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Borophosphate host glasses doped with zinc oxide (ZnO), titanium dioxide (TiO 2), tellurium dioxide (TeO 2), or cerium oxide (CeO 2) were synthesized using rapid quenching techniques. Fourier transform infrared (FTIR) spectra, along with deconvoluted FTIR spectra, were recorded in the 400–4000 cm−1 range. Using the models of Tauc and Urbach, the optical energy band gaps of these glasses were found to be 3.212, 3.289, 3.262, 3.087, and 2.475 eV respectively. Due to the incorporation of different metal ions into the prepared glasses, the density increased and the molar volume decreased, making the glass structure highly compact. Since the elastic moduli are directly related to the average cross-link density, the shear and longitudinal moduli show a forward proportionality with the average cross-link density. Detailed reporting focused on the mass attenuation coefficients (μ m) and exposure build-up factors (EBF), crucial for evaluating the shielding properties of the material within the energy range of 0.015–15 MeV and penetration depth up to 40 mean free paths (mfp). Glass samples doped with tellurium dioxide exhibited the highest gamma attenuation due to their higher effective atomic number compared to the other samples. Compared to Portland concrete, the prepared glass composites showed higher mass attenuation coefficients across the entire investigated energy range. These results suggest that although Borophosphate glasses doped with cerium oxide have preferred mechanical properties compared with the other prepared glasses, Borophosphate glasses doped with tellurium dioxide could serve as transparent shielding material for medical applications due to their higher attenuation coefficient. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM), also recognized as 3D printing, has gained significant attention in various industries for its potential to revolutionize production processes. One critical aspect of AM is ensuring the quality and performance of printed parts, particularly concerning mechanical properties like tensile stress. In the present work, the effect of process variables on 3D‐printed acrylonitrile butadiene styrene (ABS)/Glass fiber composite materials was explored. The machine learning approach, classification and regression trees (CART) algorithm, was used to predict tensile stress in ABS/Glass fiber composite materials based on predictor variables such as layer thickness, nozzle temperature, bed temperature, and infill density. The objective is to develop an accurate and interpretable model that captures the relationships between these variables and tensile stress. The model is evaluated using performance metrics such as R‐squared, mean absolute deviation (MAD), and root mean squared error (RMSE) on both training and test datasets. From results the highest tensile stress of 39 MPa was achieved at nozzle temperature of 250°C, bed temperature of 80°C and infill density at 60%. The CART model predicts the most influencing parameter as infill density followed by nozzle temperature and bed temperature. Highlights: Novel material is manufactured by sandwiching glass fiber in ABS layers.FDM process for novel material is optimized based upon process parameters.SEM analysis reported good interlayer adhesion with few micro‐porosities.Modeling of tensile stress by classification and regression tree algorithm.CART model predicts significant impact of infill density on tensile stress. [ABSTRACT FROM AUTHOR]

Owing to the outstanding properties of boron carbide (B4C) particles, material researchers have shown potential in filler‐reinforced polymer composites. The present work studied the implication of B4C fillers on the mechanical and ballistic properties of glass fiber epoxy reinforced composites. Two different weight percentages of 2 and 4 wt% B4C fillers were used to modify the epoxy resin. The composite samples with glass fabric woven were made through compression molding. The results show that the tensile, flexural, interlaminar, impact strength and hardness of glass fiber composite were improved by addition of 2 wt% of B4C. The high‐velocity ballistic tests were conducted on the unfilled and B4C filler‐reinforced composites using a 9 mm parabellum projectile with an initial striking of 372 ± 15 m/s. The least back face signature (BFS) and highest specific energy absorption (SEA) were observed for 2 wt% B4C filler composite. Adding B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix. Matrix cracking and fiber breakage result in the least ballistic resistance for unfilled composite. Fracture behavior was studied on tensile, impact, and ballistic‐tested samples using scanning electron microscopy. The fractured surfaces of filler‐reinforced composite demonstrated good interfacial bonding, matrix hardening, and fiber pullouts. Highlights: The addition of B4C with epoxy up to 2 wt% improves the mechanical and ballistic properties of the composites.The least back face signature and highest specific energy absorption were observed for 2 wt% B4C filler composite.B4C filler enhanced matrix toughening and interfacial bonding between fiber and matrix.Failure of unfilled glass fiber composites is a combination of matrix cracking, fiber pullout, and interface debonding. [ABSTRACT FROM AUTHOR]

Although lightweight fiber‐reinforced polymer (FRP) composites are widely used in various engineering fields due to their high specific strength and modulus, the mutual exclusion of strength and toughness is one of the bottlenecks in the field of FRP design because of the inherent brittleness of fiber themselves. In this research, discontinuous fiber structures with vertical and bi‐angled slits are introduced into the thin‐ply carbon fiber prepreg. The fracture energy and delamination degree of the center carbon fiber layer could be controlled by adjusting the structural parameters to design the pseudo‐ductility of carbon/glass (C/G) hybrid laminates and obtain the higher pseudo‐yield stress. The hybrid specimens with 20 mm slits exhibit obvious pseudo‐ductility, and the pseudo‐ductility strain increases as the C/G ratio increases, while the plateau stress decreases. The larger slit distance provides sufficient propagation space for the delamination damage, which dissipates tensile energy and results in a smoother plateau area of the stress–strain curve. The stress–strain curve of the specimen with a smaller slit exhibits a noticeable rapid load decrease caused by the transient propagation of delamination damage. The peak stress of hybrid laminate with bi‐angled slits shows the highest pseudo‐yield stress. The present finite element model successfully analyzed the pseudo‐ductile damage propagation of C/G hybrid laminates with vertical slits, and the results are in good agreement with the experiments. Highlights: Revealed the pseudo‐ductility behavior of carbon/glass hybrid composites.The pseudo‐ductility of carbon/glass hybrid composites is controllable.The pseudo‐ductility strain increases with the increase of C/G ratio. [ABSTRACT FROM AUTHOR]

The mechanical properties of the carbon fiber and glass fiber composite honeycomb sandwich structure were studied through compression experiments. The influence of different aluminum honeycomb edge lengths, upper and lower panel thickness, aluminum honeycomb thickness, and loading speed on the compression failure load of carbon fiber composite laminates sandwich structure is analyzed. The influence of different aluminum honeycomb edge lengths and thicknesses on the compression failure load of glass fiber composite laminates sandwich structure was studied. The results show that the thickness of the panel has a significant effect on the failure load of the carbon fiber composite laminate sandwich structure, and the loading speed has a significant effect on the failure load of the carbon fiber composite laminate sandwich structure. The greater the loading speed, the greater the value of the failure load. The edge length and thickness of the aluminum honeycomb have a certain effect on the damage load of the carbon fiber composite laminates sandwich structure, but the influence on the mechanical properties of the glass fiber composite laminates sandwich structure is much greater. Highlights: The compression performance of composite sandwich structures was experimentally studied.The influence of composite panel thickness was studied.The influence of aluminum honeycomb edge length and thickness was studied.The influence of loading speed was studied. [ABSTRACT FROM AUTHOR]

Hybrid kenaf/glass fiber reinforced polymer composites have emerged as promising structural materials, garnering significant attention due to their unique blend of natural kenaf fibers and synthetic glass fibers. However, despite their potential, there remains a gap in the comprehensive understanding of their quasi‐static mechanical behavior, creep resistance, and fatigue performance. This paper addresses this gap by presenting recent advancements in studying these key properties of hybrid composites. Studies reveal that the combination of kenaf and glass fibers results in enhanced tensile, flexural, and impact strengths compared to individual fiber composites. Additionally, the hybridization offers improved creep resistance, with the glass fibers reinforcing the polymer matrix against deformation under sustained loads. Furthermore, investigations into fatigue properties demonstrate the resilience of hybrid composites to cyclic loading, contributing to prolonged service life in high‐stress environments. By elucidating the interplay between kenaf and glass fibers, this review underscores the potential of hybrid composites in various structural applications. The synergistic effects between natural and synthetic fibers offer a balance between sustainability, performance, and durability, making hybrid kenaf/glass fiber reinforced polymer composites a compelling choice for industries seeking lightweight, high‐performance materials in which aligns with the sustainable development goals (SDGs) especially on Goal 12. Highlights: In composite engineering, combining glass and kenaf fibers could cut production costs, yield high‐performance materials, and promote green technology.Substituting part of the glass fiber with kenaf can enhance the strength‐to‐weight ratio and promote greater biodegradability in current synthetic composites.Quasi‐mechanical properties of hybrid kenaf/glass‐based composites was enhanced by optimal stacking sequences, filler addition, and fiber treatment.Failures due to fatigue and creep can be reduced by hybridizing kenaf/glass fiber composites can prevent in polymer composite due to enhance elastic modulus.Enhanced tribological performance of hybrid kenaf/glass‐based composites due to less damage in microstructure via good interlocking of kenaf and glass in matrix. [ABSTRACT FROM AUTHOR]

Highlights Glass fiber‐reinforced polymer composites are widely used in marine applications, including renewable energy devices and submarines, due to their strength‐to‐weight ratios and corrosion resistance. As sustainability becomes more important, recyclable thermoplastic composites are gaining attention in marine energy applications. These materials face harsh conditions such as high chloride water, UV radiation, pressurization, and thermal cycling, which can affect their durability and recyclability. This study examines the impact of hygrothermal aging on the recyclability of an Elium glass fiber (GF) composite. Samples were mechanically ground for recycling, and mechanical and thermal properties were compared between aged and unaged samples. After seawater aging, the tensile strength and modulus of the unaged composite dropped by 25% and 13% respectively, due to water ingress along the fiber‐matrix interface. The recycled composite showed reduced flexural strength as the long fiber composite was converted into short fibers during the process. Differential scanning calorimetry (DSC) revealed no change in glass transition temperature after aging. Weight loss (25%) was attributed to the thermal stability of the glass fibers. Dynamic mechanical analysis (DMA) showed that the storage modulus increased with aging, and fracture analysis confirmed a mixed mode of failure for aged composites. Hygrothermal aging lowers mechanical performance of Elium® GF composites. Failure mechanism tends to be matrix cracking and interface bonding. Glass transition temperature is not reduced by hygrothermal aging. Fractured composite was successfully recycled via thermoforming. Flexural strength of the recycled composite is lower. [ABSTRACT FROM AUTHOR]

Highlights Thermoplastic PMMA was rarely exploited in continuous fiber‐reinforced composites due to its viscous high‐temperature molten fluid as well as pessimistic wettability into fiber fabric. Redox‐active polymerization is a green route to develop a new liquid PMMA resin at room temperature to provide an in situ curing with the advantages of energy saving and consumption reduction. In this paper, BPO/DMA was adopted as a redox initiator pair, and the effect of MMA:BPO:DMA ratio on curing time, Mn, Tg, and mechanical properties of PMMA were systematically studied. When the ratio of MMA:BPO:DMA is 200:1.2:1, PMMA‐200 achieved optimistic mechanical properties at 20°C (tensile strength, 64.7 MPa; tensile modulus, 3352 MPa; bending strength, 125.3 MPa; bending modulus, 3023 MPa). Moreover, the mechanical properties were further improved at low temperatures. The maximum tensile strength and tensile modulus were up to 97.43 and 4297 MPa (−40°C) respectively. The tensile strength (0°, 1103 MPa; 90°, 52.3 MPa) and tensile modulus (0°, 47.5 GPa; 90°, 14.2 GPa) of glass‐fiber‐reinforced PMMA composite at 20°C were found to be comparable with epoxy resin‐based composites and even higher at lower temperature. In summary, redox‐initiated PMMA and its fiber‐reinforced composites are promising thermoplastic materials as new lightweight alternatives. Preparation method of PMMA resin and glass fiber composite. Research on the mechanical properties, molecular weight, glass transition temperature, curing time, etc. of PMMA resin. Testing of mechanical properties of PMMA glass fiber composites at room temperature and low temperature. Current applications and prospects of PMMA glass fiber composites. [ABSTRACT FROM AUTHOR]

Highlights Glass fabric‐reinforced composites (GFRC) and other revolutionary engineered materials find extensive application in the aerospace, construction, and automobile sectors. It is challenging to predict damage under real‐time stresses due to the anisotropic behavior of composite materials. This study presents the development of a glass textile‐based multifunctional composite sensor and demonstrates its application as a change in resistance or gauge factor in structural health monitoring (SHM) systems. This sensor is coated with reduced graphene oxide (rGO) nanomaterial. Its electrical resistance is evaluated by examining the concentration of nanoparticles and varying geometrical parameters. A three‐point bending method assessed the piezoresistive behavior of the integrated sensor in the GFRC. The impact of sensor width and relative placements in the material's thickness direction within the composite samples is evaluated. Cyclic flexural testing was also performed to demonstrate real‐world applications. The research concludes that it can be utilized as a damage assessment technique for GFRC. The developed sensor can be used to provide an electrically conductive path or as a resistor in the field of E‐textiles. The developed piezoresistive sensor has the flexibility to be used as a multifunctional sensor for multiple purposes, such as force, torque, weight, pressure, flow, acceleration sensors, etc. Glass textile‐based multifunctional materials are reported as strain‐monitoring sensors. Tailored sensor resistance could be achieved through rGO current conduction paths. Glass textile‐based sensors could potentially be used in the field of E‐textile. [ABSTRACT FROM AUTHOR]

This article deals with the impact of short glass fiber (GF) on the performance of 60/40 wt% of polyamide 6/polyamide 12 (PA6/PA12) blend. The short fiber-reinforced composites were fabricated by using melt compounding via twin screw extruder and injection molding. The morphological, water uptake, rheological, thermo-mechanical, and mechanical properties of the composites were discussed. The morphological observations show that the PA6/PA12 blend exhibited compatible morphology and also adhesion between the fiber and matrix was quite strong. The tensile strength/modulus and storage modulus of the blend were substantially improved with GF reinforcement as a result of these morphological findings. While the water uptake of neat PA6 decreased significantly after blending with PA12, the incorporation of GF further reduced the water uptake of the PA6/PA12 blend. The thermomechanical analysis showed the enhancement of the stiffness of the composites and also glass transition temperature increment. [ABSTRACT FROM AUTHOR]

Advanced engineering materials like glass fabric-reinforced composites (GFRC) are frequently utilized in automotive components, civil structures, aviation sectors, etc. Contrary to metals, the anisotropic nature of composites makes it difficult to forecast damage and failure under real-time loads. GFRC is employed in this work to demonstrate structural health monitoring (SHM) using a reduced graphene oxide (rGO) coated glass fabric piezo-resistive sensor. The sensor was embedded in the GFRC composite to detect changes in the fractional electrical resistance under flexural strain. The developed composite specimens were subjected to three-point bending to examine the piezo-resistive performance. Throughout testing, the effect of sensor width and relative positions in the thickness direction within the composite specimen on strain and damage detection was assessed. The results of the tests revealed that these parameters were responsively associated with the piezo-resistance of the developed sensor. This study concluded that the developed piezo-resistive sensor has the potential to be used as a strain and damage detection mechanism for glass fabric-reinforced composite structures for disparate applications. [ABSTRACT FROM AUTHOR]

The present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content. [ABSTRACT FROM AUTHOR]

Steel plate girders are susceptible to web buckling due to slender web. This phenomenon creates an undesirable failure mode and limits their ultimate load capacity. The use of fiber-reinforced polymer (FRP) composite materials offers a good prospect of strengthening the slender web of plate girders to avoid web buckling. This paper presents the details of experimental testing of steel plate girders with nonrigid end posts. These girders were tested in three-point bending. The end shear panels of the girders were strengthened by glass FRP (GFRP) pultruded section stiffeners or glass fiber fabric composite. GFRP stiffeners were applied either vertically or along the compression diagonal in the shear panel. All strengthened panels failed by web shear buckling associated with a breakdown of the employed strengthening scheme. It was found that the shear capacity of the panel remained unchanged by replacing the steel stiffener with GFRP stiffeners in the end panel. The critical buckling load of the strengthened panels increased up to 44% compared to the unstrengthened panel. The shear capacities of the panels strengthened by the glass fabric composite and diagonal GFRP pultruded section were the highest and similar to each other. Both these panels resisted a 50% larger shear compared to the unstrengthened panel. The positions of the plastic hinges in all tested panels were the same due to the same ratio of panel length and depth of the web. [ABSTRACT FROM AUTHOR]

This experimental work involves characterization and fractography of a bio‐based epoxy and an in‐situ polymerisable thermoplastic polymer matrix based non‐crimp glass and carbon fiber composites under compressive loading. The laminates are characterized under compression loading using a combined loading compression (CLC) fixture. Laminates made using the thermoplastic matrix exhibit higher compressive strength (approx. 20% along fiber direction) compared to the bio‐epoxy based laminates. Further, both composites exhibit comparable compressive modulus characteristics. The tested composites are subjected to fractography analysis using Scanning Electron Microscopy (SEM) and Computed tomography (CT). SEM results indicate a difference in fiber‐matrix interface characteristics between the thermoplastic matrix and the bio‐epoxy matrix. Additionally, the CT scans reveal a difference in failure modes due to fiber orientations. A difference between failure mode of the exterior and interior plies of the specimens was also noticed. However, no specific influence of matrix type was observed on the overall macroscopic failure behavior. Highlights: Bio‐epoxy and thermoplastic based laminates were characterized in compression.Post‐test fractography was performed using SEM and x‐ray CT scans.Use of thermoplastic matrix exhibits better fiber‐matrix adhesion compared to bio‐epoxy.Both laminates performed well in compression under laboratory test conditions. [ABSTRACT FROM AUTHOR]

In this study, we investigate the relationship between structure and properties of fiber–matrix adhesion for material extrusion–based 3‐dimensional (3D) printed composites. We examine the influence of fiber length and fiber content on the tensile properties of glass, basalt, and carbon fiber–reinforced polylactic acid (PLA) composites. Short fiber–reinforced filaments were produced, then, simple micromechanical models were used to predict the in‐plane tensile properties. We found that interlayer tensile properties are strongly influenced by fiber–matrix adhesion. If adhesion is sufficient, the fibers and matrix deform together under tensile load. A second‐order relationship describes interlayer tensile strength in relation to fiber content between 5 and 25 w%, with a maximum at 15 w%, for carbon and basalt fiber–reinforced composites. If adhesion is weak, the crack propagates along the fiber–matrix interface, causing brittle fracture and low strength. This behavior was noted for the glass fiber composite, for which the calculated interface shear strength was the lowest (1.4 MPa). In this case, fiber content is inversely proportional to interlayer tensile strength. Our results show the role of fiber–matrix adhesion quality on tensile properties, which has a major impact on both the accuracy of predictions and the damage processes. Highlights: Critical fiber length determines accuracy of tensile property estimatesQuality of fiber–matrix adhesion governs interlayer damage processPoor adhesion causes brittle fracture and low strengthSecond‐order relationship of interlayer tensile strength and fiber contentLoss of interlayer tensile strength in composite due to fiber–matrix interface [ABSTRACT FROM AUTHOR]

This article aims to investigate the mechanical properties and substrate adhesion of the pull-off method in polymer mortars modified with styrene-butadiene resin polymer (SBR) containing glass powder and composite fiber-reinforced slag. Different mix designs were investigated with and without SBR, taking into account different amounts of glass powder and slag separately and in combination, along with the effect of glass, polypropylene, and steel fibers alone and in combination. The flexural performance and energy absorption of beams retrieved with these layers were also assessed. The results revealed significant differences and increases in the substrate adhesion of the restored modified polymer layers containing SBR compared to the polymer-free repair overlays. Furthermore, an improvement was observed in the adhesion performance of the repair overlay using a combination of slag and glass powder and the glass and polypropylene fiber composite. The highest adhesion was related to the modified polymer mortar design containing composite fibers of glass, polypropylene, and steel with 25% replacement of SBR polymer for 10% glass powder, 10% slag, and 5% slag with 5% glass powder. The adhesion was increased by about 3.74, 3.72, and 3.78 times compared to the repair overlay of the control design. Modified polymer mortars had a higher T 150 D toughness. Moreover, the energy absorption was significantly improved by the presence of SBR polymer. The highest toughness values were found in the beams restored with modified polymer mortars containing polypropylene, glass, and steel composite fibers with an increase of 48.51%-66.42% compared to the samples without polymer as a result of the pozzolans used in this mix. [ABSTRACT FROM AUTHOR]

Highlights: A novel anisotropic sensor with oriented piezoelectric filaments was prepared, capable of detecting both the magnitude and direction of micro-deformations. Due to the efficient load transfer of continuous fibers and the formation of porous ferroelectrets, an ultra-low strain detection limit of 0.06% was achieved in the sensor. Given the sensor's ultra-low detection limit and deformation direction sensing capability, we developed the sensor for detecting micron-scale deformations in thin-film structures and for robotic tactile sensing applications. Monitoring minuscule mechanical signals, both in magnitude and direction, is imperative in many application scenarios, e.g., structural health monitoring and robotic sensing systems. However, the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix, and achieving sensitivity for detecting micrometer-scale deformations is also challenging. Herein, we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement, capable of detecting minute anisotropic deformations. The as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%, thereby enabling its utility in accurately discerning the 5 μm-height wrinkles in thin films and in monitoring human pulse waves. The ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate phase. Additionally, when integrated with machine learning techniques, the sensor's capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100% accuracy. The structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli, offering a novel perspective for enhancing recognition accuracy. [ABSTRACT FROM AUTHOR]

Glass-based sealing materials exhibit significant potential for utilization in solid oxide fuel cells (SOFCs). We conducted a study on the impact of mullite fibers with varying particle sizes on glass composite sealing materials. We evaluated and discussed properties such as coefficient of thermal expansion (CTE), softening temperature (Ts), gastightness, interfacial compatibility, and flexural strength of the sealing materials with different ranges of fiber particle sizes. Our findings indicate that the three different particle sizes of mullite fiber-glass composite sealing materials met the required coefficients of thermal expansion, displayed good interfacial compatibility, and exhibited gastightness lower than 0.0016 sccm cm−1. Notably, the mullite fiber-reinforced sealing material that underwent ball-milling for 1 h outperformed the other two variants. It demonstrated fewer defects, a 57.1 % increase in flexural strength, and a 117.4 % higher maximum strain value. [ABSTRACT FROM AUTHOR]

Highlights In this study, the axial crushing response and energy‐absorbing mechanisms of circular composite tubes, which were reinforced by carbon fiber (C10) and carbon/glass hybrids (C3G4C3), were investigated experimentally and numerically. Both samples exhibited similar crushing responses comprising delamination and intralayer shear failure. The impact kinetic energy is primarily converted into frictional and composite damage energies. C3G4C3 had poorer crashworthiness with a mean crushing force and specific energy absorption of 313.3 kN and 58.0 kJ/kg, which are by 39.3% and 30.8% less, respectively, than those of C10. The influence of glass fiber reinforced polymers (GFRP) content (hybrid ratio) and stacking sequence on tubal crashworthiness was investigated numerically. For composite tubes with a hybrid ratio of 40%, the central distribution of GFRP (C3G4C3) achieved optimal energy absorption performance. Additionally, when GFRP layers were centralized stacked, a reduction of the hybrid ratio from 60% (G3C4G3) to 20% (GC8G) helped improve the crashworthiness of the hybrid tubes, where the mean crushing force increased by 23%. Impact responses of composite tubes reinforced by carbon fiber and carbon/glass hybrids were investigated experimentally and numerically. Carbon/glass hybrid tubes exhibited lower crashworthiness. The effects of stacking sequence and hybrid ratio on the energy absorption performance were studied. [ABSTRACT FROM AUTHOR]

Highlights Present study comprehensively explores the phenomenon of in‐plane fiber waviness in glass/epoxy fiber reinforced polymer (GFRP) composites. Utilizing a pioneering technique that employs a semi‐circular bar to induce controlled fiber waviness, coupled with image processing using OpenCV library in Python coding for precise measurement and analysis of in‐plane fiber waviness. This defect is commonly found in components fabricated with fiber‐reinforced composites. During the process of manufacturing fibers may deviate from their intended orientation due to process variables or resin flow dynamics. Understanding in‐plane fiber waviness is crucial due to its impact on mechanical properties of composites. It is essential for optimizing manufacturing processes and ensuring enhanced structural performance in diverse engineering applications through analysis of strength and failure mechanism. A novel study was conducted by introducing a circular cutout within the fiber waviness region to investigate the combined effect of multiple defects. The experimental tensile test reveals that as waviness ratio (WR) increases a significant decrease in its tensile strength and vice versa. The study incorporates scanning electron microscopy (SEM) image analysis to examine composite failure. By advancing the understanding of in‐plane fiber waviness and its implications, this research significantly contributes to ongoing efforts in composite design and optimization. Adopting a cutting‐edge method to create controlled fiber waviness that makes use of a semi‐circular bar. Image processing with Python code that makes use of the OpenCV package to precisely measure and analyze in‐plane fiber waviness. A new investigation was carried out to examine the combined effect of multiple flaws by creating a circular cutout within the fiber waviness zone. [ABSTRACT FROM AUTHOR]

Although numerous investigations study the improvement of flame retardancy of epoxy resins using additives, maintaining the flame retardant (FRs) modes of action present in the resins upon transfer to composites is challenging. In this study, ammonium polyphosphate (APP) and inorganic silicate (InSi) are loaded at 10%, 30%, and 50% by weight, in a diglycidyl ether of bisphenol A (DGEBA) resin cured with dicyandiamide and transferred to bidirectional (BD) glass fiber (GF) composites. Although a 50% loading of the FRs impacts the curing kinetics of the resin system, the effect on the glass transition temperature of the resin system remains negligible compared to reactive FRs in the state of the art integrated into the resin's chemical structure. Increasing the FR content improved the heat release characteristics in both the resins and composites. However, the charring mode of action is completely suppressed in the formulation with 10% APP + InSi. A 30% concentration of the FRs restored the charring action in the composite and the GFs provide increased protective layer action upon transfer to the composites. This study highlights the importance of accounting for the changing dynamics related to processing and flame retardancy upon transferring FRs from resins to composites. [ABSTRACT FROM AUTHOR]

Due to their excellent chemical properties, mechanical strength and electrical conductivity, carbon nanofibers (CNFs)‐doped materials show immense potential in energy storage, electromagnetic shielding, aerospace, and other fields. In this study, we propose a new highly conductive chalcogenide glassy composites: 0.6[40GeS2‐60Sb2S3]−0.4(AgI)‐xCNFs (GSSA‐xCNFs), where x = 0, 0.5, 1.0, 1.5, 2.0 wt%. The mechanical behaviors of the glass composites were significantly improved due to the strong cohesive bonding at the CNFs/glass interfaces. The introduction of 2.0 wt% CNFs has raised the hardness from 1.35 to 1.66 GPa; meanwhile, Young's modulus increased from 22.3 to 25.8 GPa. The doped Ag ions endow the chalcogenide glass with excellent electrical properties. Moreover, the introduction of CNFs further enhanced the DC conductivity of glassy composites from 2.79 × 106 to 4.48 × 10−5 S/m at 293 K due to a percolation network of CNFs formed when its concentration from 0 to 2.0 wt%. Additionally, positive temperature dependence of resistance was observed in the glassy composites, possible mechanisms have been discussed based on the determined thermodynamic features, microscopic morphology, and structural characteristics of the composites. [ABSTRACT FROM AUTHOR]

Basalt fibers, known as "green materials without pollution in the 21st century", have gained widespread attention due to its good mechanical properties. Basalt fiber‐based composites have applications in various fields such as construction, transportation, energy, and protection. However, as an inorganic fiber material, basalt fiber is hard and brittle and prone to catastrophic failure, reducing the safety of the material. Therefore, it is important to strengthen the toughness of basalt fiber‐based composites. This paper reviews the contributions made by researchers in recent years to enhance the toughness of basalt fiber reinforced composites. It mainly focuses on four aspects: physical and chemical modification of fibers surface, mixed application of multiple fibers, different textile and 3D printing technology, and design of biomimetic structures. Through these methods, the toughness of basalt fiber‐reinforced composite materials was increased by 10%–90%. In today's advocacy for green industrial development, the research and application of basalt fibers are very important for advancing the process of green development. These contributions can promote the application of basalt fiber in engineering fields. Highlights: Basalt fiber is a green material without pollution.Basalt fiber reinforced composites is the key material for engineering field.Strengthening interfacial adhesion can significantly improve the toughness of composites.Basalt fibers can serve as an alternative to glass fibers in composite materials.The hybridization of basalt fibers with soft fibers can effectively enhance the toughness of composites. [ABSTRACT FROM AUTHOR]

Currently, composites based on glass fibers and epoxy resins are successfully used to produce various structural elements. Such structures often serve under extreme conditions of both the Far North and the tropics, with such conditions having a destructive effect on the materials causing degradation of their properties. In this case, water resistance is an important characteristic of the materials. One of the ways to protect such materials is the use of organosilicate coatings (OSCs) obtained on the basis of organosilicon varnishes and highly dispersed hydrosilicates. This article presents the results of laboratory studies and field tests carried out in areas with very cold, as well as tropical savannah and subequatorial climates, of composite and metallic materials protected with OSCs. The objects of the studies are OSCs based on a binder, KO-921 varnish modified with the aim to improve weather resistance, primarily, moisture resistance, with poly(dimethylsiloxane) and epoxy resin. Water absorption, contact angle, and hardness of OSCs have been studied as depending on the composition of the polymer binders, and the optimal concentrations of the precursors have been determined. The results of field tests have shown that the developed OSCs retain their water-repellent properties during long-term exposure in different climatic conditions, thereby confirming their applicability to protecting various materials under the conditions of both tropics and the Far North. [ABSTRACT FROM AUTHOR]

This study investigated the influence of moisture absorption on the electromagnetic (EM) wave absorption performance and mechanical strength of a radar-absorbing structure (RAS) with nickel-coated pristine glass fibers and polyamide 6. To construct the RAS, nickel was deposited on pristine glass fibers via electroless plating, and the RAS was fabricated using a hot-press process. An environmental test was conducted under a high humidity of 85%, and the EM wave absorption capacity of the RAS was measured at 2-week intervals. Moreover, compressive and interlaminar shear tests were conducted to verify the degradation of mechanical strength and the effect of the nickel coating on moisture absorption resistance. The test results revealed that immersion in moisture degraded the EM absorption capacity of the RAS. Nevertheless, an improvement in the mechanical strength of the RAS after saturation was observed due to the nickel coating. [ABSTRACT FROM AUTHOR]

Ni2+‐doped glass–ceramics containing Zn(GaxAlx−1)2O4 crystals were successfully synthetized using both parent glass crystallization (Technique 1) and a direct doping method also called "frozen sorbet" (Technique 2) to get a ZnGa2O4 crystal/glass composite. The frozen sorbet technique allows the survival of ∼10 nm crystalline particles. Both materials are further crystallized near their respective temperature of crystallization to get glass–ceramics with the stabilization of Zn(GaxAlx−1)2O4 crystals. Although these two materials exhibit the same glass transition temperature, a shift in the crystallization temperature is observed. The glass–ceramics are transparent in the near infrared range, and the Ni2+ doping provides a broadband emission centered around 1300 nm with a full width at half‐maximum (FWHM) equal to 228 nm. The structure, microstructure, and thermal and optical properties of these materials are discussed in the present study. [ABSTRACT FROM AUTHOR]

This paper describes the in-plane impact behavior of 3D woven honeycomb sandwich composites comprising glass fiber reinforced epoxy composite. In this study, 3D woven honeycomb structures with similar cell shapes were developed with different cell geometry by varying the cell size, free wall length, bonded wall length, opening angle, and the number of honeycomb layers keeping the overall thickness of the composite constant. The variation of cell geometry was carried out by changing the number of picks in the honeycomb walls. Composite samples were made using VARIM (vacuum-assisted resin infusion method) process. The behavior of the force-displacement curve and the energy-time relationship under impact loading of 100 J were analyzed. The total energy absorption was determined for different cell geometry and the number of layers of the honeycomb composites. The results showed that structural changes in honeycomb composite significantly affect the specific energy absorption. The specific energy absorption increases with a large cell size, less opening angle, higher wall length, and a greater number of layers. [ABSTRACT FROM AUTHOR]

Ceramic-based back covers are commercially utilized as a high-end option for the physical protection of mobile phones. Herein, an unprecedented composite structure consisting of a cordierite (2MgO.2Al 2 O 3 5SiO 2) glass–ceramic strengthened with yttria-stabilized zirconia (YSZ) fillers is introduced as a protective back cover, specifically for next-generation communication mobile phones additionally requiring a low dielectric constant at gigahertz frequencies. Crystallization sequence was rather complicated with the involvements of multiple crystalline phases, α- and μ-cordierite, tetragonal and monoclinic ZrO 2 , and ZrSiO 4 , depending on the glass and composite compositions. This unique approach effectively induced the best mechanical performance for the 10 wt% YSZ/glass–ceramic structure, despite the low sintering temperature of 1050 °C, with the highest Vickers hardness of ∼9.2 GPa and flexural strength of ∼196.8 MPa attained for the optimal composite. Although effective dielectric constant of the composites depended on the relative contents of the evolved crystalline phases, overall dielectric constant was kept low due to the utilization of cordierite glass as the main component. [ABSTRACT FROM AUTHOR]

Complex processing parameters need to be adjusted for expected qualities in injection molding processing. Once the process is abnormal, it is essential to spend time and human work on fault diagnosis. In this study, we focus on fault diagnosis of injection molding processing parameters for polylactic acid/glass fiber composites. The injection molding processing parameters include the melt temperature, injection speed, packing pressure, packing time, and cooling time. The qualities include tensile strength, hardness, impact strength, and flexure strength. When processing parameters deviate from the optimal process condition, the multivariate statistical control chart monitors downgraded qualities. The machine is operated at the optimal process conditions to generate normal samples and the corresponding four qualities of data are chosen as the historical data. Hotelling's T 2 is used to calculate the upper control limit (UCL) from the historical data to detect abnormal samples. If the T 2 value exceeds the UCL, the corresponding sample is considered abnormal. Then, the residuals of qualities for abnormal samples are obtained by a residual control chart. They are chosen as the feature values for the backpropagation neural network (BPNN) to identify the abnormal processing parameters. The experimental results proved that the BPNN can achieve a 100% recognition rate for single-factor abnormal samples. For the single-/double-factor mixture, the accuracy rate of double-factor classification can reach 97.44%. This proposed study has the advantage of high stability, being non-destructive, high precision, and low cost, and can be widely promoted in injection molding industries. [ABSTRACT FROM AUTHOR]

Strengthening of Reinforced Concrete (RC) beams using GFRP to increase flexural capacity often fails due to premature debonding and delamination of old concrete joints and grouting. The current research introduces a method of repairing and strengthening RC beams using grouting mortar, dyna-bold anchors, and Glass composite FRP (GFRP) sheets. Dyna-bold anchors are used as shear connectors between the old concrete and the grouting. In this research, 10 RC beams measuring 150 mm x 200 mm x 3300 mm, consisting of 2 control specimens (BK), 4 GFRP strengthening beams, and 4 GFRP strengthening beams with dyna-bolt anchors, were tested. The results show that the use of dyna-bold anchors in the joints between old concrete and grouting can increase the bending and shear capacity of the beam by 44.70%, indicating that the addition of dyna-bold anchors is able to prevent premature cracking along the joints and increase the stiffness and flexural capacity of the RC beams. These findings have significant practical implications for the repairing and strengthening of RC beams in real-world applications. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present investigation, conventional melting techniques were employed to fabricate the fluorophosphate glass composites with a composition of 20NaF–60P 2 O 5 –20Na 2 O–3Fe 2 O 3 (mol.%). An investigation was conducted to analyze the impact of various doses of gamma-ray irradiation on certain optical properties. The alteration in the localized defects caused by gamma irradiation can explain the reduction in the refractive index (n) as the doses of gamma-ray irradiation increase, up to 10 kGy. The results of the solar skin protection factor (SSPF) and solar material protection factor (SMPF) tests demonstrate that the un-irradiated composite offers the highest level of protection against the harmful effects of solar energy on both human skin and materials. Some optical parameters, such as the concentrations of the charge carrier (N opt), the relaxation time (τ), the optical electronegativity (η opt), and the optical mobility (μ opt) showed gamma dose-dependent. The effects of gamma-ray irradiation on the composites were analyzed using Electron Spin Resonance (ESR) and Fourier Transform Infrared (FTIR) spectroscopic studies, both before and after exposure to 10 and 20 kGy. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) sulfonation process is a reasonably easy but time‐consuming to manufacture composites. This study focuses on altering PEEK powder in a sulfuric acid solution via a sulfonation process to develop sulfonated PEEK (SPEEK) resin for the fiber‐reinforced thermoplastic composite manufacturing and characterization steps. In this study, about 5 wt% PEEK powder was sulfonated in 98% sulfuric acid solution for 12 h at 65°C. The water bath technique was used for the precipitation process to obtain the SPEEK polymer. After proper washing and drying, the SPEEK matrix (resin) was obtained by dissolving it in dimethylformamide in a ratio of 1:2. This resin solution was then used to manufacture thermoplastic Kevlar and glass fiber‐reinforced composites employing wet layup process and cured at an elevated temperature under pressure. These SPEEK composites passed the flame retardancy UL94 test with a V0 rating. The average water contact angle of the glass fiber‐ and Kevlar‐SPEEK composites is 93.67° and 102.24°, respectively. The average tensile strength values of these composites were found 222.22 and 284.35 MPa, correspondingly. The smoke density and toxicity tests of the glass fiber‐SPEEK composite confirmed lower smoke generation with the modifications. These SPEEK‐fiber composites can be considered for various industrial applications, including aviation, energy, drone, defense, and automotive. [ABSTRACT FROM AUTHOR]

Crash boxes are safety elements generally made of metallic materials and mounted on the chassis of vehicles to prevent possible injuries to driver and passengers by absorbing the energy generated during a collision and ensuring integrity of vehicle. In order to save fuel and reduce harmful gases released into the environment, the proportion of metallic materials used in vehicles is decreasing and being replaced by composite materials. While composite materials are as durable as metallic materials, they are preferred because they are lighter. In this study, circular composites consisting of glass (S1), aramid (S2), carbon (S3), and hybrid combinations of aramid‐carbon‐glass (S4), carbon‐glass‐aramid (S5), and glass‐aramid‐carbon (S6), all with epoxy resin matrices, were produced using the vacuum infusion method and investigated. Crush parameters, maximum peak loads and specific energy absorption of hybrid tubes with different fiber types and winding order were compared. S3 tube had the best energy absorption performance among all samples of 257.288 Joules, while the worst energy absorption performance was obtained for S2 tube with 30.944 Joules. Among the hybrid samples, the best result was determined as 166.50 Joule with hybrid S5. Although the energy absorption capacities of hybrid composite tubes were close to each other, they had lower results for energy absorption and specific energy absorption than S1 and S3. For specific energy absorption, as with energy absorption, the best result was obtained with S3, while the lowest result was obtained with S2. Highlights: The aim of this study is to evaluate the performance of composite crash boxes.The effect of fiber type and hybridization was examined.Specific energy absorptions and maximum contact forces were compared.Cylindrical samples were produced by vacuum infusion.The variation of damage depending on fiber type was investigated. [ABSTRACT FROM AUTHOR]

Thermoplastic polycarbonate provides minimal structural weight and ductility and is a recyclable material. However, investigation of the characteristics of hybrid composites reinforced with woven glass and polycarbonate sheets is limited. This current study investigated the effect of integration of polycarbonate sheets on glass fiber‐epoxy hybrid composite performance. Non hybrid laminate was fabricated from eight layers of woven glass fiber impregnated with epoxy resin (NG). However, the hybrid samples utilized various symmetric stacking patterns which were made by alternating two processed polycarbonate (PC) sheets with six layers of woven glass fiber embedded with epoxy matrix. The manufacturing was made using the hand layup procedure. Mechanical testing includes compressive, tensile, bearing, and hardness was performed on hybrid and non‐hybrid composites. The results showed that employing PC sheets instead of fibers affect the laminate's strength, ductility, bearing capacity, and hardness. Utilization of PC sheets reduces both compressive and tensile strength. However, an enhancement in tensile, compressive, and bearing failure strain was achieved by 2.5%, 31.25% and 31.7%, respectively with hybrid composite having PC in the skin layers as compared with NG. The extent of failure damage is correlated with the position of the PC sheets in the tested samples. Highlights: Novel hybrid composites of woven glass fiber and polycarbonate sheet as reinforcement with various stacking orders were successfully prepared by the hand lay‐up method.The compressive strain of hybrid PC samples are higher than NG sample.The hybrid PC composites showed an improved bearing strength and strain performance.The influence of sample configuration on the damage mechanisms has been investigated. [ABSTRACT FROM AUTHOR]

Bioinspiration offers alternative solutions to overcome the inherent drawbacks of glass, such as low fracture toughness, strength, and impact resistance. Synthetic composites inspired by natural materials, such as nacre, have been recently introduced as an alternative to glasses. However, these have all suffered from trade‐offs between rigidity, optical clarity, fabrication scalability, and complexity. Here, two wave‐based fabrication techniques are presented to create a nacreous structure from glass flakes and polymethyl methacrylate. The glass's surface energy is controlled by adjusting the silane coverage on the glass surface, enabling high levels of structural compactness, mechanical properties, and optical clarity. The scalable glass composite, with a ≈60% glass volume fraction, possesses strength, fracture toughness, and impact resistance values, outperforming annealed glass by 4300%, 350%, and 400%, respectively. It also has a haze level of ≈18%, almost 60% less than that of the similar centrifuged‐based glass composite. This composite is proposed as a potential glass alternative in diverse applications. [ABSTRACT FROM AUTHOR]

The sensitive and rapid detection of thermal neutrons holds significant importance in various fields such as energy utilization, medical treatment, and national defense. However, the available thermal neutron scintillator is difficult to reach this target, mainly limited by the optical and scintillating performance. Herein, the in situ crystallization strategy of glass to construct scintillation glass composites for efficient thermal neutron detection is proposed. The congruent crystallization of the hybridized alkali earth silicate glass system may not only achieve high crystallinity, but also will keep the refractive indexing matching between the precipitated crystal and precursor glass phases. The prepared glass composites feature high luminescence efficiency, optical transmission and excellent neutron response properties. These factors collectively contribute to the robust neutron scintillation performance with a light output of ≈36 000 photons/neutron, which represents the highest value among glass‐based scintillators. Moreover, the composite configuration brings about the additional function of thermal neutron and γ‐ray discrimination. By using this composite scintillator, the neutron detector is constructed and demonstrates its application for detecting thermal neutron and distinguishing it from γ‐ray in an online way. The studies prove that glass composites with high crystallinity are expected to be promising candidates for a new generation of multifunctional neutron detectors. [ABSTRACT FROM AUTHOR]

Highlights Environmental hazards caused by the ever‐increasing end‐of‐life (EoL) glass fiber reinforced polymer (GFRPs) composite waste is of major concern for the sustainable development of the industry. Compared to land filling or incineration, pyrolysis is one of the most promising environmentally friendly methods of disposal of EoL GFRPs. Pyrolysis not only results in recovery of clean glass fibers but other valuable products, such as oils. However, long processing time at elevated temperature leads to aggravation of already existed surface flaws along with the structural changes. Therefore, thermal conditioning of glass fibers results in severe deterioration of the strength in recovered fibers and hence limiting the use of recovered fibers to low end‐products. In this study, a new strategy was adopted where instead of complete cleaning of the fibers at pyrolysis stage, the fibers were partially oxidized and the complete removal of char from the surface of glass was done during hot alkaline etching. This strategy was opted to enhance the quality of the required fibers while reducing the processing time. The results showed ~200% increase in strength of fibers after the combined treatment of pyrolysis and post etching compared to the just pyrolyzed samples with etching time of just 1 min. End‐of‐life panels of GFRPs were pyrolyzed under inert environment of Argon. Residual char was partially removed through post oxidation under flowing air. Hot alkaline etching resulted in complete removal of char and surface defects. Partial oxidation and short etching cycles resulted in improved strength of recovered glass fibers. [ABSTRACT FROM AUTHOR]

In this study, we prepared electromagnetic cobalt-coated glass fiber (Co@GF) composites via an electroless plating method. Subsequently, a conductive sandwich flexible film consisting of Co@GF composites and liquid silicone rubber (RTV-2) was successfully formed using the tape casting method at room temperature. Based on the perfect coating and excellent electrical conductivity of the Co@GF composites, the resultant RTV-2/Co@GF/RTV-2 sandwich flexible film showed a low volume resistivity of 0.264 Ω·cm and could stretch to 100% (of 4.40 Ω·cm) without obvious fracture. When a magnetic field was applied during the curing process, the electromagnetic Co@GF composites were aligned automatically in the RTV-2 matrix because of their ferromagnetic nature. The as-prepared film exhibited anisotropy in its electrical performance. The volume resistivity parallel to the magnetic field direction is approximately two times lower than that in the perpendicular direction. The maximum difference in the volume resistivity (ρ∥ = 0.768 Ω·cm and ρ⊥ = 1.549 Ω·cm) was obtained at a magnetic field intensity of 800 mT. In addition, a magnetic field intensity of 100 mT helps improve the electrical conductivity of the as-obtained sandwich film. The anisotropic RTV-2/Co@GF/RTV-2 sandwich flexible film is considered a promising flexible electronic sensor, where discrepant inductive sensitivity is required in orthogonal directions. [ABSTRACT FROM AUTHOR]

The primary characteristic of ablative materials is their fire resistance. This study explored the development of cost-effective ablative materials formed into application-specific shapes by using a polymer matrix reinforced with ceramic powder. A thermoplastic (polypropylene; PP) and a thermoset (polyester; UPE) matrix were used to manufacture ablative materials with 50 wt% silicon carbide (SiC) particles. The reference composites (50 wt% SiC) were compared to those with 1 and 3 wt% short glass fibers (0.5 mm length) and to composites using a 1 and 3 wt% glass fiber mesh. Fire resistance was tested using a butane flame (900 °C) and by measuring the transmitted heat with a thermocouple. Results showed that the type of polymer matrix (PP or UPE) did not influence fire resistance. Composites with short glass fibers had a fire-resistance time of 100 s, while those with glass fiber mesh tripled this resistance time. The novelty of this work lies in the exploration of a specific type of material with unique percentages of SiC not previously studied. The aim is to develop a low-cost coating for industrial warehouses that has improved fire-protective properties, maintains lower temperatures, and enhances the wear and impact resistance. [ABSTRACT FROM AUTHOR]

This study investigates the potential of natural fibers, commonly used as cost-effective fillers in the plastic industry, as replacements for glass fibers in composite materials. Despite their advantages, these natural fibers possess a strong polar nature, causing compatibility issues with certain thermoplastic platforms, particularly aromatic compounds. Surface-level treatments, though not cost-effective, offer a solution to this issue. This research focuses on optimizing and qualifying two treatment methods, the acetyl method and stearic treatment, applied to two types of flax fibers: long and short. Examining variables such as temperature, treatment duration, and compound recovery, this study employed diffraction and gas chromatography techniques to evaluate treated and untreated fibers. Results revealed that both treatments effectively reduced non-crystalline segments within the fibers, altering surface topography. Notably, the acetyl method increased fiber surface energy, while the stearic treatment decreased it. These findings underscore the significant impact of the acetyl method and stearic treatment on modifying fiber properties, particularly surface characteristics and energy levels. The study sheds light on the potential applications of these treatments in enhancing the compatibility of natural fibers with thermoplastic platforms, despite their inherent polarity. Incorporating visuals depicting the treatment processes would further enrich the study's authenticity and engagement, providing a tangible representation of the methods employed. [ABSTRACT FROM AUTHOR]

The goal of this study was 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 were presented. Composites reinforced by glass and aramid fibres are approved for certified production of air vehicle elements (AMC-20). Cutting was applied to each material using different technologies, such as: milling, laser cutting and abrasive water jet cutting. The authors focused on the edge quality of the tested specimens cut using 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 focused 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). [ABSTRACT FROM AUTHOR]

Slicing of material using a thin wire reduces the loss of material and provides better cutting quality compared to any other machining techniques. Moving wire electrochemical spark machining (WECSM) is a hybrid, non-conventional wire slicing process, specially for non-conducting materials such as ceramics, composites and glasses. In this research article, alumina epoxy nanocomposite (AENC) has been taken as a workpiece. AENC is a polymer-based nanocomposite with a property of mixed nature such as ceramics and polymer. Due to its high electrical insulation performance, AENC is in demand in various applications. However, its mixed properties limit the machining capabilities for various applications. In the present work, modelling of the moving WECSM process has been performed using response surface methodology, and GRA with entropy method was applied for finding the optimum set of parameters. The results show that the optimal machining performances for material removal rate, surface roughness and kerf taper were obtained at 55 V applied voltage, 2.5 m/min wire velocity, 200 g/l electrolyte concentration and 200 µs pulse-on time. [ABSTRACT FROM AUTHOR]

In this study, the effect of fiber angle on the tensile load-bearing performance and damage failure characteristics of glass composite laminates was investigated experimentally, analytically, and numerically. The glass fabric in the laminate was perfectly aligned along the load direction (i.e., at 0°), offset at angles of 30° and 45°, or mixed in different directions (i.e., 0°/30° or 0°/45°). The composite laminates were fabricated using vacuum-assisted resin molding. The influence of fiber orientation angle on the mechanical properties and stiffness degradation of the laminates was studied via cyclic tensile strength tests. Furthermore, simulations have been conducted using finite element analysis and analytical approaches to evaluate the influence of fiber orientation on the mechanical performance of glass laminates. Experimental testing revealed that, although the composite laminates laid along the 0° direction exhibited the highest stiffness and strength, their structural performance deteriorated rapidly. We also determined that increasing the fiber offset angle (i.e., 30°) could optimize the mechanical properties and damage failure characteristics of glass laminates. The results of the numerical and analytical approaches demonstrated their ability to capture the mechanical behavior and damage failure modes of composite laminates with different fiber orientations, which may be used to prevent the catastrophic failures that occur in composite laminates. [ABSTRACT FROM AUTHOR]

Copyright of Acta Odontologica Latinoamericana: AOL is the property of Acta Odontologica Latinoamericana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glass fiber/polymer composites are widely utilized in many structural applications because of their high specific strength and stiffness-to-weight ratios. In this study, woven glass fiber/epoxy was hybridized with short glass fibers of different lengths (2, 4, 6, 2+4, 2+6, and 4+6 mm) and contents (3, 6, 9, and 12 wt%) to produce hybrid woven SGF/epoxy composites. Variations in the thickness, fiber volume fraction, density, and void content of the prepared composites were determined. Mechanical tests such as tensile and Charpy impact tests were conducted. Compared to the woven fabric composites without short glass fibers (control samples), the tensile strength increased by approximately 13% at an optimum weight fraction of 3 wt% using short glass fiber lengths of 4 mm. Meanwhile, the incorporation of short glass fibers into the woven glass composites decreased the tensile modulus for all lengths. The maximum enhancement in the impact strength (approximately 14%) was achieved by the hybrid composite samples reinforced with 4 mm of short glass fibers at 3 wt%. This hybrid composite offers 18% and 20% improvements in the specific tensile and impact strengths, respectively. In summary, filling the woven fabric composites with specified short fiber contents and lengths can increase their mechanical performance when resin-rich regions are reinforced with short fibers without forming relatively thick interleaves between the woven fabric plies. [ABSTRACT FROM AUTHOR]