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Biocomposite materials made of natural plant fibers are becoming a viable alternative to the use of synthetic ones such as glass fibers, thanks to many economic, ecological, and technical benefits. However, their massive use in the industry requires optimal control of their mechanical performances, which constitutes a real scientific issue to be overcome. Indeed, biocomposites suffer from an important variability in their mechanical properties because of their multiscale structure, natural growth conditions, and various processing parameters, in addition to eventual chemical treatments. Biocomposites are also highly sensitive to the surrounding environment in terms of humidity and temperature because of the hydrophilic properties of natural plant fibers. In this context, this Perspective aims to provide a critical look at the influence of the main factors that affect the mechanical properties of biocomposites in order to suggest some possible research outlooks that could contribute to optimizing the control of these mechanical properties and expanding the use of biocomposites in industry. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effects of post length, post material, and substance loss on the fracture resistance of endodontically treated mandibular premolars. Materials and Methods: A total of 96 extracted human mandibular first premolars were endodontically treated and divided into 12 test groups (n = 8 each) based on the number of residual walls (one/two), post material (glass-fiber/titanium), and post length (5 mm, 7.5 mm, and 10 mm). After luting the posts, specimens received a composite resin core and a crown preparation with a 1.5-mm ferrule. Cast cobalt-chromium crowns were cemented using glass-ionomer cement. After 1,200,000 chewing cycles with a load of 49 N and simultaneous thermocycling (5°C to 55°C), specimens were quasi-statically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed using three-way, two-way, and one-way ANOVA (a = .05). Fracture modes were examined under a stereomicroscope (×25 magnification) and recorded. Results: The mean ± SD fracture loads ranged from 642 ± 190 N (one wall, glass fiber, 5 mm) to 1,170 ± 130 N (two walls, titanium, 7.5 mm). The mean fracture load of titanium posts was significantly higher than that of glass-fiber posts (P < .001), and the 7.5-mm post length exhibited significantly higher fracture loads than groups with 5-mm and 10-mm post length (P = .008). Conclusions: Teeth restored with titanium posts revealed considerably higher fracture resistance than teeth restored with glass-fiber posts, especially if 7.5-mm-length posts were used. [ABSTRACT FROM AUTHOR]

This study aims to investigate the crashworthiness properties of thin-walled foam-filled Auxetic metal/composite cellular tubes under quasi-static and low-velocity impact axial loading. The specimens were fabricated using thin-walled steel tubes and Glass Fiber Reinforced Composite (GFRC) laminates. The crashworthiness characteristics including peak load, absorbed energy, specific absorbed energy, and failure mechanisms of the hybrid structures were studied and compared with individual hollow section and foam-filled Auxetic tubes. In addition, detailed FE simulations were performed using LS-DYNA software, which was verified by the experiments. [ABSTRACT FROM AUTHOR]

The bonding performance and formation of the interphase region between fiber and matrix have significant effects on the strength and durability of composites. A new approach, involving combined experimental and numerical analyses, has been developed to avoid the shortcomings and scattering associated with local experimental methods. For this purpose, tensile tests are performed on specimens fabricated from a single glass fiber and epoxy resin. The elongations for specified lengths are measured using the digital image correlation (DIC) technic. The size of the fiber diameter and specimen section are also measured from SEM images. The obtained experimental displacements for micro tensile tests are used in an inverse elastic finite element solution to obtain the interphase elastic modulus. It is shown that, considering the interphase thickness of 1.0 μm that is more realistic, the interphase elastic modulus is in the range of 12 ∼ 19 GPa. However, the performed sensitivity analysis shown that considering interphase thickness ranging from zero to 2.0 μm the interphase elastic modulus varies between 9 and 46 GPa. It is shown that the proposed procedure can be used to obtain the overall mechanical properties of the matrix/fiber interphase in long fiber composites. [ABSTRACT FROM AUTHOR]

The study proposes a novel way of amalgamating three different materials to develop an effective electromagnetic interference (EMI) shielding material by completely utilizing the distinct properties of each one. First and foremost, binary composites have been prepared by combining with various weight of silver (1, 2, and 3 g) and constant weight percentages of glass fiber. The synthesis of the glass fiber‐silver‐PANI ternary composite is then brought about by PANI particles precisely encased on the surface of the glass fiber‐silver binary composite. The intertwining of a thin PANI coating on the binary composite is done successfully via simple in‐situ polymerization of aniline using lime juice as the dopant. The structural properties have been studied with XRD and FT‐IR. The SEM analysis reveals the effectual distribution of PANI on binary composite. The thermal stability of the composites has been studied using TG analysis. Most importantly, the glass fiber‐silver‐PANI ternary composite shows significantly high EMI shielding effectiveness up to 41 dB in the x‐band region. [ABSTRACT FROM AUTHOR]

The effects of steel, polyvinyl alcohol, polypropylene and glass fibre reinforcements on alkali-activated concrete (AAC) were investigated by conducting various mechanical strength tests. The fibre dosage was 0.1–0.3% by volume of AAC. Furthermore, the effects of acidic exposure on the strength of fibre-reinforced alkali-activated concretes (FRAACs) were examined by immersing samples in 10% v/v solutions of hydrogen chloride, sulfuric acid or nitric acid for 28 days. It was found that fibre additions improved the compressive and flexural strength by up to 13% and 27%, respectively, while the modulus of elasticity was significantly improved by up to 52%. Acid attack tests on AAC specimens demonstrated sulfuric acid to be highly detrimental to the mechanical and chemical properties of AACs. The strength loss in FRAAC after acidic exposure was up to 50% less than that of the plain AAC. The glass-fibre-reinforced AACs were found to be highly resistant to acid attack, whereas the steel-fibre-reinforced AACs had less resistance. These findings were further validated by scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy, which showed the changes in the microstructure of the specimens subjected to acidic environments. Overall, the fibre reinforcements improved the mechanical and durability properties of AACs. [ABSTRACT FROM AUTHOR]

In this study, the correlation between the Raman structure, thermal stability, and mechanical properties of TeO 2 -ZnO-La 2 O 3 –WO 3 glasses with varying WO 3 contents are systematically established. By exploring the critical point in the transformation process of glass network structural units, the optimal glass components of 74TeO 2 -12ZnO-5La 2 O 3 –9WO 3 glass possess the maximum thermal stability (158 °C) and the highest mechanical properties at the same time. The maximum Vicker hardness and Young's modulus of the optimal glass can reach up to 4.007 GPa and 56.212 GPa, which are higher than those of the well-known TeO 2 -ZnO-Na 2 O (TZN) and TeO 2 -ZnO-La 2 O 3 (TZL) glasses. Furthermore, the 0.5 mol% Er3+-doped glass at this critical point (TZLW-0.5Er) exhibits a higher laser figure of merit (54.29 × 10−21 cm2 ms), a larger laser gain bandwidth value (116 nm) and higher emission cross-sections at 1600 nm (2.52 × 10−21 cm2) and 1625 nm (1.06 × 10−21 cm2) than other host glasses. Finally, high-efficiency laser outputs at 1600 and 1625 nm based on TZLW-0.5Er glass fiber are successfully achieved by simulation. These results show the greater practical potential of TZLW-0.5Er glass with higher mechanical strength compared to TZN and TZL fibers for the 1.6 μm-band laser. [ABSTRACT FROM AUTHOR]

Leaf springs play a vital role in heavy-duty vehicles by offering substantial load support, durability, and convenient maintenance. Lightweight leaf springs enhance vehicle performance, offering benefits like improved fuel efficiency and a smoother ride. Glass fiber reinforced composites enhance fuel efficiency and durability, providing corrosion resistance. Their design flexibility improves ride comfort, and damping properties enhance vehicle stability. The examination conducted through finite element analysis, utilizing ANSYS software, demonstrated a substantial 75.32% decrease in weight for the E-Glass-Epoxy composite leaf spring (GECLS), affirming its efficacy in enhancing strength, reducing weight, and enhancing stiffness. This underscores its superiority as a viable alternative to traditional steel leaf springs (SLS) in vehicular applications. The mono-GECLS exhibited a natural frequency that was found to be 1.9 times higher than that observed in the traditional SLS. It indicates the potential to mitigate resonance issues. After analysing the SLS and GECLS using ANSYS, it was observed that the GECLS exhibits greater values in deflection, natural frequency, and strain energy, measuring 4.659 mm, 29.98 Hz, and 440.68 mJ, respectively, compared to its steel counterpart. Conversely, the SLS demonstrates elevated values in stress, mass, and density, with readings of 283.84 MPa, 3.7695 kg, and 5920 kg/m³, respectively. [ABSTRACT FROM AUTHOR]

Concrete is used as a material in the construction of several types of structures. The structural behavior of concrete is constrained by its lower tensile strength, bending strength, and toughness. Fiber-reinforced concrete is gaining importance in various concrete applications. Research has been carried out to use multiple types of fibers in concrete in different combinations to improve its mechanical characteristics, such as toughness, strength, ductility, and durability. In traditional concrete, microcracks have developed before loading the structure because of volume changes and drying shrinkage. When the load is applied, the microcracks start opening and propagating. Therefore, failure of the concrete member occurs. Hence, the usage of fibers helps arrest the growth of the crack and improves concrete characterization. The goal of this research study is to examine mechanical properties of concrete when used in combination with steel, basalt, and glass fibers. Steel fiber is useful in arresting macrocracks, whereas basalt and glass fibers are effective in preventing microcracks. In this research, the specimens incorporated hybrid (steel, glass, and basalt) fibers in the concrete mix with various percentage proportions at a 0.5% volume fraction. Experiments were carried out to assess the bending strength, compression strength, and splitting tensile strength. Therefore, this research can show comparative analysis for different percentages of fibers to enhance the qualities of concrete and can show the optimum fiber percentage among the proportions selected for this study. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)‐doped glass fibers are being developed into next‐generation broadband amplifiers and tunable lasers. Yet, the well‐developed Bi‐doped fiber devices only realize silica‐based optical fibers prepared by the modified chemical vapor deposition method, which faces challenges such as low doping concentration, high cost, intricate device structure, and high preparation difficulty. Here, a novel highly Bi‐doped multicomponent phosphate glass was developed. The high ion solubility of this phosphate glass facilitates achieving a Bi doping concentration of 8 mol%. The introduction of aluminum nitride (a new reducing agent) can create a local reducing environment, further increasing the concentration of low‐valence near‐infrared (NIR) active Bi ions. Furthermore, the resulting enhanced highly Bi‐doped multicomponent phosphate glass with efficient 900–1600 nm NIR emission can be drawn into corresponding optical fibers by a rod‐in‐tube method. Broadband NIR amplified spontaneous emission with a 3 dB bandwidth of 275 nm was achieved in this new fiber. As far as we know, this is the first successful preparation of Bi‐doped multicomponent phosphate glass fiber. Our results indicate that this fiber will be a powerful alternative to Bi‐doped silica‐based fibers for the preparation of related Bi‐doped fiber devices. [ABSTRACT FROM AUTHOR]

Glass sealing materials applied in Solid Oxide Fuel Cell (SOFC) are prone to excessive softening and outflow at high temperatures, while cracks tend to form upon cooling. To address these challenges, this study develops mullite fiber reinforced glass sealing materials based on K 2 O–Na 2 O–CaO–BaO–SiO 2 silicate glass, incorporating varying amounts of mullite fibers. The mechanical properties, phase structural transformations, and microstructural changes of these composite sealing materials are thoroughly investigated. The fibers form a network skeletal structure within the sealing material, enhancing the material's strength and high-temperature thermal stability. By incorporating 10% mullite fibers, the G10 sealing material, as compared to pure glass, exhibits a 44% increase in flexural strength and an 85% improvement in maximum strain value. Additionally, G10 boasts a thermal expansion coefficient of 10.25 × 10−6 K−1, demonstrating excellent chemical compatibility with interconnect and achieving tight adhesion at the interface. Most importantly, G10 possesses superior sealing capabilities, maintaining its gastightness even after undergoing 1000 h and 7 thermal cycles without any degradation. • The mullite fiber improves the strength and toughness of the sealing materials. • Mullite fiber form a support structure in the glass and prevent the glass flowing out. • The additional mullite fiber significantly hindered the chromium diffusion at the sealant/interconnect interface. • The leakage rate of the mullite fiber-glass composited sealing material is less than 0.002 sccm cm−1. • The sealant remain gas tightness after 1000 h at 750 °C and 7 thermal cycles. [ABSTRACT FROM AUTHOR]

Highlights The use of composite materials, particularly glass fiber‐reinforced polymers (GFRP), has considerably increased. The present investigation seeks to ascertain how sodium hydroxide (NaOH) treatments and the incorporation of graphene nano‐particulates (GNP) in GFRP flat‐joggle‐flat (FJF) composite joints. The experiments demonstrated that surface treatment with 0.1 N NaOH and the addition of 0.25, 0.50, and 0.75 wt% GNP reinforcement to the resin considerably enhanced the shear behavior of the FJF joints by 5.48%, 16.04%, and 32.77%, respectively, as compared to plain GFRP specimens, due to the improved chemical bonding and excellent IR radiation retention. 0.2 N NaOH treated with the same GNP concentrations lowered the shear strength compared to 0.1 N NaOH due to the linear reduction in fiber size. Field emission scanning electron microscopy gives a clear failure analysis of the FJF joint specimens. Fourier transform infrared spectroscopy investigation determines the chemical structure of GFRP materials based on distinctive peak intensities in the infrared range and different functional groups contained in the composite materials. Atomic force microscopy testing was done to evaluate the surface textures. The vibration analysis firm that the FJF joint having 0.1 N NaOH with 0.75 wt% of graphene had the highest natural frequency. The effect of NaOH treatment and graphene influence on FJF joints. Shear analysis of the FJF composite joints. FTIR and AFM techniques were adopted to analyze the surface properties. Modal analysis is used to evaluate the natural frequencies. [ABSTRACT FROM AUTHOR]

In this semi‐quantitative study, laser crystal microparticles which are potentially capable of generating mid‐infrared (MIR) light are incorporated into MIR transmitting optical fibers using a volumetric interface doping technique that combines interface doping with volumetric doping. Using confocal microscopy with a refractive index matching fluid, the Er:YAP microcrystals (MCs) inside the tellurite glass fiber are observed based on the detection of the green upconversion fluorescence emission of Er3+ ions, produced under excitation at 976 nm and localized at the central region within the fiber. The key outcome from this proof‐of‐concept study is that MC particles that are fused with the glass during the fiber drawing process survived heat treatment because the MC particles are exposed for a short time to a glass fluid with high viscosity of ≈105 Pa.s, which prevented the glass from exerting a dissolution effect. The survival of the MCs demonstrated the viability of the doping technique for fabricating fibers with exotic crystal‐glass combinations for applications including good refractive index matching across the pump and lasing bands of rare earth ions. This latter parameter provides significant particle size flexibility whilst minimizing additional loss from scattering especially at MIR wavelengths where the MC diameter‐to‐wavelength ratio becomes smaller. [ABSTRACT FROM AUTHOR]

Highlights In the present work, the tribological as well as thermo‐mechanical properties of glass‐filled and carbon‐filled PTFE composites are investigated. Solid lubricants like molybdenum disulfide (MoS2) and graphite are also incorporated in such composites in order to achieve better friction and wear properties. When compared to virgin PTFE, both carbon‐filled PTFE and glass‐filled PTFE composites showed the lowest wear rate. Again, the specific wear rate of glass‐filled PTFE composite was lower as compared to carbon‐filled PTFE composite sample under all test speed. A novel combination of a reinforcing filler (glass fibers) and a solid lubricant (MoS2) incorporated PTFE composite sample [PTFE (90 wt%) + glass fibers (5 wt%) + MoS2(5 wt%)] exhibited the lowest wear rate of the order of 10−9 mm3/Nm which was reduced to around 100‐fold as compared to virgin PTFE under sliding speed of 6.28 m/s. The wear rate was reduced due to the reinforcement of fibers but fibers support the load preferentially, whereas MoS2 and graphite offers a good lubricating effect. The morphological, thermo‐physical and thermo‐mechanical characterization of such composite materials were also carried out using various techniques such as SEM, TGA, DSC, TMA, and DMTA. Such PTFE composites having very good thermo‐mechanical as well as tribological properties have potential to be used as seals, gears, bearings etc. in dynamic aerospace applications. This investigation relates to the PTFE composites to obtain good thermo‐mechanical as well as tribological properties Incorporation of a novel combination of glass fibers and MoS2 exhibited lowest wear rate of the order of 10−9 mm3/Nm The wear property was around 100‐fold lower as compared to virgin PTFE. Such PTFE composites could be used as seals, gears, bearings etc. in dynamic aerospace applications. [ABSTRACT FROM AUTHOR]

Fibre reinforced metal laminates (FMLs) are widely used in various fields due to their excellent properties. However, the weak interlayer properties of FMLs limit their applications. In this paper, the interlayer properties of FMLs are enhanced by anodising the 2024-T3 aluminium alloy layer in FMLs or by epoxy matrix modification of graphene nanoplatelets (GNPs). The effect of both synergistic impacts on the interlayer properties of most FMLs is investigated. The FMLs were manufactured using the wet lay-up technique using 2024-T3 aluminium alloy, E51 epoxy and EW100 glass fibre. The results showed that the type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of FMLs after anodic oxidation treatment were increased by 406.4%, 10.3%, 18.3%, 42.6% and 28.3%, respectively, compared with those of pure FMLs. The type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of the GNPs-modified FMLs matrix were increased by 280.4%, 3.7%, 6.8%, 34.5% and 19.1%, respectively, compared with those of pure FMLs. Moreover, the synergistic effect of FMLs indicates that the simultaneous anodic oxidation and GNPs modification of FMLs can lead to the best mechanical properties of FMLs. Microscopic images and schematics illustrate the toughening mechanism of anodising and GNPs, including the enhancement of aluminium/resin interface and fibre/resin interface and the enhancement of resin matrix properties. [ABSTRACT FROM AUTHOR]

Highlights Acoustic emission (AE) serves as a non‐destructive testing (NDT) technique with unique potential for assessing structural integrity and potentially predicting failures in pressure bottles. The authors have effectively demonstrated its applicability in predicting burst pressures of glass fiber reinforced plastic (GFRP) pressure bottles. In their study, five identical GFRP pressure bottles underwent pressurization cycles, and the AE data collected during these cycles was analyzed to develop a straightforward empirical relationship for predicting burst performance. This approach highlights a significant finding: impending failure can be detected with notable accuracy even when pressure levels are at 50%–60% of the maximum expected operating pressure (MEOP), with a reasonable margin of error. Notably, there exists a gap in the existing literature concerning clear methodologies for predicting burst pressures of composite pressure bottles. This methodology, however, can be extended beyond GFRP to predict the burst pressure of pressure bottles made from other material systems in real‐time. The composite pressure bottle failure is predicted at very low pressure. The prediction is at a range of 50%–75% of MEOP. To predict the burst pressure of GFRP pressure bottle an empirical formula is generated. The empirical formula is generated using Acoustic Emission parameters. Major AE parameters are determined from a set of GFRP pressure bottles. [ABSTRACT FROM AUTHOR]

Laser glass deposition is an additive manufacturing method to produce individualized glass components. This process uses a CO2 laser with a defocused beam as a heat source to additively melt-fused silica filaments. The fiber filament is fed laterally in the process zone and is deposited layer-by-layer to form 3D structures. The formation of boundary layers in conventional 3D-printing methods is a usual byproduct of the process. In this paper, the boundary layer formation of deposited fused silica filaments is investigated in detail by means of varying different process parameters such as, laser power, feed rate, laser spot diameter, and printing strategy. This involves examining both thin-walled and thick-walled test specimens. Quality characteristics like the surface roughness and the optical transmission are analyzed for the printed specimen. Finally, fully transparent structures with surface roughness below 100 nm and a transparency of 90% could be printed boundary layer-free and without post-processing. [ABSTRACT FROM AUTHOR]

Alkali-free aluminoborosilicate glasses without (GDMC-Si) and with La2O3 addition (GDMC-La) were fabricated with an aim to develop low dielectric glass fibers for use in printed circuit boards (PCBs) as a reinforcing material in high-speed 5G/6G telecommunications application. This study presents the structural, thermo-physical, and dielectric properties of the glasses. The decrease in glass transition temperature (Tg) and the increase in coefficient of thermal expansion (CTE) were found by the addition of SiO2 and La2O3 in the present glass system, which are due to the depolymerization of the glass networks confirmed by the FTIR analysis. The dielectric constants (Dk) and the dissipation factors (Df) of the glasses were investigated at a high frequency of 10 GHz. The Dk values of the GDMC-Si and GDMC-La glass systems reached a minimum of 4.50 and 4.75, while their Df values reached a minimum of 2.86 × 10−3 and 3.01 × 10−3, respectively. Notably, the Dk and Df values of the present glasses were lower than the commercial E-glass (Dk: 6.9, Df: 7.0 × 10−3 at 10 GHz) and L-glass (Dk: 4.8, Df: 3.0 × 10−3 at 10 GHz). Glass fibers with a diameter of 10 μm were successfully drawn by the continuous melt-spinning process and their mechanical properties were investigated. [ABSTRACT FROM AUTHOR]

Highlights In this paper, the mechanical properties and vibration characteristics of Carbon‐Glass Hybrid Fiber Composites (CGHFC) are experimentally investigated with varying axial directions and blending ratios. The experimental results demonstrate a significant increase in the tensile strength of the CGHFC with an increasing content of carbon fibers. The biaxially CGHFC exhibits a maximum static tensile strength of 413.27 MPa in the 0° direction and 466.33 MPa in the 90° direction, surpassing both the quadratic and uniaxial directions. Notably, compared to biaxially oriented glass fiber material, the tensile strength of CGHFC is enhanced by 44.36%, thereby significantly improving its overall performance, making them particularly suitable for blade structures subjected to simultaneous tensile and vibratory loads. By optimizing the fiber orientation and blend ratio, the CGHFC provides good vibration control and fatigue resistance while ensuring high strength, thus maximizing the overall performance and service life of the blades. The results of this paper provide important data and theoretical support for the selection and design of wind turbine blade materials and help to promote the development of composite materials in wind turbine blade structure and design. CGHFCs show enhanced tensile strength with more carbon fibers. Biaxial CGHFCs have max tensile strength at 0° and 90° directions. CGHFCs' strength improves by 44.36% over glass fiber materials. Optimized CGHFCs offer superior vibration control and fatigue resistance. Research supports wind turbine blade material innovation. [ABSTRACT FROM AUTHOR]

Introduction: Glass fibers with polyester resin structural composites are highly sought after in many sectors such as transportation industries, thanks to their low density and fairly good mechanical properties. However, their end-of-life management is not yet satisfactory. Composites mostly end in energy recovery in the best-case scenario or, worse, in landfills. Transformation into shreds and powders for reuse as a new source of raw material for the construction sector (concrete) is an economically and environmentally attractive recovery solution. The present study investigates the development of a concrete filled with glass/polyester composite shreds. Methods: To this end, rheological (cone spread) and physico-mechanical (density and mechanical strength in flexion and compression) characterization tests were carried out. Several mix designs were tested in order to understand the impact of introducing composite shreds as a substitute for sand. Composite shreds were introduced in the following ratios by volume: 0, 1, 1.5, 2, 2.5, 3, and 7% with water and cement ratio equal to 0.5, 0.6, and 0.7. Results and discussion: The results obtained indicate that workability decreases with the substitution of sand by shreds. For a substitution of sand by shreds of 2%, it is relatively small, and the pouring of the mortar is still feasible. The decrease can be attributed to the water absorption of the composite shreds. Concerning mechanical results, for formulations with a substitution percentage of composite shreds lower than 3%, the mechanical strength (both compression test and flexure test) is slightly higher than that of the reference sample. The increase in compressive strength that can be observed is at its maximum, equal to 10%, compared to that of the reference sample. These results are in line with density results, which are also slightly higher than that of the reference sample. This effect can be attributed to water absorption of composite shreds and the filling effect of the powders. For a percentage of substitution equal to 7%, the mechanical strength is lower than that of the reference sample (30% decrease), with a compressive strength equal to 33 MPa (47 MPa for the reference sample). For this percentage of substitution equal to 7%, a decrease in density is also observed (6% decrease) and can be explained by the porosity created by the incorporation of the composite shreds into the mortar. [ABSTRACT FROM AUTHOR]

With the improvement of radar absorption performance requirements, the research of absorbing materials is an important research direction. In this paper, a graphene/glass fiber/epoxy (GN/GF/EP) structure design scheme is proposed. By measuring the electromagnetic parameters, the influence of different GN content on the absorber performance is analyzed, and the bilayer absorber material combination with the best absorber performance is determined. The double layer absorbing material was made of GN/GF/EP-1.0% (thickness 0.4 mm) and GN/GF/EP-2.5% (thickness 1.7 mm). The peak reflection loss of the double layer absorbing material is −41.55 dB, the center frequency is 10.93 GHz, and the effective absorption bandwidth is 2.86 GHz (9.34∼11.20 GHz). [ABSTRACT FROM AUTHOR]

Highlights This study investigates the mechanical properties of composites made from biaxial warp‐knitted glass fiber/epoxy prepregs (BW‐GF/EP) in comparison to plain woven glass fiber/epoxy prepregs (PW‐GF/EP). The BW‐GF/EP composites demonstrated superior tensile strength, with an increase of 9.5%, and bending strength, with an increase of 12.2%, compared to the PW‐GF/EP composites. Despite having a lower tensile modulus, the BW‐GF/EP composites exhibited 8.7% higher interlaminar shear strength. Dynamic mechanical analysis showed that both materials had similar storage and loss moduli at lower temperatures, with PW‐GF/EP performing better at higher temperatures. Microscopy revealed that failure in PW‐GF/EP occurred at weave intersections, while BW‐GF/EP composites showed fiber rupture and delamination. The findings highlight the advantages of using biaxial warp‐knitted fabrics for improved composite performance. Developed biaxial warp‐knitted fabric prepregs to replace liquid molding techniques. Improved interlaminar shear strength, reducing delamination risks in composites. Achieved higher tensile and bending strength compared to plain weave composites. Enhanced resin impregnation and molding efficiency with biaxial warp‐knitted fabrics. Reduced environmental impact and costs by avoiding VOCs and minimizing waste. [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]

State‐of‐the‐art organosheets suffer from several shortcomings that limit their applicability in high‐performance materials, mainly due to the imperfect combination of glass fibers and polymer. To overcome these issues, a novel hybrid fiber is presented, in which every single filament consists of a glass core and an individual, thin, thermoplastic polymer coating. Those fibers can immediately be consolidated into organosheets, without the necessity of the critical combination step. Production is realized by an ultra‐rapid inline coating of the filaments, incorporated into a standard spinning system. This solvent‐free process is realized by coating of the fibers with a tailor‐made, monomeric precursor solution, which is radiation‐polymerized immediately after application. Within fractions of a second, the coating layer is thus solidified, before coiling of the hybrid fiber. Due to the very low thickness of the coating and specific formulation of the precursor, tackless layers can be achieved before the coiling, even at industrial spinning speeds. Highlights: Glass fibers are coated with a thermoplast via in situ polymerization.A precursor is developed which polymerizes in 100 ms.Glass fibers are coated completely with thermoplast by using a UV tunnel.Spinning velocities of about 600 m/min can be achieved.Hybrid fibers are consolidated into glass fiber‐reinforced plastics (GFRP). [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]

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]

Wood plastic composite (WPC) is a kind of eco‐friendly material made of agricultural and forest industry waste and residues compounded with thermoplastic. The defects of traditional WPC, such as low strength and high creep, greatly limit its engineering applications. To solve the problem, this paper proposed two methods of glass fiber reinforced polymer (GFRP) reinforced PVC‐based WPC panels (G‐WPC) by bonding GFRP sheets or embedding GFRP bars in the tensile zone of the WPC panels. The effects of the thickness of GFRP sheet and reinforcement ratio of GFRP bar on the flexural property of G‐WPC were comparatively analyzed by carrying out four‐point bending tests and finite element simulations. The results showed that the failure modes of the GFRP sheets reinforced specimens were mainly flexural fracture and interface debonding, and the GFRP bars reinforced specimens were flexural fracture and excessive deformation. The ultimate flexural bearing capacity of both GFRP sheets/bars reinforced specimens could be improved by more than 200%. GFRP bar reinforced specimens had better ductility than reinforced with sheet. The effects of WPC density, GFRP sheet fiber layup angle and GFRP bar diameter on the flexural behavior of G‐WPC were further parametrically analyzed using the finite element model (FEM). Highlights: Two effective flexural reinforcement methods of WPC were proposed.The optimum thickness of GFRP sheet was obtained based on experimental tests.The suitable reinforcement ratio of GFRP bars was studied by tests and FEM.Effects of WPC density, GFRP fiber layup angle and bar diameter were analyzed. [ABSTRACT FROM AUTHOR]

Fiber‐reinforced polymers (FRP) feature high strength‐to‐weight ratio amongst the emerging class of natural composites. This paper presents the impact of the glass fiber on the tensile strength of the flax epoxy laminate. The mechanical behavior and damping characteristics of flax fiber reinforced polymer (FFRP) and the hybrid flax‐glass fiber reinforced polymer (HFRP) are experimentally investigated. Both the flax and hybrid FRPs are made using vacuum infusion process. The specimens without and with holes of 4, 5, and 6 mm in diameter are subjected to tensile test using acoustic emission monitoring and free vibration test. In the former testing, HFRP resulted in higher peak frequencies and cumulative counts. Also, the natural frequency and damping factor of HFRP vary proportionately with the hole size, as identified in the latter tests. Different damage mechanisms during the tensile test revealed that the presence of glass fibers in HFRP increased resistance for certain damage mechanisms. Highlights: Adding glass fiber to flax fiber reinforced polymer (FFRP) creates a hybrid FRP (HFRP) with increased resistance to damage and improved damping characteristics.HFRP exhibits a distinction in failure mechanisms compared to FFRP.The study utilizes acoustic emission (AE) to identify various damage mechanisms in the material, providing a more detailed information.The addition of glass fibers in HFRP leads to a more pronounced increase in damping factors. [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]

Polyamide 6 (PA6) thermoplastic‐based composites are often used in automobile, aerospace, marine, and biomedical applications. Here, PA6 and its composites with varied chopped glass fiber (GF) concentrations of 5, 10, and 20 mass% were fabricated by injection molding. The specimens were characterized by structural, thermal kinetic, mechanical, as well as tribological analyses. Tribological performance was evaluated in dry pin‐on‐disc test apparatus with three different levels of time, speed, and load factors. The PA6/GF composites showed high decomposition activation energy compared to pure PA6. Thermal activation, Ea increased to 46.16% with increasing of GF content up to 10 mass% in the composites compared to PA6. PA6/5GF exhibited best mechanical properties (e.g., strength = 44.46 MPa and Hardness = 45.2). Addition of GF in PA6 significantly improved tribological properties, coefficient of friction (COF) and specific wear rate (WR) besides thermal stability and mechanical properties of the composites. Especially, COF and WR of PA6/5GF composite decreased by 17%–65% and 68%–92%, respectively, compared to PA6. ANOVA statistical results determined the significant contribution of the tribological factors to the performance metrics of the composites for COF and WR. Therefore, the PA6/5GF composite would highly be useful for tie‐rod gears and bearings as a crucial structural component in automotive bodywork. [ABSTRACT FROM AUTHOR]

Polymer composites with continuous fibers are expected to exhibit good mechanical performance due to orientation and high aspect ratio of fillers. Fused filament fabrication (FFF) provides an affordable method for processing these materials as products with tunable architecture. By incorporating continuous bioactive fibers coated with biodegradable polymer, the degradation rate of printed scaffolds may vary over time. As proof of concept, macroporous composites were 3D printed using continuous glass fiber‐reinforced polycaprolactone filament. Parametrization and challenges associated with printing on non‐dedicated equipment are discussed. A model describing the melt flow was employed to evaluate the velocity and shear rate profiles. Although the maximum velocity is approximately 18 mm s−1 for both neat and reinforced polymer, the obstruction caused by fibers results in higher shear rate, up to 481 s−1, higher pressure gradient, 1.95 MPa mm−1, and higher velocity gradient, conditions that limit print quality. Additionally, it was also possible to determine the shear stress experienced by the fiber bundle, 300 KPa, and the influence of different processing conditions. This investigation advances the development and understanding of manufacturing of continuous fiber‐reinforced polymers via FFF. [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]

Alternative matrices, especially exhaled breath (EB), have gained increasing attention for a few years. To interpret toxicological findings, knowledge on the toxicokinetic (TK) properties of a substance in EB is indispensable. While such data are already accessible for various drugs (e.g. Δ9-tetrahydrocannabinol), they are still not available for new psychoactive substances, particularly synthetic cannabinoids (SCs). As SCs raise a high public health concern, the aim of this study was to assess these data in future TK studies in pigs. For this purpose, an in vitro sampling technique of EB was initially developed, which is prospectively applied to anesthetized and ventilated pigs for the detection of SCs in a controlled and reproducible manner as exemplified by cumyl-5F-P7AICA. Furthermore, a method for the qualitative and quantitative detection of cumyl-5F-P7AICA in EB using glass fiber filters (GFFs) was established and fully validated. Therefore, cumyl-5F-P7AICA (0.5 mg/mL in ethanol absolute) was initially nebulized using a ventilation machine and a breathing tube, as they are also used in surgeries. The aerosol was delivered into a simulated pig lung. To collect EB, a pump was connected to that part of the breathing tube, which contains EB (expiratory limb), and sampling was performed repeatedly (n  = 6) for 15 min (2 l EB/min) each using GFF. For extraction of the substance, the GFFs were macerated with acetone and the remaining experimental components were rinsed with ethanol. After sample preparation, the extracts were analyzed by liquid chromatography tandem mass spectrometry. In the complete experimental setup, about 40% of the initially nebulized cumyl-5F-P7AICA dose was found, with 3.6 ± 1.3% being detected in the GFF. Regarding the comparably high loss of substance, the open ventilation system and a conceivable adsorption of the SC in the ventilator have to be considered. However, the herein introduced approach is promising to determine the TK properties of cumyl-5F-P7AICA in EB. [ABSTRACT FROM AUTHOR]

During recent years, the optical-fiber-based simultaneous sensing of strain and temperature has attracted increased interest for different applications, e.g., in medicine, architecture, and aerospace. Specialized fiber layouts further enlarge the field of applications at much lower costs and with easier handling. Today, the performance of many sensors fabricated from conventional fibers suffers from cross-sensitivity (temperature and strain) and relatively high interrogation costs. In contrast, customized fiber architectures would make it possible to circumvent such sensor drawbacks. Here, we report on the development of a high-quality coupled-core fiber and its performance for sensors—from the initial fiber layout via elaboration of the preform and fiber up to the sensor evaluation. A compact, high-speed, and cost-effective interrogation unit using such a specialized coupled-core fiber has been designed to monitor reflectivity changes while even being able to distinguish the direction of the force or impact. Several fiber core material techniques and approaches were investigated, which made it possible to obtain a sufficient volume of material for the required fiber core number and a specialized fiber core geometry in terms of core distances and radial refractive index profile, whilst handling the non-symmetrical fiber architectures of such modeled, complex structures and balancing resources and efforts. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) methods are increasingly being adopted as an alternative for mass production. In particular, Fused Deposition Modeling (FDM) technology is leading the way in this field. However, the adhesion of the layers in products produced using FDM technology is an important issue. These products are particularly vulnerable to forces acting parallel to the layers and especially to impact strength. Most products used in the industry have complex geometries and thin walls. Therefore, solid infill is often required in production, and this production must take place in the ZX orientation. This study aims to optimize the impact strength against loads acting parallel to the layers (ZX orientation) of PA6, one of the most widely used materials in the industry. This orientation is critical in terms of mechanical properties, and the mechanical characteristics are significantly lower compared to other orientations. In this study, filaments containing pure PA6 with 15% short carbon fiber and 30% glass fiber were utilized. Additionally, the printing temperature, layer thickness and heat treatment duration were used as independent variables. An L9 orthogonal array was employed for experimental design and then each experiment was repeated three times to conduct impact strength tests. Characterization, Taguchi optimization, and factor analyses were performed, followed by fracture surface characterization by SEM. As a result, the highest impact strength was achieved with pure PA6 at 8.9 kJ/m2, followed by PA6 GF30 at 8.1 kJ/m2, and the lowest impact strength was obtained with PA6 CF15 at 6.258 kJ/m2. Compared to the literature and manufacturer datasheets, it was concluded that the impact strength values had significantly increased and the chosen experimental factors and their levels, particularly nozzle temperature, were effective. [ABSTRACT FROM AUTHOR]

Over recent decades, numerous strong earthquakes have caused widespread devastation, including citywide destruction, significant loss of life, and severe structural damage. Seismic base isolation is a well-established method for mitigating earthquake-induced risks in buildings; however, its high cost often limits its implementation in developing countries. Simultaneously, the global rise in vehicle numbers has led to the accumulation of discarded tires, intensifying environmental challenges. In response to these issues, this study investigates the development of a seismic isolator matrix using recycled rubber from vehicle tires, proposed as a sustainable and cost-effective alternative. Ten recycled rubber matrices were experimentally evaluated for their physical and mechanical properties. The matrix with optimal granulometry and binder content, demonstrating superior performance, was identified. This optimized matrix underwent further validation through compression and cyclic shear tests on reduced-scale prototypes of fiber-reinforced isolators, which included five prototype designs, two of which featured flexible reinforcement. The best-performing prototype comprised a recycled rubber matrix with 15% binder and glass fiber, exhibiting vertical stiffness and damping characteristics superior to those of natural rubber. Specifically, this prototype achieved a damping ratio of up to 22%, surpassing the 10% minimum required for seismic isolation, along with a vertical stiffness of 45 kN/mm, critical for withstanding the vertical loads transferred by buildings. These findings suggest that the recycled tire rubber matrix, when combined with glass fiber, is a viable material for the production of seismic isolators. This combination utilizes discarded materials, contributing to environmental sustainability. [ABSTRACT FROM AUTHOR]

The development of dental materials needs to be supported with sound evidence. This in vitro study aimed to measure the fracture toughness of a short fibre-reinforced composite (sFRC), at differing thicknesses. In this study, 2 mm, 3 mm and 4 mm depths of sFRC were prepared. Using ISO4049, each preparation was tested to failure. A total of 60 samples were tested: 10 samples for each combination of sFRC and depth. Fractured samples were viewed, and outcomes were analysed. EXF showed greater toughness than EXP, with a mean of 2.49 (95%CI: 2.25, 2.73) MPa.m1/2 compared to a mean of 2.13 (95%CI: 1.95, 2.31) MPa.m1/2, (F(1,54) = 21.28; p < 0.001). This difference was particularly pronounced at 2 mm depths where the mean (95%CI) values were 2.72 (2.49, 2.95) for EXF and 1.90 (1.78, 2.02) for EXP (Interaction F(2,54) = 7.93; p < 0.001). Both materials performed similarly at the depths of 3 mm and 4 mm. The results for both materials were within the accepted fracture toughness values of dentine of 1.79–3.08 MPa.m1/2. Analysis showed crack deflection and bridging fibre behaviour. The optimal thickness at the cavity base for EXF was 2 mm and for EXP 4 mm. Crack deflection and bridging behaviour indicated that restorations incorporating sFRCs are not prone to catastrophic failure and confirmed that sFRCs have similar fracture toughness to dentine. sFRCs could be a suitable biomimetic material to replace dentine. [ABSTRACT FROM AUTHOR]

Highlights The bio‐sandwich composites are lightweight, economical, recyclable, and easily obtainable. Sandwich panels comprising glass fiber/epoxy face sheets and hemp fiber/epoxy core with varying fiber orientations, thickness, and montmorillonite nanoclay are prepared by stirring the epoxy/clay mixture to have uniform dispersion followed by compression molding. The sandwich and monolithic composites are loaded under quasi‐static punch shear. The sandwich panel with 3 wt.% nanoclay shows optimum quasi‐static tensile modulus and strength than the neat panel. Energy absorption, and specific energy absorption of sandwich panels G0/H(0)5/G0‐0%, G0/H(0)10/G0‐0%, G0/H(0)15/G0‐0% are 2%, 76%, 111%, and 28%, 132%, 183% higher than same weight glass/epoxy composites G(0)5‐0%, G(0)8‐0%, G(0)10‐0%. Energy absorption and specific energy absorption of panels G0/H(0)3/G0‐3%, G0/H(0)7/G0‐3%, G0/H(0)9/G0‐3% are similar, 25%, 24%, and 18%, 55%, 57% higher than same thickness composites G(0)5‐0%, G(0)8‐0%, G(0)10‐0%. The energy absorption of sandwich panel G0/90/H(0)15/G90/0‐0% is 49% lower than same weight composite G0/90/(0)9/90/0‐0%. Similar behavior is observed for panels with ±45° face sheets, 0° core, and 0°/90° face sheets, ±45° core compared to composites. Therefore, sandwich panels with 0° face sheets and core outperform composites and can replace them in structural applications in automotive. Particularly, panels show greater improvement over same‐weight composites than same‐thickness ones. Energy absorption of sandwich panels having 0° and ±45° cores is comparable while it is higher than a panel with 0°/90° core, each of 0°/90° face sheets. This is observed for monolithic composites as well. The quasi‐static indentation response of bio‐sandwich composites is examined. Bio‐sandwich composites outperform synthetic composites, each of the same weight. Bio‐sandwich panels with 3 wt. % nanoclay perform better than the same thickness synthetic composites. The behavior of sandwich and monolithic composites varies with fiber orientations. [ABSTRACT FROM AUTHOR]

In the field of composite materials, many reports have shown that catastrophic structural damage is caused by lightning strikes. In this study, new design concepts were proposed for the lightning-strike protection of nickel-coated glass/epoxy foam-core composites. Instead of using a neat metal mesh, glass fibers were modified with nickel particles via a plating technique to improve their thermal and electrical conductivities. In addition, a thin Invar plate was inserted at the middle of the structure and a foam core was introduced to reduce damage to the structure. Three models with different materials and stacking sequences were used in this study. Severe damage was experimentally observed following artificial lightning at a peak current of approximately 150 kA when considering a waveform A. Furthermore, numerical prediction was performed to identify the damage mechanisms of the structures. Besides the heat flux source, a mechanical source known as the shock wave overpressure was investigated separately as a new factor for dielectric materials. These two sources of lightning were determined as minor reasons for the structural damage. The failure modes were analyzed for further discussion about the failure mechanism in this study. [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]

Environmental awareness has driven a crucial search for biodegradable materials. Over the past few decades, the machining of these materials, particularly through drilling, has garnered significant research interest. This study presents an evaluation of the drilling performance of a hybrid composite (jute/glass), considering factors such as the concentration of chemical treatment with sodium bicarbonate, the type of glass fiber (random or woven), the degree of hybridization between the jute and glass fibers, and cutting parameters like rotation speed, feed rate, and drill diameter. Drilling operations were conducted to determine the maximum temperature in the cutting zone, the surface roughness of the drilled holes, and the maximum delamination factor. A Sobol sensitivity analysis was performed to identify the input parameters influencing these responses studied. Predictive modeling of the results based on the input factors was then conducted using the deep neural network (DNN) and Adaptive Neuro-Fuzzy Inference System (ANFIS) approaches. The results show that the type of glass fiber significantly affects surface roughness, while rotation speed primarily influences cutting temperature. Similarly, the drill diameter directly impacts the maximum delamination factor. Finally, the predictive modeling demonstrates that the ANN-IGWO models provide the best predictions of drilling parameters compared to the ANN-GA and ANFIS models, with mean absolute errors ranging from 1.22 to 12%. [ABSTRACT FROM AUTHOR]

In this paper, the friction properties of the port pair with non‐smooth surface in the pump were studied. The lubrication film was modelled and simulated to analyse dynamic pressure, velocity vector and friction coefficient. Tests were made for studying the effects of pit shape and revolution speed on friction properties of glass fibre epoxy resin (GFER) samples under seawater lubrication, with the wear of the surface and friction coefficient discussed. The results show that GFER is mainly manifested as adhesive and abrasive wear during the tests. The simulations and tests suggest that the hydrodynamic lubrication effect is improved by increasing revolution speed and using non‐smooth surfaces, with the friction coefficient being decreased. Moreover, a roughness test was conducted, and it was found that the Ra value of the 316L sample decreased, whereas the Ra value of the GFER sample increased. [ABSTRACT FROM AUTHOR]

Polyamide (PA) composites exhibit excellent properties such as stiffness, impact resistance, chemical resistance, and thermal stability, making them widely used in automotive interiors, engine parts, and bodywork. To leverage these advantages, high-content composite materials that enhance the wettability and interfacial adhesion between polyamide 66 (PA66) and glass fiber are essential. In this study, we synthesized linear and hyperbranched amide-based flow modifiers to improve the flowability of PA66 composites. H-NMR and FT-IR analyses confirmed the successful preparation of these structures. FT-IR analysis confirmed the successful synthesis of flow modifiers, showing characteristic amide peaks at 1650 cm−1 and the absence of -NH2 peaks at 3300 cm−1. Five flow modifiers were mixed with PA66 in various ratios using a micro-compounder, and viscosity reduction was confirmed by rotational rheometer measurements. Tensile strength and DMA indicated that PA66 composites with flow modifiers showed improved mechanical properties without significant reduction. Notably, PA66 composites with ACDA exhibited a superior viscosity reduction effect while maintaining mechanical strength. The DMA results indicated that the mechanical properties of PA66 composites with flow modifiers showed no significant reduction. The tensile strength of samples with flow modifiers ranged from 208 to 212 MPa, and the elongation at break was between 8.94 and 9.18%. These findings demonstrate that the synthesized flow modifiers improve the viscosity of PA66 composites while maintaining or enhancing mechanical properties. [ABSTRACT FROM AUTHOR]

Glass fiber reinforced phenolic composites (GFRP) are an advanced composite material with good processability, fatigue resistance, corrosion resistance and stability, and are widely used in the production of structural parts for aircraft and ships. Our research described in this article explores the performance changes of GFRP in different aging media with prolonged aging time using GFRP with different fiber/matrix ratios. The research results indicated that aging time had the most significant impact on the various properties of the composite materials among all variables. With the extension of aging time, the bending strength of our composite materials decreased significantly, with a maximum decrease of 33%. The water absorption rate gradually increased and tended to stabilize, but the thermal decomposition temperature remained at 300 °C, and the mass residual rate remained stable at around 61% with little change. As the content of GF was increased, the aging of the composite gradually slowed down, and the rate of decline in its bending strength gradually decreased. In addition, the influence of different aging media on the performance was also studied, and it was found that the presence of NaCl in artificial seawater could cause changes in the osmotic pressure at the interface of the composite materials and the sea water, thus exacerbating interface damage and affecting the material's performance. [ABSTRACT FROM AUTHOR]

Er3+‐doped fluoride glass and fiber have been widely used in multiple fields such as mid‐infrared laser, visible laser, and amplifier. However, there is no unified conclusion on the thermal and optical properties with respect to varying concentrations of Er3+ doping. Furthermore, this is a paucity of systematic guidance on the preparation of Er3+‐doped fluoride glass and fiber. In this study, fluorozirconate fiberglass with Er3+ doping is systematically examined. Additionally, a preliminary explanation of the evolutionary behavior of glass devitrification, thermal properties, and fluorescence properties is provided. Energy transition models were built for 1.5 and 2.7 µm emissions in Er3+‐doped fluorozirconate at room temperature. Moreover, a suitable doping concentration is proposed based on the evolutionary behavior of thermal and optical properties. In this study, guidance on appropriate Er3+ doping concentration levels in fluorozirconate glass is provided and potential applications are explored. [ABSTRACT FROM AUTHOR]

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Featured Application: Building materials for products with lower carbon footprints and increased mechanical properties. This article's aim is to analyze physical, mechanical, and fracture properties as well as the thermal investigation of geopolymer composites reinforced with flax, glass fiber, and also the hybrid combination of fibers. Two types of matrices were considered as composites matrices. The first composition was based on fly ash and river sand. The second matrix composition contained fly ash and glass spheres. The content of reinforcement was 1% by mass. Compressive strength and three-point bending fracture tests were performed. The values of fracture toughness and fracture energy were determined. The resonance method was used to verify the dynamic characteristics, such as the dynamic modulus of elasticity and the dynamic Poisson ratio. The results show that single-type fibers in composites based on fly ash and glass spheres did not affect compressive strength. However, introducing hybrid reinforcement increased compressive strength by about 10% compared to the reference specimens. Flax fibers and hybrid reinforcement ensured higher fracture toughness and energy. The results also revealed great potential for glass sphere application to geopolymer materials in terms of fracture mechanics and thermal properties. Despite the lower strength properties in relation to geopolymers based on sand aggregate, applying reinforced fibers into the composite with glass spheres enhanced the compressive strength compared to other materials. Materials modified with glass spheres have a thermal conductivity twice as low as that of materials containing river sand. [ABSTRACT FROM AUTHOR]

The design and development of efficient microwave-absorbing and electromagnetic interference (EMI) shielding materials and structures to conceal electromagnetic (EM) waves remains a consistent and challenging task. Despite advancements in materials science and microwave engineering, there is a need for optimized materials that offer both effective microwave absorption and EMI shielding while minimizing material layer thickness. This research aims to address this gap by utilizing the firefly algorithm (FFA) to predict the optimal medium properties and thickness of microwave-absorbing and EMI shielding materials under specific constraints. In this context, a comprehensive investigation was carried out at the X-band involving numerical and experimental EM characterization of novel lightweight fiber-based samples. Additionally, the FFA has been applied to optimize these fiber-based microwave structures within the given constraints. Two separate objective functions (OBF) targeting minimum sample thickness, maximum microwave absorption, and shielding effectiveness (SE) bandwidth have been integrated into the FFA to address the thickness–bandwidth trade-off issue. Subsequently, resistive ink-coated glass fiber (IGF) and ink-coated mesh fiber (IMF) were developed and characterized based on the optimal solutions provided by the FFA. Consequently, an optimized IMF sample provides a minimum reflection coefficient (RC) of −19.0 dB at 10.7 GHz with a bandwidth of 2.8 GHz (9.6 to 12.4 GHz) below the −10 dB threshold. Besides, the optimal IGF sample achieves maximum SE of 11 dB at thickness of only 0.8 mm and covers the entire operating band. Furthermore, the response of the proposed structure was assessed for various oblique angles of incidence, revealing significant potential for various practical applications. A strong correlation between measured and theoretical findings underscores the potential of the proposed approach in realizing efficient microwave stealth and EMI shielding materials. [ABSTRACT FROM AUTHOR]