Volume Fraction Of Glass Fibers Research Articles

Study on thermal expansion coefficient and absorbing properties of fiber reinforced resin-based absorbing composites

In this paper, non-woven fabric and glass fiber fabric were used to prepare resin-based absorbing composite. The thermal expansion coefficient and the microwave absorbing properties of the absorbing composites with different glass fiber volume fraction were studied. The results show that the simulation results of the thermal expansion coefficient calculated by Schapery model are inconsistent with the experimental results, the metallographic results were studied to reveal that it is the added absorbent in the composite that partially replaced the resin at the interface between resin and fiber bundle causes the parameters of the material substituted in the Schapery model to be improper. A different simulation model was proposed to introduce a set of different parameters of the material to reduce the error between simulation and experiment results and the simulation results show that the error is reduced from a maximum of 53 % to a minimum of 3 %. Meanwhile the microwave absorbing properties show that the absorbing peaks of the composite materials move to low frequency with the increasing glass fiber volume fraction and the minimum reflection loss (RL) first increase and then decrease. The metallographic results show that the different distribution of absorbent in the composites within different reinforced fibers causes the movement of the absorbing peaks and the change of its minimum RL. Those research results lay a foundation for the further popularization and application of the absorbing composites.

Novel method for fiber volume fraction of carbon/glass hybrid fiber composites

Because the physical properties of carbon fiber and glass fiber are very different, the fiber volume fraction in carbon/glass hybrid fiber composites cannot be tested by burning method or digestion method, respectively. Furthermore, these methods partially consume the fiber, especially for carbon fibers. To investigate the fiber volume fraction in carbon/glass hybrid fiber composites correctly, the test method is put forward. The burning method and the digestion method were combined to calculate the volume fraction of carbon fiber and glass fiber, respectively. The results show that the relative error between the measured value and the theoretical value is very small. The result of the present work implies that the feasibility and accuracy of this method through experimental verification.

Influence of fiber types on the properties of the artificial cold-bonded lightweight aggregates

Abstract The cold-bonded pelletizing method is often employed in aggregate production since it uses less energy and helps reduce issues with gas emissions, contributing to economic and environmental benefits. In this study, fly ash was chosen as the raw material and used to partially replace cement in manufacturing artificial aggregate. Three types of fibers (polypropylene, polystyrene, and glass fiber) in different volume fractions were used to investigate their effect on the properties of the artificial cold-bonded lightweight aggregate. After the manufacturing process, aggregates were cured with a 28-day water curing. Their specific gravity, water absorption, density, impact value, and crushing value were tested to analyze the properties of the cold-bonded artificial aggregate. Results show that adding various volume fractions of PS, glass, and PP fibers during pelletization caused a more stable generation of aggregates with enhanced mechanical and physical properties.

Numerical and Experimental Studies on Crack Resistance of Ultra-High-Performance Concrete Decorative Panels for Bridges

This study develops a new type of decorative bridge panel by ultra-high-performance concrete (UHPC) based on the project of the Guangyangwan Bridge. First, the numerical analysis was carried out using MIDAS and ABAQUS to find the critical position of the bridge and decorative panels. The numerical results showed that the last concrete cantilever segment had the greatest vertical deflection, and the corresponding panel had the greatest stress response. Based on the numerical results, this study conducted a series of full-scale, self-balanced bending tests to examine the crack resistance of six UHPC panels and six glass fiber-reinforced concrete (GRC) panels with varying curved section thicknesses (from 25 to 40 mm). The experimental results indicate that, due to the high strength of the UHPC matrix and the wall effect of steel fiber distribution, the crack resistance of UHPC panels is significantly superior to that of GRC panels. UHPC panels possessed superior stiffness and ductility, while GRC panels showed brittle fracture when the curved section thickness reached 34 mm. The uniaxial tensile cracking strength of UHPC with a steel fiber volume fraction of 1.6% was 14.7% greater than that of GRC with a glass fiber volume fraction of 5%. At the same curved section thicknesses, UHPC decorative panels exhibit cracking loads and ultimate loads that are 64.3% to 123.0% and 29.2% to 115.0% greater than GRC panels, respectively. Hence, UHPC is more suitable to produce ultra-thin decorative panels for bridges that are subjected to severe environmental action and external forces.

Analysis of loading modes and rates on the mechanical responses of glass fiber weft-knitted biaxial tubular fabric reinforced composites

With the increasing demand for lightweight and high-strength tubes in the civil engineering, many researchers have investigated the weft-knitted biaxial tubular (WKBT) fabric reinforced composites due to their excellent mechanical properties. WKBT fabric is characterized by its seamless tubular reinforcement, with the warp yarns being straight in the axial direction and the weft yarns spinning in the circumferential direction. The mechanical response of WKBT fabric reinforced composites under three different loads (tensile load, puncture load, compression load) and three different rates (5, 10, 15 mm/min) are discussed in this paper. The results indicate that the mechanical properties and failure modes of WKBT fabric reinforced sheets are significantly affected by the glass fiber volume fraction. The concertina progressive folding is the energy absorption mode of WKBT fabric reinforced tubes under compressive load. The number of folds changes from two to three as the height of the tube increases. At the compression rate of 15 mm/min, the initial peak strength of the tubes increases by 28.14 % as their height (100, 150, 200 mm) of the tubes increases. The initial peak strength of the tubes increases by 72.78% as the compression rate increases to 200 mm height.

Effect of graphene nano-additives on the fatigue limit of fiber-reinforced polymer hybrid composites—A micromechanical modeling procedure

In this article, the effect of graphene nanoadditives on the fatigue limit of unidirectional glass fiber-reinforced polymer (GFRP) composites has been investigated. A micromechanical model based on the crack growth has been used to analyze the fatigue limit response of unidirectional GFRP hybrid composite containing nanoadditives. The influence of different percentages of graphene nanosheets (GNS) and different types of nanofiller dispersion has been investigated by the micromechanical model. The fatigue limit of unidirectional GFRP hybrid composites has been plotted in terms of glass fiber volume fraction, interfacial friction shear stress, interfacial fracture energy and reference length. The fatigue limit of unidirectional composites can be improved by addition of GNS into the polymer matrix of such composite systems. The obtained results on the GNS dispersion type demonstrate that the uniform dispersion of GNS into the polymer matrix increases the fatigue limit of unidirectional GFRP hybrid composites. As the agglomeration density of GNS is low, the fatigue limit of GFRP hybrid composites will be improved more than when the density of agglomeration is high.

Effects of Rebar Size and Volume Fraction of Glass Fibers on Tensile Strength Retention of GFRP Rebars in Alkaline Environment via RSM and SHAP Analyses

Effects of Rebar Size and Volume Fraction of Glass Fibers on Tensile Strength Retention of GFRP Rebars in Alkaline Environment via RSM and SHAP Analyses

Influence of Counter-Face Grit Size and Lubricant on the Abrasive Wear Behaviour of Thermoplastic Polymers Reinforced with Glass Fibres

Thermoplastic composite materials are widely used for aerospace, automobile and structural applications due to their good combination of high strength to weight ratio and specific modulus. Combined with the ease of melt processing, good resistance to corrosion, low friction, and noise damping are attributes which make them a popular choice in a wide range of emerging applications. Random, short-fibre, E-glass fibre reinforced Polyamide 6 (PA6) composites were manufactured by injection moulding in three different fibre volume fractions (25%, 33% and 50%) and the samples were scanned using micro-CT. The tribological properties of PA6 and glass fibre reinforced PA6 were investigated in the abrasive wear mode by using a pin-on-disc test setup. The tests were done at an abrading distance of 257 m and applied load of 10 N. The abrasive wear experiments were performed against three abrasive grit size papers (220, 500 and 1000 grit), to ascertain the wear response of the studied materials with respect to these adverse running conditions. Moreover, the mechanical properties of PA6 and PA6 composites were examined using tensile testing and compression testing. The surface roughness of the worn surfaces was analysed using a 3D digital profilometer. The worn surface topographies were scanned using field emission scanning electron microscopy. It was observed that the optimum fibre loading that was associated with the highest wear resistance was 33% volume fraction of glass fibres, and the wear performance deteriorated with higher fibre loadings. The increase in the grit size showed a significant reduction to the wear rates of all compositions. The results confirmed that the wear performance of polyamide composites is highly dependent on the tribological system under which it is being tested.Graphical

Investigating the lap shear adhesion of coir and glass-fibre reinforced epoxy bonding to mild steel with varying volume fractions

Bonding synthetic fibres to metals to improve strength, durability, and corrosion resistance is a prevalent practise in the automotive, marine, and aerospace industries. Lap shear adhesion, a measurement of the bonding strength between composites and metallic substrates, is essential for structural integrity. The emergence of natural fibre composites as sustainable alternatives to synthetic composites makes it essential to investigate their lap shear behaviour and the effect of fibre volume fraction on composite properties. This research investigates the adhesion behaviour of coir and glass fibre epoxy composites to mild steel. Coir fibres, which are known for their resilience and tenacity, were treated with an alkaline solution to improve their adhesion to the resin. Samples of lap shear adhesion were prepared in accordance with ASTM specifications, and tests were conducted using a tensile machine. Increasing the volume fraction of coir or glass fibres decreased the bond strength, as demonstrated by the results. Due to the fibres’ greater tensile strength and rigidity, glass fibre composites exhibited superior strength. However, under tensile loading conditions, coir fibres exhibited superior adhesion to mild steel surfaces. SEM micrographs confirmed that coir composites exhibit shear failure while glass composites exhibit fibre pull-out behaviour. This study concludes by highlighting the engineering potential of coir fibres, considering their natural properties and cost-effectiveness. It is necessary to further optimise the fiber-matrix interface and comprehend the mechanical behaviour of coir composites in order to maximise their effectiveness. To assure the long-term durability of composite-metal joints, surface preparation, adhesive type, application procedure, and environmental conditions must also be considered. At a content percentage of 10%, glass fibres exhibited 100% higher shear strength compared to coir fibres in epoxy composites. Conversely, coir fibres at 10% content demonstrated approximately 75% greater shear strength than the values obtained with 40% glass fibres. The failure mechanisms observed are delamination or fibre fracture in the bonding area under tensile and shear loading. Increasing the fibre volume fraction reduces bond strength. Factors such as limited space for the matrix, tension concentrations, and the mechanical properties of the fibres contribute to weakened bonds. Glass fibres have better strength and rigidity than coir fibres, affecting load transfer and adhesion. Interfacial bonding is crucial, and maintaining it becomes more difficult with higher fibre volume fractions, resulting in weakened bonds.

Influence of fine-grain fly ash along with glass fiber on strength and cost of proposed concrete mixes

Present novelty focuses on examining the strength and cost of proposed concrete mixes using fine grain fly ash along with glass fiber. The present analysis aims to use high volume fine-grain fly ash as a partial substitute material for cement as well as fine aggregate with a very low volume fraction of glass fiber. For a durable concrete, a concrete mix consisting of up to 40% cement and up to 40% sand replacement by fine-grain fly ash along with glass fiber is feasible. Ten different mixes were prepared using 0.35 water cement ratio and evaluated with each other. To examine the strength and cost of proposed concrete mixes, the experimental work was carried out on hardened concrete. Based on experimental result it was observed that the cost of proposed concrete mixes reduced over control concrete without hampering the strength. Addition of 600 gm/m3 of glass fibers increased the total cost up to 5% than normal concrete but cost per N/mm2 is lower than control concrete. When combined cement and sand was replaced by fly ash together with glass fiber, the total cost for 1 m3 of concrete mixes is cheaper than control mix up to 16.11%. Present investigation reveals that cement and sand replacement by proper combination of fly ash with nominal dose of glass fibers produced high 28 days strength and durable concrete with lower cost than control concrete. This discovery is also important for reducing the CO2 emission which is produced during cement production as well as for reducing the use of natural sand which is depleting every day being a natural resource.

Influence of adding steel – glass – polypropylene fibers on the strength and flexural behaviour of hybrid fiber reinforced concrete

This experimental research investigates the strength and load deflection characteristics of hybrid fiber reinforced concrete. Two or more types of fibers are combined to improve the overall properties of concrete. Grade of concrete chosen for study is M40 and the specimens were incorporated with 0.75% volume fraction of Steel, Glass and polypropylene fibers in equal proportions and in different combinations. This study primarily focused on compressive strength, split tensile strength and flexural tensile strength of composite with two types of fiber combinations. Results were compared with non-fibrous control concrete and strength effectiveness was observed to be more in Steel- Polypropylene fibers combination. Negative results were produced by Glass- polypropylene hybrid fiber composites. Based on the best strength results reinforced concrete beam specimen is made with Steel – polypropylene hybrid fiber combinations as a secondary reinforcement and it is tested under flexural loading conditions. Load deflection behaviour and crack studies were carried out on tested beam specimens. Finally experimental results were compared with Finite element software results and close agreement was observed between them.

Fatigue response of glass-filled epoxy composites: A crack initiation and propagation study

This paper presents a comprehensive experimental investigation on the fatigue response of glass-filled epoxy composites when subjected to cyclic loading. Rod-shaped particulate glass fibers in a volume fraction of 0%, 5%, 10% and 15% are reinforced in the epoxy matrix. The mechanical behavior of the resulting composite is studied under monotonic tensile loading and tension–tension cyclic fatigue loading. The undergoing damage mechanisms leading to the crack initiation and its propagation are studied using the in-situ low cycle fatigue testing. The crack initiation behavior and the crack initiation life are found to be affected by different crack initiation sites such as the epoxy-fiber interface, the matrix and the fiber itself. Fractography reveals that the crack coalescence, crack propagation and the failure are largely affected by the varying volume fraction of glass fibers. The specimen with 10% volume fraction is found to exhibit the maximum fatigue life under the applied cyclic loading.

The effect of non-dental glass fiber volume fraction on flexural strength of heat cured acrylic resin

Background: Heat-cured acrylic resin is a material that is often used for the manufacture of removable partial dentures in dentistry because it uses simple equipment, relatively inexpensive, and is easy to repair. Acrylic resin also has a disadvantage, such as the low value of flexural strength so that it can cause the denture to fracture. This study determine the effect of non-dental glass fiber volume fraction on the flexural strength of heat cured acrylic resin. Method: This research are post-test only control group design. Acrylic resins were divided into four groups (6 sample each group), group 1 without the addition of non-dental glass fiber or 0% and heat cured acrylic resin group with the addition of non-dental glass fiber 1%,2%, and 3% (group 2, 3 and 4). Result: The average flexural strength of acrylic resin with a volume fraction of 2% of non-dental glass fiber had the highest value compared to other groups. The results of the Mann-Whitney test from several test groups showed significant differences in the value of flexural strength from each group (p<0.05), except for the 0% and 3% group. Conclusion: There is an effect of volume fraction of non-dental glass fiber on the flexural strength of heat cured acrylic resin.

Pengaruh Fraksi Volume Terhadap Sifat Mekanis Komposit Forged Fiberglass Metode Compression Mould

Fiber-reinforced composites can be classified into two parts, namely short fiber composites and long fiber composites. Long fibers are stronger than short fibers. Long fiber (continuous fiber) is more efficient in laying than short fiber but short fiber is easier to lay than long fiber. Fiber length affects the processability of the fiber composite. Judging from the theory, long fibers can continue the load and stress from the stress point to the other fiber. In this study, the volume of chopped glass fiber composite with random matrix direction was varied with respect to polyester resin. Making forged fiberglass composites with the press mold method to minimize the occurrence of air bubbles during the composite molding process. Testing the mechanical properties of the forged fiberglass composite using the three-point bending and tensile testing methods. The expected result is the variation of the volume fraction of random chopped glass fiber to polyester resin. The TKT to be achieved from this research is TKT level 3, which is an analytical study that supports the prediction of the performance of the effect of the volume fraction between glass fiber and resin on the mechanical properties of the tensile and bending strength of forged glass fiber composites.

Non-isothermal direct bundle simulation of SMC compression molding with a non-Newtonian compressible matrix

Compression molding of Sheet Molding Compounds (SMC) is a manufacturing process in which a stack of discontinuous fiber-reinforced thermoset sheets is formed in a hot mold. The reorientation of fibers during this molding process can be either described by macroscale models based on Jeffery's equation or by direct mesoscale simulations of individual fiber bundles. In complex geometries and for long fibers, direct bundle simulations outperform the accuracy of state-of-the-art macroscale approaches in terms of fiber orientation and fiber volume fraction. However, it remains to be shown that they are able to predict the necessary compression forces considering non-isothermal, non-Newtonian and compaction behavior. In this contribution, both approaches are applied to the elongational flow in a press rheometer and compared to experiments with 23% glass fiber volume fraction. The results show that both models predict contributions to the total compression force and orientation reasonably well for short flow paths. For long flow paths and thick stacks, complex deformation mechanisms arise and potential origins for deviation between simulations models and experimental observations are discussed. Furthermore, Jeffery's basic model is able to predict orientations similar to the high-fidelity mesoscale model. For planar SMC flow, this basic model appears to be even better suited than the more advanced orientation models with diffusion terms developed for injection molding.

Hygrothermal aging effect on the water diffusion in glass fiber reinforced polymer (GFRP) composite: Experimental study and numerical simulation

Understanding the water diffusion process in glass fiber reinforced polymer (GFRP) is critical to bridging the gap between the long-term degradation performance of GFRP composite and the retained strength of glass fibers under water attack. In this study, the water diffusion in GFRP with consideration of defects is systematically investigated through experimental and simulation methods. The water diffusivity of GFRP decreased from 6.60 × 10−7 to 2.05 × 10−7 mm2/s as glass fiber volume fraction increased from 0 to 50.21%. In addition, the diffusivity increases slightly with the presence of voids, and significantly with matrix cracking, debonding and fiber erosion, while it is insensitive to fiber size. Furthermore, the square or hexagonal fiber arrangement models produce similar results to random fiber arrangements in the actual situation. GFRP water absorption curves are found to be underestimated and overestimated respectively for models without and with defects taken into consideration. Finally, the simplified and refined FE models are supposed to be employed to rapidly estimate the water absorption of GFRP composite.

Reduction of Deep Dielectric Charging of Polyimide by Incorporation of Glass Microsphere or Glass Fiber Reinforcement

In outer space’s extreme electron radiation environment, the insulating medium will experience a deep dielectric charging effect. As an excellent insulating medium, polyimide is widely used in spacecraft. In practical use, glass microspheres and glass fibers are often added to increase its mechanical strength. However, the influence of glass microspheres and glass fibers on deep dielectric charging effects has often been ignored in previous studies. Therefore, the work in this article established a 3-D deep dielectric charging model of glass microsphere and glass fiber reinforced polyimide. Using the model, the effects of glass microsphere and glass fiber volume fraction, glass microsphere spacing, glass fiber orientation, and 3-D glass fiber structure were investigated. The results show that the larger the volume fraction of glass fiber or glass microsphere, the more obvious the decrease of polyimide composite media’s average electric field strength. Under the same volume fraction, glass fibers are more favorable to reduce the average electric field strength than glass microspheres. The surface of glass microspheres will form charge accumulation, increasing local maximum electric field intensity, which is greater than the maximum electric field value of pure polyimide under electron radiation. When the spacing of glass microspheres decreases, the degree of electric field distortion increases, but the electric field value decreases when the microspheres contact each other. When the glass fiber orientation is perpendicular to the ground plane, it can better provide the electronic release channel, thereby reducing the deep dielectric charging effect. Using 3-D glass fiber structures can reduce the polyimide’s average electric field value and reduce the maximum local electric field distortion.

Glass/polypropylene hybrid knitted fabrics for toughening of thermoset composites

This paper investigates tensile, flexural, impact and compression after impact (CAI) performance of weft knitted fabric reinforced thermoset composites containing glass/polypropylene (PP) hybrid yarns. Glass and PP yarns were combined at three different PP ratios and converted to supreme hybrid knitted structures using a circular knitting machine. Using PP yarns helped to decrease glass fibre breakages during the knitting process. It was observed that the addition of PP yarns decreased overall density of composites up to 22%. Fabric tensile test indicated that using PP yarns enhanced ductility of the knitted fabrics. Flexural strength of composites was decreased by addition of PP yarns for both wale and course direction at 3 and 4-point bending tests. However, hybrid composites had higher specific flexural strength when they all had same glass fibre volume fraction for 3-point bending strength. Similar results were achieved for tensile properties whilst hybrid composites had higher values after normalising the same fibre volume fractions. Impact and CAI test results exhibited that the addition of PP yarns enhanced impact and damage tolerance of composites as well as reducing impact induced areas.

Multi-parameter optimization (grey relational analysis) and modeling of a cellulosic plant/glass fiber hybrid reinforced polymer composite (P x G y E z ) for offshore pressure vessels development

The aim of this research is to produce more environmentally friendly materials for offshore applications. Due to their high water absorption, cellulosic fibers are known to be hydrophilic, making composites reinforced with them perform poorly and unreliable in humid settings. Previous research has focused on the development of natural fiber-based composite materials, but none has focused on the optimization of these cellulosic-based fiber-reinforced composites for offshore applications where weight, water absorption, and strength are important considerations. This paper presents the optimization of the composite material P x G y E z (with x, y, and z representing the volume fraction of pineapple leaf fiber (PALF) (P), the volume fraction of glass fiber (G), and fiber length respectively in an epoxy matrix) using the grey relational analysis for offshore pressure vessels. The material at 10% PALF, 15% glass fiber, and 15 mm fiber length, which is, P10G15E15 was the optimum, having a grey relational grade of 0.716. Also, statistical analysis showed that the treated PALF fibers contributed 45.73% to the water absorption properties of the P x G y E z composites as compared to the 0.3% contribution of glass fiber to the grey relational grade and a 9.5% contribution of fiber length. Also, there was an improvement in the grey relational grade by 73.61%. SEM and Fourier-transform infrared spectroscopy (FTIR) analysis showed microstructural and chemical formations that explained the water absorption behavior of the optimized hybrid composite. Also, regression analysis was carried out and an equation was developed for the prediction of grey relational grades at different combinations of P x G y E z . A thick pressure vessel developed with the optimized material was simulated and results showed operational reliability with its yield starting at 30.01 MPa, which is 44.98% higher than the 20.7 MPa limit by the ASME X Class I cylinders.

Experimental investigation on mechanical properties and free vibration characteristics of epoxy‐based glass/flax laminates

AbstractIn the present study, an attempt is made to replace the synthetic glass fiber used in the FRP structures in terms of natural flax fibers without much sacrifice on static and dynamic stability of the structure. Three types of glass/flax hybrid composite laminates were prepared with different fiber volume fraction of glass and flax fibers. For better understanding purpose, a dedicated glass and dedicated flax laminates were also fabricated. All the laminates were fabricated by vacuum bag molding method with uniform laminate thickness. The mechanical properties of the fabricated laminates, such as tensile strength and flexural strength, were evaluated in accordance with ASTM standards. The impulse excitation technique was used to assess the free vibration characteristics of glass/flax laminates such as modal frequency and material damping. Based on experimentally evaluated mechanical and vibration characteristics a suitable fiber volume fraction for the preferred laminate thickness was suggested to achieve optimum static and dynamic stability.