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With the increased use of fibre reinforced composites (FRP), the design of new generation of composite structures with high stiffness and a ductile material behaviour is required to cope with complex load scenarios and high damage tolerances. This can be achieved, in particular, by a combination of conventional fibre-reinforced composites (FRP), which possess high stiffness and strength with metallic materials characterized by their high ductility and associated higher energy absorption capacity. Currently, there are no solutions for hybridisation of high performance filament yarns, metal filament yarns and thermoplastic filament yarns on micro level. Therefore, the main objective of this study is to develop a fibre hybrid composite based on hybrid yarn consisting of glass, steel and polypropylene filament yarns and to compare its tensile and impact properties with those of the composite reinforced only with glass filament yarn. The tensile and impact properties of the unidirectional hybrid composites produced from the developed multi-material hybrid yarn consisting of steel, glass and polypropylene filament yarns are compared with those of a non-hybrid composite reinforced exclusively with glass filament yarn. The results show that by hybridising with steel fibres a characteristic post-failure behaviour can be achieved, so that the developed multi-material hybrid yarns have a high potential for use in composites with high crash and impact performance requirements, where safety demands are essential. [ABSTRACT FROM AUTHOR]

The construction of lunar stations for research and habitation requires high-performance building materials that can adapt to the harsh lunar environment. One of the feasible building materials is fiber-reinforced composites, for which the composition of glass fibers can be designed like lunar soils, i.e., terrestrial basalt, and in turn the "lunar glass" can be drawn into fibers. Because of a wide variation of TiO 2 in lunar soils, our study focused on a series investigation on the effect of TiO 2 (0.55 wt%-6.14 wt%) on fiber spinnability and strength of the simulated "lunar glass and glass fibers". The baseline glass composition was derived from a simulated TiO 2 -lean lunar soil and other glasses were made at different TiO 2 doping levels. The addition of TiO 2 was found to reduce the thermal stability of the melt, there appears a TiO 2 threshold (6.14 wt%), at which fibers cannot be drawn without breakage because of melt devitrification. The fiber tensile strength exhibits a nonlinear characteristic with an apparent maximum at 1.52 wt% TiO 2. FTIR and Raman spectroscopic studies were carried out to investigate the glass network structure responses to TiO 2 modifications and show TiO 2 functions as a network modifier, depolymerizing the silicate network. Statistical structure (FTIR & Raman based)–property modeling was attempted to further elucidate the effect of TiO 2 -induced structure change on T g and fiber tensile strength. Good agreements were found between the model predictions and the measured values. [ABSTRACT FROM AUTHOR]

In the present research, glass and basalt fiber-reinforced polypropylene composites' behaviour in quasi-static and dynamic conditions is studied. Composites were fabricated by vacuum assisted Compression molding method. Composites failure under quasi-static tension and compressive conditions was studied along with its failure behaviour under low-velocity impact and super-sonic shock loading under dynamic conditions. The study results showed that basalt fiber-reinforced polypropylene (Basalt/PP) composite's tensile and compressive strength is higher than glass fiber-reinforced polypropylene (Glass/PP). The Basalt/PP showed no penetration against low velocity impact (LVI) with negligible deformations till 50 J. However, the Glass/PP perforated at 50 J with various failure patterns occurring at back side. The fiber-matrix interface adhesion plays an important role in super-sonic shock loading by absorbing shock wave energy due to ductile nature of polypropylene and the two composites absorbed energy via matrix and fibers failure, no brittle failure of laminates occurred under shock loading. [ABSTRACT FROM AUTHOR]

In the pursuit of sustainable and high‐performance materials, this study presents a groundbreaking approach to enhance the mechanical properties of glass fiber‐reinforced polymer composites. Railway waste provides an unexpected source of recycled glass fibers (RGFs), which, when combined with bamboo fibers (BFs) and nano SiO2 in a resilient epoxy matrix, unleashes a transformative synergy. The epoxy‐SiO2 matrix ratio was kept constant, that is,70% by weight while varying the ratio of RGF and BFs weight. The experimental results demonstrated notable improvements in mechanical properties. Specifically, a 36.92% increase in tensile strength was observed with an RGF and BF ratio of 20:10. Flexural strength exhibited a substantial enhancement of 44.67%, and impact strength increased by 31.28% at a ratio of 15:15. The composite achieved a remarkable 42.64% improvement in hardness, while attaining the lowest density value of 0.862 at a ratio of 25:05.Water absorption tests, conducted in both distilled and saline water, provided insights into the material's resistance to environmental conditions. The morphological and dispersion behaviors of the prepared composites were analyzed using advanced characterization techniques, including field‐emission scanning electron microscopy (FE‐SEM) to study the orientation, shape, and size of fibers and particles, bonding between the fibers and matrix, defects, voids, etc. Combined with energy dispersive x‐ray spectroscopy (EDX), FESEM allows for elemental analysis, helping to identify and quantify the chemical composition of different phases within the polymer composite. X‐ray diffraction (XRD) analysis to know the compositions of developed composites. The findings from this study underscore the efficacy of incorporating recycled materials. Highlights: Extraction and reusing GF to develop a new hybrid composite.BF and RGF in epoxy‐SiO2 matrix present high mechanical property composite.Density and water absorption tests were done to see the swelling properties.Characterization technique employed to see the interphase of composites developed. [ABSTRACT FROM AUTHOR]

This paper presents a study on the mechanical characterization of novel short curauá/glass fibre reinforced interlaminar hybrid composite adhesive joints. The study aims to optimize the performance of these joints by analysing their mechanical properties as a function of the number of external synthetic layers and the architectural symmetry. Short curauá fibres and glass fibre bidirectional fabrics were used with a bi-component epoxy matrix in order to fabricate the hybrid composite adherends. The glass fibre bidirectional fabrics were placed on the outer layers, while the short curauá fibres were used as the core of the hybrid composites. The mechanical properties of the composites used as adherends, including tensile strength, flexural strength, and impact resistance, were determined through mechanical testing. Single lap joints bonded with a structural ductile bi-component epoxy automotive adhesive were fabricated and tested for each case. The results show that the failure mode of the bonded joints is strongly influenced by the composition and configuration of the adherends' composite layers. It was found that the effect of the number of synthetic layers is highly significant for bonded joint failure load, while no significant variation was observed as a function of architecture symmetry. This study provides valuable insights into the mechanical properties of adhesively bonded joints in hybrid curauá/glass fibre reinforced composites, which can be useful in the design and optimization of these materials for various engineering applications. [ABSTRACT FROM AUTHOR]

To simultaneously endow thermal conductivity, high glass transition temperature (Tg) and healing capability to glass fiber/epoxy (GFREP) composite, dynamic crosslinked epoxy resin bearing reversible β-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth (GFC@BNNSs). The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated BNNSs. Then, the GFC@BNNSs were impregnated with the mixture of lower concentration (3-glycidyloxypropyl) trimethoxysilane grafted BN micron sheets, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride, which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical performances. The resultant GFREP composite containing less boron nitride particles (17.6 wt%) exhibited superior in-plane (3.29 W·m−1·K−1) and through-plane (1.16 W·m−1·K−1) thermal conductivities, as well as high Tg of 204 °C (Tg of the unfilled epoxy=177 °C). The reversible transesterification reaction enabled closure of interlaminar cracks within the composite, achieving decent healing efficiencies estimated by means of tensile strength (71.2%), electrical breakdown strength (83.6%) and thermal conductivity (69.1%). The present work overcame the disadvantages of conventional thermally conductive composites, and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application. [ABSTRACT FROM AUTHOR]

In this study, the mechanical performances of glass fiber-reinforced notched and pin-connected composite plates were investigated experimentally and numerically. For this purpose, composite plates with a circular hole, semicircular double-edge notched, U-edge notched, and single and double pin joints were prepared from [ 0 ° ] 8 layer glass fiber composites. Tensile tests were carried out on the obtained specimens. The effect of notch type, number of pins, and position of pins on plate damage load and type was investigated for linear and non-linear material behavior. Progressive failure analysis was performed using the Hashin damage criteria. Subprogram codes were written in the Ansys program using the finite element method. According to the obtained data, it was determined that the type of notch and the number of pins have a significant effect on the damage loads of the plates and the behavior of the material is important in terms of convergence to the experimental results in numerical solutions. In single-pin composites, the type of damage changed from net-tension to shear out as the pin approached the free edge of the plate. It was observed that the distance between the pins did not have any effect on the damage type of the composites in the double-pin joint structure. Compared to single-pin joint composites, double-pin joint composites were found to carry a maximum of 34% more damage load. The convergence rate of experimental and numerical data was obtained as a minimum of 92.1% for nonlinear material behavior and a minimum of 73.4% for linear material behavior [ABSTRACT FROM AUTHOR]

Hybrid composites are an advanced solution that offers multifunctional capabilities, including exceptional strength-to-weight ratios, vibrational damping and impact absorption. This work describes the damping capacity and flexural behaviour of a hybrid fibrous-particulate system composed of glass/carbon fabrics and three distinct micro-inclusions: silica particles, carbon waste microfibres, and cement. A statistical methodology based on the full factorial design is applied to identify the effects of fibre stacking sequence, including carbon-C5, glass-G5, C2G3, G3C2, GCGCG and CG3C, microparticle inclusions and matrix/fibre volume fraction (40/60 and 60/40) on damping and bending responses. A non-linear finite element (FE) analysis is conducted to explore the stress distribution based on the stacking sequence and predict the failure mechanisms of the hybrid laminate. The results indicate significant interaction effects, with hybrid architectures showcasing approximately 33% higher performance compared to glass fibre composites. A greater dependence on the fibre layup sequence is found for the damping factor, flexural modulus and strength. Notably, the incorporation of silica microparticles leads to an increase in flexural strength. Furthermore, a greater volume fraction of the matrix phase enhances the rheological efficiency in terms of the fibre-particle interface. Carbon fibre layers placed symmetrically on both beam sides (CG3C) and bottom layers (G3C2) significantly enhance the bending performance of hybrid composites. [ABSTRACT FROM AUTHOR]

In this study, the enhancement in strength and toughness of multi-piece glass fiber reinforced plastic (GFRP)/GFRP joints was demonstrated. These joints are bonded with repurposed short glass fiber reinforced adhesive and find their application in rehabilitation of sewage pipelines. These short fibers were produced by grinding and milling the fiberglass wastes, collected during the lamination process of pipes. To study the effect of glass fiber content on the mechanical properties of the composite adhesive, short fiber composite (SFC) specimens with varied milled fiber content were tested under flexural loads. A finite element-based numerical homogenization study was carried out on a micro-mechanical periodic unit-cell representing a non-homogeneous SFC to predict the mechanical properties of the microstructure. The dispersion state of fibers and fracture surface characteristics of SFC were analyzed via scanning electron microscopy. Further, the shear strength of the adhesive with and without reinforcement was experimentally evaluated using a lap shear test. Increasing the fiber content in the adhesive transforms it from a compliant state with poor strength into a much stiffer and stronger composite with reduced strain tolerance. The optimized SFC was selected for joining the two segments of the GFRP sewage pipe using a unidirectional composite as a tongue. Subsequently, the tongue-in-groove joints (TGJs) were tested under tension. [ABSTRACT FROM AUTHOR]

This study explores the investigations of bamboo fiber-reinforced polyester composites with chopped glass fiber (CGF) filler, focusing on addressing the challenges of low mechanical properties, limited thermal stability, and high moisture absorption. The two types of composites were fabricated using the hand layup method, that is, long unidirectional 0° bamboo fiber (BF) and randomly oriented short bamboo fiber (BP) reinforced a polyester matrix with chopped glass fiber (CGF) filler. By incorporating CGF filler, significant improvements in mechanical properties were achieved across both types of bamboo fiber, surpassing the limitations of unfilled composites. Notably, the composite formulation consisting of 40% wt. of unidirectional 0° BF and 5% wt. of CGF filler exhibited superior ultimate tensile strength, flexural strength, impact strength, water absorption, and thermal stability. This composite demonstrated remarkable enhancements, with increases of up to 131.22 MPa, 128.76 MPa, 113.3 kJ/m2, 1.94% water absorption, and up to 255°C (representing a 10% improvement) in thermal stability compared to the unfilled composite. Statistical analysis revealed quadratic models for the mechanical properties of long unidirectional 0° bamboo fiber composites, while water absorption exhibited a linear two-factor interaction model. For randomly oriented short bamboo fiber, the models for tensile, flexural, and water absorption properties were linear, while the impact energy model showed a quadratic relationship. These statistical models provide valuable insights into predicting the properties of bamboo fiber-reinforced polyester composites. This research underscores the significance of bamboo fiber-reinforced polyester composites in wall partition systems. This study paves the way for improved performance in these areas. The findings highlight the potential of incorporating CGF filler, enabling enhanced mechanical strength, increased thermal stability, and improved resistance to moisture-related issues. The derived statistical models offer valuable guidance for predicting the properties of these composites, facilitating their application and adoption in the construction industry. [ABSTRACT FROM AUTHOR]

Wind turbine blades are the main component of wind turbines to capture effective wind energy, and require good quality and reliable performance. Therefore, the manufacturing cost of wind turbine blades is much higher than that of other components of wind turbines. The blade is a slender elastomer prone to vibration. The wind turbine vibration always arises in the blade instability. At the same time, the blade is also a typical aerodynamic component. In the process of rotation, it will not only produce mechanical vibration but also bear aerodynamic force. In this paper, the mechanical properties and modal numerical simulation analysis of composite blades with different hybrid ratios of carbon fiber and glass fiber are analyzed, it is found that with the increase of carbon fiber content, the mechanical properties of the blade gradually increase, and the torsional vibration resistance of the blade become stronger. Therefore, the wind turbine blades of hybrid fiber composites have a longer service life, which can reduce material wastage and help protect the environment. [ABSTRACT FROM AUTHOR]

This study investigates the effects of filler content and type on the mechanical (tensile strength and impact resistance) and tribological properties of woven glass fiber‐reinforced composites (WGFC) produced using three different nanofillers (MgO, CuO, and Al2O3) at various loading levels (0.7, 1.4, and 2.8 wt%). Additionally, analyses of the artificial neural network algorithm were reported for the predictions of wear rate, mass loss, and coefficient of friction (COF) by given applied load, sliding distance, filler ratio, and filler type. The composites were fabricated using the hand lay‐up method. The filled composites were characterized using Fourier Transform Infrared (FTIR) spectroscopy, and the worn surfaces of the samples after the wear test were analyzed using Scanning Electron Microscopy (SEM). The wear resistance of the composite samples improved at 0.7 wt% CuO and 1.4 wt% MgO filler contents. At 200 m sliding distance and 1.4 wt% filler ratio, the highest wear ratio was determined as 55 mm3/m × 10−3 in the Al2O3‐filled composite, and the lowest was determined as 31 mm3/m × 10−3 in the MgO‐filled composite. At 1.4% filler ratio and 15 N load, the lowest friction coefficient was determined as 0.45 μ in MgO‐filled composite, and the highest was 0.56 μ in Al2O3‐filled composite. Al2O3 filler increased the mass loss and wear rate of the composite material. In Charpy impact tests, the maximum impact energy of 13.9 J/m2 was obtained with a 2.8 wt% Al2O3 filler content. Tensile tests showed an increase in tensile strength for all filler contents compared to unfilled composites. The highest tensile strength of 242.1 MPa was achieved with 0.7 wt% CuO reinforcement. Highlights: In all applied wear parameters and filler ratios, the Al2O3 filler adversely affected the wear resistance of the composite, while the MgO filler showed the best performance in terms of wear resistance.All types and ratios of fillers increased the tensile strength compared to the unfilled composite.Contrary to its negative effect on wear, the Al2O3‐filled composites exhibited the highest impact resistance.The prediction analysis of the tribological behavior of composite material using ANN reveals that the Levenberg–Marquardt algorithm fits very well. [ABSTRACT FROM AUTHOR]

Liquid composite molding (LCM) is a process for manufacturing fiber-reinforced resin matrix composites. The chemical rheological properties of resin in the filling stage of LCM will produce a non-isothermal flow process that includes multi-field coupling of thermal field, flow field, and chemical field. During the filling stage, the resin is injected into a closed mold pre-laid with a fiber at a certain temperature and pressure to flow continuously and undergo a curing chemical reaction. The viscosity of resin changes constantly under the influence of temperature and the curing reaction, which affects the flow of resin. The simulation of this multi-field coupling filling stage in LCM can provide an effective reference for the design of process parameters. The simulation method of the filling stage in LCM is studied in this paper. The mathematical model of the filling stage is derived based on the air–resin two-phase flow volume of the fluid model. Based on the secondary development of the ANSYS FLUENT software, the mathematical model is solved to realize the simulation. The parameters of an alkali-free glass fiber plain weave fabric are measured and the calculation model of thermosetting resin viscosity is established by designed experiments, which are applied in simulation. The filling stage experiment of LCM is designed to verify the accuracy of simulation results. Meanwhile, by comparing with the traditional simulation method, it is found that the data error obtained by the simulation method in this paper is significantly reduced. [ABSTRACT FROM AUTHOR]

An evaluation of the interlaminar fracture toughness of polyamide/glass fiber laminates with various layups is reported. Due to large differences in thermal expansion coefficients of fiber and binder the laminates with layups where single layers are swapped exhibit high warping. A technique for avoiding this is proposed, allowing evaluating interlaminar fracture toughness of various angle interfaces. Two different layups for evaluating the Mode I and II interlaminar fracture toughness are tested. The differences of delamination behavior of a number of different-angle fiber interfaces are shown and analyzed. The applicability of the proposed testing technique is discussed. [ABSTRACT FROM AUTHOR]

The preparation of basalt and S‐glass fiber‐reinforced poly(dicyclopentadiene) via ring‐opening metathesis polymerization using a thermally latent pre‐catalyst, that is, Mo(N‐3,5‐Me2‐C6H3)(= CH‐(2‐MeO‐C6H4))(IMes)(OTf)2 (1, IMes = 1,3‐dimesitylimidazol‐2‐ylidene; OTf = SO3CF3) is reported. Complementarily, the non‐latent first‐generation Grubbs initiator RuCl2(PPh3)2(CHPh) (2) is used. 2 can be rendered latent by the addition of ppm amounts of triphenylphosphine (PPh3). Both 1 and 2/PPh3 allow the realization of thermally latent single‐component systems with sufficient pot life that do not require pre‐mixing of the individual components shortly before use. The prepared fiber matrix composites are characterized in terms of mechanical, thermal, and chemical stability. [ABSTRACT FROM AUTHOR]

"Interleaving" is widely used for interlaminar toughening of fiber-reinforced composites, and the structure of interleaving is one of the important factors affecting the toughening efficiency of laminates. Several experiments have demonstrated that compared to continuous and dense structures, toughening layers with structural heterogeneity can trigger multiple toughening mechanisms and have better toughening effects. On this basis, this work further investigates the application of heterogeneous toughening phases in interlaminar toughening of bidirectional GFRP. CNT was selected to construct toughening phases, which was introduced into the interlaminar of composites through efficient spraying methods. By controlling the amount of CNT, various structures of CNT toughening layers were obtained. The fracture toughness of modified laminates was tested, and their toughening mechanism was analyzed based on fracture surface observation. The results indicate that the optimal CNT usage (0.5 gsm) can increase the initial and extended values of interlayer fracture toughness by 136.0% and 82.0%, respectively. The solvent acetone sprayed with CNT can dissolve and re-precipitate a portion of the sizing agent on the surface of the fibers, which improves the bonding of the fibers to the resin. More importantly, larger discrete particles are formed between the layers, guiding the cracks to deflect in the orientation of the toughened layer. This generates additional energy dissipation and ultimately presents an optimal toughening effect. [ABSTRACT FROM AUTHOR]

The efficient modeling of 3D-printed parts, especially long fiber-reinforced composite parts, is a significant concern. This paper discusses finite-element modeling using the embedded element technique to simulate the mechanical behavior of specimens reinforced with long glass fibers. The study considered the concentric deposition mode of the fibers, the walls, and the solid filling pattern of the printed parts as parameters. In addition, classical numerical modeling of the composites using 2D Shell elements and an analytical prediction of the Young's modulus using the rule of mixtures were implemented. The results showed that both the classical 2D Shell modeling and the law of mixtures predict the Young's modulus with acceptable prediction error. However, these approaches have limitations in predicting the overall behavior of the specimens. The use of the embedded element technique allowed for the prediction of both the Young's modulus and the global behavior of the specimens with acceptable prediction error. [ABSTRACT FROM AUTHOR]

The chemical structure of the surface of glass fibers, including silanized fibers, was studied. Highly efficient heat-resistant composites were obtained by impregnating silanized glass fiber with a polysulfone solution, and the effect of modification of the surface of glass fibers on the physical, mechanical and thermophysical properties of the composite materials was studied. As a result of the study, it was found that the fiber-to-polymer ratio of 70/30 wt.% showed the best mechanical properties for composites reinforced with pre-heat-treated and silanized glass fibers. It has been established that the chemical treatment of the glass fibers with silanes makes it possible to increase the mechanical properties by 1.5 times compared to composites reinforced with initial fibers. It was found that the use of silane coupling agents made it possible to increase the thermal stability of the composites. Mechanisms that improve the interfacial interaction between the glass fibers and the polymer matrix have been identified. It has been shown that an increase in adhesion occurs both due to the uniform distribution of the polymer on the surface of the glass fibers and due to the improved wettability of the fibers by the polymer. An interpenetrating network was formed in the interfacial region, providing a chemical bond between the functional groups on the surface of the glass fiber and the polymer matrix, which was formed as a result of treating the glass fiber surface with silanes, It has been shown that when treated with aminopropyltriethoxysilane, significant functional unprotonated amino groups NH+/NH2+ are formed on the surface of the fibers; such free amino groups, oriented in the direction from the fiber surface, form strong bonds with the matrix polymer. Based on experimental data, the chemical structure of the polymer/glass fiber interface was identified. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced composite aerogel felt is an important thermal insulation material, but its thermal insulation performance is often compromised due to the limitation of preparation methods. In this study, the high performance glass fiber composite silica aerogel insulation thin felt was successfully prepared by in-situ sol-gel impregnation and combustion drying process for the first time. Especially, the drying time for the whole procedure is extremely quick, only taking a few minutes. The composite felt shows the characteristics of light weight, porous, hydrophobic, and has good mechanical properties. More importantly, due to the unique composite structure of the prepared felt, it has extremely low thermal conductivity (0.016 W/(m·K)) and thermal stability. The infrared thermal imager further confirmed that glass fiber composite silica aerogel thin felt has excellent thermal insulation ability, and has promising application potential in the thermal management system of power battery. Finally, the preparation process and drying mechanism based on sol-gel impregnation combined with combustion drying technology were discussed. Compared with the common technology, the preparation method has significant advantages of high efficiency and low cost, which offer an innovative technical approach for producing composite aerogel felt. [ABSTRACT FROM AUTHOR]

Frontal polymerization (FP) is a self-sustaining reaction that relies on polymerization exothermicity and heat transfer. This study explores the inplane and in-depth FP mechanisms of continuous fiber-reinforced epoxy composites. First, the effects of initiator and diluent concentrations on the FP behaviors of neat epoxy resins were examined. It was found that the frontal velocity and frontal temperature of the neat resins increase with an increase of either the initiator concentration or the diluent content, depending on the polymerization enthalpy and curing kinetics. Then, the FP behaviors of continuous carbon fiber and glass fiber-reinforced epoxy woven composites were investigated. The results showed that the in-plane FP behavior of the composites was primarily controlled by the thermal conductivity and specific heat capacity of the continuous fibers, whereas the in-depth FP behavior mainly depended on the pores of the woven fabrics. Highlights • Frontal velocity and temperature of neat resins are controlled by the polymerization enthalpy and curing kinetics. • The in-plane FP behavior of continuous fiber reinforced composites is dependent on the thermal conductivity and specific heat capacity of the fibers. • The in-depth FP behavior of composite is determined by both the thermal conductivity of fibers and the pores of fabrics. [ABSTRACT FROM AUTHOR]

This work compares the tensile and fatigue behavior of unidirectional glass fiber/epoxy (GFRPs) and basalt fiber/epoxy (BFRPs) composites manufactured using vacuum-assisted resin infusion molding (VARIM). The tensile and fatigue tests are performed, and results show that both GFRPs and BFRPs have very similar tensile behavior, whereas BFRPs perform better than the GFRPs in terms of fatigue life and degradation of properties, showing about 75 MPa more fatigue limit. The S-N curve shows that BFRPs resist fatigue failure and stiffness degradation due to their better interfacial adhesion. Fractographic observations reveal fatigue failure mechanisms of both BFRPs and GFRPs. From the regression analysis performed, an S-N curve was fitted with a model available in the literature, and regression parameters were calculated. Dynamic mechanical analysis of both BFRPs and GFRPs was performed to evaluate parameters like glass transition temperature, storage modulus, and loss modulus. From the findings of this research, BFRPs may be recommended as a suitable alternative to GFRPs. Highlights • This article compares the tension-tension fatigue properties of unidirectional GFRPs and BFRPs. • From the research work, the authors found that BFRPs perform better than GFRPs under fatigue loading. • The stiffness degradation behavior of GFRPs and BFRPs are studied and compared. • Scanning electron micrographs of fractured samples are used to observe fatigue failure mechanisms. • Dynamic mechanical analysis (DMA) was performed to determine the storage modulus, loss modulus, glass transition temperature, and damping coefficient (tand) for both composites. [ABSTRACT FROM AUTHOR]

Composite structures with L, C, and T shape geometries are commonly used in the design of aerospace structural components. These complex structures are prone to delamination failure at the curved region. This study investigates the effect of thickness and recycled milled glass fiber fillers to improve the strength properties and delamination resistance of glass/epoxy composite angle brackets. Different thicknesses of 3.5 mm (16 layers), 5 mm (24 layers), and 6.5 mm (32 layers) specimens were subjected to four-point bending test with acoustic emission (AE) monitoring for evaluating damage resistance. Mechanical results reveal that the specimen with a higher thickness of 6.5 mm has better damage tolerance, followed by 3.5 and 5 mm angle brackets. Moreover, the location of AE signals and % of AE hits noticed the initiation and propagation of delamination in 5 mm thickness specimen at the earlier stage of loading. However, the curved beam strength and interlaminar tensile strength (ILTS) of 5 mm thickness specimen were improved by 31.02% and 19.2% respectively, through the incorporation of 2 wt% of fillers. Further, the interfacial adhesion between the fillers and epoxy matrix was studied using Fourier-transform infrared analysis to confirm the improvement of delamination resistance in 5 mm thickness specimen. Finally, the mechanical and AE results were well correlated with field emission scanning electron microscope images to characterize the damage mechanisms in composite angle brackets. Highlights • Effect of thickness on the delamination resistance of composites was studied. • Interlaminar properties of composite angle brackets were assessed. • Acoustic emission parameters were used to study the damage mechanisms. • Recycled milled glass fillers were employed to improve delamination resistance. • Mechanical and acoustic emission results were correlated with field emission scanning electron microscope images. [ABSTRACT FROM AUTHOR]

Because the physical properties of carbon fiber and glass fiber are very different, the fiber volume fraction in carbon/glass hybrid fiber composites cannot be tested by burning method or digestion method, respectively. Furthermore, these methods partially consume the fiber, especially for carbon fibers. To investigate the fiber volume fraction in carbon/glass hybrid fiber composites correctly, the test method is put forward. The burning method and the digestion method were combined to calculate the volume fraction of carbon fiber and glass fiber, respectively. The results show that the relative error between the measured value and the theoretical value is very small. The result of the present work implies that the feasibility and accuracy of this method through experimental verification. [ABSTRACT FROM AUTHOR]

The purpose of the study was to evaluate selected mechanical properties and structural characteristics of samples manufactured using composite filament fabrication (CFF) technology from Onyx material, whichwas filled with continuous glass fiber. Selected mechanical properties were correlated with the density of the resulting composite to determine the specific strength of the fabricated parts. The test specimens were manufactured on a Mark Two Enterprise machine (Markforged, USA) using composite filament fabrication (CFF) technology. The material used was polyamide 6.6 with a 20% short carbon fiber content with the trade name Onyx. Continuous glass fiber was used to reinforce the fabrication. The density of the manufactured samples was determined using a hydrostatic method. Methanol was used as the liquid. By determining the density of the samples, it was possible to estimate through appropriate calculations what specific strength and specific modulus the obtained composites would have. Determination of tensile and flexural strengths was carried out in accordance with ISO 527-1:2012 and ISO 178:2003. Determination of the impact tensile strength of the samples was carried out in accordance with ISO 8256, the beams were tested using the A method. Due to the high impact tensile strength, two 1 mm notches with an angle of 45°were made on the specimens. The image of the sample structure obtained by the CFF method was recorded using a CT scanner. A thermogravimetric test (TG) of the Onyx matrix material was carried out. The samples were tested approximately 72 hours after fabrication. Filling the samples with continuous glass fiber above 50% leads to a slight increase in impact resistance. The density of the composite increased by only 16% relative to the reference samples, resulting in a 389% increase in the maximum average flexural strength. Despite significant discontinuities in the structure of the produced composite, it was possible to record an increase in tensile strength and Young's modulus by 606% and 370%, respectively. [ABSTRACT FROM AUTHOR]

By integrating fiber-reinforced composites (FRCs) with Three-dimensional (3D) printing, the flexibility of lightweight structures was promoted while eliminating the mold's limitations. The design of the I-beam configuration was performed according to the equal-strength philosophy. Then, a multi-objective optimization analysis was conducted based on the NSGA-II algorithm. 3D printing was utilized to fabricate I-beams in three kinds of configurations and seven distinct materials. The flexural properties of the primitive (P-type), the designed (D-type), and the optimized (O-type) configurations were verified via three-point bending testing at a speed of 2 mm/min. Further, by combining different reinforcements, including continuous carbon fibers (CCFs), short carbon fibers (SCFs), and short glass fibers (SGFs) and distinct matrices, including polyamides (PAs), and polylactides (PLAs), the 3D-printed I-beams were studied experimentally. The results indicate that designed and optimized I-beams exhibit a 14.46% and 30.05% increase in the stiffness-to-mass ratio and a 7.83% and 40.59% increment in the load-to-mass ratio, respectively. The CCFs and SCFs result in an outstanding accretion in the flexural properties of 3D-printed I-beams, while the accretion is 2926% and 1070% in the stiffness-to-mass ratio and 656.7% and 344.4% in the load-to-mass ratio, respectively. For the matrix, PAs are a superior choice compared to PLAs for enhancing the positive impact of reinforcements. [ABSTRACT FROM AUTHOR]

The demand for fiber-filled polymers has witnessed a significant upswing in recent years. A comprehensive understanding of the local fiber orientation is imperative to accurately predict the mechanical properties of fiber-filled products. In this study, we experimentally investigated the fiber orientation kinetics in uniaxial extensional flows. For this, we equipped a rheometer with a Sentmanat extensional measurement device and with an optical train that allows us to measure the fiber orientation in situ during uniaxial extension using small angle light scattering. We investigated an experimental system with glass fibers for the suspended phase (L / D = 8 − 15), and for the matrix either low density polyethylene, which shows strain hardening in extension, or linear low density polyethylene, which shows no strain hardening. For these two polymer matrices, the fiber orientation kinetics were investigated as a function of fiber volume fraction (ϕ = 1 % , 5%, and 10%) and Weissenberg number (by varying the Hencky strain rate, ϵ ˙ H = 0.01 − 1 s − 1 ). We found that all these parameters did not influence the fiber orientation kinetics in uniaxial extension and that these kinetics can be described by a multiparticle model, based on Jeffery's equation for single particles. Our results show that, in uniaxial extension, fiber orientation is solely determined by the applied strain and that, up to the concentrated regime (ϕ ≈ D / L), fiber-fiber interactions do not influence the fiber orientation. The extensional stress growth coefficient of these composites, which is measured simultaneously with the orientation, shows high agreement with Batchelor's equation for rodlike suspensions. [ABSTRACT FROM AUTHOR]

In the present work, four layered Palmyra-Palm-Leaf-Stalk (PPLSF)/Glass hybrid composites laminates with six distinct stacking orders were made by following hand lay-up method. Different experiments were carried out to determine the tensile, flexural, impact and hardness of the laminates as per ASTM standard. The results reveal that the addition of glass fiber to PPLSF significantly enhanced the mechanical performance of the laminates. On successive replacement of PPLSF by glass fiber, an enhancement of properties such as 291.39% for tensile strength, 72.08% for flexural strength, 75.82% for impact strength, and 78.44% for micro-hardness was observed. Again, it is also noticed that the stacking order plays an important role in influencing the properties while comparing experimental finding of laminates with equal weight percentages PPLSF and glass fiber. Further to perform Finite Element Analysis (FEA), a 3D CAD model of tensile and flexural specimen was created in space-claim modeler of ANSYS R19.0 and subsequently imported to generate numerical predicted values. While comparing the numerical and experimental results, there was very good agreement among the results was found. Scanning Electron Microscope (SEM) was used for fractography analysis of the tested samples to examine the different mode of failures. [ABSTRACT FROM AUTHOR]

Helicoidal composite has been found naturally existing in many species of crustaceans and it has recently raised a significant amount of interests among researchers due to its great impact performance resulted from unique fiber layup architecture. This work is focused on developing a novel bio-inspired helicoidal thermoplastic composite and studying its mechanical behaviors under different testing conditions. Continuous glass fiber reinforced polypropylene composite preforms were used for compression molding the helicoidal structure with a pitch angle of 16.3° and nonlinear pitch angle. Composites with conventional fiber layups such as 0/90 and quasi-isotropic layup sequences were also prepared and tested for comparison purpose. Various tests at different strain rates, including quasi-static test (flexural test and compression after impact test), low strain rate test (Izod impact test and drop tower impact test), and high strain rate test (Split Hopkinson pressure bar test), were performed to evaluate the mechanical properties of the helicoidal composites and conventional composites. The helicoidal composites showed twisting fracture pattern for deflecting cracks involving more areas for energy absorption in addition to common failure mechanisms in the Izod impact test. It was also found that the helicoidal composite showed considerably higher damage tolerance than the conventional composites in high strain rate scenarios. [ABSTRACT FROM AUTHOR]

Detecting the low-velocity impact damage on the FRP composite structures can be challenging because the visible signs on the surface may be subtle. Mitigating the effects of BVID (Barely Visible Impact Damage) is crucial in ensuring the safety and reliability of composite components, especially in industries where these materials are commonly used, such as aerospace and automotive. This article explores the experimental investigations of the impact and post-impact damage propagation under compression in the Graphene Nano-Platelets (GNPs) infused glass fiber epoxy composite laminates. A comparative study of varying the percentage of the nano-platelets (0, 0.25, 0.5, and 0.75%) in the matrix material of the composite laminate is presented. The impact tests at low energies (15 J, 20 J, and 25 J), followed by the quasi-static compression tests, are carried out as per the procedures mentioned in the ASTM D7136/D7137. The digital image correlation technique (DIC) is used to measure strains and plot the strain field on the impacted face of the specimen under compression. Damage envelopes of the impact and compression tests are studied using X-ray CT scans. Micro-level failures are observed through Scanning Electron Microscopy (SEM) to get better insights into the failure mechanism of the composite materials under impact and compression loadings. Upon completing the study, it is found that the addition of the GNP into the matrix materials not only increased the impact performance but also increased the load-carrying capacity of the laminate under compressive loading. A decrement of 2–21% in the energy absorbed in the damage formation is seen with the incorporation of GNPs into composite materials. A maximum increment of 17% in the compressive strength is observed for the composite laminates with the 0.75% GNPs. However, for a particular percentage of the GNP, the compressive strength of the laminate is reduced with an increase in impact energy compared with its virgin counterpart. From X-ray CT scans, it is seen that the laminate under the compression tests fails due to excessive ply-splitting and the delamination at the damage site created during the impact. Fiber breakage, fiber brooming, matrix cracking, fiber-matrix debonding, etc., are some of the other failure modes observed in SEM studies. [ABSTRACT FROM AUTHOR]

In this study, we compare the effect of various precursor‐based graphene oxide (GO) nanofillers on enhancing the mechanical performance of E‐glass fiber‐reinforced epoxy resin composites (EGFPs). GO derived from bituminous coal (BC‐GO) and graphite (Gr‐GO) were dispersed into an epoxy resin matrix. The resulting mixture was combined with E‐glass fiber mats using vacuum‐assisted resin infusion molding. Notable improvements (38.9% in flexural strength, 22.9% in tensile strength, and 21.6% in impact strength) were observed in BC‐GO‐reinforced EGFPs at 0.25 phr loading of BC‐GO. The improvements for Gr‐GO‐reinforced EGFPs were 28%, 9.3%, and 6.8%, respectively. XRD analysis of BC‐GO showed a diffraction peak at 2θ = 20.9°. Except for this peak, no other crystalline peaks were observed when BC‐GO was incorporated into EGFPs. FTIR spectra of both composite samples, with or without the nanofiller, were similar due to the spectral peaks overlap. TEM demonstrated the exfoliated morphology of BC‐GO in EGFPs. These findings underscore the potential of BC‐GO as a cost‐effective reinforcement for polymer nanocomposites across various industrial applications, including the development of lightweight and strong materials for aerospace and automotive industries, protective coatings, petroleum, and aerospace production systems. Highlights: BC‐GO demonstrates superior mechanical performance compared to Gr‐GO in EGFPs.0.25 phr BC‐GO improves 38.9% flexural, 22.9% tensile, and 21.6% impact strengths.Beyond 0.25 phr, BC‐GO and Gr‐GO showed a decline in mechanical enhancement.Role of particle size, loading & adhesion to matrix analyzed using XRD, FTIR, and DLS.Coal‐GO is an attractive alternative nanofiller for EGFPs. [ABSTRACT FROM AUTHOR]

Research on Bio-based natural fiber material promoted the development of reinforcement and expand their possible structural applications. In this study, fibers are extracted from the stem of Calamus rotang (common rattan-Indian Species). Further, the fiber is processed to get novel hybrid combinations with glass fibers by manual hand lay-up technique. Three sets of samples were prepared for the different volume fractions of 60:40, 30:30:30, and 60:32:8 of glass fiber/epoxy as neat composite sample (NCS), a hybrid combination of C. rotang /glass fiber with epoxy as modified reinforced composite sample (MRCS) and glass fiber/epoxy with calamus stem powder as modified matrix composite sample (MMCS) respectively. Mechanical tests including tensile, flexural, impact, and ILSS tests are conducted as per ASTM Standards. Comparative studies have been done to evaluate the effect of novel species of C. rotang on mechanical properties with neat GFRP composites. Addition to this regression analysis has been carried out to achieve the experimental correlation for tensile and bending tests. Microstructural analysis for all the tested samples has been done to assess the fracture mode. Novel findings on retrieval bending strength for MMCS has been reported for the first time for composite materials. Study proves that novel species have a significant impact on the basic properties of materials. [ABSTRACT FROM AUTHOR]

Composite materials made up of polymer matrix reinforced with synthetic fibers have gained popularity of late owing to their enhanced mechanical properties. However, very little work is reported to date on metals being used as filler material. Research gaps were obtained pertaining to the use of metallic fillers in synthetic fiber reinforced polymer composites. This paper demonstrates an attempt to fabricate composites made of Epoxy polymer matrix and E-glass fiber reinforcement with Mild Steel in its powdered form as fillers. Composites are prepared in varying weight percentages of the filler in the order of 2 wt. %, 4 wt. % and 6 wt. %. Hand layup method is employed for fabricating these composites which are later subjected to compression. Further, the samples are machined according to ASTM D3039 standard for tensile test and ASTM D256 standard for Izod impact test. Hardness test is also performed using a Shore D Durometer and these properties are compared with the unfilled samples. The results indicated that the weight percentage of the filler clearly influenced the mechanical properties of the developed composites. This study also revealed that the hardness and tensile strength of these composites improved with the incorporation of fillers up to 2 wt. % whereas, the impact strength improved up to 4 wt. %. Thereafter, there was a decline in their impact and tensile properties. However, hardness marginally increased beyond 4 wt. %. This area is open for research with regard to their usability under tribological, high temperature or magnetic conditions. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymer composites are manufactured using various methods, with vacuum-assisted resin transfer molding (VARTM or VARIM). This study's primary focus lies in assessing how the orientation of sampling impacts the mechanical properties of glass fiber-reinforced pure and nanocomposites. 2 wt.% nano Al2O3- doped and non-doped composites were produced using the VARTM process. Tensile, flexural, and density test specimens were extracted from three distinct zones and two distinc direction those aligned horizontally to the resin flow (HRF) and those oriented vertically to the resin flow (VRF). Remarkably, results showed up to a 3.91% increase in values from samples in the third zone, particularly on the vacuum outlet side. To facilitate precise stress value comparisons across plates, uniform sample orientation and consistent zone selection are essential. [ABSTRACT FROM AUTHOR]

Glass fibre reinforced composite facings on PVC (poly(vinyl chloride)) foam cores are widely used sandwich materials in boat structures, but life cycle analysis suggests that alternative materials may be preferable for the environment. However, in order to design with these alternative materials their mechanical behaviour must be characterized and understood. This paper describes an experimental campaign to evaluate the performance of alternative sandwich materials with reduced environmental impact, under loading conditions relevant to boat design. Flax and bamboo composite faced PET (poly(ethylene terephthalate)) foam sandwich materials are compared to the current PVC foam sandwich on a constant weight basis. A series of quasi-static tests is described first and analysed. Then hard and soft impact tests are described, which allow a comparison to be made between existing and alternative sandwich options. The results indicate that the alternative materials show lower flexural stiffness. Damage initiation levels are also lower, but the impact energy levels they can support are promising, and facing improvements could raise these further. [ABSTRACT FROM AUTHOR]

Since high costs restrict the wide-range implementation of green hydrogen production capacities based on proton exchange membrane water electrolysis (PEMWE), efforts on cost reduced components need to be made. Beside the necessary noble metal catalyst, the membrane material is a main cost driver. In this work, a novel glass fibre reinforced PFSA/ssPS composite membrane is investigated as an alternative to widely used Nafion®. These membranes are processed into membrane-electrode-assemblies (MEAs) in conjunction with catalyst-coated substrates, prepared via electrochemical catalyst deposition. This approach is promising to reduce costs due to less expensive raw materials and due to increasing catalyst utilization by graded catalyst layers. Characterisation of the components and entire MEAs was performed ex-situ as well as in-situ via PEMWE operation. Novel MEAs revealed 2.0 V at 0.5 A cm2, which indicates good potential, but still requires further development efforts. • PEM based on Aquivion ionomer, glass fibre fabric and crushed ion exchange resin. • CCM based on glass fibre reinforced composites reveals 2 V at 2 A cm−2. • Ti-PTL/ATO/Ir anode unveils 2 V and GDL/CNF/Pt cathode 2.3 V at 2 A cm−2. • Electrodeposited electrodes maintain 2.2 V during 62 h of operation at 2 A cm−2. [ABSTRACT FROM AUTHOR]

In this paper, the repeated low velocity impact responses and compression‐after‐impact (CAI) behaviors of woven glass fiber‐reinforced composite laminates were studied at the same total impact energy. Three types of impact energies, 30, 40, and 60 J, were chosen for the repeated impact tests relative to the single 120 J impact event. The impact behaviors including impact contact force–displacement and energy–time curves during the impact testing were recorded. The variations of the impact mechanical characteristics such as peak impact force, maximum displacement, and energy absorption were evaluated. The methods of visual inspection and stereo microscope were applied to identify the damage morphology of the impacted laminates. The damage accumulation was evaluated employing the absorbed energy fraction and normalized maximum displacement. It was found that the influences of impact energy on the repeated impact mechanical response are more remarkable than that of the impact number, and the impact events with fewer impact numbers cause more damage to the laminates for the same accumulative impact energy. Furthermore, the load–displacement and the CAI strength versus impact number curves were compared for the CAI testing. The ultimate load and the resulted CAI strength decrease with the increase of impact number owing to the influence of damage accumulation in repeated impacts. Highlights: Repeated impact responses were studied at the same total impact energy.The impact energy makes significant influence on the impact dynamic responses.The impact events with fewer impact numbers cause more damage to the composites.The CAI behavior was explored considering the effect of damage accumulation.The CAI strength of damaged laminates decreases with impact number increasing. [ABSTRACT FROM AUTHOR]

Glass fibers (GFs) are frequently employed as reinforcement fibers for polymer resins such as epoxy and polyester. The mechanical behaviors of GFs polymer composites are nevertheless constrained by weak interfacial adhesion between polymer matrix and GFs. Herein, we invented a cross‐linking modified sizing agent using polyethyleneimine and bisphenol A epoxy emulsion, and studied the effect of cross‐linking extent on GF surface characteristics and GF/epoxy interfacial adhesion. The treatment of GFs with cross‐linking modified sizing agent facilitated the formation of interpenetrating polymer networks in composites for strengthening interface interaction. The results show that the modified GFs have a rough surface and improved interfacial adhesion with epoxy matrix. When sizing agents with cross‐linking extent of the 23.0%, the GF/epoxy composites show advanced interfacial shear strength (IFSS) and transverse fiber bundle tension (TFBT) strength. This work demonstrates that the cross‐linking extent of sizing agent could regulate interfacial adhesion, which is a facile and promising strategy in reinforcing glass fiber polymer composites. Highlights: Crosslink the sizing agent to enhance GF mechanical properties was reported.GF surface energy was enhanced and thickness of GF/epoxy interphase increased.IFSS and TFBT strength of the GF/resin composites increased by 23.65% and 30.54%, respectively. [ABSTRACT FROM AUTHOR]

This study aimed to ascertain the alterations in aging responses of fiber‐reinforced composites, as well as the effects of their natural particle reinforcement, through exposure to acidic and alkaline solutions. Specimens were produced with 0 wt. % (neat), 1 wt. %, 2 wt. % and 3 wt. % particle ratios from acorn and pinecone particles. A particle content of 2 wt. % was determined to yield the best mechanical properties in all mechanical tests conducted for pinecone reinforcement. The highest improvement in strength, observed in 3 wt. % pinecone‐reinforced composites, reached 22.5% at flexural strength. HCl and NaOH diluted in water were chosen as aging solutions. Mechanical tests were repeated at different stages of aging. According to the findings, 1 wt. % particle‐reinforced composites showed better resilience to the mechanical property reduction effect of aging compared to the 2 wt. % and 3 wt. % particle‐reinforced composites. At a particle ratio of 2 wt. %, the acorn‐reinforced specimens exhibit their highest maximum penetration force, which is 5% higher than that of the 0 wt. % composite, consistent with the results of tensile and compressive tests. Highlights: Composite material was manufactured by hand lay‐up and vacuum bagging method.Specimens were aged using acid and base solutions.Tensile, compressive, and bending results were obtained depending on particle type and ratio.Tensile, compressive, and bending strengths of composites were compared according to various aging times. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of the residual thermal and mechanical properties of pultruded glass fiber reinforced polymer composite bars following a decade of conditioning in an alkaline solution and exposure to natural weather conditions. The study focuses on evaluating the changes in the glass transition temperature (Tg) of the polymer matrix and its impact on the bar's mechanical performance. The results indicate that the Tg retained approximately 94.7% of its initial value, with the decrease attributed to the plasticizing effect of absorbed water. The flexural modulus, flexural strength, and transverse shear strength were found to retain 91.8%, 77.2%, and 97.3% of their original values, respectively. The reductions in strength and stiffness were primarily attributed to a weakening in the bonding between the fibers and the polymer matrix. Fractographic analysis revealed that the failure of the plasticized and softened polymer matrix contributed to the observed reductions in strength. Interestingly, the short beam shear strength remained relatively unchanged, as the diffusion of water into the core of the bars at ambient temperatures had a minimal effect. This slower water diffusion in the core led to insignificant degradation of the short beam shear strength. Highlights: GFRP bars were exposed to alkaline solution and natural weather for a decade.The water diffusion was a key factor in determining the residual properties of the GFRP bars.The absorbed water plasticises the polymer matrix in GFRP bars.The mechanical property losses in GFRP bars were associated with changes in the matrix property. [ABSTRACT FROM AUTHOR]

In this paper, the effect of a novel fibre reinforcement architecture in the adhesively bonded joint efficiency of natural fibre reinforced composites (NFRC) was investigated. Two different reinforcement techniques were used: intralaminar reinforcement (2D) and orthogonal-through-the-thickness reinforcement (3D). The aim of the novel architecture is to enhance the transverse properties of the adherend (transverse strength and fracture toughness) in order to delay or avoid delamination failures. A jute bidirectional fabric was used as a base primary reinforcement phase and curauá, sisal, ramie, hemp and glass fibres were used as secondary reinforcement phases for the 2D and 3D fibre reinforcement architectures. Single lap joints (SLJs) bonded with an epoxy adhesive used in the automotive industry were fabricated with these adherends and the efficiency of the joints was investigated by comparing them to glass (GFRP) and carbon (CFRP) pure synthetic fibre reinforced composite joints. It was found that the novel architecture was successful in reaching the failure load of the synthetic composite joints for SISAL 3D, CURAUÁ 2D and CURAUÁ 3D SLJs. Therefore, NFRC bonded joints can be a viable replacement for synthetic fibre composite joints at no load-bearing loss. [ABSTRACT FROM AUTHOR]

Glass fiber‐reinforced polymer‐matrix (GFRP) composites are used to manufacture devices such as radomes, electrical insulators, and radar‐absorbing structures, many of which are used in applications with strict mechanical and dielectric property requirements. As such, designs and properties of GFRP composite materials should be regularly improved to guarantee their safe operation and meet their constantly evolving application requirements. In this study, glass fiber (GF) particles and epoxy resin 128 (EP‐128) were used to manufacture high‐performance EP/GF‐X composites with GF particle contents ranging from 5% to 40%. An investigation into their mechanical and dielectric properties revealed that EP/GF‐20 composite specimens presented the best mechanical performance with their bending strength and modulus reaching 159.68 MPa and 6521.92 MPa, respectively, and an average dielectric constant of 4.862 within the 10–105 Hz frequency range. A theoretical analysis of the EP/GF‐X composite specimens' dielectric constants using classic dielectric models based on the Lichtenecker, Bruggeman, Jaysundere‐Smith, and Maxwell‐Garnett rule‐of‐mixture equations indicated that the dielectric model based on the Bruggeman rule‐of‐mixture equation provided the dielectric constants closest to the measured values with a maximum deviation of less than −0.321% for EP/GF‐40 composites. This study provides a feasible strategy to control the mechanical and dielectric properties of GFRP composites. Highlights: Glass fiber (GF) particles and epoxy 128 (EP‐128) resin were used to manufacture high‐performance glass fiber‐reinforced epoxy (EP/GF‐X) composites.The composite manufacturing process was carefully controlled to ensure uniform distribution and orientation of GF particles in the EP‐128 resin.The mechanical and dielectric properties of the manufactured EP/GF‐X composites were effectively tailored by controlling the content and distribution of GF particles in the EP‐128 resin matrix.The dielectric constants of the EP/GF‐X composites were measured experimentally and predicted using various theoretical dielectric models.The Bruggeman model provided the dielectric constants of the EP/GF‐X composites closest to the measured values. [ABSTRACT FROM AUTHOR]

In this research, the effect of adding aluminum oxide nanoparticles on the flexural strength of glass/phenolic composites that were exposed to water environment was experimentally investigated. To make glass/phenolic composites, IL‐800 phenolic resin, H002 hardener, T400 bidirectional glass fibers and Al2O3 nanoparticles were used. Four‐layer composite plates were made by hand layup method. Beam‐shaped samples were extracted from the plates with the help of laser cutting method. Rectangular composite beams made of glass/phenolic and Al2O3/glass/phenolic were subjected to three‐point flexural test. The moisture absorption test was continued until the amount of water absorption reached a constant level. Bending test was performed on the samples before and after immersion in water. Based on the results, the average flexural strength of the samples after water absorption shows a decrease of about 15%. This parameter is equal to 118.96 MPa for glass/phenolic composite samples immersed in water, and by adding 0.25 wt% of Al2O3 nanoparticles into the matrix material of glass/phenolic composite samples, the flexural strength reaches 142.54 MPa, which shows an increase of 19.82% compared to samples without nanoparticles. Furthermore, the amount of flexural modulus decreases after water absorption, and the addition of nanoparticles in the base material can compensate this reduction. Scanning electron microscopy images illustrate that the addition of Al2O3 nanoparticles into the phenolic resin can enhance the strength of matrix material and improve the adhesion of glass fibers to the resin. Highlights: Addition of nano Al2O3 reduces water absorption of glass/phenolic composites.Nano Al2O3 improves composite flexural strength after water absorption.Addition of nano Al2O3 increases the adhesion between the layers of the specimens. [ABSTRACT FROM AUTHOR]

Composites with excellent flame retardant and mechanical properties are in high demand in the aerospace and various industrial fields. Glass fiber (GF) reinforced polyimide (PI) composites (GFRPCs) were fabricated using a simple ball milling and hot pressing technique. The effect of GF content on the thermal stability, mechanical and flame retardant properties of composites has been systematically studied. The Rockwell hardness of GFRPCs increase with increasing GF content, while the compressive strength, impact strength and flexural strength initially show an increase followed by a decrease due to the excellent dispersibility of the fillers and the strong interfacial interaction between the one‐dimensional GF and PI matrix. Thermogravimetric analysis results show that the addition of GF with very low thermal conductivity and excellent temperature resistance can effectively improve the thermal stability of PI. Adding GF into PI can obviously improve the limiting oxygen index value. Moreover, as the GF content increased, the time to ignition of the composites prolonged while total heat release decreased. These findings suggest a viable solution for enhancing both the flame retardance and mechanical properties of PI‐based composites. Highlights: GFRPCs with high GF content fabricated via ball milling‐hot pressing method.Silane modified GF obviously improves the thermal stability of PI matrix.GFRPCs‐28 exhibits superior mechanical properties.An increases in time to ignition (TTI) and mass residual rate (MRR) of the GFRPCs was observed on adding GF. [ABSTRACT FROM AUTHOR]