Fiber Reinforced Epoxy Hybrid Composites Research Articles

Biodegradability and mechanical properties of pineapple leaf/coir Fiber reinforced hybrid epoxy composites

Environmental policies set the boundary conditions for industries and commercial market regarding the maximum utilization of biodegradable material. In this context, the current research work deals with the development of cellulosic fiber filled epoxy composites and test for biodegradability in the natural soil environment. Moreover, an experimental investigation has been carried out to study the effect of relative fiber volume content and alkaline treatment of cellulosic fibers on the biodegradability and mechanical properties of Pineapple leaf/Coir fiber reinforced hybrid epoxy composites. To accomplish the desired objectives, the total of 23 biocomposite specimens (untreated and alkali-treated) has been developed by hand lay-up molding technique and test for tensile, flexural, impact, and weight loss properties as per ASTM standard. In all composite specimens, the total fiber to polymer resin ratio was kept fixed at 40:60 (v/v). The total of four samples for each composite specimen was tested and their average values were reported. The experimental results showed that the hybrid composites exhibit rapid loss of mechanical strength in natural soil environment than the pure Pineapple leaf-Epoxy composite. The single pineapple leaf fiber reinforced material revealed a higher rate of biodegradation and greater loss of tensile and flexural strength as compared to the pure Coir-Epoxy composite. The alkali-treated coir fiber enriched composites have a higher weight loss and greater reduction in mechanical strength than the untreated one. The mechanical strength and biodegradability of an epoxy thermoset were increased with the incorporation of PALF and COIR fibers which leads to easy and smooth adoption in engineering applications.

Sandwich-structured bamboo powder/glass fibre-reinforced epoxy hybrid composites – Mechanical performance in static and dynamic evaluations

A layer of woven E-glass fibre was embedded each at top and bottom layer of bamboo-filled epoxy, producing sandwich-structured hybrid composites. The incorporation of woven glass fibre was intended to slow down the crack propagation in composites. Different bamboo powder loading was applied to analyse its effect on the static and dynamic mechanical properties of composites. The composite with the lowest bamboo powder loading of 10% marked the highest tensile strength, where the strength decreased as the loading increased. Poor bamboo-epoxy adhesion, observed from the SEM, leads to more chances of pull out fibres when tensile load was applied. Opposite trend was observed in flexural strength, where the highest loading of 30% marked the highest value of flexural strength. The dynamic evaluation was carried out with respect to temperature, which ranged from 25°C to 150°C, and at a fixed frequency of 1 Hz. Effective stress transfer between the fibre and the matrix takes place in composites with 30% bamboo powder loading, shown by the lowest peak height of the Tanδ curves. The significant increase in the storage modulus values for the composites at low temperature compared to the rubbery plateau region at high temperature suggested the high utility of the composites at low temperature regardless of the effect of the percentage increment in bamboo powder loading. These results showed that the bamboo powder inclusion helps in bestowing stiffness to the composites with 30% as the optimum percentage in this dynamic mechanical evaluation. It can be suggested that the introduction of woven-typed fibre into short fibre composites in sandwich structure, as discussed in this study, can slow down the failure of composites, and thus notify users before the total failure.

MULTIOBJECTIVE OPTIMIZATION FOR UNIDIRECTIONAL GLASS AND CARBON FIBER-REINFORCED HYBRID EPOXY COMPOSITES UNDER FLEXURAL LOADING

A multiobjective optimization study for unidirectional carbon fiber- and glass fiber-reinforced epoxy hybrid composites under flexural loading is presented in this paper. The flexural strength of the hybrid composite was conveniently expressed by regression formulas. Two optimization methods—WSM and NSGA-II—were employed for multiobjective optimization with the cost and weight being the objective functions. When WSM was used, two algorithms, viz., interior point algorithm (IPA) and genetic algorithm (GA), were used. The results suggest that positive hybrid effects can be utilized to improve the flexural strength.

Study on the Effect of Surface Modification on the Mechanical and Thermal Behaviour of Flax, Sisal and Glass Fiber-Reinforced Epoxy Hybrid Composites

Natural fiber-reinforced hybrid composites can be a better replacement for plastic composites since these plastic composites pose a serious threat to the environment. The aim of this study is to analyze the effect of surface modification of the natural fibers on the mechanical, thermal, hygrothermal, and water absorption behaviors of flax, sisal, and glass fiber-reinforced epoxy hybrid composites. The mechanical properties of alkaline treated sisal and flax fibers were found to increase considerably.Tensile, flexural and impact strength of glass/flax-fiber-reinforced hybrid samples improved by 58%, 36%, and 51%, respectively, after surface alkaline treatment. In addition, the hygrothermal analysis and water absorption capacity are studied and also the Interfacial bonding properties were analyzed using Scanning Electron Microscopic images. The thermal analysis using thermogravimetric analyzer reveals that the decomposition temperature for hybrid fiber reinforced composites are between 306 and 312℃. In conclusion,surface treatment improves the performance of natural fiber in hybrid fiber-reinforced composites, particularly flax fiber.

Comparative investigation on physical and mechanical properties of water hyacinth and cattail fiber reinforced epoxy hybrid composites

In this research, the study to investigate and compare the physical and mechanical properties of water hyacinth and cattail fiber reinforced epoxy hybrid composites. The composites were fabricated by hand lay-up process. The effect of investigation was analyzed via water absorption, microstructure, tensile properties, flexural properties and impact strength tests for total fiber contents, 15 wt% and different water hyacinth- cattail fiber ratios (10/0, 8/2, 6/4, 4/6, 2/8 and 0/10). The results showed that the addition of water hyacinth and cattail fiber in epoxy, improves tensile properties, flexural properties and impact properties, but decrease water absorption. The analysis of the microstructure found that surface fracture behavior and void between the fiber and matrix of the composites using scanning electron microscope (SEM).

Effects of Fabric Counts and Weave Designs on the Properties of Laminated Woven Kenaf/Carbon Fibre Reinforced Epoxy Hybrid Composites

The effects of different fabric materials namely weave designs (plain and satin) and fabric counts (5 × 5 and 6 × 6) on the properties of laminated woven kenaf/carbon fibre reinforced epoxy hybrid composites were evaluated. The hybrid composites were fabricated from two types of fabric, i.e., woven kenaf that was made from a yarn of 500tex and carbon fibre, by using vacuum infusion technique and epoxy resin as matrix. The panels were tested for tensile, flexural, and impact strengths. The results have revealed that plain fabric is more suitable than satin fabric for obtaining high tensile and impact strengths. Using a fabric count of 5 × 5 has generated composites that are significantly higher in flexural modulus as compared to 6 × 6 which may be attributed to their structure and design. The scanned electron micrographs of the fractured surfaces of the composites demonstrated that plain woven fabric composites had better adhesion properties than satin woven fabric composites, as indicated by the presence of notably lower amount of fibre pull out.

Experimental investigation on the mechanical properties and water absorption behavior of randomly oriented short pineapple/coir fiber-reinforced hybrid epoxy composites

To elevate the progressive utilization of natural fiber reinforced composites in structural applications, it is extremely required to heighten the properties of NFRC’s by the exploitation of hybridization tool. In most of the cases, the mechanical properties of hybrid composites reinforced with natural fibers are far better than the pure single fiber reinforced composites and comparable to the synthetic fiber reinforced composites. Therefore in this research work, an experimental investigation has been carried out to study the mechanical properties and water absorption behavior of hybridized PALF/COIR fiber reinforced epoxy matrix composites. The biocomposite sheets consist of randomly oriented and intimately mixed short fibers (20 mm in length) were fabricated by employing the hand lay-up technique at 11 levels of COIR fiber loading (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 vol%) with fixed total fiber content (40 vol%). The mechanical properties (tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength) and water uptake behavior with water diffusion mechanism of various formulated composites have been studied according to ASTM standard. The total of four samples for each composite specimen was tested and their average values were reported. The results showed the improvement in tensile and flexural properties (strength and modulus) of COIR/Epoxy composite by the hybridization with pineapple leaf fiber, up to 50 vol%. The hybrid composite reinforced with equal volume content of pineapple leaf fiber (PALF) and coconut husk fiber (COIR) possess the highest tensile, flexural, and impact strength. Water absorption test revealed the decrement in sorption affinity with the increase of coir fiber content. The hybrid composite (P50-C50) absorbs 62% and 32% less water than that of pure PALF/Epoxy and COIR/Epoxy composites.

Fabrication and Mechanical Characterization of Glass fibre reinforced Epoxy Hybrid Composites using Fly ash/Nano clay/Zinc oxide as filler

In this work the characterization of the mechanical behaviour of glass fibre reinforced epoxy hybrid composites were carried out. With three types of fillers- Nano clay- Zinc oxide- fly ash at different weight ratios and combinations were dispersed with matrix material epoxy by ultra-sonication method. Epoxy glass composites with various fillers were fabricated by hand lay-up technique. Mechanical characterization of Glass fibre reinforced Epoxy Hybrid Composites using Fly ash/Nano clay/Zinc oxide as filler were carried out for tests for tensile, flexural and impact strength properties. Experimental analysis shows Nano clay/fly ash epoxy composites show comparatively higher tensile and impact strength. While Zinc oxide/fly ash epoxy glass composite exhibited better flexural strength. Hybrid filler material dispersed glass fibre reinforced composites can be used for structural application as properties it processes are higher as compared to plain glass fibre reinforced epoxy composites.

Mechanical and Morphological Properties of Epoxy Based Hybrid Composites Reinforced with Banana-Pineapple Fiber

The aim of this paper is to investigate the mechanical properties of Banana-Pineapple natural fiber reinforced epoxy hybrid composites. The hybrid combination of fibers with various weight fractions i.e. (40/0, 30/10, 20/20, 10/30 and 0/40) are incorporated into the epoxy LY556 and HY951and hand layup technique is used for fabrication. Initially fibers are cut to a length of 5mm and weight percentagesare determined. Banana fiber was hybridized with Pineapple fiber. While overall fiber weight fraction was fixed as 0.4Wf. Tensile, Flexural and Impact specimens are prepared according to ASTM standards. The Dog-bone shaped specimens are prepared for tensile test. Tensile testing was conducted on 5 ton universal testing machine (FIE Make). Flat bar and V-notch shaped specimens are prepared for conducting Flexural, Impact tests.The results are compared with pure Banana and pure Pineapple. Tensile, Flexural and Impact properties of Hybrid Composites are improved as compared to pure composites. The interfacial relationships between the fiber and matrix, internal cracks, fiber pullout, fiber dispersion into the matrix and the inner surfaces of the specimens are examined through SEM analysis.

Effect of stacking sequence on the flexural properties of carbon and glass fibre-reinforced hybrid composites

A study on the flexural properties of carbon and glass fibre-reinforced epoxy hybrid composites is presented in this paper. For the purpose of understanding the effect of stacking sequence on the flexural properties, test specimens of both glass/carbon and sandwich stacking sequences were studied both experimentally and by simulation. The experimental flexural properties were obtained by three-point bend test in accordance with ASTM D7264/D7264M-15. Simulation was achieved with the aid of finite element analysis (FEA) and classical lamination theory (CLT). From the experimental and simulation results, it is concluded that for the hybrid composites with glass/carbon stacking sequences, when glass/epoxy laminas are placed on the compressive face, positive hybrid effects are present. When glass/epoxy laminas are placed on the tensile face, the hybrid effect is dominantly negative. For the sandwich-type hybrid composites, carbon/epoxy laminas should be the skin and glass/epoxy laminas should be the core.

Advanced 3D and 2D damage assessment of low velocity impact response of glass and Kevlar fiber reinforced epoxy hybrid composites

This work focuses on quasi-static mechanical (tensile, flexural, indentation), low velocity impact (LVI) and viscoelastic behaviour of different stacking sequences and ] of 16 layers woven roving Kevlar-E-glass/epoxy interply hybrid composites. The outermost layers are Kevlar and remaining 14 E-glass layers are placed as interior for making these hybrid laminates. The viscoelastic properties are measured over the temperature range from 25 °C (room temperature) to 180 °C at three different frequencies (1, 10 and 50 Hz) by using the dynamic mechanical analyzer (DMA). The LVI results indicated that Kevlar-glass/epoxy hybrid laminates exhibit the highest damage threshold load (DTL) whereas laminates possess the higher peak load and threshold and maximum energies. Advanced non-destructive testing techniques (NDT) such as X-ray computed tomography (X-CT) and ultrasonic C-scan are employed to evaluate the micro and macro damage mechanisms of LVI tested specimens, respectively. Detailed observations have been made on the onset and growth of cracks in 30°, 45° and 0° plies using X-CT scan imaging. These images show that the bottommost plies subjected to more impact than the topmost plies, the outer Kevlar plies protect the inner 0° glass plies and delays the delamination propagation. ‘C’ scan images indicate that laminates spread the damage to more area. The scanning electron microscopy (SEM) is used for examining the failure mechanisms of indentation specimens.

Micromechanical analysis of the elastic response of glass-epoxy hybrid composites containing silica nanoparticles

ABSTRACTThe effects of adding silica nanoparticles on the elastic properties of glass-epoxy hybrid composites are investigated using a micromechanical method. Influences of silica nanoparticle volume fraction and diameter, the interphase elastic modulus and thickness, the glass fiber volume fraction and aspect ratio as well as off-axis angle on the elastic properties of unidirectional glass fiber-reinforced epoxy hybrid composites containing silica nanoparticles are studied. The results reveal that the addition of silica nanoparticles can improve the elastic modulus in the transverse direction, while the axial elastic modulus is not affected by silica nanoparticles.

Effect of fiber fibrillation on impact and flexural strength of coir fiber reinforced epoxy hybrid composites

This study aims to develop fiber-reinforced epoxy resin composites. This study presents the effect of fiber fibrillation on the impact and flextural strength of the epoxy hybrid composite reinforced by coir fiber. Coir is soaked in 5% NaOH solution for 5 hours. Then fiber is rocessed using a blender of 2000 rpm density fibrillation. The length of time the fibrillation varied for 10, 20 and 30 minutes. Volume fraction of 30% fiber and matrix 70% composited. The composite uses a matrix of epoxy by hand lay up method. The implemented tests are impact and flexural tests. The test results show fiber fibrillation treatment can improve the composite mechanical properties. The highest impact and flexural strength, 24.45 kJ/m2 and 87.91 MPa were produced with fiber fibrillation for 10 minutes.

Evaluation of mechanical behavior of banana fibre reinforced hybrid epoxy composites

The applications of composite materials are escalating progressively in engineering and medical. Composite materials because of having better mechanical properties, thermal properties, static and dynamic properties had occupied major division in present scenario. This article deals with the fabrication of composite materials by using banana fibre, glass fibre, epoxy resin and evaluation of mechanical behavior of fabricated composite materials. Banana fibre and glass fibre are mixed with epoxy resin to get composite materials. Totally nine sample specimens were fabricated with increasing the fibre length. These composite materials were fabricated using hand lay-up technique. The tensile test, flexural (three-point bending) test, impact test and hardness test were evaluated and reported. The result shows that, the better mechanical behaviours were found in the composite specimen of 10 mm fibre length and 15% fibre loading.

Thermal Conductivity of Carbon/Basal Fiber Reinforced Epoxy Hybrid Composites

Thermal Conductivity of Carbon/Basal Fiber Reinforced Epoxy Hybrid Composites

Multi-objective robust optimization of multi-directional carbon/glass fibre-reinforced hybrid composites with manufacture related uncertainties under flexural loading

Multi-objective robust optimization of multi-directional carbon/glass fibre-reinforced epoxy hybrid composites has been presented in this study. Two conflicting objectives, namely minimizing the density and minimizing the cost under the constraint of a specified minimum flexural strength, were considered with the design variables being the fibre type, fibre orientation angle and fibre volume fraction of each lamina. A modified version of the non-dominated sorting genetic algorithm (NSGA-II) was used in order to find the Pareto optimal solutions. Furthermore, robust optimization problems were defined by including manufacturing related uncertainties in the thickness and orientation of each lamina. These uncertain variables were considered as uncertain-but-bounded with the worst case for the minimum flexural strength being determined through an internal anti-optimization solver. The optimization and anti-optimization problems were solved with Pareto optimal and robust solutions being presented for carbon/glass fibre hybrid composites with different levels of minimum flexural strength. The results showed that, in general, consideration of uncertainties in thickness and fibre orientation angle increased the material cost and/or density with this effect being more important for high strength composites.

Effect of Accelerated Ageing on Hardness and Flexural Behaviour of Woven fabric Glass/ Carbon Hybrid Epoxy Composites

Carbon fibre reinforced composites finds diverse range of applications in the fields of automobiles, aircrafts, marine structures etc. Even though carbon fibres offer higher flexural strength, expensiveness of these fibres limits their use. This article suggests an alternative in the form of carbon/ glass fibre hybrid composites. The present article throws light on the study of flexural behavior and hardness on the specimens of glass and carbon fibre reinforced hybrid epoxy composites subjected to accelerated ageing. Four sets of laminated composites were prepared by hand layup process by adding graphite filler of 5%, 10%, 15%. Three sets of specimens with different filler content aged by boiling at different temperatures of 40 °C, 60 °C and 80 °C respectively with one set left unaged were subjected to shore D hardness test and flexural test. It was observed that the specimens with 5% graphite filler showed better flexural behaviour in comparison to the specimens with other filler content. Also it was observed that the flexural strength and flexural modulus decreases with increase in filler proportion and boiling temperature. However a little variation was found in the hardness of specimens with varying filler proportion and boiling temperatures.

Moisture and filler induced effects on the dynamic mechanical properties of glass fiber reinforced epoxy hybrid composites

The paper reports the results of moisture and filler induced effects on the dynamic mechanical properties of glass fiber reinforced epoxy hybrid composites. The rate of water diffusion into the composites has been determined to understand the effect of moisture on the dynamic mechanical properties. Significant differences in the moisture uptake properties of the composites are observed which induce changes in storage modulus (E′), loss modulus (E″), and damping factor (tan δ). It is also observed that water diffusion depends on the free volume content of the hybrid composites. Results of this study indicate that hybrid composites with combination of micro and nanofillers possess good dynamic mechanical properties in presence of moisture at higher temperatures.

Numerical investigation of the hybridisation mechanism in fibre reinforced hybrid composites subjected to flexural load

Abstract Whilst the presence of a hybrid effect for the flexural strength of hybrid polymer matrix composites has been noted by several researchers, the reasons behind such a phenomenon remain unclear. In this work the authors have investigated the effect of hybridisation on the flexural strength of carbon/glass fibre reinforced epoxy hybrid composites with the aim of elucidating the mechanisms behind the hybrid effect. Classical lamination theory (CLT) and finite element analysis (FEA) were employed to determine the stress distribution within the composites with the maximum allowable load at first ply failure (FPF) and apparent flexural strength being determined based on four commonly used failure theories, namely, maximum stress, maximum strain, Azzi-Tsai-Hill and Tsai-Wu. Using the results of this analysis, general rules for the improvement of flexural strength in hybrid composites were proposed. Through application of these rules it was shown that a positive hybrid effect could be achieved for the flexural strength in both unidirectional and bidirectional hybrid composites when an optimal stacking configuration was used. Furthermore, the flexural strength predicted by the different failure theories was compared with it being noted that the strength obtained using the Tsai-Wu failure theory was significantly different from the strength obtained by other theories under certain circumstances, in particular for situations when the laminas contained different angles and/or materials. Overall it is hoped that the explanation of the mechanisms behind the hybrid effect of flexural strength together with the general design rules outlined in this work will lead to the improved optimization of hybrid composites.

Uncertainties in flexural strength of carbon/glass fibre reinforced hybrid epoxy composites

Abstract A study on the flexural behaviours of the of glass and carbon fibre reinforced epoxy hybrid composites is presented in this paper. Two types of glass fibres: S-2 and E, and two types of carbon fibres: T700S and P-100 are investigated. The flexural strength is obtained using an approach based on finite element analysis. Three compressive strength models: Lo-Chim, Budiansky and the shear models are used to obtain the flexural strengths. It is shown from the results that when shear failure occurs, the flexural strength is 20–30% lower compared to other failure modes.