Glass Fabric Composites Research Articles

Simultaneous reinforcing and toughening of PTFE/glass fabric composites based on polyaniline/carbon microcapsule network

Through designing dispersed well and assembled orderly structures, a series of polyaniline (PANI)/carbon (CB) microcapsules were successfully synthesised. In the formation of the PANI/CB microcapsules, PANI/CB microcapsules were in good dispersion and ordered state, which resulted in exceptional mechanical properties and electrical conductivity for polytetrafluoroethylene (PTFE)/glass fabric (GF) composites. Here, the authors have developed the PTFE/GF composites that have not only tensile strength up to 21.5 MPa, but also toughness up to 17.5 MJ/m3, and surface resistivity up to 5 × 108 Ω cm, it is difficult to obtain by other methods. This was achieved by only assembled orderly and ordered arrangement for forming highly ordered network structures in an oriented direction, without introducing a third component or chemical cross-linker as in interfacial systems. More importantly, they believe that the design principles and processing strategies, which can be applied to other material systems to develop superconducting, strong and flexible materials.

Effects of fabric structure on the formability characteristics of thermoplastic composites under various process conditions

Thermoplastic composites are broadly utilized for structural and automotive applications due to their higher specific strength and modulus, higher strain to failure, recyclability, and unlimited shelf life. This study investigates the effects of fabric structure on the forming behaviour of glass fabric reinforced polypropylene composites during the sheet forming of a doubly curved shape. Stamp forming, a novel thermoforming technique, is mostly used for hemispherical forming of thermoplastic composites. The study also investigates the influence of process parameters such as die temperature, blank temperature, and blank holder force on sheet formability. Forming ratio, thickness distribution, material draw-in, and punch force were used for the evaluation of the formability of composites. Conventional and novel plain weave glass fabric reinforced polypropylene composite laminates were fabricated using the film stacking technique. Thermo-stamp forming experiments were conducted on the basis of the Taguchi’s L9 orthogonal array. Experimental results revealed better forming characteristics by the novel glass fabric reinforced composite than for the conventional glass fabric reinforced composite. Production of defect-free components under high die temperature, low blank holder force, and medium blank temperature process condition was observed.

Manufacturing and Mechanical Properties of Graphene Coated Glass Fabric and Epoxy Composites

The processing characteristics and mechanical properties of glass fabric reinforcements coated with graphene nanoparticles were investigated. Graphene was coated onto either one or both sides of a plain weave glass fabric. The coated fabrics were investigated to measure key process characterization parameters used for vacuum assisted resin transfer molding (VARTM) process which are, reinforcement compaction response, in-plane, and transverse permeability. It was found that graphene coated glass reinforcements were stiffer than the pure glass reinforcements which will have direct influence on final fiber volume fraction obtained during VARTM processing. The permeability measurement results show that the graphene coated reinforcements filled relatively slower compared with the pure glass samples. Composite samples were then tested for flexural and low velocity impact. The initial results show that the flexural modulus did not change as the wt % of graphene increases. However, a decrease in flexural strength with increasing wt % of graphene was observed. It was also observed that the coating of graphene on glass reinforcements caused delamination between plies and resisted localized damage under low velocity impact as compared to pure glass samples.

Carbon fiber assisted glass fabric composite materials for broadband radar cross section reduction

Carbon fibers (CFs) have been widely used as absorbing materials for radar cross section (RCS) reduction. Here, an alternative approach for CFs is proposed to achieve the same goal and has been performed by the glass fabric composites loaded with a small number of CFs. The reduction mechanism of our proposal is phase cancellation instead of absorption. Two prototypes in chessboard and random patterns are analyzed numerically and measured experimentally. The short CF yarns are designed as the patterned configurations and embedded into the composite surface layers. It is demonstrated that the proposed composites allow for remarkable suppressing of the specular scattering over a broad frequency band. The designed RCS reduction level more than 10 dB covers the frequency range from 8.7 to 19.2 GHz, while the overall thickness is 2.7 mm. The proposed composites are of a simple configuration and robust for the defects. It is also believed that the study of this work can be easily extended to the curved surfaces.

English

English

Challenges in Compression Testing of 3D Angle-Interlocked Woven-Glass Fabric-Reinforced Polymeric Composites

Abstract In this paper, the challenges are described in determination of compressive strength for three-dimensional (3D) angle-interlocked glass fabric-reinforced polymeric composites (3D-FRPCs). It makes use of both experimental investigation and finite-element analysis. The experimental investigation involved testing both two dimensional (2D) and 3D-FRPC using ASTM D6641/D6641M-14 and subsequent scanning electron microscopic (SEM) imaging of failed specimens to reveal the stress state at failure. This was further evaluated using laminate level finite-element (FE) analysis. The FE analysis required input of effective orthotropic elastic material properties of 3D-FRPC, which were determined by customizing a recently developed micro-mechanical model. The paper sheds new light on compressive failure of 3D angle-interlocked glass fabric composites, as only scarce data is available in literature about this class of materials. It showed that although the tests produce acceptable strength values the internal failure mechanisms change significantly and the standard deviation (SD) and coefficient of variance (COV) of 3D-FRPC ends up being much higher than that of 2D-FRPC. Moreover, while reporting and using the test data, some additional information about the 3D-fabric architecture, such as the direction of angle interlocking fabric, needs to be specified. This was because, for 3D angle interlocking of fabric along the warp direction, the strength values obtained in the warp and weft direction were significantly different from each other. The study also highlights that, because of complex weave architecture, it is not possible to achieve comparable volume fractions with 2D and 3D fabric-reinforced composites using similar manufacturing parameters for the vacuum-assisted resin-infusion process. Thus, the normalized compressive strength values (normalized with respect to volume fraction) are the highest for 3D-FRPC when measured along the warp direction, they are at an intermediate level for 2D-FRPC and the lowest for 3D-FRPC, when measured in the weft direction.

Mechanical properties of non-woven glass fiber geopolymer composites

This experimental research focuses on mechanical properties of non-woven glass fabric composites bound by geopolymeric matrix. This study investigates the effect of different matrix composition and amount of granular filler on the mechanical properties of final composites. Matrix was selected as a metakaolin based geopolymer hardened by different amount of potassium silicate activator. The ceramic granular filler was added into the matrix for investigation of its impact on mechanical properties and workability. Prepared pastes were incorporated into the non-woven fabrics by hand roller and final composites were stacked layer by layer to final thickness. The early age hardening of prepared pastes were monitored by small amplitude dynamic rheology approach and after 28 days of hardening the mechanical properties were examined. The electron microscopy was used for detail description of microstructural properties. The imaging methods revealed good wettability of glass fibers by geopolymeric matrix and results of mechanical properties indicate usability of these materials for constructional applications.

Fabrication of copper-coated glass fabric composites through electroless plating process

Copper-coated glass fabric was successfully fabricated via electroless plating method, and the copper layer on the surface of glass fabric was continuous and compact. The chemical composition of the copper coatings was investigated by X-ray diffraction, and the microstructures were invested by scanning electron microscopy. It was found that the quality of the copper layer was closely related to the dosage of NaOH and reducing reagent, respectively. These composites possessed excellent conductivity with the volume resistivity up to 2.57 × 10−3 Ω cm, and can be used as shielding materials.

Silver-coated glass fabric composites prepared by electroless plating

Silver-coated glass fabrics have been successfully obtained by a facile and versatile electroless plating method, and the silver layers on the surface of glass fabrics were compact and uniform. The purity and quality of these silver coatings were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. It was found that the quality of the coating layer was influenced by the dosage of reducing agent and reaction time. The composites possessed an excellent conductivity, and the optimal volume resistivity could reach 6.54×10−4Ωcm. It was expected that such conductive composites have extensive application in shielding materials.

Response of glass fiber-reinforced hybrid shear thickening fluid (STF) under low-velocity impact

This paper addresses the response of glass fiber-reinforced shear thickening fluid (STF) under low-velocity impact. Experimental tests were performed according to ASTM: D5628 for initial impact energy 6.89 J and for samples with STF+ nanoclay (30% silica and 3% clay nanoparticles), STF+ nanoclay (30% silica and 1% clay nanoparticles), STF (30% silica nanoparticles), and STF (20% silica nanoparticles).The effect of impregnating glass fabrics with STFs on their quasi-static puncture resistance performance has been investigated. A STF was prepared successfully, and rheological behavior was investigated. The results of rheological tests indicate that the increase in the fraction weight of nanosilica and nanoclay leads to the increase in suspension viscosity and reduction in the critical shear rate. One of the disadvantages of STF is high concentration. Glass fabrics were soaked in STF/ethanol solution to prepare STF–glass fabric composite and STF–nanoclay–glass composite. For better immersion of fibers, at first STF is diluted in ethanol, and then, the fibers are left therein for a specified period in order to impregnate all fibers with the fluid. After this stage, to eliminate the ethanol in the sample, it is heated at a temperature range of 60–70 °C. The composite’s sensitivity to the impact will be reduced through ethanol combining with the fluid and its elimination. Quasi-static resistant tests were carried out on both the neat glass fabrics and STF–glass fabric and STF–nanoclay–glass fabrics composites using a hemispherical penetrator based on the areal density. This study clearly displays a significant enhancement in penetration resistance of glass fabric impregnated with different combination of STF and STF–nanoclay. In sample with higher weight fraction of nanosilica and nanoclay, displacement to yield point is higher and resistance to penetration does not have much difference.

Effects of interface strength gradation on impact damage mechanisms in polypropylene/woven glass fabric composites

The attention of the present work is focused on the behaviour of interlaminar graded interface strength (IGIS) laminated structures under impact. IGIS structures are made of layers of a woven glass fabric alternated with compatibilized and not compatibilized polypropylene film layers, symmetrically and asymmetrically arranged with respect to the middle plane. For each configuration some specimens are subjected to impact tests at energies of 6 and 25 J while one specimen is left unloaded. Impacted and not impacted specimens are non-destructively evaluated with lock-in thermography (LT). Results highlight the role played by the stacking sequence in the IGIS laminate and confirm data previously obtained through mechanical characterization.

Design of flexible copper clad laminate with outstanding adhesion strength induced by chemical bonding

The preparation method of two-layer flexible copper clad laminate (FCCL) including coating method, sputtering method, and electrochemical plating method has many disadvantages such as complex production process and large investment. In this paper, the two-layer FCCL based on polyarylene ether nitriles terminated with phthalonitrile (PEN-t-Ph)/glass fabric (GF) composite was prepared by a simple laminating method without the adhesive. The morphology of the PEN-t-Ph/GF composite was investigated, and the morphology, electrical properties, and adhesion strength of the FCCL were also investigated in detail. In the presence of copper ions, the copper phthalocyanine will be formed, so that the copper clad adheres to PEN-t-Ph/GF composite tightly, which can be confirmed by FTIR, SEM, EDS, and XPS. Moreover, The FCCL possesses excellent thermal property with glass transition temperature (Tg) of 187.50 °C, good electrical properties with dielectric constant of about 4.5 and dielectric loss of about 0.008 at 200 kHz as well as outstanding adhesion strength with shear strength of 71.23 MPa and peel strength of 1.52 N/cm.

Manufacturing method of carbon and glass fabric composites with dispersed nanofibers using vacuum-assisted resin transfer molding

AbstractFiber-reinforced composites have favorable structural characteristics such as their light weight, high specific strength, and high stiffness. Vacuum-assisted resin transfer molding (VARTM), used for manufacturing these composites, is relatively simple and provides materials with excellent mechanical properties. In this study, the author investigated the utility of VARTM in improving the performance of a carbon nanofiber (CNF)/carbon fiber composite impregnated with thermosetting resin. Processing parameters were determined, and the integrity of the manufactured composites was assessed. Carbon and glass fibers were used as reinforcing materials in an epoxy resin matrix. CNFs, which have excellent thermal and electrical characteristics, were dispersed in the composites. The pore sizes using the 0°/90°- and 90°/45° types of laminates were about 45 and 50 μm, respectively. The integrated composites produced had low porosity (below 3.7×10-5%).

A biobased photocurable binder for composites with transparency and thermal stability from biomass-derived isosorbide

A biobased photocurable binder was synthesized from isosorbide in a high yield (91%) and used as a binder for transparent glass fabric composites. The photocurable isosorbide binder showed a lower refractive index (n = 1.489) than that of glass (n = 1.560) and low viscosity (48.6 cP at 25 °C) owing to the wedge-shaped fused ring structure of the isosorbide moiety. Transparent glass fabric composites were prepared by refractive index matching using a cardo-type fluorene based binder (n = 1.583) as a co-binder. A glass fabric composite photocured with equal wt% of the cardo- and isosorbide-based binder showed 85% of transmittance at 550 nm by UV-visible spectroscopy. It also showed a considerably good coefficient of thermal expansion (α1 = 16.3 ppm K−1) and glass transition temperature (142 °C by DMA). As the wt% of the isosorbide-based binder increased, the network structure of the binder mixture became tight to give a higher glass transition temperature but the composite's transparency was decreased.

Multi-Criteria Optimisation in Drilling of Epoxy/Glass Fabric Hybrid Nanocomposite Using Grey Relational Analysis

This paper presents a study on the influence of cutting parameters (Cutting speed and Feed rate) on drilling multi walled carbon nanotubes (MWCNTs) filled epoxy / glass fabric hybrid polymeric nanocomposite. For comparison neat epoxy / glass fabric polymeric composite was also fabricated. Drilling tests were carried out on these materials with HSS twist drill of diameter 6mm. Optimal cutting conditions were found using grey relational analysis by simultaneously considering the surface delaminations of the drilled holes at the entrance and exit sides. Surface delaminations of the drilled holes were quantified in terms of delamination factor. From the mean grey relational grades, it is observed that the multi walled carbon nanotubes (MWCNTs) has significant effect in improving the drilled hole quality. Mean grey relational grades of MWCNTs filled epoxy composite was found to be better than that of neat epoxy composite.

English

Conventional materials are being replaced in the field of engineering by composite materials, due to their tailorable properties and high specific properties. These materials are extensively used in structural applications. Damping is one of the important properties of the materials used in structures, and needs to be enhanced in order to reduce structural vibrations. In the present work, the improvement of the material damping of glass fabric epoxy composites with particle rubber inclusions is studied. The effect of particle size on the damping and stiffness parameters at different frequencies and temperatures is studied experimentally. Considerable enhancement in damping without significant reduction in stiffness is observed at lower particle sizes. The damping property in both bending and shear modes is more with 0.254 mm rubber particle inclusions among the selected sizes. A lower reduction in stiffness is observed with the inclusion of lower particle sizes (0.254 mm and 0.09 mm) when compared with higher particle sizes. An ANN-based prediction model is developed to predict these properties for a given frequency/temperature and particle size. The predicted values are very close to the experimental values with an maximum error of 5%.

Improvement in the fracture toughness (Mode I) of laminated glass fabric composites through air-jet texturing

Delamination is the most common failure mode in laminated composites due to the reduced strength in the through-the-thickness direction. Air-jet texturing was used to provide more surface contact between the fibres and the resin by producing bulk and loops in the yarn. The development and characterization of core-and-effect textured glass yarns and the effect of texturing on the mechanical properties of laminated composites were presented in the previous papers. This paper describes the effect of texturing on the inter-laminar fracture toughness (Mode I) of glass laminated composites. The composites of twill weave fabrics were developed from both the textured and non-textured yarn and fracture toughness is tested in warp and weft directions. Significant improvement was observed in the Mode I fracture toughness of the composites after texturing. The bulkier, loopy structure of the textured yarn provided more surface contact between the fibre and the resin and significantly improved the bonding strength.

Simulation of impact response of multi-layered panels composed of bonded and unbonded plies

This paper presents an investigation into low velocity impact response of different configurations of resin bonded and unbonded layups of glass fabric composites for armour application. A numerical simulation was developed using the finite element code LS-Dyna to model the impact response at low velocities. The numerical results have been validated by comparison with results of impact tests on epoxy-bonded glass fibre-reinforced plastic plates with all edges fixed. Further impact testing of composite panels with various lay-up configurations have been performed using two different types of support: all edges fixed and with the panels mounted on clay foundation with all edges free. Experimental results show that a combination of unbonded flexible and adhesively bonded rigid composite lay-ups, which has a lower weight than fully bonded panels, yields comparable levels of energy absorption.

Comparing the fracture toughness of 3-D braided preform composites with z-fiber-reinforced laminar composites

Organic polymer engineering composite materials based on layered fabrics have many advantageous properties and processing features. However, performance properties of the layered OPECs, especially impact strength, delamination resistance, and fracture toughness are poor. Three-dimensional preforms fabricated with 3-D weaving, knitting and braiding techniques, are employed to improve the shortcomings of 2-D layered fabric reinforcements. z-directional microfiber-reinforced laminar composites were recently developed to improve impact strength and fracture toughness without reducing in-plane performance properties at minimal added cost and at higher productivity in the Flock Materials Laboratory at the University of Massachusetts Dartmouth. The effectiveness of laminar composite z-directional microfiber reinforcement (by a flocking process) in improving fracture toughness was compared with that of a 3-D braided 8-layer glass fiber preform/epoxy composite plate. The results show that the Mode I fracture toughness (GI) of the 3-D braided preform reinforced composites are about 10 times of the 2-D layered glass fabric laminar composites (control) as expected. This is comparable to the results of z-directional microfiber-reinforced composites; up to 9 times increase in GI over that of 2-D glass fabric/epoxy laminar composite (control). The presence of through-thickness microfiber (flock fiber) reinforcements in the matrix resin between reinforcement layers is found not to reduce the in-plane mechanical properties; the fracture toughness however, increases significantly.

Mechanical properties of particulate‐filler/woven‐glass‐fabric‐filled vinyl ester composites

AbstractStudies of the effect of particulate fillers on specific mechanical properties of vinyl ester epoxy (VE) reinforced with woven glass fiber composites were carried out with different filler types and particulate filler contents (1%, 3%, and 5% by weight). Two types of particulate filler were used, i.e., calcium carbonate (CC) and phenolic hollow microspheres (PHMS). The composites were prepared by using a hand lay‐up and vacuum bagging method. Woven glass fabric composites filled with particulate PHMS were observed to have better specific flexural strength and specific impact strength, as well as lower density, than those filled with particulate CC. Morphological features determined by scanning electron microscope (SEM) proved that the PHMS filler experienced good bonding in the VE matrix, a feature which contributed to the improvement in the properties of the composites. The incorporation of particulate fillers into the composites also influenced the storage modulus with a minimal effect on Tg. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers