S-glass Fiber Research Articles

Physicochemical properties of discontinuous S2-glass fiber reinforced resin composite.

The objective of this study was to investigate several physicochemical properties of an experimental discontinuous S2-glass fiber-reinforced resin composite. The experimental composite was prepared by mixing 10 wt% of discontinuous S2-glass fibers with 27.5 wt% of resin matrix and 62.5 wt% of particulate fillers. Flexural strength (FS) and modulus (FM), fracture toughness (FT), work of fracture (WOF), double bond conversion (DC), Vickers hardness, volume shrinkage (VS) and fiber length distribution were determined. These were compared with two commercial resin composites. The experimental composite showed the highest FS, WOF and FT compared with two control composites. The DC of the experimental composite was comparable with controls. No significant difference was observed in VS between the three tested composites. The use of discontinuous glass fiber fillers with polymer matrix and particulate fillers yielded improved physical properties and substantial improvement was associated with the use of S2-glass fiber.

Selective laser melting of fiber-reinforced glass composites

A selective laser melting (SLM) process is developed for manufacturing of a novel glass fiber-reinforced glass (GRFG) composite material. Experiments using a continuous wave fiber laser are conducted for demonstrating this SLM process using borosilicate S-glass fibers and fine soda lime glass powders, which have distinct glass transition temperatures. During laser scanning, fine glass powders turn into viscous flow. The molten glass flows through and encapsulates the relatively solid fibers, which are not fused due to their relatively higher glass transition temperature. Upon cooling, a compacted GRFG composite forms with a high volume ratio of intact and well-encapsulated glass fibers.

A Theoretical Model for Estimation of Yield Strength of Fiber Metal Laminate

The paper presents a theoretical model for estimation of yield strength of fiber metal laminate. Principles of elasticity and formulation of residual stress are employed to determine the stress state in metal layer of the laminate that is found to be higher than the stress applied over the laminate resulting in reduced yield strength of the laminate in comparison with that of the metal layer. The model is tested over 4A-3/2 Glare laminate comprising three thin aerospace 2014-T6 aluminum alloy layers alternately bonded adhesively with two prepregs, each prepreg built up of three uni-directional glass fiber layers laid in longitudinal and transverse directions. Laminates with prepregs of E-Glass and S-Glass fibers are investigated separately under uni-axial tension. Yield strengths of both the Glare variants are found to be less than that of aluminum alloy with use of S-Glass fiber resulting in higher laminate yield strength than with the use of E-Glass fiber. Results from finite element analysis and tensile tests conducted over the laminates substantiate the theoretical model.

Effect of S-glass fabric on the mechanical characteristics of a hybrid carbon/aramid fabric reinforced epoxy composites

The aim of this study is to investigate the hybridization effects of intraply carbon/aramid fabric layers with S-glass fabric layers on the tensile and flexural behavior of asymmetric and symmetric arrangements of hybrid composite laminates. The results revealed that the replacement of some carbon/aramid fiber layers with S-glass fiber layers in the composite laminate can provide enhancements in tensile strain, tensile modulus and flexural properties while the tensile strength results were slightly degraded. Three-point bending test results indicated a significant improvement in flexural properties when S-glass fibers employed in compressive side across the depth of composite laminates. The maximum increment in tensile modulus, flexural modulus and flexural strength of hybrid composite laminates were 19.7%, 50.0% and 42.3%, respectively compared to carbon/aramid fiber reinforced epoxy composite.

Effects of stacking sequence on mechanical properties of hybrid composites reinforced with carbon, Kevlar and S-glass fibers

Abstract This study explores the influences of laminates stacking sequence configuration on the mechanical behavior of hybrid composites. The woven carbon, Kevlar and S-glass fibers with epoxy resin were used to produce hybrid composite specimens in addition to full composites. The hybrid specimens were prepared by introducing different fiber volume fractions between carbon/glass, carbon/Kevlar, glass/Kevlar and carbon/glass/Kevlar fibers. Stacking sequence and fibers in outer skin of the laminates obviously showed the effective influence on tensile and flexural strength with modulus. The maximum change in tensile strength due to hybridization effect was achieved with carbon/glass epoxy laminate by replacing the two face sheets of the carbon fibers with glass fibers, resulting in an increase of tensile strength by 60 % according to full carbon/epoxy laminates. On the other hand, flexural strength of glass/Kevlar hybrid laminates showed the highest hybrid effect, resulting in 78 % increase according to full Kevlar/epoxy composites.

Properties of discontinuous S2-glass fiber-particulate-reinforced resin composites with two different fiber length distributions

PurposeTo investigate the reinforcing efficiency and light curing properties of discontinuous S2-glass fiber-particulate reinforced resin composite and to examine length distribution of discontinuous S2-glass fibers after a mixing process into resin composite. MethodsExperimental S2-glass fiber-particulate reinforced resin composites were prepared by mixing 10wt% of discontinuous S2-glass fibers, which had been manually cut into two different lengths (1.5 and 3.0mm), with various weight ratios of dimethacrylate based resin matrix and silaned BaAlSiO2 filler particulates. The resin composite made with 25wt% of UDMA/SR833s resin system and 75wt% of silaned BaAlSiO2 filler particulates was used as control composite which had similar composition as the commonly used resin composites. Flexural strength (FS), flexural modulus (FM) and work of fracture (WOF) were measured. Fractured specimens were observed by scanning electron microscopy. Double bond conversion (DC) and fiber length distribution were also studied. ResultsReinforcement of resin composites with discontinuous S2-glass fibers can significantly increase the FS, FM and WOF of resin composites over the control. The fibers from the mixed resin composites showed great variation in final fiber length. The mean aspect ratio of experimental composites containing 62.5wt% of particulate fillers and 10wt% of 1.5 or 3.0mm cutting S2-glass fibers was 70 and 132, respectively. No difference was found in DC between resin composites containing S2-glass fibers with two different cutting lengths. ConclusionDiscontinuous S2-glass fibers can effectively reinforce the particulate-filled resin composite and thus may be potential to manufacture resin composites for high-stress bearing application.

Development of indigenous insulation material for superconducting magnets and study of its characteristics under influence of intense neutron irradiation

Epoxy based glass fiber reinforced composites are the main insulation system for the superconducting magnets of fusion machines. 14MeV neutrons are generated during the DT fusion process, however the energy spectra and flux gets modified to a great extent when they reach the superconducting magnets. Mechanical properties of the GFRP insulation material is reported to degrade up to 30%. As a part of R & D activity, a joint collaboration with IGCAR, Kalpakkam has been established. The indigenous insulation material is subjected to fast neutron fluence of 1014 - 1019 n/m2 (E>0.1 MeV) in FBTR and KAMINI Reactor, India. TRIM software has been used to simulate similar kind of damage produced by neutrons by ion irradiation with 5 MeV Al ions and 3 MeV protons. Fluence of the ions was adjusted to get the same dpa. We present the test experiment of neutron irradiation of the composite material (E-glass, S-glass fiber boron free and DGEBA epoxy). The test results of tensile, inter laminar shear and electrical breakdown strength as per ASTM standards, assessment of micro-structure surface degradation before and after irradiation will be presented. MCNP simulations are carried out for neutron flux, dose and damages produced in the insulation material.

Dry Friction Clutch Disc of an Automobile under Transient Thermal Load: A Comparison of Friction Lining Materials

This paper shows the comparison of temperatures produced in a dry friction clutch disc with different materials during a single engagement to assist in clutch plate design and analysis. A study of usage of different materials for friction lining of clutch disc is required, which will provide improved performance and enhanced life. This investigation is modelled mathematically and solved numerically using finite element method. ANSYS ® 15.0 is a dedicated finite element package used for determining the temperature distribution across a clutch disc. In the present work, an investigation of a conventionally used harmful friction lining material asbestos is compared with carbon-carbon composite, S2-glass fibre and aluminium metal matrix composite. The transient thermal analysis of a clutch disc with different materials is performed and the temperature distribution on the clutch system is compared. Simulation results indicate that all the values of the temperature obtained from the analysis of aluminium metal matrix are less than those of asbestos based lining material, therefore clutch disc made up of aluminium metal matrix composite will assure the extended service life and the longer stability due to the fact that the temperature responsible for the wear and tear has been reduced. Furthermore, the slipping time is also considered in this investigation.

Evaluation of Impact Properties of Fly Ash and S-Glass Reinforced Al-4046 Hybrid Metal Matrix Composites

In recent years, Metal Matrix Composites (MMC’s) reinforced with Fly Ash particulates have attracted considerable interest due to their inherent good mechanical properties such as tensile strength, compression strength, hardness, wear resistance and impact etc. This research work is concerned about the production of Fly Ash, S-Glass reinforced hybrid Aluminium 4046 Metal Matrix Composites (MMC’s) and further to investigate on mechanical properties of the processed composites. In this work, experimental study begins with mixing of Aluminium powder, Fly Ash particulates and S-Glass fibers using a stir casting technique at different weight fraction addition of Fly Ash (2%, 4%, 6%) and S-Glass (3%, 5%, 7%). The test specimens are prepared as per standard to conduct impact test. It has been observed that addition of Fly Ash significantly improves impact strength as compared with that of unreinforced matrix.

Dynamic effects of single fiber break in unidirectional glass fiber-reinforced composites

In a unidirectional composite under static tensile loading, breaking of a fiber is shown to be a locally dynamic process that leads to stress concentrations in the interface, matrix and neighboring fibers that can propagate at high speed over long distances. To gain better understanding of this event, a fiber-level finite element model of a two-dimensional array of S2-glass fibers embedded in an elastic epoxy matrix with interfacial cohesive traction law is developed. The brittle fiber fracture results in release of stored strain energy as a compressive stress wave that propagates along the length of the broken fiber at speeds approaching the axial wave-speed in the fiber (6 km/s). This wave induces an axial tensile wave with a dynamic tensile stress concentration in adjacent fibers that diminishes with distance. Moreover, dynamic interfacial failure is predicted where debonding initiates, propagates and arrests at longer distances than predicted by models that assume quasi-static fiber breakage. In the case of higher strength fibers breaks, unstable debond growth is predicted. A stability criterion to define the threshold fiber break strength is derived based on an energy balance between the release of fiber elastic energy and energy absorption associated with interfacial debonding. A contour map of peak dynamic stress concentrations is generated at various break stresses to quantify the zone-of-influence of dynamic failure. The dynamic results are shown to envelop a much larger volume of the microstructure than the quasi-static results. The implications of dynamic fiber fracture on damage evolution in the composite are discussed.

Effect of short glass fibers on the polymerization shrinkage stress of dental composite.

This study examines contraction stresses of seven short fiber reinforced composites (sFRC) exhibiting different volume loads and aspect ratios (AR)* of fibres. The shift towards a greater utilization of posterior resin composites in dentistry has seen increased interest in the use of randomly oriented short glass fibers in these restorative materials. While the effect of these fibers on modulus, strength, and toughness has been studied, very little information exists on their effect on polymerization shrinkage and even less on shrinkage stress. S2-glass fibers with an average AR of 68 were used to form three experimental groups with 5%, 10%, and 20% volume loads. Commercial sFRC with ARs of 20 and 100 were also tested. A tensilometer set up was used with moderate compliance, 5.4 J/cm2 irradiance, and a C-factor of 2.75. Data was statistically analyzed using ANOVA followed by post hoc Tukey's test. The addition of 5% of the experimental fiber did not significantly increase stress while the 10% and 20% groups resulted in 36.3% and 39.1% higher stress values, respectively, compared to the non-fiber control group (p < 0.05). Of all the sFRC groups, the very low AR material exhibited the lowest stress [0.682 MPa (p = 0.001)] while another commercial material with higher AR fibers exhibited the highest overall value [1.822 MPa (p < 0.001)] when compared to the control group. The results indicate that both short fiber volume and AR are important variables to consider with regards to setting stresses of sFRC. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1930-1937, 2017.

Experimental investigation on tensile and Charpy impact behavior of Kevlar/S-glass/epoxy hybrid composite laminates

Abstract The aim of this study is to evaluate the effect of hybridizing Kevlar and glass fibers on the tensile and Charpy impact properties of their composites. Produced hybrid samples were designed as unbalanced and asymmetric structures in terms of different mixing ratios between woven Kevlar and S-glass fibers, and their tensile properties were determined using ASTM standards. A series of Charpy impact tests were performed to evaluate the amount of impact strength and absorbed energy by impacting each side of the hybrid composite samples. When the hybrid samples were impacted on the surface of the Kevlar side, they exhibited higher impact resistance compared with glass side impact. The resulting degree of hybridization effects showed that addition of Kevlar layers instead of glass layers contributed a significant increase in impact strength and absorbed energy of the overall composite laminate.

Mechanical Properties of Preliminary Designed Insulation for CFETR CSMC

Glass-fiber reinforced plastics is commonly designed as insulation materials for fusion magnet coils and is selected for the turn and ground insulation for the China Fusion Engineering Test Reactor (CFETR) Central Solenoid Model Coil (CSMC). The mechanical properties are being subjected to investigations with respect to the design requirements and operating conditions at present. The preliminary designed insulation system for CFETR CSMC mainly consists of S-glass fiber reinforced tape, interleaved with corona-treated Kapton HN, and vacuum-pressure impregnated in a DGEBF epoxy system. For the composite structure, the tensile and shear performance of the insulation system at room temperature and liquid nitrogen temperature (77 K) were assessed. Meanwhile, effects on the tensile and inter-laminar shear performance from cycling in liquid nitrogen were investigated. The failed specimens were observed to verify the insulation system failure mechanisms.

Micromechanical modeling and characterization of damage evolution in glass fiber epoxy matrix composites

This paper develops an experimentally calibrated and validated 3D finite element model for simulating strain-rate dependent deformation and damage behavior in representative volume elements of S-glass fiber reinforced epoxy-matrix composites. The fiber and matrix phases in the model are assumed to be elastic with their interfaces represented by potential-based and non-potential, rate-dependent cohesive zone models. Damage, leading to failure, in the fiber and matrix phases is modeled by a rate-dependent non-local scalar CDM model. The interface and damage models are calibrated using experimental results available in the literature, as well as from those conducted in this work. A limited number of tests are conducted with a cruciform specimen that is fabricated to characterize interfacial damage behavior. Validation studies are subsequently conducted by comparing results of FEM simulations with cruciform and from micro-droplet experiments. Sensitivity analyses are conducted to investigate the effect of mesh, material parameters and strain rate on the evolution of damage. Furthermore, their effect on partitions of the overall energy are also explored. Finally the paper examines the effect of microstructural morphology on the evolution of damage and its path.

Hybridization effects on quasi-static penetration resistance in fiber reinforced hybrid composite laminates

Abstract Quasi static penetration tests (QSPT) were conducted on fiber reinforced hybrid composite laminates with a circular and cylindrical punch. Woven Carbon, Kevlar and S-glass fibers were used as reinforcing fibers for production of hybrid and non-hybrid composite laminates. Punch shear test procedures were employed until the perforation and complete plugging shear out of the laminate. During QSPT experiments, a flat end punch with diameter of 12.7 mm has been used for two different support spans (25.4 and 63.5 mm) to obtain two different support span (D s ) to punch diameter (D p ) ratios (SPR = D s /D p = 2 and 5). After the experiments, the extent of compression-shear and tension-shear based failure modes were characterized at constant punch displacements of 8 and 10 mm for SPR = 2 and 5, respectively. In addition to visualize of front and back side surfaces, composite samples were half sectioned at damage region to observe the amount of delamination and damage through the thickness of the laminate. It was found that hybridization effects were distinctly observed with dominated tension-shear damage mode at SPR = 5.

Response of hygrothermally aged GLARE 4A laminates under static and cyclic loadings

Abstract An experimental investigation focusing on the hygrothermal aging-structural degradation–mechanical property relationship of GLARE 4A laminates was conducted. Water immersion conditioning at 80 °C for up to 4 months was carried out on GLARE 4A laminates. It was found that although the outer aluminum layers effectively protected the glass/epoxy composite layers from hygrothermal attack, the composite layers absorbed moisture through the edges. Consequently, significant decrease in both, the tensile strength and fatigue life of the GLARE 4A laminates, was observed although no structural defects were apparently identifiable in the microstructures of the conditioned laminates. Detailed experimental investigation was conducted to study the mechanism of mechanical property decay due to hygrothermal aging. It is proposed that the strength of the S2-glass fibers was not fully realized due to the weakening of the fiber/matrix interface and the deterioration of the sizing, which consequently led to the reduction in the tensile strength and fatigue life of the GLARE 4A laminates. The stiffness degradation characteristics of GLARE 4A laminates under cyclic loading were also investigated.

Experimental investigation on influence of Kevlar fiber hybridization on tensile and damping response of Kevlar/glass/epoxy resin composite laminates

This study investigates the tensile and damping behavior of Kevlar/glass/epoxy hybrid laminates. Hybrid Kevlar/glass with epoxy resin composites is fabricated considering different fiber volume fractions in combinations to show the influence of hybridization. Mechanical properties were inspected by an instrumented tensile test machine. A series of vibration tests were conducted to determine dynamic characteristics of the samples. Damping properties are calculated from logarithmic decrement method by using vibration response envelope curve. In addition, effects of fiber angle on natural frequencies were examined using ANSYS. The results show that the hybridization of relatively brittle material S-glass fibers with tough and high performance Kevlar fibers has showed to be highly effective in improving damping capacity of S-glass fiber composite laminates.

Hybridization effects on lateral buckling behavior of laminated composite beams

The aim of this study is to investigate the influence of hybridization on lateral buckling behavior of composite beams consists of symmetrical and unsymmetrical ply orientations, various cutout shapes, and length/thickness ratio. Carbon, S-glass, and Aramid fibers are used as reinforcement with epoxy resin. Experiments are performed to see the effects of various combinations of fibers on lateral bucking loads with [(0/90)3]s, [(30/-60)3]s, [(45/-45)3]s symmetrical, and [(0/90)6]us unsymmetrical ply orientations. Numerical studies are also performed to see the effects of length/thickness ratio, and various cutout shapes on the lateral buckling loads using finite element analysis software ANSYS. It is concluded that stiffness and shear properties are affecting the lateral buckling characteristics of the composite beams. Also, fibers having higher stiffness and higher shear properties in the upper layers increase the lateral buckling strength. POLYM. COMPOS., 37:2511–2521, 2016. © 2015 Society of Plastics Engineers

Fabrication of novel fiber reinforced aluminum composites by friction stir processing

In this study, chopped and attrition milled high strength carbon, E-glass, and S-glass fibers have been used as the reinforcing agents in an aluminum alloy (Al1100) considered as the matrix. The Surface Metal Matrix Composites (SMMCs) then are produced by Friction Stir Processing (FSP). Tensile and micro-hardness examinations represent a magnificent improvement in the hardness, strength, ductility and toughness for all of the processed samples. Scanning Electron Micrographs reveal a proper distribution of the reinforcements in the matrix and a change in the fracture behavior of the FSPed specimens. The synergetic effects of reinforcing by fibers and Severe Plastic Deformation (SPD) lead to an extra ordinary improvement in the mechanical properties.

Three-dimensionally woven glass fiber composite struts: characterization and mechanical response in tension and compression

Three-dimensionally woven E- and S2-glass fiber textiles have been used in the past to create delamination-resistant corrugated core sandwich panels. During subsequent out-of-plane loading, the E-glass composite core struts and S2-glass composite faces are subjected to either compressive or tension loads. This study has investigated the relationships between the three-dimensional fiber architecture, fiber properties and the mechanical response of representative samples of the core and faces. Using X-ray computed tomography and optical microscopy to characterize the three-dimensional fiber architectures, it is found that the in-plane warp and weft fibers suffer significant off-axis displacement (waviness) due to their interaction with through thickness z-fiber tows. The consequence of this fiber waviness on the relationships of the in-plane tensile and compressive mechanical properties, along with fiber type, fiber volume fraction, and strut aspect ratio are experimentally investigated. The large initial misalignment angle of the warp and weft fiber tows results in a strut compressive strength that is substantially lower than its tensile strength due to compressive failure by either elastic or localized fiber microbuckling. Simple micromechanical models are used to relate the compressive strength of the three-dimensional woven composite struts to strut aspect ratio, fiber volume fractions in the three directions and the three-dimensional fiber architecture.