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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]

The dissolution behavior of calcium aluminosilicate based glass fibers, such as stone wool fibers, is an important consideration in mineral wool applications for both the longevity of the mineral wool products in humid environments and limiting the health impacts of released and inhaled fibers from the mineral wool product. Balancing these factors requires a molecular-level understanding of calcium aluminosilicate glass dissolution mechanisms, details that are challenging to resolve with experiment alone. Molecular dynamics simulations are a powerful tool capable of providing complementary atomistic insights regarding dissolution; however, they require force fields capable of describing not-only the calcium aluminosilicate surface structure but also the interactions relevant to dissolution phenomena. Here, a new force field capable of describing amorphous calcium aluminosilicate surfaces interfaced with liquid water is developed by fitting parameters to experimental and first principles simulation data of the relevant oxide-water interfaces, including ab initio molecular dynamics simulations performed for this work for the wüstite and periclase interfaces. Simulations of a calcium aluminosilicate surface interfaced with liquid water were used to test this new force field, suggesting moderate ingress of water into the porous glass interface. This design of the force field opens a new avenue for the further study of calcium and network-modifier dissolution phenomena in calcium aluminosilicate glasses and stone wool fibers at liquid water interfaces. [ABSTRACT FROM AUTHOR]

Mixed valence manganites are potential functional materials due to their unique electromagnetic properties. In this work, half-doped ceramics with the perovskite structure Sm 0.5 Ca 0.5 MnO 3 polycrystalline samples are synthesized by the solid-state reaction method in open air at different final sintering temperatures. Structures and particle sizes are studied by x-ray diffraction and scanning electron microscopy, respectively. Positron annihilation spectroscopy and density-functional theory calculations are used to characterize the intrinsic vacancies in the bulk. Thereafter, the effect of vacancies on the magnetic and magnetoresistance (MR) properties is investigated. We find that Mn monovacancies (V Mn ) exist in the bulk among all the samples, and the concentration of V Mn is different. We suggest a possible defect model that can be well applied to explain the phenomena of their electromagnetic properties. The transition temperature of the charge-order state (T CO ) and ferromagnetic and anti-ferromagnetic (T N ) are most likely related to the concentration of V Mn and the particle sizes or pore sizes, respectively. The glass spin state transition temperature seems to be independent of the defect concentration and type. The metal conductive behavior does not appear in a high magnetic field and at low temperatures, which may be caused by the presence of a high concentration of V Mn in the bulk and oxygen-related defects in the boundary, and the double exchange interaction is suppressed. At temperatures below T N and under a weak magnetic field, the MR is related to the total defect concentration. In addition, the high concentration of V Mn is unfavorable for obtaining a high MR value. [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]

Purpose: To evaluate different protocols for recementation of dislodged glass fiber posts (GFPs).Materials and Methods: The root canals of 50 bovine incisors were prepared to receive GFPs, which were conditioned with 24% hydrogen peroxide, silanized, and cemented with a self-adhesive resin cement. After light curing, the specimens were submitted to a pullout test. The dislodged GPFs were distributed into five experimental groups (n = 10 each) according to surface treatment for recementation: NT = no treatment; SI = silane; ET = 92.8% ethanol/silane; HP = 24% hydrogen peroxide/silane; AL = airborne-particle abrasion (50-μm alumina)/silane. The GFPs were recemented with the same self-adhesive resin cement, and specimens were submitted to a second pullout test. Data were analyzed by Student t test and one-way ANOVA (α = .05).Results: For all groups, the recementation bond strength was higher than the strength obtained after the first cementation (P < .05). There were no statistical differences among the experimental recementation protocols (P = .096).Conclusion: All recementation protocols might be reliably applied since they led to higher bond strength than the first cementation. [ABSTRACT FROM AUTHOR]

Abstract Degradation of polymer composites is a significant problem in many engineering aspects. Due to the interaction of various degradation factors during the exploitation of composites, a synergistic effect of destruction is observed. The article describes the phenomena occurring in glass fiber reinforced polyester laminates under the influence of ultraviolet radiation (UV) in an aquatic environment. The laminates were exposed to UV-A, UV-B and UV-C radiation for 1000 h in free-air and underwater conditions. During the test, the materials were immersed at stable depth of 1 mm and 10 mm, respectively. The three-point bending tests performed on the samples after being exposed to UV showed an increase in the flexural strength of the composites. Simultaneously, degradation of the outer surface layer was observed. The degradation removed the thin resin film from the surface which resulted in a direct exposure of the reinforcing fibers to the environment. The transformations taking place in the deeper layers of the composite increased the mechanical strength due to the additional cross-linking reactions excited by the energy arising from the radiation. Moreover, the formation of polymer structures from free styrene remaining after the technological process and the occurrence of free radical reactions as a result of the cage effect was also observed.

Zinc‐based aqueous batteries (ZABs) are attracting extensive attention due to the low cost, high capacity, and environmental benignity of the zinc anode. However, their application is still hindered by the undesired zinc dendrites. Despite Zn‐surface modification being promising in relieving dendrites, a thick separator (i.e. glass fiber, 250–700 μm) is still required to resist the dendrite puncture, which limits volumetric energy density of battery. Here, we pivot from the traditional interphase plus extra separator categories, proposing an all‐in‐one ligand buffer layer (ca. 20 μm) to effectively modulate the Zn2+ transfer and deposition behaviors proved by in situ electrochemical digital holography. Experimental characterizations and density functional theory simulations further reveal that the catechol groups in the buffer layer can accelerate the Zn2+ reduction reaction (ZRR) through the electron‐donating p‐π conjugation effect, decreasing the negative charge in the coordination environment. Without extra separators, the elaborated system endows low polarization below 28.2 mV, long lifespan of 4950 h at 5 mA cm−2 in symmetric batteries, and an unprecedented volumetric energy density of 99.2 Wh L−1 based on the whole pouch cells. The concomitantly "separator‐free" and "dendrite‐free" conjugation effect with an accelerated ZRR process could foster the progression of metallic anodes and benefit energetic aqueous batteries. [ABSTRACT FROM AUTHOR]

This study explores the application of abrasive waterjet drilling (AWJD) for varied patterns of GF/Al mesh hybrid composites (neat glass NG, AG: Al in the exterior surface, and GA: Al in the center). Key parameters such as jet pressure (P), standoff distance (S), and traverse speed (V) are systematically varied, influencing material removal rate (MRR), hole taper ratio (Tr), and roundness error (Re). Employing a Taguchi approach with an L9 design. It was indicated that the optimal conditions for maximum MRR are (P: 150 MPa, S: 2 mm, and V: 900 mm/min). V and S are the main influential parameters on Tr and Re. Gray relational analysis (GRA) is employed for simultaneous optimization, enhancing drilling performance. The optimal parameters P of 150 MPa, S of 2 mm, and V of 300 mm/min are determined. Validation trials confirm the effectiveness of the determined parameters. A robust multiple regression equation is formulated, providing a predictive model that aligns closely with experimental observations. Highlights: The hybrid composites were drilled via a nontraditional process.The attributes of the hole geometry and the material removal impacts were studied.Operation parameters were optimized to improve MRR, Re, and Tr.A multiple regression model and a confirmation test were performed and validated. [ABSTRACT FROM AUTHOR]

Elium® Acrylic/Glass Fiber thermoplastic laminate composites are liable to develop irreversible local defects under quasi‐static loading. To reinforce the damaged material, repair is a cost‐effective mechanical alternative. The present study investigates the tensile behavior of an Elium® glass‐fiber‐based acrylic laminate composite panel, repaired by vacuum bonding with Elium® repair resin and double overlap of external patches (DP). The results obtained for all repaired laminate composites E190/GF_D(10, 20, 30)R with diameters 10, 20, and 30 mm showed an improvement in the mechanical properties of the repaired panels, compared with the drilled and pristine samples. Average load recovery rates were significant for E190/GF_D10R (7.9%, 3.55%, 13%) E190/GF_D20R (23%, 18%, 3.32%), E190/GF_D30R (7.2%, 9.36%, 32.37%) at strain rates of 0.001, 0.01, and 0.05 s−1 respectively. Finite element (FE) models for the virgin, drilled, and repaired composite, performed by coupling the Hashin criteria with the cohesive zone model (CZM), provided a relevant prediction of intra‐ and interlaminar failures of these woven laminated composites. Highlights: The effect of vacuum bonding repair with Elium E351 EOT resin was studied.Symmetrical repair of acrylic laminate drilled by fiberglass patches.Tensile strength of the repaired laminates was investigated.Intra‐ and interlaminar damage was predicted by finite elements modeling. [ABSTRACT FROM AUTHOR]

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

Glass fiber-reinforced cement-based material incorporating hollow glass beads (GFRC-HGB) is an innovative lightweight building material with exceptional energy-saving properties. Based on the framework of variational asymptotic homogenization theory, a micromechanical model is developed for predicting the effective elastic properties and recovering the local fields of unidirectional GFRC-HGB. This model starts with expressing the displacements of the heterogeneous GFRC-HGB in terms of those of the corresponding homogeneous material and fluctuation function. Then, the principle of minimum potential energy is used along with variation asymptotic method to formulate the governing variational statement for the micromechanics model, the micromechanical model is used to quantitatively investigate the influence of internal structural parameters of HGB on the elastic properties of unidirectional GFRC-HGB. The numerical results demonstrate the effectiveness and accuracy of the micromechanical model in predicting the effective elastic modulus and local fields. The numerical simulation and SEM images of the tensile fracture prove that the local stress distributions are closely related to the loading direction, and the transverse deformation is restrained by glass fibers. [ABSTRACT FROM AUTHOR]

With the current development of the 5G infrastructure, there presents a unique opportunity for the deployment of battery-less mmWave reflect-array-based sensors. These fully-passive devices benefit from having a larger detectability than alternative battery-less solutions to create self-monitoring megastructures. The presented 'smart' skin sensor uses a Van-Atta array design enabling ubiquitous local strain monitoring for the structural health monitoring of composite materials featuring wide interrogation angles. Proof-of-concept prototypes of these 'smart' skin millimeter-wave identification tags, that can be mounted on or embedded within common materials used in wind turbine blades, present a highly-detectable radar cross-section of − 33.75 dBsm and − 35.00 dBsm for mounted and embedded sensors respectively. Both sensors display a minimum resolution of 202 μ -strain even at 40 ∘ off-axis enabling interrogation of the fully-passive sensor at oblique angles of incidence. When interrogated from a proof-of-concept reader, the fully-passive, sticker-like mmID enables local strain monitoring of both carbon fiber and glass fiber composite materials. The sensors display a repeatable and recoverable response over 0–3000 μ -strain and a sensitivity of 7.55 kHz/ μ -strain and 7.92 kHz/ μ -strain for mounted and embedded sensors, respectively. Thus, the presented 5G-enabled battery-less sensor presents massive potential for the development of ubiquitous Digital Twinning of composite materials in future smart cities architectures. [ABSTRACT FROM AUTHOR]

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

Lee, H.-J.; Jeung, H.-D.; Song, J.-H.; Hur, Y.B., and Hong, H.-K., 2024. Enhancing seed harvest of wild Manila clam (Ruditapes philippinarum) through fiberglass mesh installation in the tidal flat of Jugyo, west coast of Korea. Journal of Coastal Research, 40(3), 613–616. Charlotte (North Carolina), ISSN 0749-0208. The Manila clam, Ruditapes philippinarum (Bivalvia: Veneridae), is a commercially important species cultivated in tidal flats along the coasts of Korea. However, the local clam industries on the west coast face challenges due to a shortage of seed clams, primarily relying on catching wild juveniles or importing seeds from China. This study aimed to enhance the natural seed harvest of Manila clams by installing fiberglass mesh on the tidal flats of Jugyo, Korea. Fiberglass mesh was installed at three different stations on the tidal flats in October 2017 and clam density was monitored monthly from November 2017 to January 2018. Sediment samples were collected at each station three times using stainless steel quad-rats, and clams were categorized by size (<5 mm, 5–10 mm, 10–20 mm, 20–30 mm, and >30 mm). The results revealed spatial and temporal variations in clam density, with higher concentrations observed closer to the tidal waterline. Clam size distribution also differed across stations, with smaller clams dominating certain areas. The mesh installation in November 2017 did not significantly affect clam density compared with the control group. However, clam density substantially increased in December 2017 and January 2018 because of mesh installation, especially at the lowest station. These findings suggest that installing fiberglass mesh can enhance the survival of newly settled Manila clams, providing a potential solution to the seed shortage the local clam industries face. [ABSTRACT FROM AUTHOR]

Glass fibre-reinforced polymer (GFRP) wastes may be mechanically processed into small strips called "macro fibres," which were used as short reinforcement fibres to produce macro fibre reinforced concrete (MFRC). The addition of such macro fibres into concrete has proven to be effective in enhancing the flexural strength and toughness of concrete, but it also slightly reduces the compressive strength of concrete. This paper presents a study on the behaviour of CFRP-confined MFRC. A total of 84 CFRP-confined MFRC cylinders were prepared and tested in axial compression. The test parameters included the CFRP confinement stiffness, macro fibre content, and fibre length. The test results show that the compressive strength and ultimate axial strain can be significantly enhanced through the use of CFRP confinement. The ultimate axial strain of CFRP-confined concrete with macro fibres is slightly higher than that without macro fibres. The test results were compared with two well-known stress-strain models for FRP-confined concrete, including Teng et al.'s design-oriented model and Jiang and Teng's analysis-oriented model. A comparative analysis showed that both models slightly underestimate the compressive strength and slightly overestimate the ultimate axial strain for CFRP-confined MFRC. [ABSTRACT FROM AUTHOR]

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

In the present work, a combination of virgin polypropylene and E-glass fiber was subjected to ten (10) reprocessing cycles via extrusion and compression molding techniques to mimic recycling and its impacts on the bending properties of the composites. The samples were characterized using Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), scanning electron microscopy (SEM), and melt flow index (MFI). The results revealed a gradual depreciation in flexural properties after each reprocessing cycle. The XRD analysis indicated a substantial reduction of peak intensities, degrees of crystallinities, and average crystallite sizes, explaining the lowered flexural properties in addition to a possible reduction in glass fiber lengths (fiber attrition). Melt-processing behavior shows a progressive increase of MFI from 7 to 19.16 g/10 min, confirming the probable damage in molecular weight and loss of complex viscosity. Chemical and structural analysis showed no alteration in the polypropylene major functional groups. It is concluded that the reductions in molecular weight and composites' properties occurred due to chain scission from recycling effects; hence, glass fiber-reinforced polypropylene composites can be recycled only three (3) times unless it is refreshed by the addition of virgin parts to compensate for the lost property. [ABSTRACT FROM AUTHOR]

In the field of lightweight structures, foldcore sandwich structure is regarded as a promising replacement for conventional honeycomb sandwich structure. In this study, a new M-type glass fiber foldcore structure was fabricated by hot-pressing molding technology, and the effects of various factors on the low-velocity impact characteristics were investigated. In addition, a 3 D progressive damage numerical model matching the experimental results was established. The results showed that the impact energy exerted a certain influence on the response characteristics of the sandwich structure, but did not change the development trend of the load curve. The sandwich panel was able to achieve the overall load-carrying potential for the impactor whose size was longer than the foldcore span (25 mm). In addition, as the sharpness of the impactor increased, the damage range of the sandwich panel became concentrated and the load-bearing capacity gradually decreased. As revealed by the findings, the maximum load and specific energy absorption of laminated sandwich panels were improved by 150 and 40% respectively compared to single sandwich panel at base position. Therefore, it is beneficial to appropriately reduce the core span and increase the number of laminations to improve impact resistance of foldcore sandwich in practical applications. [ABSTRACT FROM AUTHOR]

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

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

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

The present study investigates the flexural failure properties of a hybrid laminate beam subjected to three-point bending. A symmetrically laminated hybrid beam is constructed using high-strain and inexpensive glass fibre on the top layers and low-strain and expensive carbon fiber on the middle layers. Classical lamination plate theory is used to find the stress and strain distribution that occurs due to the bending moment on the compressive side. The theoretical failure limits of the laminated hybrid beam are analyzed considering the targeted span-to-depth ratios, volume fractions of the fibers and hybrid ratios using the Tsai-Wu failure criterion and Matlab codes. Using the graph of failure index versus hybrid ratios, the minimum thickness of carbon fiber needed for the delay of failure and cost efficiency of the laminated hybrid beam is identified by applying the linear interpolation method. The numerical results indicate that the failure index increases with the increasing loading span and decreases when the volume fraction of fiber increases. In particular, the placement of glass fiber on the top layer of the laminated hybrid beam might have contributed to obtaining higher strains and curvatures before the catastrophic failure properties of carbon fiber. The flexural stiffness of the laminates is found to increase when the hybrid ratio increases. Overall, it is noted that the theoretical analysis is one method that is less time-consuming and cost-effective than other alternative approaches, such as finite element methods and experimental tests to estimate the minimum thickness of high-stiffness and the expensive material needed to maintain the strength and stiffness of the hybrid composite structures over long periods. [ABSTRACT FROM AUTHOR]

Improving indoor air quality through the use of air purifiers has become a major focus, with emphasis on developing filters with high efficiency, high holding capacity, and low-pressure drop to improve the clean air delivery rate (CADR) for air purifiers. However, although most studies focused on developing media and evaluating their performance, few studies have reached the employment for a pleated filter. In this study, we newly synthesized flat media and pleated filters by combining polytetrafluoroethylene membrane (PT) and melt-blown (MB) materials (PM) and compared its initial performance to that of other air purifier filters (MB, glass fiber, and PT). Additionally, we analyzed how the performance changed after the particles were loaded. The initial efficiency of the PM filter showed a higher quality factor (QF) than the other filters. Furthermore, when more particles were loaded, the penetration of the PM did not change. These results demonstrate the potential of the PM. However, the CADR and submicron-sized (0.02–0.113 μm) CADR (sCADR) were highest for the MB filter due to the initial pressure drop. Therefore, additional improvements are required to apply the PM in air purifiers. However, the results suggest that the PM can be a new alternative for air purifier filters used in medical centers or facilities with vulnerable populations where a high-efficiency particle air (HEPA) filter must be used. [ABSTRACT FROM AUTHOR]

Glass fiber‐reinforced resin matrix composites have good mechanical and impact resistance properties, while with particle co‐reinforcement, a synergistic effect can further improve their performance. In this paper, continuous glass fiber‐reinforced nylon 6 (GF/PA6) and continuous glass fiber (GF) with glass beads (GBs) co‐reinforced nylon 6 (GB–GF/PA6) were prepared to investigate the co‐reinforcement mechanism and the synergistic effect of particle and fiber. A quantitative parameter of the residual impact force divided by the critical force Pr/Pcr, as the damage degree of the low‐velocity impact, is defined to evaluate the impact resistance of the composite. The results indicate that the damage of GB–GF/PA6 was lower than that of GF/PA6, and the synergistic effect reaches the most obvious at the GB addition of 10 wt%. Scanning electron microscope (SEM) and x‐ray computed tomography (XCT) images disclose that GB impedes the type II crack spread in the matrix and fiber/matrix interface. With the type II cracks reducing, the materials' resistance to delamination can be significantly enhanced. For the composite structure, in which 10 wt% GB and 60 wt% GF are introduced, the flexural strength, shear strength, and pendulum impact strength were tested with the maximum values of 379.4 MPa, 53.1 MPa, and 219.0 J/m2, respectively. This composite structure design, presenting a continuous GF and GBs co‐reinforce effect, offers a manufacturing process that is easily scalable to achieve excellent characteristics. [ABSTRACT FROM AUTHOR]

Composite thin‐walled tubes made of glass fiber reinforced plastics (GFRP) are attracting great attention due to their lightweight and outstanding crashworthiness capacity. Implementing triggers to the design of GFRP composite tubes enables a further increase in specific energy absorption while simultaneously reducing peak crushing force. Motivated by these facts, a notch‐type triggering mechanism is suggested in this work to enhance the energy absorption capabilities of circular GFRP composite tubes. GFRP tube samples with (0°/90°)8 layups are manufactured using the roll wrapping process. Subsequently, these samples are triggered and subjected to quasi‐static axial compression tests. The diameter, quantity and placement of the triggering notches are selected as design parameters, and experiments are carried out using Taguchi's L9 orthogonal array. Each of these parameters has three levels to identify the optimal combination of design parameters. To optimize multiple responses, the weighted aggregated sum product assessment, a multiple criteria decision‐making technique, is employed in conjunction with mono‐criteria optimization. The findings indicated that substantial enhancements can be realized in all parameters related to energy absorption performance by triggering progressive crushing modes in a controlled manner using a notch‐type triggering mechanism. In particular, the findings indicated that the specific energy absorption and the crush force efficiency of the intact GFRP composite tubes could be improved up to 18% and 68.3%, respectively, by the selection of appropriate triggering parameters. Highlights: Axial crushing and optimal design of triggered GFRP tubes are investigatedNumber, diameter, and center distance of the notches are chosen as parametersTaguchi experimental design is used for the best configuration of parametersThe optimum configurations are investigated using the entropy‐WASPASSignificant improvements are achieved using the trigger mechanism [ABSTRACT FROM AUTHOR]

This study looks at the mechanical and free vibration properties of glass laminated with functionalized aluminium reinforced epoxy. NaOH, K2Cr2O7, Fe2(SO4)3. XH2O, and C8H18O3Si were employed to functionalize aluminum. The flexural, impact, and shear strengths, as well as their failures, were investigated using electron microscope images. The impulsive hammer approach was applied to investigate laminate vibration behaviour. The results showed that the flexural strength (623.83 MPa), impact strength (76.41 J/mm2), and shear strength (55.31 MPa) of C8H18O3Si functionalized laminates outperformed those of other functionalized laminates. The improvement of mechanical properties was due to the change in interfacial adhesion. This is dependent on the functionalization of aluminium used in stacked laminates. Moreover, C8H18O3Si functionalized laminates exhibit a higher natural frequency and higher damping than other functionalized laminates. This natural frequency and damping are enhanced due to the strong mechanical interlocking between polymer and metal adhesion. It was noted that the same laminates have higher toughness than other laminates because of the high impact energy obtained. [ABSTRACT FROM AUTHOR]

Hydrogen as a fuel of the future for mobile applications has the potential to increase energy efficiency and reduce emissions significantly (Groos et al., 2023 [1]). A main focus to enable hydrogen powered aviation is the efficient storage onboard (Prewitz et al., 2023 [2] ; Verstraete et al., 2010 [3] ; Prewitz et al., 2020 [4]). Especially the storage volume is a major challenge because of the rather low volumetric energy density of compressed or either liquified hydrogen in comparison with kerosene (Hassan et al., 2021 [5] ; Stetson et al., 2014 [6] ; Troeltsch et al., 2020 [7]). Glass capillaries have a high strength, also their geometry and low hydrogen permeability make them a suitable micro pressure tank (Prewitz et al., 2018; Veziroglu et al., 2003 [8] ; Meyer-Scherf, 2015 [9]). By combining glass capillaries and carbon fibers in a polymer matrix, a material composite could be developed that is both a structural element, contributing to load bearing, and a hydrogen tank at the same time. The synergetic use of the structure as storage could be a solution to tackle the problem of the increased required storage volume for hydrogen powered aviation. This paper presents a theoretical micromechanical analysis, the design and manufacturing process of the composite material, and the experimental results of tensile testing conducted on a glass capillary hybridized carbon fiber reinforced plastic (GCRP). The aim is to determine the influence of the glass capillary content on the tensile strength and tensile modulus of the GCRP. • Development of carbon fiber and glass capillary hybrid structural hydrogen storage. • Multipurpose utilization and potential synergetic effects could save weight. • Tensile mechanical properties shows degradation with increasing capillary fraction. [ABSTRACT FROM AUTHOR]

Three‐dimensional woven spacer composites (3DWSCs) with lightweight and excellent mechanical properties have promising application in communication, transportation, aerospace and other fields. However, traditional single‐layer 3DWSCs exhibit insufficient strength, especially when dealing with high thickness, as the pile yarns tend to buckle. In this study, inspired by the structural features of the Thalia dealbata, 3D woven integrated double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated. Innovative integrated double‐layer structure design effectively improves the performance and failure mode of 3DWSCs under bending loads. Compared to single‐layer 3DWSCs, the resulting double‐layer 3DWSCs exhibited a 41.79% increase in peak bending load, a 46.85% increase in bending stiffness, and a 99.38% increase in energy absorption. In addition, the double‐layer 3DWSCs showed a low density of 0.52–0.55 g/cm3. This work introduces bioinspired double‐layer 3DWSCs with characteristics of lightweight and superior bending performance, potentially offering novel ideas for the design of high‐performance composites. Highlights: Inspired by the structural features of the Thalia dealbata, a 3D integrated woven double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated.3D woven double‐layer spacer composites are lightweight (0.52–0.55 g/cm3) and can effectively improve the bending properties of single‐layer structures.Based on the analysis of the fracture morphology, the significant improvement of the fracture pattern of the single‐layer structure by the double‐layer structure is effectively demonstrated.This study introduces novel design strategies for multi‐layer lightweight composite materials and holds broad applications. [ABSTRACT FROM AUTHOR]

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

The present scenario forces researchers to reduce raw material usage for future conservation and imposes a responsibility to reuse the waste by converting it into valuable products. With a state of potential, the components are put forward for reusing the diamond-cutting waste as effective filler particles in the polyepoxide-glass laminated hybrid composite. The polymer composites were prepared using the hand lay-up process under hydraulic loading conditions. The composites were formulated by changing the diamond filler fraction (1, 3, 5 and 10 wt%) and keeping a constant glass weight percentage of 20%. The composite's mechanical, thermal stability and erosion properties were evaluated to study the effect of diamond filler material in glass fibre composites. With the addition of 5% diamond particles, the tensile, flexural, and Shore D hardness were improved by a maximum of 48, 34 and 26%, respectively, compared to the polyepoxide glass fibre composite, due to the restraint on deformation of polymer chains. There was minor diamond particle aggregation due to fines in more than 5% of the diamond filler, reducing the rate of improvement of the mechanical behaviour. The higher thermal conductivity and increased strength offered by diamond filler improved thermal resistance and slowed down the thermal degradation of composites. The sand erosion test reveals that diamond particles boosted the erosive wear resistance of the composites by offering high mechanical strength, which could change the erosion wear mechanism. Erosion morphology determined through SEM analysis found that high-volume diamond particles reduced erodent-polymer matrix interaction at the micro level, decreasing the erosion wear of diamond-filled composites. [ABSTRACT FROM AUTHOR]

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

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

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

In this paper, the glass-fiber-fabric-reinforced resin-based absorbing composites were prepared, and their microwave-absorbing properties were studied via simulation and experiment. The simulation results show that the absorption bandwidth of the absorbing material can cover the X\C\S band, respectively, at different thicknesses. The minimum reflection loss (RL) of the composite with a thickness of 2.2 mm is −27.4 dB at 5.95 GHz. However, the experiment results are quite different from those of the simulation. The metallographic results indicate that it is the change of the mass fraction of the absorbents in the composites after curing that causes the difference. According to the metallographic results, three shape approximation methods were proposed to calculate the real mass ratio of the absorbents in the composites, namely, parallelogram approximation, bows approximation, and elliptical approximation. Meanwhile, the structural parameter K f was introduced to optimize the calculation results. The electromagnetic parameters of the material based on the calculation results were measured, and the results show that the simulation results obtained via bow approximation have a better coincidence to the experiment results, and the mass ratio of the absorbent raises by around 9.95%, which lays a foundation for the subsequent design of microwave-absorbing composites. [ABSTRACT FROM AUTHOR]