Glass Fiber Research Articles

Infiltration of glass nanofiber-reinforced polylactic acid into delignified hardwood toward photoluminescent and mechanically reliable smart windows

Ultraviolet-protective, mechanically reliable, and photoresponsive wood that can switch color under ultraviolet light was developed. A combination of alkaline earth-doped strontium aluminate (ASA) as a photoluminescent pigment and glass nanofiber-supported polylactic acid as a hosting agent was infused into a delignified wood, producing transparent wood with photochromic activity. The ASA phosphor has proven high thermal stability and photostability. A typical process for producing colorless photoluminescent wood includes the well-dispersion of ASA in glass nanofiber-supported polylactic acid without agglomeration. As proven by the coloration measurements, the current photoluminescent wood becomes green under ultraviolet light and remains transparent under daylight. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) were employed to determine the morphology of the phosphor particles and glass fibers, demonstrating sizes of 12–21 nm and 50–125 nm, respectively. The luminescent wooden samples were studied by numerous microscopic and spectroscopic techniques, including SEM, X-ray fluorescence (XRF), and energy-dispersive X-ray (EDX). Upon excitation at 365 nm, the luminescence wood demonstrated an emission peak at 518 nm. When increasing the ASA concentration, the photoluminescent hardwoods displayed improved ultraviolet protection and better water resistance. The responsiveness of the luminescent wood to UV irradiation was fast and reversible.

In‐situ fabrication of poly‐l‐lactide & its application as a glass fiber polymer composites using resin transfer molding

In‐situ fabrication of poly‐l‐lactide & its application as a glass fiber polymer composites using resin transfer molding

Numerical analysis of FRP retrofitting in RC beam-column exterior joints at high temperatures and predictive modeling using artificial neural networks

PurposeThe purpose of this study is to perform a numerical analysis of fiber-reinforced polymer (FRP) retrofitting in reinforced concrete (RC) joints at high temperatures and predict models using artificial neural networks (ANN). The aim was to gain insights into their structural behavior across a range of loading conditions from room temperature to 800°C. Additionally, the research assessed the efficiency of carbon fiber-reinforced polymer (CFRP), glass fiber reinforced polymer (GFRP) and aramid fiber reinforced polymer (AFRP) strengthening in enhancing the structural performance of the critical sections.Design/methodology/approachThe linear numerical simulations were conducted to evaluate the performance of RC beam-column joints using finite element modelling (FEM) analysis. The ANN model demonstrated exceptional effectiveness in predicting the stiffness of frames with openings, establishing itself as the premier machine learning algorithm for frame stiffness estimation. In the conventional model, 300°C was proven to be an effective temperature approach. Subsequently, maintaining a constant temperature of 300°C, an in-depth analysis of nearly 30 models of three retrofitting techniques was conducted under thermomechanical loading.FindingsThe CFRP retrofits yielded 15% less deflection and 30% more stress than the remaining FRPs, and the ANN models predicted the deflection, main stresses, bending moment and shear force. The ANN model results were compared with those of other frequently used models. The R thresholds (R = 0.954, 0.981, 0.986, 0.968, 0.978 and 0.936) for training, testing and validation indicated that the ANN model achieved data variability. The findings indicate that the ANN model is more accurate because of the strong connection between the numerical model and the prediction.Originality/valueTo identify the pinpoint of critical segments within the rehabilitation section and determine the most effective wrapping method among the three laminates.

Research on low-velocity impact performance of polyurethane foam-filled M-type GFRP foldcore sandwich plate

The M-type GFRP (Glass Fiber Reinforced Polymer) foldcore was prepared by thermal pressing method, and was bonded with the panel to obtain the complete foldcore sandwich structure and filled the core with polyurethane foam. The influence of foam filling, impact energy and impact position on the damage mode and impact dynamic response under the low-velocity impact of GFRP M-type foldcore sandwich structure is studied through low-velocity experiment. The results show that the impact resistance of N-side impact is better than the B-side impact. Foam filling could effectively closing the gap between the N-side impact and B-side impact. In addition, foam filling could absorb about 15%-25% more energy than the empty core sandwich plate.

Ductility assessment of GFRP reinforced concrete beams with a wedge-based mechanical model accounting for discrete fibers and confinement

Glass fiber-reinforced polymer (GFRP) bars for internal reinforcement for concrete have gained attention due to their non-corrosive properties, high resistance, and electromagnetic transparency. On the other hand, the brittle behavior and low modulus of elasticity of FRP bars limit their application and diffusion in the civil construction market. From this perspective, this work investigates the influence of three components on the increase of ductility of GFRP beams: i) discrete alkali-resistant glass fibers added to the concrete; ii) confinement of the concrete with GFRP stirrups; and iii) use of longitudinal reinforcement on the compression zone. An experimental program including four over-reinforced beams with different reinforcement configurations was conducted. The beams were tested in four-point bending configuration and the use of fibers, stirrups and compression reinforcement contributed to substantially increasing the beam ductility index. Finally, a concrete wedge model was developed to obtain equivalent stress-strain relationships for the concrete in compression. The model was successfully validated against experiments and proved to be a useful tool for rationally evaluating GFRP RC beams’ ductility.

Characterization of bauxite residue filled sisal/glass fiber reinforced hybrid composites for structural applications

Abstract Composite materials with high compressive, flexural, and shear strength are essential for constructing various structural elements in automotive, aerospace, marine, and construction sectors. The present research aims to create bauxite residue filled sisal/glass fiber reinforced polyester composites. The different weight percentages of sisal fiber (35 %, 30 %, 25 %, and 20 %), red mud (0 %, 5 %, 10 %, and 15 %), glass fiber (5 %), and polyester matrix (60 %) were used to fabricate composites. The combined use of compression molding and hand layup technique was employed in the creation of composite materials due to its frequent utilization in the manufacturing of large-scale components found in various sectors, including automotive, aerospace, marine, and construction. In this work, investigated the physical, compressive, flexural and v notch rail shear strength of the fabricated composites. Results revealed that the composites with 30 % of sisal fiber and 5 % of red mud has the highest compressive, flexural, and v notch rail shear strength of 83.45 MPa, 182.74 MPa, and 10 MPa, respectively. Further, this composite showed high density, less void content, and less thickness swelling than other composites. According to the outcomes, this composite material demonstrates suitability for various structural applications across automotive, aerospace, marine, and construction sectors.

Ultra‐Broadband Emission in Bi/Ge Co‐Doped Silica Glass and Fiber via Bismuth Coordination Engineering

AbstractBismuth (Bi) and Germanium (Ge) co‐doped silica glass and fiber, as advanced gain media with broadband near‐infrared (NIR) emission and amplification, have promise for extending communication bandwidth. However, efficiently modulating the NIR emissions of bismuth to cover the C+L communication bands remain a significant challenge. In the study, a high‐temperature and high‐pressure reduction treatment on Bi/Ge co‐doped silica glass is employed to tailor the coordination environment around bismuth active center. This method facilitated the creation of new bismuth NIR luminescence centers, resulting in the luminescence spectrum with a peak position at 1550 nm and a FWHM exceeding 350 nm. The changes in the bismuth coordination environment are elucidated using HRTEM, photoluminescence decay, temperature‐dependent emission, EXAFS and CW‐EPR. Furthermore, the feasibility of this method in Bi/Ge co‐doped silica fiber is validated, and obtained >5 dB amplification in the range of 1400–1700 nm. This coordination engineering method holds significant potential for widespread application in Bi/Ge co‐doped silica glass and optical fiber is believed. It presents a promising prospect for expanding communication bandwidth by effectively modulating the NIR emissions of bismuth to cover the S to U communication band.

Post-Space Disinfectants With Sodium Hypochlorite and Methylene Blue Loaded in Silver and Quartz Nanoparticles Activated by Photodynamic Therapy. A SEM Analysis.

Post-space disinfectants methylene blue loaded with silver (Ag) and Quartz nanoparticles (NPs) and MB alone activated by photodynamic therapy (PDT) on the survival of Enterococcus faecalis, smear layer (SL) removal efficacy, and extrusion bond strength (EBS) of fiber posts to canal dentin. Hundred mandibular premolars underwent root canal treatment using the rotary ProTaper system. The canals were obturated and post-space was prepared up to a length of 8 mm, maintaining a 5 mm seal. To assess antibacterial efficacy E. faecalis were inoculated in the canal (n = 20). The samples were then randomly allocated into four groups according to the canal disinfectant used to sterilize the canals. Group 1: 2.5% NaOCl+17% EDTA, Group 2: MB-PDT, Group 3: MB@QP-PDT, and Group 4: MB@AgNP-PDT (n = 25). SEM analysis was conducted on five samples from each disinfectant group to assess the removal of the SL. Survival rates were calculated (n = 5 from each group). Glass fiber post (GFP) was cemented to the root dentin of the remaining samples followed by artificial aging. Sectioning of the specimens was performed in all three-thirds of the canals. PBS was assessed followed by failure evaluation. ANOVA and Tukey post hoc test were used to compare the E. faecalis survival rate and PBS of fiber post among different investigated groups. Group 4 (MB@AgNP-PDT) treated canals exhibited the minimum survival rate (0.30 ± 0.04 CFU/mL) of E. faecalis and maximum PBS. However, the highest survival rate and minimum bond strength of GFP were observed in Group 1 (NaOCl+17% EDTA) and Group 2 (MB-PDT) treated teeth respectively. The highest SL removal was recorded in the coronal section of the samples of Group-4 disinfected with MB@AgNP-PDT. The lowest removal of SL was recorded in Group 2 samples sterilized with MB-PDT at apical one-third. Silver nanoparticles when utilized as nano-carriers to enhance the efficiency of MB activated by PDT, have been shown to exhibit the highest antimicrobial potency, improved capacity for SL removal and improved PBS.

Experimental and numerical investigation on RC beams with web openings subjected to pure torsion strengthened by ferrocement technique or GFRP sheets

The main objective of the current experimental and numerical study is to investigate the effect of strengthening by ferrocement layers on the behavior of reinforced concrete (RC) beams with openings subjected to pure torsion and compare it with the beams that were strengthened by Glass Fiber Reinforced Polymer (GFRP). The experimental investigation consists of twelve reinforced concrete (RC) beams that have been divided into four groups. The parameters under investigation included the strengthening technique (ferrocement or External Bonded Glass Fiber Reinforced Polymer EB-GFRP), type of steel mesh (welded wire mesh and expanded metal mesh), number of layers of mesh (1, 2, 3), extension length outside opening (50, 100 or 200) mm, strengthening configuration (full or U-shape) wrapping, and the anchoring system effect. The experimental work consists of one solid beam and eleven beams with openings. The tested beams yielded results such as cracking and ultimate torques, angle of rotation, and mechanism of failure. Creating an opening in the control solid beam resulted in a 38.46 % decrease in ultimate torque, while using different techniques during this research proved efficiency in the strengthening process. Using GFRP U-wrapping and fully wrapping to strengthen the area around the beam's opening increased the ultimate torque by 50 % and 81.25 %, respectively, compared to the un-strengthened beam with an opening. Adding fully wrapped ferrocement layers to the beam with an opening greatly improved its torsional strength. The ultimate torque increased by 40.63 % to 81.25 % compared to the beam with an unreinforced opening. Increasing the number of welded steel mesh layers from 1 to 3 in the ferrocement strengthening technique led to an increase in ultimate torque from 40.63 % to 75 % compared with the un-strengthened beam with the opening. The tests showed that using expanded metal mesh instead of welded wire mesh in strengthened beams with holes led to a 9.43 % higher ultimate torsional capacity, indicating that the expanded metal mesh worked better than the welded wire mesh. Using the U-shape ferrocement wrapping with anchors was better than without anchors, resulting in a 9.1 % increase in the ultimate torsional capacity. Applying a fully wrapped GFRP sheet or expanded metal mesh ferrocement strengthening achieved the highest ultimate torque, 81.25 % more than the un-strengthened beam with an opening. Moreover, a 3D non-linear finite element analysis is conducted using ABAQUS software to forecast the torsional properties of beams strengthened by either ferrocement or EB-GFRP. The numerical model captured the failure patterns, twisting angle, and ultimate load of tested beams. The experimental and analytical results were in good agreement. The research concluded the effectiveness of using the ferrocement reinforced with different steel mesh types in strengthening reinforced concrete beams with openings under pure torsion, the cost-efficiency and simplicity of ferrocement as a solution compared to its results with EB-GFRP techniques.

Very high cycle fatigue properties of short glass fiber reinforced polyetheretherketone (PEEK)

The fatigue properties of 14 wt-% short glass fiber reinforced polyetheretherketone (PEEK–GF14) have been investigated in the high and very high cycle fatigue (VHCF) regime. Experiments were performed at a load ratio of –1 with servohydraulic and electrodynamic equipment at cycling frequency 10–20 Hz, and with ultrasonic equipment at 19 kHz. A new specimen geometry has been developed that allows ultrasonic tests up to high stress amplitudes. The same specimen shape was used in both testing series to exclude size effects, which enabled to focus on the influence of cycling frequency and testing technique. Ultrasonic fatigue testing with intermittent loading served to avoid heating of specimens. The S-N curves measured at 10–20 Hz and 19 kHz show a similar slope exponent (i.e., 10 % deviation). Mean S-N curve determined with ultrasonic equipment is shifted to slightly lower stress amplitudes, which may be attributed to statistical scatter. PEEK–GF14 does not show a fatigue limit and failures still occurred above 109 cycles. The VHCF strength of PEEK-GF14 is approximately two times higher compared with unreinforced PEEK. Fractographic investigations revealed fiber fracture and, less frequently, fiber pull-out.

Characterization of woven composite material under multiaxial loading regimes using FE-based stereocorrelation

In this paper, woven glass fiber composite samples were subjected to three different cyclic loading histories (i.e., tensile, shear and combined loading at 45° via the Modified Arcan Fixture. During the experiments, the samples were monitored by a stereovision system. Finite Element based stereocorrelation was used to measure the displacement and strain fields. The analysis of the experiments revealed different damage mechanisms. Furthermore, for the 45° experiment, the highest strain levels were reached, whereas for the tensile test, the highest stress levels were achieved.

Delamination inspection in composite laminates with S0 Lamb wave using flexible macro-fiber composite transducers

Abstract Delamination in composite laminates poses a serious threat to structural integrity in aerospace applications due to its potential to cause structural failure. Effective structural health monitoring (SHM) methods are needed to identify such damage. The objective of this paper is to measure and localize delamination in a glass fiber reinforced polymer (GFRP) cross-ply composite laminate based on the S0 Lamb wave detection method, using the Macro-Fiber Composite (MFC) as both actuator and receiver. To analyze the interaction behaviors between the excited S0 Lamb wave and delamination, the finite element models were established to simulate the Lamb wave propagation in composites, incorporating the local stiffness reduction method to model the delamination region. The simulation results indicate that the interaction behaviors between the excited S0 wave and the delamination occur mainly at the end of the delamination, and the generated new wave packets in the received signals can be used to identify the delamination. Furthermore, the S0 wave reflected from the end edge of delamination was used to localize the delamination. Reflection coefficients were found to vary significantly with delamination depth, and the delamination's longitudinal position was accurately localized using Time-of-Flight (ToF) extraction. Finally, a pitch-catch experiment with MFC transducers was conducted to detect an artificial delamination, demonstrating that it is a promising approach to inspect delamination accurately with end-edge reflected waves.

Corrigendum to: “The ductility performance of concrete using glass fiber mesh in beam specimens”

Corrigendum to: “The ductility performance of concrete using glass fiber mesh in beam specimens”

Post-fire performance of hybrid GFRP-steel reinforced concrete columns

The fire safety requirements and knowledge on the use of Glass Fiber Reinforced Polymer (GFRP) bars as an alternative to conventional steel in reinforced concrete structures have been progressively evolving. This study investigates the post-fire axial performance of square GFRP reinforced concrete (RC) columns, addressing a significant gap in current knowledge. Five column specimens of the same cross-section and length were tested, where the main parameters considered are the clear cover depths (40, 50, and 65 mm) and the use of a 40-mm insulation on one column. The columns were subjected to a long 3-hour fire exposure per ASTM E119 standard without sustained loading. The columns were tested upon cooling under concentric axial loading. Despite the notable temperature differences between columns with 40 and 65 mm concrete cover (300 and 500 °C after 3 hours), the post-fire residual axial capacity appeared unaffected. This is primarily attributed to the minimal differences in the retained mechanical properties of GFRP bars at temperatures exceeding 200 °C. The study's findings indicate that GFRP longitudinal bars do not significantly influence the performance of columns in fires. Consequently, future research should focus on columns reinforced with GFRP ties as well. The predicted values of post-fire axial capacity closely match the experimental data for non-insulated columns, indicating a high degree of accuracy. The study provides design recommendations to enhance the fire performance of such elements. The use of insulation results in a substantial reduction of temperature at various depths of the column. Post-fire residual capacities for non-insulated columns were approximately 30 %, whereas insulated columns demonstrated a 60 % residual capacity.

Compressive Properties and Failure of Aluminum/Epoxy Resin Interpenetrating Phase Composites Reinforced by Glass Fiber

Compressive Properties and Failure of Aluminum/Epoxy Resin Interpenetrating Phase Composites Reinforced by Glass Fiber

Crushing responses of carbon/glass hybrid composite tubes under dynamic compressive loads

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

Impact of Runner Size, Gate Size, Polymer Viscosity, and Molding Process on Filling Imbalance in Geometrically Balanced Multi-Cavity Injection Molding.

The injection molding process is one of the most widely used methods for polymer processing in mass production. Three critical factors in this process include the type of polymer, injection molding machines, and processing molds. Polypropylene (PP) is a widely used semi-crystalline polymer due to its favorable flow characteristics, including a high melt flow index and the absence of a need for a mold temperature controller. Additionally, PP exhibits good elongation and toughness, making it suitable for applications such as box hinges. However, its tensile strength is a limitation; thus, glass fiber is added to enhance this property. It is important to note that the incorporation of glass fiber increases the viscosity of PP. Multi-cavity molds are commonly employed to achieve cost-effective and efficient mass production. The filling challenges associated with geometrically balanced layouts are well documented in the literature. These issues arise due to the varying shear rates of the melt in the runner. High shear rate melts lead to high melt temperatures, which decrease melt viscosity and facilitate easier flow. Consequently, this results in an imbalanced filling phenomenon. This study examines the impact of runner size, gate size, polymer viscosity, and molding process on the filling imbalanced problem in multi-cavity injection molds. Tensile bar injection molding was performed using conventional injection molding (CIM) and microcellular injection molding (MIM) techniques. The tensile properties of the imbalanced multi-cavity molds were analyzed. Flow length within the cavity served as an indicator of the filling imbalance. Additionally, computer simulations were conducted to assess the shear rate's effect on the runner's melt temperature. The results indicated that small runner and gate sizes exacerbate the filling imbalance. Conversely, glass fiber-filled polymer composites also contribute to increased filling imbalance. However, foamed polymers can mitigate the filling imbalance phenomenon.

Mechanical properties of glass and jute fiber reinforced thermoplastic composites with waste PET needle-punched carpet matrix

Mechanical properties of glass and jute fiber reinforced thermoplastic composites with waste PET needle-punched carpet matrix

On the Fabrication Processes of Structural Supercapacitors by Resin Transfer Molding and Vacuum-Assisted Resin Transfer Molding

This study investigated the manufacturing processes for structural supercapacitors (SSCs) using smear molding (RS), resin transfer molding (RTM), and vacuum-assisted resin transfer molding (VARTM). Woven carbon fibers were used as the electrode, woven glass fibers as an insulating layer, and an alkaline/epoxy compound as the electrolyte. In the RTM process, due to the vacuum and the high-pressure injection of the electrolyte, the electrochemical and mechanical properties of the SSC can be greatly improved, and the void contents in the SSC can be reduced. The balanced electrochemical performance and mechanical properties of SSCs were observed in the range of epoxy content from 15 wt% to 30 wt%. This study contributes to the development of SSCs through the establishment of the fabrication process for improvements in part quality. The fabrication method demonstrated here can be directly applied by industries to produce even larger-scale SSCs, opening up new possibilities for practical implementation and scalability.

Natural Silkworm Cocoon-Derived Separator with Na-Ion De-Solvated Function for Sodium Metal Batteries.

The commercialization of sodium batteries faces many challenges, one of which is the lack of suitable high-quality separators. Herein, we presented a novel natural silkworm cocoon-derived separator (SCS) obtained from the cocoon inner membrane after a simple degumming process. A Na||Na symmetric cell assembled with this separator can be stably cycled for over 400 h under test conditions of 0.5 mA cm-2-0.5 mAh cm-2. Moreover, the Na||SCS||Na3V2(PO4)3 full cell exhibits an initial capacity of 79.3 mAh g-1 at 10 C and a capacity retention of 93.6% after 1000 cycles, which far exceeded the 57.5 mAh g-1 and 42.1% of the full cell using a commercial glass fiber separator (GFS). The structural origin of this excellent electrochemical performance lies in the fact that cationic functional groups (such as amino groups) on silkworm proteins can de-solvate Na-ions by anchoring the ClO4- solvent sheath, thereby enhancing the transference number, transport kinetics and deposition/dissolution properties of Na-ions. In addition, the SCS has significantly better mechanical properties and thinness indexes than the commercial GFS, and, coupled with the advantages of being natural, cheap, non-polluting and degradable, it is expected to be used as a commercialized sodium battery separator material.