Glass Fiber-reinforced Composites Research Articles

Evaluation of interlaminar shear strength of co-cured fiber-reinforced fabric composite structures by lap joint method

Interlaminar shear strength (ILSS) indicates the resistance to interlaminar delamination of fiber-reinforced composite structures. The short beam shear (SBS) method has been commonly used for ILSS measurement, but unwanted failure modes can appear like a compressive or tensile failure in surface, and diagonal shear failure, causing poor measurement accuracy. The lap joint method has advantage that leading to a clear measurement of the shear strength. This paper proposed the lap joint method for extracting ILSS values of co-cured carbon or glass fiber-reinforced fabric composites (CFRC or GFRC) by minimizing the discrepancy between the experiment and finite element analysis of ILSS test. The lap joint method can compensate for the shortcomings of the SBS method. The calculated ILSS based on the lap joint method (LJ-ILSS) with correction factors showed similar values to the ILSS values by SBS method (SBS-ILSS) done by our work and other works of literature. Therefore, the proposed lap joint method has shown potential as a method to measure ILSS of the co-cured fiber-reinforced fabric composites, but also it can be extended to other types of fiber-reinforced composites.

A Comparative Study of the Static and Dynamic Characteristics of Jute and Glass Fiber-Reinforced Polyester Composites

A Comparative Study of the Static and Dynamic Characteristics of Jute and Glass Fiber-Reinforced Polyester Composites

Intraradicular Diameter, Remnant Dentin Thickness, and Endodontic Post to Dentin Distance: CBCT and Microscopic Analyses

The objective of this work was to measure the tooth root canals’ diameter, remnant dentin thickness, endodontic post to dentin distance, and resin-matrix cement layer after three types of root canal shaping. Thirty extracted human premolars were endodontically treated and groups of specimens were divided according to the cementation with two different endodontic posts as follow: A) Fibio Fiberglass Post™, Anthogyr, France; B) multi-filament GFRC (Rebilda GT™, VOCO, Germany). Cone beam computed tomography (CBCT) and conventional X-ray analyses were performed before and after the endodontic post cementation. After cementation, specimens were cross-sectioned and inspected by optical microscopy and scanning electron microscopy at magnification ranging from × 30 up to × 2000. Changes in shaping of the root canals caused a decrease in the thickness of the remnant tooth tissues. CBCT and microscopic analyses also revealed a clear variation of resin-matrix cement around the glass fiber-reinforced composite (GFRC) posts. A multi-filament GFRC post provided an adequate distribution of filaments although the resin-matrix cement revealed a high volume among the filaments. An increase in thickness and volume of resin-matrix cement was noticed at the coronal third since the fitting was compromised due to tooth anatomic variations and root canal preparation. Defects such macro-scale pores, cracks, and voids were also detected by microscopic analyses. The root canal shaping can promote a decrease in the thickness of the remnant tooth tissues that can increase the risks of clinical failures by fracture. The thickness and volume of resin-matrix cement varied around both GFRC posts and increased from the apex up to the coronal third due to the lack of fitting.Graphical

Manufacture and Vibration-Damping Effect of Composites for Archery Carbon Fiber-Reinforced Polymer Limb with Glass Fiber-Reinforced Polymer Stabilizer.

Typically, archers prepare two sets of bows for competitions in case of bow breakage, but if the limbs of the bow break during a match, archers can become psychologically disadvantaged, leading to potentially fatal consequences. Archers are very sensitive to the durability and vibration of their bows. While the vibration-damping properties of Bakelite® stabilizer are excellent, its low density and somewhat lower strength and durability are disadvantages. As a solution, we used carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) for the archery limb with stabilizer, commonly used for the limbs of the bow, to manufacture the limb. The stabilizer was reverse-engineered from the Bakelite® product and manufactured using glass fiber-reinforced plastic in the same shape as the existing product. Analyzing the vibration-damping effect and researching ways to reduce the vibration that occurs during shooting through 3D modeling and simulation, it was possible to evaluate the characteristics and the effect of reducing the limb's vibration by manufacturing archery bows and limbs using carbon fiber- and glass fiber-reinforced composites. The objective of this study was to manufacture archery bows using CFRP and GFRP, and to assess their characteristics as well as their effectiveness at reducing limb vibration. Through testing, the limb and stabilizer that were produced were determined to not fall behind the abilities of the bows currently used by athletes, and they also exhibited a noticeable reduction in vibrations.

Structural health monitoring of carbon nanotube-modified glass fiber-reinforced polymer composites by electrical resistance measurements and digital image correlation

A method based on changes of electrical resistance was used to evaluate non-visible damage inflicted to multiscale hierarchical composites subjected to monotonic and cyclic bending loads. The composites comprise glass fiber weaves modified by carbon nanotubes in a vinyl ester matrix. Damage sensing is achieved by placing an array of electrodes close to the surfaces of four-point bending specimens and is correlated to strain fields measured by digital image correlation (DIC). The top (compressive) surface exhibited lower electrical resistance changes than the bottom (tensile) one. Spatial measurements of electrical resistance allowed identification of the most severely damaged zones, which coincided with those pinpointed by DIC. DIC also indicated an important presence of irreversible interlaminar shear strains accumulating close to the supports and/or loading introduction elements, which coincided with the location of delamination. The electrical technique allowed not only the detection of the onset of damage in the form of initial fiber breakage and matrix cracking, but also the detection of damage progression under cyclic loading and low-velocity impact.

Short Flax Fibres and Shives as Reinforcements in Bio Composites: A Numerical and Experimental Study on the Mechanical Properties.

The complete flax stem, which contains shives and technical fibres, has the potential to reduce the cost, energy consumption and environmental impacts of the composite production process if used directly as reinforcement in a polymer matrix. Earlier studies have utilised flax stem as reinforcement in non-bio-based and non-biodegradable matrices not completely exploiting the bio-sourced and biodegradable nature of flax. We investigated the potential of using flax stem as reinforcement in a polylactic acid (PLA) matrix to produce a lightweight, fully bio-based composite with improved mechanical properties. Furthermore, we developed a mathematical approach to predict the material stiffness of the full composite part produced by the injection moulding process, considering a three-phase micromechanical model, where the effects of local orientations are accounted. Injection moulded plates with a flax content of up to 20 V% were fabricated to study the effect of flax shives and full straw flax on the mechanical properties of the material. A 62% increase in longitudinal stiffness was obtained, resulting in a 10% higher specific stiffness, compared to a short glass fibre-reinforced reference composite. Moreover, the anisotropy ratio of the flax-reinforced composite was 21% lower, compared to the short glass fibre material. This lower anisotropy ratio is attributed to the presence of the flax shives. Considering the fibre orientation in the injection moulded plates predicted with Moldflow simulations, a high agreement between experimental and predicted stiffness data was obtained. The use of flax stems as polymer reinforcement provides an alternative to the use of short technical fibres that require intensive extraction and purification steps and are known to be cumbersome to feed to the compounder.

Compression strength analysis of glass fibre polymer composites filled with brown algae powder compared to glass fibre reinforced polymer composite

The current investigation intends to compare the compression strength analysis of glass fiber composites filled with brown algae filler. The material involved in this work is a glass fibre composite filled with and without brown algae filler. 40 specimens were tested by using selected parameters using the universal testing machine. In this work, the control group was a glass fiber epoxy composite and the experimental group was a brown algae-filled glass fiber-reinforced polymer. The mean compressive strength obtained for the brown algae-filled glass fibre reinforced polymer is, whereas it is for the Glass fibre reinforced polymer with the significant value is 0.018 (p<0.05). Within the scope of this investigation, experimental data reveals that strength in compression is high when the glass fiber-reinforced composite is filled with brown algae powder.

Electrical degradation dynamics of glass fiber-reinforced epoxy composites considering different fiber orientation

Glass fiber-reinforced epoxy composites (GFREC) have been widely used in the mechanical components of electrical and electronic devices because of its lightweight, high mechanical strength, excellent electrical insulation properties and corrosion resistance. The research on the electrical degradation dynamics of GFREC is of great significance to avoid the failure of electrical insulation system. Herein the composite samples were prepared using vacuum impregnation technique. The electrical degradation morphology and statistical characteristics (electrical tree length, width, expansion coefficient, breakdown probability and breakdown time) were discussed. The results show that the electrical tree will develop towards the fiber side and grow rapidly along the interface in GFREC. The interfacial orientation will affect the growth characteristics of electrical tree. When the angle between the glass fiber and the needle electrode is 45°, the composite material has relatively superior tree propagation resistance performance, lower breakdown probability and higher breakdown time. The effects of electric field distribution on the tree initiation and electrical degradation are discussed, which reveals the relationship between the electrical degradation and the fiber orientations. The electric field-driven tree growth (FDTG) model is used to explain the growth of trees along interfaces with different orientations from the perspective of dynamic electric field distribution.

Recycling effects on the bending, rheological, and structural properties of glass fiber-reinforced isotactic polypropylene composites

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.

Mechanical Performance of Hybrid Graphene Nanoplates, Fly-Ash, Cement, Silica, and Sand Particles Filled Cross-Ply Carbon Fibre Woven Fabric Reinforced Epoxy Polymer Composites Beam and Column

The main goal of this study is to reduce the brittleness of a fibre-reinforced cement base structure when exposed to the effects of graphene nanoplates, fly ash, silica, sand, and cement fillers to better understand the effect of hybrid nano/micro particle fillers on the mechanical performance of cross-ply carbon fibre reinforced epoxy resin composites. A three-point bending test through the width was used to measure flexural strength. The impact tests Izod at low impact velocity and Charpy through the thickness were used to determine the dynamic fracture strengths of pre-cracked and non-cracked composite samples. Also, the compressive test method was used to measure the compressive strength of hybrid particles and short glass fibre-reinforced epoxy resin composite square and circular columns. The results show compressive strength and flexural strength. Izod impact energy, Charpy impact energy, and dynamic fracture toughness of hybrid nano/microparticle-filled fibre composites have higher values than virgin fibre composites due to the influence of graphene nanoparticles and perfect interface bonding between two dissimilar molecules of nano and microparticles, which improve the fracture toughness and absorb impact energy. Overall, the results indicate that molecules of nano/microparticle-filled carbon fibre and glass fibre-reinforced epoxy resin composites can be used in aggressive environments because of the improved mechanical properties in comparison to the virgin fibre composites. In addition, SEM micrographs clearly indicate that nano- and microparticles are resistant crack propagation and deboned of matrix fibres.

Effect of silane coupling agent and concentration on fracture toughness and water sorption behaviour of fibre-reinforced dental composites.

This paper presents the effect of silane treatment of S-2 Glass fibres on the fracture toughness and water sorption/solubility behaviour of fibre-reinforced flowable dental composites. The effect of epoxy- and methacrylate-based silane coupling agents (SCAs) on the mechanical strength and hydrolytic properties were investigated. The concentration of the selected SCAs on the mechanical and physical properties were investigated. The influence of molecular structure and concentration in the interfacial adhesion at the fibre-matrix interfaces was also studied. Short S-2 Glass fibres of 250µm in length and 5µm in diameter were etched with acid to remove any impurities and roughen the surface. The acid-etched fibres were silane treated with 3MPS, 3GPS, and 8MOTS at different concentrations by weight (%). The silane-treated fibres were incorporated at 5 % into the dental resin mixture. Untreated fibres were added at 5 % to the dental resin mixture and served as the control group. The physical properties such as water sorption, solubility, and desorption along with mechanical properties such as fracture toughness and total fracture work of the fibre-reinforced dental composites grafted with the above-mentioned SCAs were evaluated. The surface morphology of the fractured surface was studied and analysed. The fracture toughness tests showed that the dental composites grafted with optimum weight per cent (wt. %) concentration of the SCA had a better stress intensity factor (KIC) when compared to the 2.0wt. % and 3.0wt. % concentration. The KIC value of dental composites grafted with untreated surface etched glass fibres was less than the KIC values of dental composites grafted with optimum concentrations of 3MPS, 3GPS, and 8MOTS by 81.6 %, 38.6 %, and 110.5 %, respectively. A similar trend was found while investigating the total work of fracture of the dental composites, between optimum concentration, 2.0wt. % and 3.0wt. % concentration of respective SCA. The increase in silane concentration also led to an increase in the water sorption/solubility characteristics. The absorption of water was most severe in the fibre-reinforced dental composites without silane treatment (32.9µg/mm3). The ANOVA results showed that the fibre-reinforced dental composites grafted with 8MOTS at optimum concentration showed an increase in fracture toughness when compared to optimum concentrations of 3GPS and 3MPS by 51.9 % and 15.9 %, respectively. The enhanced mechanical and physical characteristics are due to the increased adhesion between the fibre and silane achieved from the optimum wt. % concentration of 8MOTS. Similarly, dental composites grafted with 8MOTS at optimum concentration showed a decrease in water sorption characteristics when compared to optimum concentrations of 3GPS and 3MPS by 18.2 % and 0.6 %, respectively. The decreased water sorption characteristics at the optimum concentration of 8MOTS could be due to the reduced availability of reactive hydroxyl groups and the hydrophobic characteristics of 8MOTS. Silane coupling agents (SCAs) are important components of dental composites. The type and concentration of SCA have a significant effect on material properties. The current study focuses on understanding the effects of different SCAs and wt. % concentrations on the interfacial fracture behaviour and the influence of different SCAs on the water sorption and solubility behaviour of S-2 Glass fibre-reinforced flowable dental composites.

PC 및 ABS 전기방사 나노섬유가 매립된 유리 섬유 강화 복합체의 기계적 성질에 관한 연구

In addition to the high mechanical strengths of glass fiber-reinforced thermoset matrix composites, due to their brittle nature, their impact resistances remain at very low levels. This paper aims to embed thermoplastic nanofibers into glass fibers and see an improvement in impact resistance without reducing other mechanical properties such as tensile, toughness, and bending. Due to the nature of acrylonitrile–butadiene–styrene (ABS) and polycarbonate being able to enhance impact resistance, dimethylformamide and tetrahydrofuran as convenient/comparatively less toxic solvents were selected to produce nanofibers via an electrospinning technique. For polycarbonate (PC) 25 wt% with (60:40) tetrahydrofuran to dimethylformamide ratio and ABS 37, wt% dimethylformamide solution proved to be the best concentration ratios. For the optimum nanofibers, the electrospinning process parameters were determined and uniform, bead-free fibers were embedded into the glass fibers to be used in laminated composite manufacturing. Mechanical properties of the electrospun nanofiber embedded composites highly depend on the nanofiber type and electrospinning time.

Use of a fully biobased and non-reprotoxic epoxy polymer and woven hemp fabric to prepare environmentally friendly composite materials with excellent physical properties

In the future, materials will need to be biobased and produced sustainably without compromising mechanical properties. To date, in many cases, the advantages of the bio-origin of the raw material are overridden by the environmental impact of the process. In the present study, we have developed a novel composite material based on woven hemp fabric which reinforce a thermoset polymer produced from birch bark, a low-value forestry byproduct. Results show that this fully biobased composite has specific stiffness and strength equivalent to those of flax fibre-reinforced petroleum-based epoxy composites and slightly lower than glass fibre-reinforced petroleum-based epoxy composites. The sustainability of the material was also evaluated by life-cycle assessment from cradle to gate and showed significantly superior performance with respect to the potential global warming impact than commercial benchmark materials. Furthermore, toxicology studies showed no endocrine disruptive activities. This is an important proof of concept study demonstrating that biobased structural materials can be produced sustainably.

Torsional behavior of glass fiber-reinforced polymer composite: polymer matrix effect and acoustic emission signal analysis

Torsional behavior of glass fiber-reinforced polymer composite: polymer matrix effect and acoustic emission signal analysis

Evaluation of self-healing capability of a polycaprolactone interphase in epoxy/glass composites

Self-healing composites possess the ability to self-repair in response to damage, either autonomously (i.e., without human intervention), or when subjected to an external stimulus such as heat. This work was focused on the evaluation of the interfacial self-healing capability of glass fiber-reinforced epoxy composites in which polycaprolactone nanoparticles were deposited as a coating on the surface of the fibers. Polycaprolactone nanoparticles were synthesized following solvent displacement technique and deposited on the fibers (with and without the sizing agent) by electrophoretic deposition. Scanning electron microscopy revealed high-quality nanoparticles deposition, with good level of homogeneity and compactness. Epoxy microdroplets were cured on the fibers and microdebonding tests were performed to estimate the interfacial self-healing capability, calculated as the ratio of the interfacial shear stress measured before and after the thermal mending process. An interfacial adhesion recovery of about 50 % was obtained, thus indicating an interfacial self-healing capability induced by the polycaprolactone nanoparticles.

Electromagnetic Interference Shielding Effectiveness of Direct-Grown-Carbon Nanotubes/Carbon and Glass Fiber-Reinforced Epoxy Matrix Composites.

In this study, carbon nanotubes (CNTs) were grown under the same conditions as those of carbon fibers and glass fibers, and a comparative analysis was performed to confirm the potential of glass fibers with grown CNTs as electromagnetic interference (EMI) shielding materials. The CNTs were grown directly on the two fiber surfaces by a chemical vapor deposition process, with the aid of Ni particles loaded on them via a Ni-P plating process followed by heat treatment. The morphology and structural characteristics of the carbon and glass fibers with grown CNTs were analyzed using scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and X-ray photoelectron spectrometry (XPS), and the EMI shielding efficiency (EMI SE) of the directly grown CNT/carbon and glass fiber-reinforced epoxy matrix composites was determined using a vector-network analyzer. As the plating time increased, a plating layer serving as a catalyst formed on the fiber surface, confirming the growth of numerous nanowire-shaped CNTs. The average EMI SET values of the carbon fiber-reinforced plastic (CFRP) and glass fiber-reinforced plastic (GFRP) with grown CNTs maximized at approximately 81 and 40 dB, respectively. Carbon fibers with grown CNTs exhibited a significantly higher EMI SET value than the glass fiber-based sample, but the latter showed a higher EMI SET increase rate. This indicates that low-cost, high-quality EMI-shielding materials can be developed through the growth of CNTs on the surface of glass fibers.

Effect of Water Absorption on Graphene Nanoplatelet and Multiwalled Carbon Nanotubes-impregnated Glass Fibre-Reinforced Epoxy Composites

Effect of Water Absorption on Graphene Nanoplatelet and Multiwalled Carbon Nanotubes-impregnated Glass Fibre-Reinforced Epoxy Composites

Investigation of Wear Behavior in Self-Lubricating ABS Polymer Composites Reinforced with Glass Fiber/ABS and Glass Fiber/Carbon Fiber/ABS Hybrid

A new hybrid fabrication technique was introduced to manufacture composite laminates made of glass fiber, carbon fiber, and acrylonitrile butadiene styrene (ABS) as the matrix. The fabrication process utilized two different techniques: fused deposition modeling and hot press molding. The composite laminates were produced using five layers of glass fibers to form glass fiber-reinforced composites (GF/ABS) and five layers of glass fiber and carbon fiber to form glass fiber, carbon fiber-reinforced hybrid composites (GF/CF/ABS), with three layers of glass fibers and two layers of carbon fibers. The fabricated composite laminates were subjected to wear testing at velocities of 2 m/s, 3 m/s, and 4 m/s and under loads of 5 N and 10 N. The results indicated that GF/ABS samples had the lowest wear loss at 5 N and a velocity of 4 m/s. Additionally, the GF/CF/ABS hybrid samples had the lowest coefficient of friction (COF) of 0.28 at 4 m/s. The GF/ABS samples also exhibited the lowest friction force of 1.7 at 5 N and a velocity of 4 m/s. The worn samples were analyzed using a scanning electron microscope to examine the fiber-to-matrix adhesion behavior. GF/ABS and GF/CF/ABS composites are widely used in various applications due to their high strength-to-weight ratio and resistance to wear. These materials could be used in automotive parts, sporting goods, and marine applications.

Thermal reshaping as a route for reuse of end-of-life glass fibre-reinforced acrylic composites

Thermal reshaping has been employed to simulate the end-of-life reuse of liquid-resin-infused thermoplastic acrylic composite laminates, and the associated effects on matrix-dominated mechanical performance and microstructure have been studied. L-shaped laminates were infused at room temperature and subjected to 1 or 4 hot-press flattening cycles (25 min at 120 °C; 11 bar). Compared to the original references, up to 13% higher transverse flexural strengths were measured for the reprocessed laminates. Such a scheme may be readily implemented for high-value reuse without sacrificing fibre length scales, and with minimal cumulative mass loss over successive reheating cycles (10 cycles: 2% and 15 cycles: 2.6%). This study provides important insights to foster a greater understanding of the performance limits of hot-press reprocessing to inform the practical reuse and re-application of sustainable composites in a circular economy.

Fatigue performance of endodontically treated molars reinforced with different fiber systems.

The aim was to investigate the fatigue performance of root canal-treated (RCT) molars restored with different direct restorations utilizing discontinuous and continuous fiber-reinforced composite (FRC) systems. The impact of direct cuspal coverage was also evaluated. One hundred and twenty intact third molars extracted for periodontal or orthodontic reasons were randomly divided into six groups (n=20). Standardized MOD, regular cavities for direct restorations were prepared in all specimens, and subsequently, root canal treatment and root canal obturation was carried out. After the endodontic treatment, the cavities were restored with different fiber-reinforced direct restorations as follows: SFC group (control), discontinuous short fiber-reinforced composite (SFC) without cuspal coverage (CC); SFC+CC group, SFC with cuspal coverage; PFRC group, transcoronal fixation with continuous polyethylene fibers without CC; PFRC+CC group, transcoronal fixation with continuous polyethylene fibers with CC; GFRC group, continuous glass FRC post without CC; and GFRC+CC, continuous glass FRC post with CC. All specimens underwent a fatigue survival test in a cyclic loading machine until fracture occurred or 40,000 cycles were completed. The Kaplan-Meier survival analysis was conducted, followed by pairwise log-rank post hoc comparisons between the individual groups (Mantel-Cox). The PFRC+CC group was characterized by significantly higher survival compared to all the groups (p < 0.05), except for the control group (p = 0.317). In contrast, the GFRC group showed significantly lower survival compared to all the groups (p < 0.05), except for the SFC+CC group (p = 0.118). The control group (SFC) showed statistically higher survival than the SFRC+CC group (p < 0.05) and GFRC group (p < 0.05), but it did not differ significantly from the rest of the groups in terms of survival. Direct restorations utilizing continuous FRC systems (in the form of polyethylene fibers or FRC post) to restore RCT molar MOD cavities performed better in terms of fatigue resistance when CC was performed compared to the same FRC restorations without CC. On the contrary, teeth restored with SFC restorations performed better without CC compared to the ones where SFC was covered. In the case of fiber-reinforced direct restorations for MOD cavities in RCT molars, direct CC is recommended when utilizing long continuous fibers for reinforcement, however, should be avoided when only SFC is used for their reinforcement.