Fiber Epoxy Composites Research Articles

Experimental investigation of physical, mechanical, and thermal behaviour of Bi-directional date palm fiber reinforced epoxy composite

The present study attempts to fabricate lightweight polymer composites with superior physical, mechanical, and insulating properties by vacuum-assisted resin transfer molding (VARTM) technique. This produces bidirectional woven palm fiber epoxy composites with four different fiber loading i.e. 27, 28, 29, and 30 Wt%. The epoxy composite processed with VARTM technique has been characterized by physical, mechanical, and thermal properties along with increasing fiber loading. The test results signified that the mechanical properties including tensile, interlaminar shear, hardness, and impact strength improve with fiber loading. The maximum tensile strength and tensile modulus were observed at a fiber loading of 30 wt%, resulting in values of 64.852 MPa and 3.74 GPa, respectively. The recorded ILSS values for the epoxy composites loaded with 30 wt% were found to be 7.28 MPa. The observed improvements in the mechanical characteristics of the composite produced by the VARTM technology can be attributed to the enhanced interfacial bonding between the matrix and discontinuous prepreg fiber (DPF). The identification of a superior composite, known as DPF-4, was achieved through the incorporation of 30 wt% of bi-directional palm fiber loading. This resulted in notable improvements in the mechanical properties of the composite, as a significant enhancement of 311% and 173% in tensile and impact strength, respectively. These mechanically strengthened epoxy composites could be used as low-grade housing, structural, and automobile component applications.

Improved mechanical properties of graphene-modified basalt fibre–epoxy composites

Improved mechanical properties of graphene-modified basalt fibre–epoxy composites

3D Printing and Characterization of Carbon Fiber Epoxy Composites

3D Printing and Characterization of Carbon Fiber Epoxy Composites

Study on the laser ablation behavior of nitride coatings on carbon fiber epoxy resin composite

Study on the laser ablation behavior of nitride coatings on carbon fiber epoxy resin composite

Experimental and numerical studies on the mechanical characteristics of Timoho fiber epoxy composites with nanofiller addition

AbstractThis study is focused on the investigation of the mechanical characteristics of Timoho fiber (TF) epoxy composites with graphene as the filler material, both experimentally and numerically, for high‐velocity impacts. The composites were prepared by the compression molding process with varying wt.% of graphene. An experimental approach was undertaken to study the behavior of the composites under different wt.% of graphene. To validate the results obtained in the experimental approach, numerical studies were conducted. It was observed that there was an enhancement in the mechanical properties with the addition of graphene. For tensile strength, there was an increase of 33.17% when comparing the controlled sample (0% graphene) and the sample with 2% graphene content. Subsequently, there was an increase of 36.48%, 58.02%, and 29.79% when comparing the controlled samples and samples with 2% graphene, respectively, for flexural, impact, and interlaminar shear strength (ILSS). However, it was observed that after the addition of 2 wt.% of graphene, the mechanical strength decreased due to the agglomeration of graphene inside the composite, which was confirmed using the SEM analysis. For the numerical study, ANSYS workbench was employed, and simulation was conducted using finite element analysis (FEA) for the tensile and flexural test. The numerical findings were found to be reasonably close to the experimental values, with variations ranging from a minimum of 2% to a maximum of 15%. In the design of experiments, Taguchi's approach was used to determine the effect of a variety of parameters on the tensile behavior of the TF epoxy composites.Highlights 2 wt.% of graphene was observed to be the optimum concentration of graphene. The decline in mechanical properties was observed at 3 and 4 wt.% of graphene. Agglomeration of graphene filler in the composite was confirmed using SEM. ANOVA showed that wt.% of graphene made the top contribution to tensile strength. The nanographene‐incorporated TF composites can be used for lightweight applications.

Effect of Thermomechanical Loading at Low Temperatures on Damage Development in Glass Fiber Epoxy Laminates.

Due to the high interest in the use of glass/epoxy laminates in aerospace applications, aviation, and as cryogenic tanks, it is crucial to understand the behavior of composites under challenging environmental conditions. Polymer composites are exposed to low temperatures, including cryogenic temperatures, which can lead to the initiation of microdamage. This paper investigates damage initiation/accumulation and its influence on the properties of cross-ply woven glass fiber epoxy composites at low temperatures compared to room temperature conditions. To evaluate the influence of a low-temperature environment on the mechanical performance of glass fiber reinforced epoxy composite (GFRP) laminates, three types of test campaigns were carried out: quasi-static tensile tests and stepwise increasing loading/unloading cyclic tensile tests at room temperature and in a low-temperature environment (-50 °C). We demonstrated that the initial stiffness of the laminates increased at low temperatures. On the other hand, there were no observed changes in the type or mechanism of developed damage in the two test conditions. However, the reduction in stiffness due to the accumulated damage was more significant for the laminates tested at low temperatures (~17% vs. ~11%). Exceptions were noted in a few formulations where the extent of damage at low temperatures was insignificant (<1%) compared to that at room temperature. Since some of the studied laminates exhibited a relatively minor decrease in stiffness (~2-3%), we can also conclude that the formulation of matrix material plays an important role in delaying the initiation and formation of damage.

Optimization of drilling process parameters on customized alkali-silane treated pineapple fibre-epoxy composite using Taguchi-Grey relational approach

Optimization of drilling process parameters on customized alkali-silane treated pineapple fibre-epoxy composite using Taguchi-Grey relational approach

Influence of single and multi-walled CNT on the mechanical performance of glass fiber hybrid polymer composites

The structural materials of the twenty-first century have evolved with the inclusion of nano scale materials which can be utilized to improve the performances of the materials significantly. One of such widely adopted nano material is carbon nano tubes (CNTs) which can further be categorized as single walled and multi walled CNTs (SWCNT and MWCNT). Similarly, glass fiber reinforced polymer composites (GFRP) are a promising material for a wide range of applications, including automotive parts, aircraft components, boat hulls, wind turbine blades, and construction materials. Research by material designers continues to explore new avenues for further improving properties of GFRP composites by using nanomaterials and other advanced materials. In the present work, a new class of polymeric composite material is developed with different filler loading (i.e., 1% to 5% with a step of 1%) of single and multi-walled CNT with glass fiber as reinforcement phase. The tensile and flexural strengths of the hybrid nano composites were determined. The incorporation of CNT with glass fiber epoxy composites strengthened the matrix phase thereby enhancing the tensile and flexural strengths of the developed composites. Further, the obtained experimental findings outlined that the multi walled carbon nano tube filler provided optimum tensile and flexural strength among developed composites due to the better interphase bonding with multi walled structure of MWCNT filler structure. Further, the microscopic analysis of the fractured surfaces was conducted to analyze different mechanisms leading to failure of composite materials during loading.

Effects of silica nanoparticles on glass and carbon fiber epoxy composites

Effects of silica nanoparticles on glass and carbon fiber epoxy composites

Confidence intervals of inversely identified material model parameters: A novel two-stage error propagation model based on stereo DIC system uncertainty

Digital image correlation (DIC) is a powerful tool for characterising materials and determining material model parameters. To assess the reliability of the full-field measurement-based inverse identification procedures, it is crucial to investigate the impact of the measurement errors on the identified material model parameters. Literature indicates that conventional error propagation models, which rely on Gaussian noise-contaminated data, significantly overestimate the confidence for inversely identified material model parameters, resulting in misleadingly narrow confidence intervals. A more precise assessment of systematic errors originating from the experimental setup leads to an improved prediction of the confidence intervals, but this requires specific information about the DIC equipment, post-processing details, and a skilled experimentalist. In this work, we propose an alternative two-stage error propagation model that yields more realistic confidence interval predictions based solely on a database of past mechanical experiments conducted with the specific stereo DIC system set up in a particular way. We have validated the proposed procedure numerically using the open-hole test and an orthotropic elastic material model. Our predictions reveal a non-Gaussian probability distribution of the inversely identified material model parameters, with confidence intervals considerably wider than those obtained by considering random Gaussian noise. Furthermore, these predictions were experimentally validated in an extensive experimental campaign investigating a pultruded carbon fibre epoxy composite.

Acoustic, vibration, and viscoelastic performance of wire EDM waste-reinforced natural fiber composites

Natural fiber composites are being promoted as cost-effective substitutes for synthetic materials due to its benefits like lightweight, recyclability, cost, and biodegradability. The main objective of the present work is to reuse the electrical discharge machining (EDM) waste wire in coated hemp/ramie fiber epoxy composites. The wire lengths of 1, 3, and 5 cm were used as reinforcement in composites and its effects were studied through mechanical characterizations, dynamic mechanical analysis (DMA), acoustic study, and vibration behavior. The 5 cm wire length composite (S4) secured better mechanical properties (tensile-26%, impact-33%, hardness-12%). Additionally, S4 displayed increased storage modulus and reduced loss modulus from DMA analysis. The natural frequency has increased by 15%, whereas decrease in damping ratio was observed for S4. The sound absorption coefficient of S4 composite was lower compared to S1 due to the stiffness and lower damping properties of the reinforced wire. The developed composite can provide the necessary strength and stiffness while reducing the overall weight of the vehicle in an automobile industry.

Enhancing the mechanical performance of E‐glass fiber epoxy composites using coal‐derived graphene oxide

AbstractIn this study, we compare the effect of various precursor‐based graphene oxide (GO) nanofillers on enhancing the mechanical performance of E‐glass fiber‐reinforced epoxy resin composites (EGFPs). GO derived from bituminous coal (BC‐GO) and graphite (Gr‐GO) were dispersed into an epoxy resin matrix. The resulting mixture was combined with E‐glass fiber mats using vacuum‐assisted resin infusion molding. Notable improvements (38.9% in flexural strength, 22.9% in tensile strength, and 21.6% in impact strength) were observed in BC‐GO‐reinforced EGFPs at 0.25 phr loading of BC‐GO. The improvements for Gr‐GO‐reinforced EGFPs were 28%, 9.3%, and 6.8%, respectively. XRD analysis of BC‐GO showed a diffraction peak at 2θ = 20.9°. Except for this peak, no other crystalline peaks were observed when BC‐GO was incorporated into EGFPs. FTIR spectra of both composite samples, with or without the nanofiller, were similar due to the spectral peaks overlap. TEM demonstrated the exfoliated morphology of BC‐GO in EGFPs. These findings underscore the potential of BC‐GO as a cost‐effective reinforcement for polymer nanocomposites across various industrial applications, including the development of lightweight and strong materials for aerospace and automotive industries, protective coatings, petroleum, and aerospace production systems.Highlights BC‐GO demonstrates superior mechanical performance compared to Gr‐GO in EGFPs. 0.25 phr BC‐GO improves 38.9% flexural, 22.9% tensile, and 21.6% impact strengths. Beyond 0.25 phr, BC‐GO and Gr‐GO showed a decline in mechanical enhancement. Role of particle size, loading &amp; adhesion to matrix analyzed using XRD, FTIR, and DLS. Coal‐GO is an attractive alternative nanofiller for EGFPs.

Effect of various weaving architectures on mechanical, vibration and acoustic behavior of Kevlar-Hemp intra-ply hybrid composites

Due to the benefits of including high stiffness, low density, low cost, ecologically benign nature and abundant availability, natural fibers are employed as reinforcement in composites. These fibers however have a few shortcomings, including poor moisture resistance and incompatibility with most matrices. Therefore, the goal of this research is to combine the benefits of natural fiber (hemp) with synthetic fiber (kevlar) to develop a hybrid composite. Hemp and Kevlar yarns were handloomed to form fabrics with different architectures such as plain, twill and basket. These hybrid fiber epoxy composites were fabricated using compression molding and the samples were subjected to mechanical testing, free vibration and acoustic emission characteristics. Hemp and Kevlar fiber composites were also fabricated for comparison purpose. The results revealed that the twill and basket weave intra ply hybrid composites exhibited the better mechanical properties when compared with the plain weave hybrids. Whereas, the free vibration results showed that the all the hybrids exhibited better performance that the mono-fiber composites. Acoustic behavior of the basket weave hybrid was found to have the highest sound transmission loss value of 13.7 dB in the higher frequency range. On the other hand, the hemp-epoxy composites exhibited the highest sound transmission level of 6.3 dB in the lower frequency range.

Mechanical Characterization of Pineapple Leaf Fiber Epoxy Composites with Steel Wire Mesh

In the present experimental research work hybrid composite is manufactured using hand lay-up technique, taking epoxy resin as matrix material and stainless-steel wire mesh along with alkaline treated and untreated pineapple leaf fiber as reinforcement. Mechanical characterization such as tensile, flexural, hardness and water absorption test were performed on the samples of developed composites as per ASTM standards. Mechanical characterization revealed that treatment of fiber is having significant effect on mechanical properties. Tensile strength and flexural strength of treated fiber reinforced composite is 132.12 % and 109.98% respectively higher than untreated fiber reinforced composite. Inclusion of wire mesh along with fiber enhanced the tensile strength by 11.22% whereas bending strength decreases by 8%. Analysis of fractured surfaces using scanning electron microscope revealed there is a lack of bonding between wire mesh and epoxy resin. Water absorption test revealed that treated fiber reinforced composite is having the least water absorption capacity of 6.63 %, wire mesh included composite is having water absorption capacity of 6.96 % and untreated fiber reinforced composite is having the highest water absorption capacity of 8.7 %.

Mechanical Properties of Textile-Reinforced Composites with a 3D Printed Core

Abstract The article discusses the mechanical properties of glass fiber epoxy composites with three types of textile structures. Braided, knitted and woven sleeves were placed on a 3D printed flat core and impregnated with resin using the vacuum bag method. The 3-point flexural and tensile tests were performed. The results were compared with those of 3D-printed flat bars and proved that woven textile structures increase the strength and modulus of elasticity, whereas braided and knitted structures only increase the moduli. The advantages, drawbacks and failure modes of each reinforcement structure are also discussed including the drapeability on the spatial core.

Influence of Layering Pattern, Fibre Architecture, and Alkalization on Physical, Mechanical, and Morphological Behaviour of Banana Fibre Epoxy Composites

In the current investigation, the mechanical properties of epoxy composites reinforced with banana pseudostem fibres, specifically focusing on tensile and impact behaviour, are investigated. The manufacturing process employed the meticulous hand-lay-up technique to fabricate six distinct samples. These samples included various combinations of short and woven banana fibres, treated and untreated, as well as a hybrid configuration involving layers of woven and short fibres. A fixed weight ratio of 60% fibres to 40% epoxy matrix was maintained for consistency. To ensure optimal material integrity, a careful application of resin and hardener in a 10 : 1 weight ratio was layered, with each addition of fibre followed by thorough rolling to eliminate any potential bubbles. The density and void fraction of the resulting composites were meticulously assessed to gauge the influence of this layering approach. Additionally, an X-ray diffraction (XRD) analysis was conducted to ascertain the impact of the chemical treatment on the cellulose content of the fibres. Our findings revealed that the tensile and impact properties were notably superior in the woven fibre composites. In particular, the chemically treated woven banana fibre epoxy composite displayed impressive values of 64.95 MPa for tensile strength and 24.37 KJ/m2 for impact strength. To gain deeper insights into the structure-property relationship, test specimens were analyzed using scanning electron micrographs. Lastly, comparative analysis by mapping the tensile properties from our present work with those from existing studies was carried out.

Mechanical and vibrational study of raw and surface‐treated ramie fiber hybridized carbon fiber epoxy composites

AbstractHybrid polymer composites' lightweight, biodegradability, damping, and cost‐effectiveness have made them popular in recent decades. This study evaluated the raw and alkali‐treated hybrid composite's free vibration studies and mechanical properties by changing the ramie fiber layers (core) from two to four and keeping the carbon fiber layers (top and bottom) constant. Thus, to enhance the mechanical properties, the ramie fiber was treated prior with 2, 3, and 4 wt% of sodium hydroxide (NaOH). These composites were characterized chemically, mechanically, morphologically, and vibrationally via Fourier transform infrared spectroscopy, flexural and tensile tests, field emission scanning electron microscope, and free vibration setup, respectively. The tensile and flexural samples were loaded under quasistatic conditions and tested at 1 and 2 mm/min to evaluate tensile and flexural properties, respectively, and a free vibration test built the natural frequencies and reliable damping factor using clamped‐clamped and clamped‐free boundary conditions. Two layers of carbon fiber (exterior layer) and two layers of ramie fiber (core layer) at 3 wt% NaOH produced maximum tensile strength (523 MPa) and flexural modulus (68,869 MPa) among natural and hybrid composite combinations. This study shows that hybridization and alkaline treatment improve composite material mechanical properties in a specific ratio.Highlights Mechanical and vibration analysis of carbon/ramie hybrid composites was studied. Ramie fiber's surface treatment was carried out in NaOH at 2, 3, and 4 wt%. Surface treatment uplifts mechanical and vibration properties than untreated. Ramie fiber's chemical consequences were analyzed through Fourier transform infrared spectroscopy and field emission scanning electron microscope tests. Surface treatment at 3 wt% builds higher mechanical and vibrational properties.

Enhanced extreme temperature bending and delamination resistance of GFRP composites through z-directional aligned nano-reinforcement: Emphasizing the effects of CNT functionalization

Laminated FRP composites' weak out-of-plane mechanical performance prevents their usage in structural applications where homogeneous load bearing qualities are required. In this regard, a z-directional nano-reinforcement approach was implemented to mitigate the poor in-plane shear and out-of-plane response of laminated glass fiber epoxy (GE) composites under extreme in-service temperature conditions. CNT and functionalized CNT (FCNT) were dispersed separately in the GE composites' epoxy matrix and subjected to a z-direction electric field alignment treatment. Flexural and short beam shear tests of GE composites with random and aligned CNT/FCNT were performed at room temperature, in-situ cryogenic and elevated temperature conditions (RT, CT and ET, respectively). GE composite with aligned FCNT (A-FCNT-GE) consistently outperformed other composites at all considered temperatures with remarkable improvements, specifically ∼39%, ∼41% and ∼47% in flexural strength, and ∼30%, ∼30%, and ∼24% in interlaminar shear strength (ILSS) over the control GE composite at RT, CT and ET, respectively. Dynamic mechanical thermal analysis suggested that the synergetic impact of functionalization and alignment of FCNT improved the viscoelastic properties of the A-FCNT-GE composite across a range of temperature conditions. Fractography analysis provided insight into the interfacial and interlayer mechanisms that improved the extreme temperature condition mechanical performance. The reliability of electric field aligned FCNT as a z-directional nano-reinforcement in laminated composites at extreme temperature conditions was established in this study.

Integrating machine learning and response surface methodology for analyzing anisotropic mechanical properties of biocomposites

ABSTRACT This study enhances the anisotropic mechanical properties of banana fiber-epoxy composites by optimizing fiber loading, orientation, and treatment using Response Surface Methodology (RSM) and Artificial Neural Network (ANN). RSM suggests optimal values: fiber loading at 33 wt%, NaOH treatment at 6.8 wt%, and fiber orientation at 15 degrees. This material has exceptional mechanical characteristics, including a maximum tensile strength (TLS) of 31.72 MPa, a maximum flexural strength (FLS) of 42.86 MPa, and a maximum impact strength (IPS) of 38.56 kJm-2. ANN effectively predicts strengths with high R2 scores of 0.969, 0.984, and 0.954 for tensile, flexural, and impact strengths. Incorporating batch normalization and dropout layers enhances robustness. The study concludes that NaOH treatment and fiber orientation significantly impact the composite’s anisotropy.

Effect of green pea pod lignin addition on thermal degradation, flame resistance, DMA, and creep resistance of pineapple fibre epoxy composite

Effect of green pea pod lignin addition on thermal degradation, flame resistance, DMA, and creep resistance of pineapple fibre epoxy composite