Reinforced Epoxy Matrix Composites Research Articles

Mechanical properties: Lifespan and retention forecast for jute fiber woven fabric reinforced epoxy matrix composite

AbstractPolymer composites bonded with natural fibers are extensively used for a range of engineering purposes. Preserving their mechanical strength and estimating their maximum service life are thus essential for efficient usage. The primary goals of this effort are to analyze and forecast the longest possible life span of composites. To do this, Fick's law and the Arrhenius principle are employed to analyze the diffusion coefficient and activation energy. Compression molding technology and a manual technique for layup were employed to make the composites reinforced with epoxy laminate and woven mats of jute fiber (JRC). Three layering patterns were used to prepare the laminated composite: 45° angle‐ply laminate [0°/+45°/0°/−45°/0°], 0° balanced laminate [0°/0°/0°/0°/0°/0°], and 30° angle‐ply laminate [0°/+30°/0°/−30°/0°]. In order to examine how aging affected the composites' mechanical properties, the materials were immersed in water for 10, 20, 30, and 40 days throughout the study. The study's conclusions showed that the composite samples' weight rose with age. It was possible to make precise predictions about strength retention by comparing the mechanical characteristics of aged (wet) and unaged composites. It was discovered that the strongest composites were those with a 45‐degree stacking pattern. The activation energy of composites with a 45° angle‐ply laminate layering pattern is maximum, according to the Arrhenius principle. Additionally, using an electron microscope with scanning capabilities (SEM), it was possible to determine the fiber matrix and the tensile cracked surface contact connection.Highlights The widespread usage of polymer composites with natural fibers in engineering applications. Preservation of mechanical strength and predicting the maximum service life of these composites show how important these materials are for engineering efficiency. Fick's rule and the Arrhenius principle are used to analyze diffusion coefficient and activation energy. Laminated composites are made using 45° angle‐ply, 0° balanced laminate, and 30° angle‐ply layering patterns. The impact of simulated aging on composite mechanical characteristics by water immersion for varied periods.

Fabrication and Mechanical Testing of Glass Fiber Reinforced Epoxy Matrix Composites Modified with Powdered Metallic Fillers

Composite materials made up of polymer matrix reinforced with synthetic fibers have gained popularity of late owing to their enhanced mechanical properties. However, very little work is reported to date on metals being used as filler material. Research gaps were obtained pertaining to the use of metallic fillers in synthetic fiber reinforced polymer composites. This paper demonstrates an attempt to fabricate composites made of Epoxy polymer matrix and E-glass fiber reinforcement with Mild Steel in its powdered form as fillers. Composites are prepared in varying weight percentages of the filler in the order of 2 wt. %, 4 wt. % and 6 wt. %. Hand layup method is employed for fabricating these composites which are later subjected to compression. Further, the samples are machined according to ASTM D3039 standard for tensile test and ASTM D256 standard for Izod impact test. Hardness test is also performed using a Shore D Durometer and these properties are compared with the unfilled samples. The results indicated that the weight percentage of the filler clearly influenced the mechanical properties of the developed composites. This study also revealed that the hardness and tensile strength of these composites improved with the incorporation of fillers up to 2 wt. % whereas, the impact strength improved up to 4 wt. %. Thereafter, there was a decline in their impact and tensile properties. However, hardness marginally increased beyond 4 wt. %. This area is open for research with regard to their usability under tribological, high temperature or magnetic conditions.

Investigation of mechanical properties and damage types of E-glass fiber reinforced epoxy matrix composites under various loadings

This study presents a comprehensive experimental investigation to determine the elastic material properties of a unidirectional E-glass fiber/epoxy composite. Tension, compression, in-plane shear, and flexural tests were conducted in both longitudinal and transverse directions. The composite laminates were manufactured using vacuum-assisted resin transfer molding (VARTM) with a 65% fiber weight fraction. Mechanical tests were performed according to ASTM standards, and special fixtures were used for shear and compression tests. The damage mechanisms were interpreted for each test, revealing fiber splitting in tension and kink band failure in compression were dominant damage modes. The findings provide valuable insights into the behavior and performance of the composite under various loading conditions, which may help in its application in different engineering fields.

Mechanical and piezoresistive properties of multi-walled carbon nanotubes reinforced epoxy matrix composites for pipeline monitoring

Pipeline deformation monitoring is of vital importance for pipeline maintenance. However, no durable and effective methods have been seen for deformation monitoring of buried pipes, especially drainage pipes. In this paper, an embedded multi-walled carbon nanotubes (MWCNTs) reinforced epoxy (EP) matrix composite for pipeline monitoring was developed. The bending properties, piezoresistive properties and stability of MWCNTs/EP composites were investigated using three-point bending tests, cyclic tests, resistivity tests, and scanning electron microscope (SEM) observations. The results indicated that when the MWCNTs content was at 0.1 wt%, the bending strength, bending modulus and bending strain increased by 12.3 %, 8.7 % and 25.1 % respectively. The conductive percolation threshold was at 0.7 wt%, and the resistance changed in three stages under bending. In addition, the MWCNTs/EP composites had stable piezoresistive properties under different loading rates and small strain cyclic (ε < 1.5 %). The MWCNTs content and dispersion effect were the main factors affecting the bending properties of MWCNTs/EP composites, while the resistance change mainly originated from the change of the MWCNTs conductive network. This work provided a new idea for pipeline deformation monitoring.

Experimental Investigation on Effect of Weight Fraction of Sisal Fiber on Mechanical Properties of Sisal-E-Glass Hybrid Polymer Composites

Currently, hybridizing natural fibers with synthetic fiber is considered as the best solution for reducing the environmental pollution and the cost of materials. This is due to the lower mechanical properties and high water absorption capacity problems of natural fiber reinforced composites and nonbiodegradability and high-cost problem of synthetic fibers that can be solved by hybridizing them. This article aims to investigate the influence of the weight fraction of the sisal fiber on the mechanical property of the E-glass-sisal fiber reinforced epoxy matrix composite. The sisal fiber was treated by 8% sodium hydroxide (NaOH) for three hours. The samples of five different weight fractions of fibers (0%, 20%, 30%, 40%, and 60%) with a constant weight fraction of epoxy matrix (40%) were prepared as per the ASTM standard prepared by the manual hand layup method at room temperature. The tensile, compression, and flexural tests of the samples were carried out on the WP 310 universal testing machine. From the experimental results, it has been observed that the increasing weight fraction of the sisal fiber greatly influences the mechanical properties (tensile, compression, and flexural) of E-glass-sisal hybrid reinforced epoxy matrix composites. From all the tested samples, those consisting of 60% E-glass and 0% sisal fibers with 40% epoxy matrix showed better mechanical properties than other hybrid samples with tensile, compressive, and flexural strengths of 464.03 MPa, 40.1 MPa, and 239.06 MPa, respectively.

The effect of hydrophobic coating applied to mica reinforced epoxy matrix composites on the water absorption properties of the composite

The effect of hydrophobic coating applied to mica reinforced epoxy matrix composites on the water absorption properties of the composite

An interlayer flame retardant method to effectively fire retardant and reinforce CF/EP composites by nanofiber film intercalation

As an advanced material with wide application, carbon fiber reinforced epoxy resin matrix composites (CF/EP) are flammable, but the traditional flame retardant methods negatively affect its molding process, heat resistance, mechanical properties, and how to solve this problem has been a challenge. This paper adopts a novel flame retardant method of inserting nanofiber films of flame retardant into the interlayer of the composite laminate to achieve fire resistance, higher strength, and toughness of the composite. In this work, pentaerythritol phosphate (PEPA) nanofiber films with phenoxy resin (PKHH) as a carrier was prepared by electrospinning and placed between the layers of CF/EP laminates. The results show that a dense charring layer with isolation and protection functions can be formed between the layers of the CF/EP intercalated by the nanofiber films during combustion. Accordingly, the nanofiber film containing 50 wt% PEPA with the thickness of only 30 μm increased the LOI value of CF/EP from 27.8% to 34.7%, while reducing the THR and pSD by 14% and 27.2% respectively. What’s more, due to the Ex-situ toughening effect of the nanofibers, the flexural strength, interlaminar shear strength, and compression strength after the impact of the modified CF/EP were increased by a maximum of 11.2%, 11.3%, and 12.2% compared to unmodified CF/EP. This work proves the feasibility of interlayer flame retardant fiber reinforced resin composites, and provides a new method to prepare high-performance flame-retardant composites.

Development and evaluation of physical properties of E-glass fiber reinforced epoxy matrix composites filled with fly ash particulate

This present investigation deals with the physical characteristic influence due to the presence of fly ash particles in epoxy-based composites. The study involved four sets of composites that were fabricated using the hand layup technique, with particle weights ranging from 0% to 12% wt. The impact of the weight percentage of particles on physical characteristics is being studied. To understand the physical characteristics of fly ash with epoxy polymer, this study evaluated the density, moisture content, and dimension stability of composites. After a number of experiments, it is evident that adding fly ash decreases the density of composites due to their void content. Dimensional stability is also investigated as a function of dip time inside water and fly ash weight percentage variation.

Mechanical and tribological characterization of graphene nanoplatelets/Al2O3 reinforced epoxy hybrid composites

This study aimed to determine the effects of varying Aluminum oxide (Al2O3) and Graphene Nanoplatelets (GNP) concentrations on epoxy-based polymer composites’ mechanical and tribological characteristics. Al2O3 (1 to 5 wt.%) and GNP (0 to 1 wt.%) reinforced epoxy matrix composites were produced with sonication and stirring magnetic route. Mechanical, microstructural and tribological properties of composites were investigated via X-ray diffraction (XRD), Archimedes’ Method, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), Raman spectroscopy, hardness, impact, tensile, compressive and wear tests. The highest ultimate tensile strength and compressive strength were found at 62.83 and 137 MPa for 3 wt.% reinforced Al2O3 epoxy matrix composites, and it was observed that there was a 38% and 17% increase compared to neat epoxy, respectively. The highest impact strength was found for 3 wt.% Al2O3 and 1 wt.% GNP-reinforced composites and increased by 19% compared to neat epoxy. The best hardness was found for 3 wt.% reinforced Al2O3 and 0.25 wt.% GNP-reinforced composite, and there was a 22% increase in hardness compared to neat epoxy. Also, the highest wear resistance (1.686x10−6 mm3/Nm) and lowest Coefficient of Friction (COF, 0.13755) were determined for the same specimen.

Microscale evaluation of epoxy matrix composites containing thermoplastic healing agent

Among the strategies to produce healable thermosetting systems is their modification by the addition of thermoplastic particles. This work investigates the influence of poly(ethylene-co-methacrylic acid) (EMAA) on fiber-matrix interfacial properties of a glass fiber reinforced epoxy matrix composite. Epoxy-EMAA interactions were evaluated using differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of EMAA on the epoxy network formation were evidenced by changes in glass transition temperature, cure kinetics and alteration of chemical groups during cure. Interfacial shear strength (IFSS) measurements obtained by single fiber pull-out tests indicate similar interfacial properties for pure and EMAA modified epoxy. Additionally, the potential for self-healing ability of an EMAA modified epoxy was demonstrated. However, IFSS after a healing cycle for the EMAA modified epoxy was lower as compared to the pure epoxy, because of the lower fiber-EMAA interfacial shear strength. So, thermoplastic healing agents has not only to fill cracks in the matrix material, but also have to be optimized regarding its interface properties to the reinforcing fibers.

Effect of aloe vera natural fibre orientation on the mechanical propertiesof epoxy composites

ABSTRACT Natural fibre reinforced polymer composites have found a wide range of applications in the automobile industry, construction industry and toy industry, and so on. In this research work, bidirectional aloe vera fibre mats were used as reinforcement and epoxy as matrix materials. Hand Layup process was applied for fabrication of aloe vera fibre reinforced epoxy matrix composites which contain different fibre orientations such as 45°, 60°, 75°, and 0°/90°. The goal of this research work is to obtain the influence of fibre orientation on mechanical and water absorption properties. The experimental investigations like tensile strength, flexural strength, impact strength, and the water absorption tests were performed. The surface morphology of the tensile failed test specimens were alsoanalysed using afield emission scanning electron microscope (FE-SEM). When compared to other fibre orientation composites, 0°/90° aloe vera fibre orientation has superior mechanical capabilities and 45° fibre orientation obtained minimum mechanical properties, according to the results of the experiment. As compared to 45° fibre orientation, 90° fibre orientation obtained 283.81%, 168.41%, and 202.54% higher tensile, flexural, and impact strength, respectively.

Gamma radiation shielding property of continuous fiber reinforced epoxy matrix composite containing functional filler using Monte Carlo simulation

• MCNP model of continuous fiber reinforced composite containing filler for gamma radiation shielding was established. • The effects of filler size and distribution, fiber type and their stacking order on μ were illustrated. • The experimental results confirmed the XCOM and MCNP simulation results. Functional filler modified fiber reinforced polymer composites are promising structural/radiation shielding materials in application fields of nuclear technology. In this work, MCNP simulating models of epoxy resin matrix composites containing shielding micro-fillers (tungsten oxide and boron carbide) and continuous fiber for gamma radiation shielding were established by Lattice and Universe features in MCNP. The effects of filler size and uniformity of dispersion, types of filler and fiber, stacking order of composite layers on liner attenuation coefficient ( μ ) and mass attenuation coefficient ( μ m ) were investigated using MCNP simulation. The corresponding shielding mechanisms were discussed. Furthermore, typical kinds of composites were prepared by hot-press process and their μ were tested. The numerical results show that μ decreases more significantly with large filler size and uneven dispersion in low-energy gamma rays. For fibers, μ is proportional to density independent of element type of fiber. Besides, stacking order has negligible effect on μ . All MCNP results are in good agreements with the calculation data from XCOM and the experimental values, which demonstrates the validity of the proposed modeling method. Thus, this simulation model can be used to design and evaluate radiation shielding composites with complex component and microstructure.

Effect of graphite oxide content on shape memory performance of graphite oxide‐carbon fiber hybrid reinforced shape memory polymer composites by VIHPS

AbstractGraphite oxide (GO)‐carbon fiber (CF) hybrid reinforced shape memory polymer composites (SMPC) with different GO content were prepared by vacuum infiltration hot‐press forming experimental system (VIHPS). By studying the wettability and adhesion characteristics between the shape memory matrix and CF, it was found that the addition of GO could improve the ability of the matrix to wet the CF surface and enhance the interface bonding. The shape memory performance of the composite with GO was better than that of CF reinforced epoxy matrix composite. The shape fixed rate increased by nearly 8%, and the shape recovery rate increased by nearly 13%. Combined with the test results and the characterization analysis of microstructure, the strengthening effect of GO was mainly reflected in the following aspects. Firstly, the surface folds of GO and its two‐dimensional grid structure increased the surface roughness and wettability of CF, forming a mechanical interlock among GO, reinforcement and matrix. The mechanical interlock promoted the reinforcement and matrix to have an ideal interfacial bonding strength. Secondly, the addition of GO was conducive to the transfer of deformation force and heat to prevent stress concentration in the composite and significantly improved the shape memory performance of the composite.

Mechanical, acoustic and vibration performance of intra‐ply Kevlar/PALF epoxy hybrid composites: Effects of different weaving patterns

AbstractThe influence of different weaving patterns on tensile, acoustic, and vibration behavior of intra‐ply Kevlar and pineapple leaf fiber (PALF) hybrid woven fabric reinforced epoxy matrix composites was investigated. Intra‐ply hybrid Kevlar/PALF woven fabrics were analyzed by three weaves: plain, twill, and basket. Also, epoxy matrix, pure Kevlar, and PALF woven fabric composites were analyzed for comparison purposes. Results revealed that the basket‐type hybrid composites exhibited a higher tensile strength of 77 MPa compared to plain (63 MPa) and twill‐type (73 MPa) hybrid composites. Plain and twill weave hybrid composites presented higher sound transmission loss levels of 28.9 and 30.5 dB, respectively, at higher frequency levels. Free vibration analysis showed that the PALF composites had higher damping and a lower natural frequency whereas the pure Kevlar and hybrid composites (KP1, KP2, and KP3) exhibited lower damping and higher natural frequencies.

A dual‐scale homogenization method to study the properties of chopped carbon fiber reinforced epoxy resin matrix composites

AbstractIn this work, a dual‐scale homogenization (DSH) procedures including the representative volume element (RVE) and Unit cell (UC) with Halpin–Tsai models in the UC scale and space direction‐sensitive Hotelling expansion (SDSHE) models in RVE scale separately. These two methods are introduced and implemented to predict the response of effective elastic properties in chopped fiber reinforced epoxy matrix structures. A post‐processing scheme of subdomain in UC scale based on Gauss theorem is proposed in SDSHE method, which is used to extract the average strain and stress in UC three‐dimensional structure. In addition, the X‐ray computed tomography was used to determine the fourth order tensor orientation angle and the probability distribution information of chopped fiber length in testing samples. Homogenization properties in RVE scale, and inclusion volume fraction (VF), thickness of interface and orientation tensors are designed in UC scale and compared. The excellent correlations with experiments prove the effectiveness of the proposed models. Furthermore, the algorithm proposed in this paper realizes the homogenization of the two scales in the process of numerical analysis, and it will effectively take into account many problems that cannot be achieved by other algorithms, such as the path strain of the model, the thickness of the interface, and so on.

Development and Mechanical Testing of Carbon Fiber Reinforced Polymer Matrix Composites for Micro Wind Turbine Applications

In this century, composites have been discovered to be the most promising and discriminating material accessible. Composites reinforced with synthetic or natural fibres are becoming more popular as demand for light weight, high strength materials for specialized applications grows are on the rise in the market. In the current work Carbon fiber Reinforced Polymer Matrix Composite material is developed aiming wind turbine blade applications. This research demonstrates the successful development of a carbon fibre reinforced Epoxy matrix composite that can be utilized to make micro wind turbine blades and is very cost effective thanks to the utilization of a simple hand lay-up approach. The peak elongation varies from 12.248 mm to 14.417 mm, and the tensile strength varies from 939.472 N/mm2 to 960.910 N/mm2. It was observed that the Compressive Strength varies from 8.992 N/mm2 to 46.895 N/ mm2 and peak elongation varies from 1.808 mm to 3.462 mm. In three-point bending test, the peak load was found to be 509.96 N. Due to the presence of carbon fibre reinforcement, the bending strength of polyester resin has been greatly increased.

Synthesis and characterization of CCTO0.5-BT0.5/epoxy hybrid ceramic polymer composite for electronic applications

In the present paper, calcium copper titanate (CCTO)-barium titanate (BT)/epoxy hybrid composite has been developed using the compression moulding process for electronic applications. Two lead-free piezoelectric ceramics CCTO, and BT, have been incorporated in 50:50 ratios in hybrid filler form into the epoxy polymer matrix to prepare the CCTO0.5-BT0.5/epoxy hybrid composite. Loading a small quantity of CCTO in the epoxy matrix can increase both dielectric constant and loss: whereas BT reinforcement can lower the dielectric loss of the single filler-filled epoxy composite. The electrical propertiesof the prepared CCTO0.5-BT0.5/epoxy hybrid composite are analyzed with varying frequency and temperature. The experimental data of the CCTO0.5-BT0.5/epoxy hybrid composite has shown a significant advancement in dielectric properties compared to the single filler reinforced epoxy composites. So, CCTO-BT/epoxy composite has been evidenced as a potential candidate to replace single filler reinforced epoxy matrix composites for electronic applications.

Mechanical properties of HNT filled carbon fabric epoxy composites

Recent researches are witnessing that nano fillers are significantly contributing the enhancement of strength of solid materials. In the current investigation carbon fabric reinforced epoxy matrix added with halloysite nanotubes (HNT) composites were fabricated using hand layup technique followed by hot pressing. The carbon fabric reinforced epoxy matrix composites (C-E) were fabricated with the addition of 0.1, 0.2, 0.5 and 0.75 wt% halloysite nanotubes (HNT) and tested for its mechanical properties: tensile strength and modulus, flexural strength and modulus using ASTM testing standards. The results revealed that tensile strength and modulus were increased up to 82% and 26.8% respectively and flexural strength and modulus were increased up to 29% and 28.5% respectively as compared to the unfilled carbon fabric-epoxy composites. Failure mechanisms were analysed using SEM photographs.

Thermomechanical properties of epoxy resin/basalt fiber/hydrotalcite composites and influence of hydrotalcite particle size on their properties

AbstractNatural fibers (NFs) and inorganic particles have been successfully grown in the polymer to enhance its properties. The basalt fiber (BF) and modified hydrotalcite (LDHs) reinforced epoxy resin matrix composites were prepared, and the effects of fiber and modified hydrotalcite (G‐LDHs) on the microstructural characteristics of composites were investigated. Fourier transform infrared spectroscopy and X‐ray diffraction were respectively used to analyze the structure of modified BF and G‐LDHs, and thermogravimetric analysis was performed to study thermal stability. The mechanical properties of composites, including dynamic thermomechanical and tensile and flexural properties, were respectively studied by dynamic mechanical analysis (DMA) and universal testing machine. Experimental results show the successful synthesis of high‐performance epoxy copolymers. The impact strength, tensile strength, and elastic modulus of EP/BF/G‐LDHs respectively reached 7.07 kJ/m2, 20.52 MPa, and 2595 MPa when the content ratio of BF to hydrotalcite in the additive was 3:3. The DMA test showed that the glass transition temperature (Tg) value increased by 18.3°C, and the thermal stability of composite materials was improved. The storage modulus E′ value increased by 268.04 MPa, and the stiffness of the epoxy material and the mechanical properties were also elevated. The TGA and DTG curves indicate that the cured composites also exhibit excellent thermal stability. The effect of g‐LDHS particle size on the properties of composites was also discussed. Overall, the synergistic and complementary enhancement effect of the two materials is the best when the diameter of hydrotalcite is similar to that of BF, and the performance of the composite material is considerably improved.

Mode-I interlaminar fracture of aramid and carbon fibers reinforced epoxy matrix composites at various SiC particle contents

Abstract The Mode-I interlaminar fracture characteristics of aramid fabric andcarbon fabric reinforced epoxy composites along with the influence of SiC particle content were explored. Double cantilever beam (DCB) tests were performed in accordance with ASTM D 5528 for the purpose of examining the behavior of Mode-I delamination. The results showed that, the adhesion strength of an SiC particle within an aramid/ epoxy composite system was better than that within a carbon/epoxy composite system. The highest values of Mode-I fracture toughness of an aramid fabric/epoxy specimen and a carbon fabric/epoxy specimen were 1391 J × m-2 and 701 J × m-2 with SiC particle contents of 10 wt.-% and 5 wt.-%, respectively. The micrographs from optical and scanning electron microscopes verified the enhancements of Mode-I interlaminar fracture toughness behavior.