Glass-epoxy Composites Research Articles

Synergistic effect of nano graphene on the mechanical behaviour of glass-epoxy polymer composites

Abstract The effect of nano graphene on the mechanical behavior of Glass fabric reinforced epoxy composites was studied. The material systems selected for the study are neat epoxy (EP), 1 wt% Nano Graphene filled glass–epoxy (1GE) and 2 wt% filled glass-epoxy nano composites (2GE). These composite materials have been produced using vacuum bag molding technique. The mechanical properties were studied through tensile, flexural and impact behavior as per ASTM method. X-Ray diffraction analysis has been carried out to study the crystalline nature of composites. The experimented results revealed that the effect of nano graphene addition remarkably improved the mechanical behavior of glass epoxy composites. On the other hand, the sharp intense patterns of X-ray diffraction patterns revealed the pure crystalline behavior of material. The significant improvement in mechanical behavior of nano graphene filled composites is due to uniform distribution of nano graphene particles and also interfacial interaction of nano graphene with the glass fabric improving the structural stability of nano composites. SEM image investigation revealed the synergistic effect between nano particles and the glass fabric. Matrix deformation, agglomeration of nano graphene fillers and also fractured glass fabrics were some of the features observed during the study.

An investigation of date palm seed as effective filler material of glass–epoxy composites using optimization techniques

Glass/epoxy (G-E) products are widely used in numerous industries nowadays. This is due to favorable characteristics of these products including low cost, ease of manufacturing, good mechanical properties, and lightweight. The mechanical properties of G-E composites can be enhanced through mixing with natural reinforcement materials. In this work, we investigate the use of date seeds (DSs) as a reinforcement material for G-E composites. A DS filler has been added to G-E hybrid composites as a powder by applying a semiautomatic technique. Glass fibers reinforced with angle-ply ([±45]4) were considered as commonly used G-E composites. G-E reinforced DS composites were analyzed using various mechanical characteristics such as mica-hardness, tensile strength, and impact strength. Effects of the DS filler on the wear volume loss (VL) were investigated at different parameter settings. This loss was analyzed using the traditional Taguchi method and the nontraditional flower pollination algorithm to obtain optimal parameters. Surface inspection using a scanning electron microscope and Fourier-transform infrared (FTIR) was conducted. The results revealed that the addition of a 10% DS reinforcement to G-E composites enhanced the wear resistance and increased toughness and hardness. Finally, G-E-DS composite optimization was carried out by minimizing the wear VL. This resulted in an optimum DS reinforcement of 10% at a normal load of 10 N, an abrasive size of 1200 mesh, and an abrading distance of 420 m. Deviations from this reinforcement ratio degrade the mechanical properties of the G-E-DS composite. Moreover, the significant factors are the abrasive size, reinforcement material wt%, normal load, and abrading distance. The contributions of these factors are 30.6%, 15.5%, 11.8%, and 10%, respectively. FTIR results indicate that a chemical interaction has occurred between G-E and the organic DS. These experimental results are in good agreement with the theoretical ones.

Mechanical behavior of basalt and glass textile composites at high strain rates: A comparison

The aim of this paper is to study and compare the mechanical behavior of woven basalt and woven glass epoxy composites at high strain rates, in order to assess the possibility of replacing glass fiber composites with basalt fiber composites for aircraft secondary structures, such as radomes, fairings, wing tips, etc. Both composites were produced using the same epoxy matrix, the same manufacturing technique, and with comparable densities, fiber volume fractions, and static stiffnesses. Dynamic tensile and shear experiments were performed using a split Hopkinson tension bar, in addition to reference quasi-static experiments to compare both material behaviors over a wide range of strain rates. Normalized results with respect to the material density and fiber volume fraction showed that basalt epoxy composite had higher elastic stiffness, ultimate tensile strength, ultimate tensile strain, and absorbed energy in tension compared to glass epoxy composite. This suggests a promising potential in replacing glass fibers composites with basalt fiber composites in aircraft secondary structures and, more generally, components prone to impact. However, for the basalt epoxy composite, improvements in the fiber-matrix adhesion and in the manufacturing technique are still required to enhance their shear properties compared to glass fiber composites, and fully exploit the potential of basalt epoxy composites in aeronautical applications.

Study on thermal and erosive wear behaviour of hard powders filled glass-epoxy composite

The effect of hybrid powder fillers (WC + Ta/NbC) on thermal response and erosion wear resistance of woven glass fiber reinforced-epoxy composites has been studied. Vacuum assisted resin transfer moulding (VARTM) method was used to fabricate a set of GE composite specimen. Erosion wear test was carried out using alumina erodent, impinging at 40 m/s velocity, from a distance of 10 mm, at ambient and above glass transition temperatures. The rate of erosion was assessed at impingement angles 30°, 60° and 90°. The thermal stability of the composite samples and their response to heat was analysed by using thermal analysis methods TGA and DSC. The erosion wear mechanism of the composites was established by inspecting the eroded surface with the help of scanning electron microscopy.

Experimental and Numerical Analysis of a Composite Thin-Walled Cylindrical Structures with Different Variants of Stiffeners, Subjected to Torsion.

The aim of the study was to determine the impact of the use of isogrid stiffeners on the stress and displacement distribution of a thin-walled cylindrical shell made of layered composites subjected to torsion. It also strives to define criteria for assessing the results of non-linear numerical analysis of models of the examined structures by comparing them with the results of the model experiment. The study contains the results of experimental research using models made of glass–epoxy composites and the results of numerical analyses in non-linear terms. The experiment was carried out using a special test stand. The research involved two types of considered structures. The results of the research allowed to create the concept of an adequate numerical model in terms of the finite element method, allowing to determine the distribution of stress and strain in the components of the studied structures. Simultaneously, the obtained conformity between the results of non-linear numerical analyses and the experiment allows to consider the results of analyses of the modified model in order to determine the properties of different stiffening variants as reliable. The presented research allows to determine the nature of the deformation of composite thin-walled structures in which local loss of stability of the covering is acceptable in the area of post-critical loads.

Mechanical Characteristics of CSP Filled Glass-Epoxy Composites

Composite materials are the combination of two or more materials which are different in form and chemical compositions. These are gradually gaining more importance as structural materials in the present day engineering design and development activity; this is because they offer very attractive physico-mechanical properties. Hence composite materials can be used in automobile brake, aircraft and marine components, wind turbine blades, heat insulators, sporting equipment etc., Brake is a very important part of an automobile which causes safe emergency stop with certain predetermined distance and it was made of asbestos and continuous use of asbestos leads carcinogenic and lung disorders due to these causes use of asbestos was banned during 1990’s. Hence attempts are made to develop new eco-friendly brake friction materials for automotive applications using Glass-Epoxy FRP composites filled with Coconut Shell Powder (CSP) to estimate mechanical characteristics.

Water and brine absorption capacity of epoxy based glass fiber composite modified with CaCO3–Al2O3–MgO–TiO2/CuO filler materials

Glass fiber reinforced composite materials have versatile engineering applications and superior performance for its various level of properties. Different fillers are mixed with the composite materials to enhance product performance. However, improvements on physical properties of this class of materials are still under research for different applications. In this work, with a fixed weight percentage of plain woven glass fiber reinforcement and epoxy composites added with four different types of fillers, such as Calcium Carbonate (CaCO3), Aluminum Oxide (Al2O3), Magnesium Oxide (MgO) and Titanium Oxide (TiO2) or Copper Oxide (CuO) at different weight ratios (5, 10 and 15 gm) are studied. The composite specimens required for different tests are fabricated in conventional hand lay-up technique followed by light compression molding process as per ASTM standards. These composites are investigated for water and brine solution absorption capacity and significant improvement is observed in case of the composite made of CuO than that of the composite made of TiO2. FTIR, TGA and SEM are also characterized.

Effect of g‐C3N4 nanofiller as filler on mechanical properties of multidirectional glass fiber epoxy hybrid composites

ABSTRACTAn experimental study was carried out to investigate the flexural strength of glass‐fiber‐reinforced (multidirectional woven glass fiber) epoxy hybrid composites filled with different proportions (1, 1.5, 2, 2.5, and 3%) of graphitic carbon nitride (g‐C3N4) filler. g‐C3N4 powder filled glass epoxy composites were fabricated in conventional hand lay‐up method. Results showed an increase in flexural strength of g‐C3N4 particles content by 2% and beyond which the strength decreased. With the addition of 2 wt % of g‐C3N4 in glass‐fiber‐reinforced epoxy composites, the tensile strength increased by 11% and the flexural strength increased by 13%. The eroded surface of the specimen was observed under scanning electron microscope and the results are reported. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48413.

Hybridization Effect on Mechanical Properties and Erosion Wear of Epoxy-Glass Composites

In this research work the mechanical and erosion wear behavior of E-Glass fiber reinforced epoxy based hybrid composites were determined. Fillers like coal fly ash (CFA), Coal powder (CP) and mixture of coal fly ash and coal powder (CFA-CP) at different weight proportions of 0wt%, 5wt% and 10wt% were mixed with Epoxy Resin and composites were fabricated by manual hand lay-up technique with 50wt% of Glass Fiber as reinforcement and the prepared composites were cut in to specimens as per ASTM standards for mechanical characterizations like tensile, flexural, ILSS, Impact and Hardness properties and erosion wear behavior. Experimental analysis shows that the tensile strength of unfilled Epoxy-Glass composites is maximum (252.189MPa) where as for 10wt% coal fly ash filled epoxy-glass composites tensile modulus is maximum (7.823 GPA). The flexural strength and ILSS are 750.54 MPa and 25.188 MPa respectively for 10 wt% CP filled hybrid composites. The impact strength and hardness are 2100 J/m and 62Hv for 10wt% CFA-CP filled epoxy composites. Coming to erosion wear behavior of composites filled with CFA-CP have exhibited maximum erosion wear resistance when compared with CFA filled epoxy composites. It is observed that with the increase in weight percentages of the filler material. The mechanical properties and erosion wear resistance of the composites were enhanced. Hence, for structural applications filler materials mixed Glass- Epoxy hybrid composites can be used in place of plain glass fiber reinforced epoxy composites due to the enhanced properties of composites.

Estimation of interlaminar shear strength in glass epoxy composites by experimental and finite element method

The objective of the present work is to estimate interlaminar shear strength in glass epoxy composite by experimental and finite element method. A woven glass fabric (0°- 90°) and epoxy are used in the preparation of the composite. Interlaminar shear strength (ILSS) is estimated experimentally by ASTM D 2344 and ASTM C 1425 for thin and thick laminates. While adopting the procedure mentioned in ASTM D 2344, the sample dimensions of thin and thick laminate are 32 X 10 X 2 mm3 and 80 X 10 X 10 mm3 respectively. Three-point bend test is conducted on Universal testing machine made by United Calibration Corporation with model No. STM 50 kN at a loading rate of 1.5 mm/minute. For the standard ASTM C 1425, the sample dimensions of thin and thick laminate are 30 X 15 X 2 mm3 and 30 X 15 X 10mm3 respectively. The fixture is fabricated for both thick and thin laminate for estimating interlaminar shear strength. The obtained experimental results are compared with interlaminar shear strength estimated in ANSYS, and the correctness of finite element analysis is verified. The results interpreted in the present work are also compared with the published results available in the literature, and it is noticed that the deviation is agreeable. From the available literature, it is also suggested that ASTM C 1425 is recommended over the other methods since the sustainability of the material is achieved while examining the interlaminar shear strength.

Study of the microhardness and erosive wear behavior of organo-modified nanoclay filled glass-epoxy composites and optimization

This research concentrates on examination and optimization of microhardness and erosion resistance of epoxy-glass-nanoclay composites (EGCN’s). The parameters considered were the weight content of Cloisite 15A (A), the volume of glass fiber (B), and the direction of glass fibers (C). Hand lay-up technique was used to make the composites and tested for microhardness and erosive wear as per ASTM standards. The L9 orthogonal array was utilized to design the microhardness tests and erosive wear test, and it was noted that the composite with high clay content, low fiber volume, and 45° orientation had shown low erosion rate (Er) even though its hardness was lesser than the optimized value. At the optimum composition corresponding to the lowest Er, further erosion studies were conducted with the L18 orthogonal array for optimizing machine testing parameters. Scanning electron microscopy (SEM) was used to explain the effect of each parameter on the output. This research gives a thought regarding the consolidated effect of A, B, and C on the erosion resistance of the EGCN’s and the effect of testing parameters.

Three point bending test of glass/epoxy composite health monitoring by acoustic emission

As glass epoxy composites have special properties, they are used in different structures. Health monitoring of this kind of composite is very important due to its use in many industries. Acoustic emission technique is one of the best methods for health monitoring. Since flexural loading is widespread in utilization of this type of composite, in this research acoustic emission method was used to monitor and check the different failure mechanisms of glass epoxy composite flexural loading. In order to determine different failure mechanisms, the wavelet transform and Choi-Williams transform analysis was used to process acoustic signals. Three types of dominant failure mechanisms (matrix fracture, debonding and fiber breakage) in this composite were identified and the frequency ranges corresponding to these failure mechanisms were determined. Wavelet transform results showed that, this three type of dominant failure mechanisms (matrix fracture, debonding and fiber breakage) in flexural loading have frequency range of 62.5–125 kHz, 125–187.5 kHz and 187.5–250 kHz respectively. Also energy distribution of each frequency ranges obtained and fitted with fracture mechanisms. Finally the observations of scanning electron microscope from fracture surface of specimen validated the obtained results. This research showed the possibility of acoustic emission technique as a monitoring tool of glass/epoxy composite in flexural failure.

The impact behaviour of hybrid titanium glass laminates—Experimental and numerical approach

Fibre metal laminates (FML) constitute a group of hybrid materials made of alternating layers of metal and fibre polymer composite. One of the more prospective materials of the next FML generation is a laminate based on titanium and glass or carbon fibres. The use of titanium increases laminate stiffness in comparison to laminates based on aluminium alloys and significantly increases the corrosion resistance and impact properties. The purpose of the study was a multifaceted and complex analysis of the impact behaviour of hybrid titanium glass fibres laminates (HTGL) based on the experiment and modelling methods. Based on the obtained results of experimental studies it was proven that fibre metal laminates based on titanium and glass-epoxy composite are characterised by high resistance to low-velocity impact within the range of energy of 2.5–30 J at least, expressed by the criteria of maximum force, deformations, work performed by the indenter, impact energy absorption capacity, and the parameters describing the extent of damage after impact. The obtained results of numerical analyses indicate the correctness of the adopted calculation assumptions and the study procedure itself.

Efficiency and Stiffness of the Single Lap Bolt Joints in Glass Epoxy Composites

The present work deals with the investigations on the joint efficiency and the joint stiffness of the single lap bolt joint made of two dimensional woven glass fibre reinforced composite materials. The effect of joint geometry, bolt pretension and washer has been determined on the bolt joint performance. To estimate the effect of geometric parameters; the edge-to-hole diameter (e/d) and width-to-hole diameter (w/d) ratios are varied from 3 to 4 and 3 to 5, respectively. To study the worst loading conditions; the bolt pre-tension is set to zero, whereas 5 Nm torque is applied to investigate the joint in fully clamped conditions. Two different sizes of washer i.e., the outer diameter of 12 mm and 16 mm have been studied to estimate the effect of the washer on failure load, joint stiffness, and joint efficiency. Progressive damage analysis has been performed on the single lap bolt joint. Characteristic curve method along with Tsai-Wu failure criteria has been used for the prediction of the failure loads and failure modes. The joint stiffness and the failure load of the joint are increased with the increase of w/d ratios. However, the joint efficiency was negatively influenced by w/d ratio.

Elastic buckling of rectangular fiber-metal laminated plates under uniaxial compression

In this article, the elastic buckling response of rectangular simply supported and clamped fiber-metal laminates (FMLs) subjected to uniaxial compressive loading is investigated using the finite element method and eigenvalue buckling analysis. Using validated finite element method (FEM) models, the buckling coefficient-aspect ratio diagrams and the mode shapes of nine GLARE grades are obtained and studied along with the diagrams and the mode shapes of three unidirectional glass-epoxy composites and monolithic 2024-T3 aluminum. It is found that the critical average buckling stress and the buckling load of the materials increases for increasing metal volume fraction, when the plate aspect ratio is greater than 1.5. The rule of mixtures is evaluated and found to be a simple method to estimate approximately the average critical buckling stress of the GLARE plates. An approximate formula is derived for the estimation of the critical buckling coefficient of the GLARE plates using the buckling coefficients of their constituents. The applicability of the results to thermoplastic-based FMLs is discussed.

Assessment of mechanical, thermal and morphological behavior of nano-Al2O3 embedded glass fiber/epoxy composites at in-situ elevated temperatures

Owing to the outstanding properties of nano-Al2O3 particles have incited material researchers to have a promising invasion in the field of fibrous polymeric composites. There is an uncertainty of nano-Al2O3/polymer interfacial stability at high temperature engineering applications. Current investigations explicate the effects of nano-Al2O3 content on the mechanical behavior of glass/epoxy (GE) composites at various in-situ elevated temperatures. The flexural properties and viscoelastic behavior of the composites have been investigated and evaluated. The Weibull design parameters were analysed as a function of nano-Al2O3 content and different test temperatures. Scanning electron microscopy analyses were carried out to understand various interfacial strengthening mechanism and micro-mechanism failures. These results indicated that incorporation of 0.1 wt% of nano-Al2O3 in GE composites at room temperature could be considered an optimal value in flexural strength enhancement. The fracture surfaces demonstrated a combination of fiber pullout, interfacial debonding, matrix drainage and fiber imprints failure morphologies. Weibull analyses responded a reasonable agreement with the experimental results.

Characterization and optimization of hybrid carbon–glass epoxy composites under combined loading

This work is intended to characterize the mechanical behavior of hybrid carbon–glass composite plates under combined loading of bending and torsion, and to determine the optimal ply fiber orientations to minimize the maximum out-of-plane displacement under such loading conditions. Hybrid composite plates were manufactured with 10 plies each and different stacking sequences using hand lay-up, with carbon fiber and glass fiber reinforcements in an epoxy matrix. Two experimental setups (involving two distinct boundary conditions) are here considered to test the composite plates, both simulating combined loading of bending and torsion. Numerical simulations of the experimental tests were performed in ABAQUS® and validated with the experimental data. Using the ply fiber orientations as design variables, the hybrid composite plates were then optimized using global and local optimization using direct search (GLODS). The objective function of minimization of the maximum out-of-plane displacement is carried out through an interactive cycle between GLODS and ABAQUS®. Specimens of three optimized laminates were also manufactured for experimental validation. The optimization process contributed to improve the performance of the hybrid composite plates in more than 30% when compared to some non-optimized plates.

Elastic buckling response of rectangular GLARE fiber-metal laminates subjected to shearing stresses

In this article, the elastic buckling response of rectangular GLARE fiber-metal laminates with three different support types subjected to shearing stresses is investigated using the finite element method and eigenvalue buckling analysis. Using validated FEM models, the buckling coefficient-aspect ratio diagrams of eight GLARE grades are obtained and studied along with the diagrams of three UD glass-epoxy composites and monolithic 2024-T3 aluminum. It is found that the critical average buckling stress and the buckling load of the materials increases for increasing metal volume fraction. The effect of the fiber-volume fraction on the shear buckling strength of simply supported and clamped fiber-metal laminates is also studied. It is found that the variation of the fiber-volume fraction has a small influence on the behavior of the buckling coefficient-aspect ratio diagrams of two specific GLARE grades. Furthermore, an approximate method is proposed in order to estimate the new shear buckling strength of a GLARE plate when the fiber-volume fraction changes.

그래핀이 적용된 자동차 유리의 전기 및 열 특성 연구

For the automotive application, graphene-glass composites were fabricated using E-glass fiber(GF) coated with various types of graphene nanosheets deposited by electrophoretic deposition. Graphene oxide(GO) was first synthesized using a modified Hummer’s method and its subsequent ultrasonic treatment in deionized water produced a stable stop of the GO. Glass fiber was immersed in water and GO suspension near the copper anode. The potential applied between the electrodes caused the GO to move toward the anode. In addition, the GO coated yarn was exposed to hydrazine hydrate at 100℃ to obtain a reduced graphene oxide(rGO) coating yarn. Both GO and rGO coated glass fiber yarns were used to fabricate unidirectional epoxy-based multi-scale composites by passive lay-up. The presence of a conductive rGO coating on glass fiber improves both the electrical conductivity and thermal conductivity of the composite. In addition, rGO-based epoxy-glass composites have been used to improve the dielectric constant, providing the option of using this structure for electromagnetic interference shielding.

Determination of Strength Parameters of Glass Fibers Reinforced Composites for Engineering Applications

The manufacturing of the composite material has been developed tremendously over the years due to its superior properties like low density, stiffness, lightweight and excellent mechanical as well as physical properties. These exceptional properties of composite materials have found its applications widely in aerospace, automotive, marine and many more engineering areas. The synthesis of the varieties of composites is continuously lookout without compromising its mechanical and physical properties. This paper deals in with synthesis as well as mechanical properties (Tensile Strength, Flexural Properties and Fatigue) of Glass-Epoxy as well as Glass-Vinyl Ester composites. The resins used in combination of composites were epoxy as well as Vinyl Ester while the reinforced material was glass fibers. The ultimate tensile strength in Glass-Epoxy composite was observed from 330 to 370 MPa while it was 270 to 330 MPa for Glass-Vinyl Ester Composites. Glass-Epoxy composites showed a 32% increase in flexural strength due to post-curing strength while it was 16% in case of Glass-Vinyl Ester Composites. The results of the fatigue analysis of composites indicate faster growth of cracks and defects at higher frequencies which results in a rapid drop in stress levels in the test specimen. The statistical analysis was carried out to establish mutual correlation among mechanical as well as physical properties.