżenia nośności.

EN

This paper presents the use of fiberglass composite bars as an alternative reinforcement method for flexural elements. The concept of the minimal reinforcement calculated from the balance of forces in the element is presented and then compared with test results. It is shown that when calculating the minimum degree of GFRP reinforcement, basing only on static relationships can result in too low a load capacity.

20

Pręty kompozytowe jako alternatywa dla zbrojenia tradycyjnego w infrastrukturze

Konopska-Piechurska Małgorzata, Szaj Paweł

Inżynieria i Budownictwo

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2022

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R. 78, nr 9-10

393--396

PL

W referacie przedstawiono możliwości zastosowania prętów kompozytowych z tworzywa sztucznego wzmocnionego włóknami szklanymi jako alternatywy dla zbrojenia stalowego w budownictwie drogowym i infrastrukturalnym. Przykłady realizacji, w których większości autorzy referatu brali udział, pokazują kierunki zastosowań prętów kompozytowych w takich realizacjach, jak: nawierzchnie betonowe o ciągłym zbrojeniu, podtorza tramwajowe, zbiorniki retencyjne, płyty pomostu, pasy transmisyjne.

EN

The paper presents the possibilities of using glass fiber reinforced plastic composite bars as an alternative of steel reinforcement in road and infrastructure construction. Examples of realizations, in most of which the authors of the paper participated, show the directions of using of composite bars in such realizations as concrete pavement with continuous reinforcement, tram subgrades, retention basins, deck slabs, transmission belts.