Carbon Fiber Reinforced Epoxy Matrix Research Articles

Effect of plant short fibers on the mechanical properties of carbon fiber reinforced epoxy matrix by using FEM based numerical homogenization technique

In this study, we utilized the material design library in Ansys Product 2022 R1 to analyze the impact of short plant fibers on the mechanical properties of epoxy resin. We employed the representative volume element (RVE) approach and examined different volume fractions up to 50%. The technique employed in this study was multi-scale modeling based on the finite element method (FEM) for numerical homogenization. Subsequently, we used the same software to develop a five-layer laminated composite. The samples were based on epoxy resin enriched with short plant fibers at fractions of 20% and 30%, as well as pure epoxy resin. The laminated composites were reinforced with carbon fibers. The objective of this study was to analyze the mechanical response of each sample during a tensile test, focusing on multiple parameters. The sought-after results included total deformation, directional deformation, equivalent and elastic stress (Von-mises). The samples containing epoxy resin enriched with 30% of short hemp fibers exhibited remarkable mechanical strength compared to the other samples. These results suggest that the incorporation of short hemp fibers into the matrix led to a significant improvement in the mechanical strength of the composite.

Multiscale analysis method and experiments for the transverse mechanical property of unidirectional fiber-reinforced composites

Carbon fiber-reinforced epoxy matrix composite laminates have been widely used in the case of advanced aero-engines, due to their high specific mechanical properties and mature production technology. In order to predict accurately the transverse mechanical properties of composites, this paper developed a multiscale analysis method which consists of three scales: At the microscale, an interfacial cohesive zone model is established based on atomic potential energy to describe the interface. At the mesoscale, a unit cell model is established to represent the fiber, matrix, and interface. At the macroscale, the homogenization method, failure criteria, and damage degradation models are utilized to predict transverse mechanical properties. The results of predictions are compared with experimental tests, and it is found that the maximum errors are less than 3%. Furthermore, the predicted damage evolution path aligns with the experimental results, thus validating the accuracy of the multiscale analysis method. By employing the multiscale analysis method, the effects of interfacial strength on the macroscopic transverse mechanical properties are analyzed. The simulation results indicate that: The interfacial strength has a more pronounced influence on the transverse strength and ultimate strain compared with the transverse modulus. Reducing the interfacial strength has a greater influence on the transverse modulus, strength, and ultimate strain than increasing the interfacial strength. The interfacial cohesive zone model can reflect the nonlinearity of epoxy matrix composite materials. Overall, the multiscale analysis method proves to be effective in accurately predicting the transverse mechanical properties of composites, and provides insights into the interfacial strength’s role in these properties.

Effect of solution-blown nanofibrous web on quasi-static punch shear test results and quasi-static indentation behavior of carbon fiber-reinforced epoxy matrix composites

This study investigated the effects of the nanofiber interlayer in carbon fiber-reinforced epoxy matrix composites on quasi-static loading behaviors such as quasi-static punch shear (QS-PST), quasi-static indentation (QSI), and short-beam shear (SBS) loading. The solution-blowing technique was used to produce polyamide-6 (PA6) nanofiber with 1 g/m2 areal density. A 2×2 twill weave carbon fiber fabric with an areal density of 200 g/m2 was covered with solution-blown nanofibers. The vacuum-assisted resin transfer molding (VARTM) method was used to manufacture nanofiber interlayered composites and non-interlayered composites. QS-PS experiments were conducted at three different span to punch ratios (SPR), namely 1.1, 2, and 4. The PA6 nanofiber had a synergetic effect on the composite structure. In the QS-PST experiments, it increased the amount of work achieved by the specimen at rates of 29.5%, 13.5%, and 5.66% for SPR 1.1, 2, and 4, respectively while it provided increases in the maximum force at rates of 15.3%, 15%, and 5.7%, respectively. Additionally, the PA6 nanofiber contributed to the composite material properties determined based on the QSI test including the maximum force, punch crush strength, crush stiffness, and through-thickness modulus at rates of 7.5%, 7.56%, 2.72%, and 5.76%, respectively. Finally, an increase at a rate of 11.43% was determined in the SBS strength of the nanofiber interlayered composite, while it showed an increase in maximum force observed during the SBS experiment at a rate of 12.28%. The enhancements of mechanical properties of structural composites make them more reliable for high technology applications like aerospace, and automotive.

Notched Behaviors of Carbon Fiber-Reinforced Epoxy Matrix Composite Laminates: Predictions and Experiments

This paper experimentally studied the influence of the notch shape and size on the damage evolution and failure strength (tension and torsion) of carbon fiber-reinforced epoxy matrix (CFRP) laminates. Hashin’s damage criteria were utilized to monitor the evolution of multi-damage modes, and FEM simulations were also performed by using the ABAQUS code to clarify the specific damage modes in detail as an instructive complement. The failure characteristics of all the notched samples were analyzed and compared with those without notches. The measured results presented that the existence of a variety of notches significantly impaired the load carrying capacity of CFRP laminates. The tensile strengths of C-notch and U-notch increase with an increasing notch radius, while the ultimate torques of C-notch and V-notch decrease with an increasing notch size and angle. The variation in notched properties was explained by different notch shapes and sizes, and the failure characteristics were also presented and compared among notched CFRP laminates with varied notches.

Seawater Effects on Thermally Aged Ambient Cured Carbon/Epoxy Composites: Moisture Kinetics and Uptake Characteristics.

Carbon fiber-reinforced epoxy matrix composites using ambient- and moderate-temperature curing non-autoclave processes have broad applicability in marine, offshore, and naval applications. This research focuses on the characterization of moisture kinetics of ambient cured carbon/epoxy composites subject to immersion in seawater for up to 72 weeks after prior periods of extended thermal aging. A two-stage model is shown to best describe the overall kinetics and response. The level of maximum moisture uptake shows an increasing trend with the temperature and time of prior thermal aging, reaching asymptotic levels at the highest levels. The transition point is seen to represent a shift between the diffusion and relaxation-/deterioration-based dominant regimes, and the ratio of uptake at the transition point to the maximum uptake can be correlated to the relaxation coefficient. Diffusivity, as expected, generally increases with the temperature of prior aging and shows changes based on the level of post-curing and network changes with time. Moisture uptake kinetics and characteristics developed through the sequence of exposures provide a better understanding of phenomena towards the development of a future comprehensive model capable of long-term prediction based on the sequential prior history of exposure to elevated temperatures and immersion in seawater.

Mechanical PropertiesInvestigation of Unidirectional Woven Carbon Fiber Reinforced Epoxy Matrix Composite

In this study, the mechanical properties of an epoxy and unidirectional woven carbon with fiberglass composite were experimentally investigated. When preparing the composite samples, American Society for Testing and Materials (ASTM)standard was used. Tensile, impact and flexural test were conducted to investigate the mechanical properties of the new produced epoxy Unidirectional Woven Carbon and Epoxy Fiberglass composites. The outcome showed that the strength of the produced samples increased with the increase in the number of unidirectional woven carbon layers added. Two methods were utilized: (1) woven carbon composite with glass fiber (2) woven carbon composite). The two methods of composite were compared with each other. The results explained that woven carbon composite had higher mechanical resistance. While in impact test the toughness of the sample increased with adding layers of mixture of Fiber glass with unidirectional woven carbon and epoxy.

Femtosecond laser micromachining of carbon fiber-reinforced epoxy matrix composites

Unidirectional carbon fiber-reinforced epoxy matrix composites fabricated by compression die molding technique were exposed to femtosecond laser pulses of 1030 nm wavelength, 560 fs duration and a pulse repetition rate of 100 kHz. Laser tracks were engraved on the composite surface using pulse energy from 1 to 5 μJ both in the direction parallel and perpendicular to the fibers axis. The resulted morphology of the laser treated surface was investigated by field emission scanning electron microscopy (FESEM). The laser induced periodic surface structures (LIPSS) with an average periodicity of 195 ± 45 nm were observed on the carbon fiber surface while the epoxy matrix showed fine granular morphology. The surface topography of the laser tracks was quantitatively analyzed by 3D reconstruction of stereographic pairs of FESEM images recorded at two different inclinations of specimen with respect to the incident electron beam. The difference in ablation depth of fiber and epoxy was measured from stereographic images which showed a remarkable change in ablation depth of fiber and the matrix for pulse energy in the range 1–3 μJ and 4–5 μJ. The observations made in this study are expected to be useful for achieving improved bonding in composite structure repaired by adhesive joining.

Effects of Z-pin on moisture absorption property and damage mode under flexural load for carbon fiber composite

Abstract The effect of carbon fiber Z-pin on carbon fiber composite under moisture condition with and without flexural load was investigated in this work. Moisture absorption property and crack propagation of carbon fiber reinforced epoxy matrix composite and Z-pinned composite were evaluated under moisture only and moisture-coupled load conditions. The moisture property was evaluated by moisture content and microscopic morphology obtained using X-ray micro-computed tomography (X-ray μCT). The microstructures inside composites and Z-pinned composites after moisture conditions and three-point flexural test were detected using X-ray μCT and optical microscope. It illustrates that the moisture content of Z-pinned composites is higher due to the rich-resin pocket brought by the implantation of Z-pin. The cracks are obvious inside Z-pinned composites after moisture-coupled load conditions. It is attributed to the implantation of each pin which is the weak point for stress concentration and crack formation. Failure morphologies on the surface of composites and Z-pinned composites are different under different moisture conditions. Less macro-interlayer cracks are detected on the surface of Z-pinned composites, and plenty of microcracks initiating from pins are observed.

An Overview on Carbon Fiber-Reinforced Epoxy Composites: Effect of Graphene Oxide Incorporation on Composites Performance.

Carbon fiber-reinforced polymer (CFRP) composites are used in a variety of applications such as aircraft, automobiles, body armors, and the sports sector owing to their ultra-strong and lightweight characteristics. However, the incorporation of an untreated pristine carbon fiber surface leads to a weak interfacial interaction with the polymeric matrix, thus triggering catastrophic failure of the composite material. Graphene oxide, a 2D-macromolecule consisting of several polar functional groups such as hydroxyl, carboxyl, and carbonyl on the basal planes and edges, tends to increase the surface area and has thus been applied between the fiber and matrix, helping to improve CFRP properties. Herein, we condense different routes of functionalization of GO nanosheets and their incorporation onto a fiber surface or in a carbon fiber-reinforced epoxy matrix, helping to improve the interfacial adhesion between the fiber and matrix, and thus allowing effective stress transfer and energy absorption. The improvement of the interfacial adhesion between the fiber and carbon fiber-reinforced epoxy matrix is due to the peculiar structure of GO nanoparticles composed of polar groups, especially on the edges of the nanosheets, able to provide strong interaction with the hosting cured epoxy matrix, and the “core” part similar to the structure of CFs, and hence able to establish strong π-π interactions with the reinforcing CFs. The article also covers the effect of functionalized graphene oxide incorporation on the mechanical, thermal, electrical, and viscoelastic properties of composite materials reinforced with carbon fibers.

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.

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.

Assessment of Interfacial Interaction in Graphene Nanoplatelets and Carbon Fiber-Reinforced Epoxy Matrix Multiscale Composites and Its Effect on Mechanical Behavior

Assessment of Interfacial Interaction in Graphene Nanoplatelets and Carbon Fiber-Reinforced Epoxy Matrix Multiscale Composites and Its Effect on Mechanical Behavior

Applicability of linear elastic fracture mechanics to compressive damage in carbon fiber reinforced epoxy matrix composites

The failure of carbon fiber reinforced epoxy matrix composites has been attributed to different mechanisms involving tensile, compressive and shear failure of the fibers or the matrix. This research serves to understand whether linear elastic fracture mechanics can explain the matrix behavior under compressive loading. Experiments and finite element analysis (FEA) are used to confirm that the matrix under compressive loads follows the relationships established by linear elastic fracture mechanics. The failure load is related to the corresponding notch length, and the observed relationship is compared to the relationship defined by linear elastic fracture mechanics.

Enhancement of mechanical properties of carbon fiber reinforced epoxy matrix laminated composites with multiwalled carbon nanotubes

A manufacturing process hand layup technique was used to produce carbon fiber/epoxy laminates with the epoxy matrix with a variation of 0.5 wt % to 2 wt% carbon nanotubes (CNTs). Microstructural observations of the composites from a scanning electron microscope show a better interaction between CNTs and epoxy. In this study, the mechanical properties of the carbon fiber-epoxy system and carbon fiber-CNT/epoxy system were characterized through the tensile and flexural tests. From the studies, it was found that the tensile and flexural strength of carbon fiber/epoxy laminate with CNTs are higher than those without CNTs.

The Effect of Interlayer Materials on Ceramic Damage in SiC/Al Composite Structure.

The effect of interlayer materials on the damage of ceramics in the SiC/Al composite structure was analyzed through experiments and simulation. Using 0.25 mm thermoplastic polyurethane (TPU) as a reference, a 0.5 mm aramid fabric (AFRP) or a 0.5 mm carbon fiber reinforced epoxy matrix composite (CFRP) was added to the interlayer, respectively. Through the impact tests, it was discovered that the ceramic damaged area in the TPU composite structure was severe. With the addition of AFRP, the damaged area of the ceramic layer was reduced by 73% under the same impact conditions. The addition of CFRP also reduced the damage of ceramics. The evolution process of the tensile stress on the ceramic rear surface was presented by simulation. The tensile evolution process analysis can explain the experimental phenomenon well and can be used to predict the damage of the ceramics.

Effect of Silane Coupling Treatment on the Adhesion between Polyamide and Epoxy Based Composites Reinforced with Carbon Fibers

The increasing efforts aimed to design structures with reduced weight and better mechanical performances has led in recent years to a growing use of fiber reinforced polymer materials in several fields such as marine. However, these materials can be composed of chemically very different elements and, hence, may be difficult to joint. This research aims to improve the adhesion between a thermoplastic matrix of polyamide reinforced with short carbon fibers (PA12-CR) and a carbon fiber reinforced epoxy matrix (CFRP). Two different silane coupling agents, (3-Aminopropyl)trimethoxysilane (AM) and (3-Glycidyloxypropyl)trimethoxysilane (EP), were applied, through the spray deposition method, on the PA12-CR substrate to create a reactive layer between the adherents. Different deposition methods and coupling agents curing conditions were also investigated. The wettability of the PA12-CR surface as well as the chemical modifications induced by silane treatments were investigated through contact angle and Fourier Transform Infrared spectroscopy (FTIR) analyses. Furthermore, the interfacial adhesion between PA12-CR and CFRP substrates was evaluated through Mode I delamination tests (DCB). The effectiveness of the most promising treatment was finally verified on sandwich structures, having PA12-CR printed as internal core and CFRP laminates as external skins, through quasi-static three-point bending mechanical tests. Overall, the epoxy-based silane (EP) allowed significantly better resistance to the delamination up until the tensile failure of the CFRP substrate.

Effect of nanoclay (Kaolinite) on mechanical properties of epoxy-fiber composite

An experimental investigation using drag-out tensile test to calculate the interfacial shear strength for different embedded lengths of Kevlar and carbon fibers reinforced epoxy matrix with nanoclay (kaolinite) for different ratio weight, the interfacial shear strength increased by with increasing of embedded length and ratio weight fraction of nanoclay that adding to epoxy matrix.

Effect of curing time on phase morphology and fracture toughness of PEK-C film interleaved carbon fibre/epoxy composite laminates

The phase morphology developed by thermosetting and thermoplastic resin is one of the main concerns in interleaved thermosetting composites by thermoplastic resin, which directly affects the toughening efficiency. The carbon fibre reinforced epoxy matrix composite laminates were interleaved by Polyetherketone-cardo (PEK-C) films and the effect of curing time on the phase morphology spectrum and fracture toughness was investigated in the study. The microstructure-property correlation was explored. The results showed that the PEK-C film interlayer was efficient in the interlaminar toughening and the fracture toughness (GIC) was enhanced by 90.65% at curing time of 1 h. Nevertheless, increasing curing time weakened toughening effect of PEK-C films and GIC was only increased by 9.37% under the curing time of 3 h. The characteristic morphology spectrum in the interlaminar region, consisting of homogeneous PEK-C resin, nodular dualphase and sea-island dualphase, contributed to the improvement of toughness. The homogeneous PEK-C layer was decreased with the curing time increasing due to the more fully permeation of epoxy, resulting in the crack path change from the center of interlaminar region and the interface between interlaminar region and composite layer to merely the interface, which might be the main reason for the weakening of measured crack propagation resistance.

Development of carbon fibre reinforced polymer matrix composites and optimization of the process parameters for railcar applications

The potential use of carbon fibre for railcar application stems from its excellent properties such as high strength to weight ratio and fire retarding abilities. This work studies the development of carbon fibre reinforced epoxy matrix composites and the optimization of the process parameters for railcar applications. Using the transfer moulding process, the composite comprising of mixture of double layers of polyacrylonitrile (PAN) based carbon fibre as reinforcement, epoxy resin which serves as the binder to form the matrix and silica additives were prepared and cured in a mould. The numerical experiment was performed using the Response Surface Methodology (RSM) and central composite design (CCD) comprising of two factors namely; the curing temperature (100–180 °C) and curing time (6–24 h). The statistical analysis of the numerical and physical experimentations were used to obtain a predictive model that correlates the tensile strength as a function of the curing temperature and curing time. There is a high degree of correlation between the results obtained from both the numerical and physical experimentations which implies that the developed model is suitable for predictive and correlative purposes. In addition, the results of the mechanical properties of the developed composite material indicate high tensile strength under varying loading conditions. This is an indication that the material possesses good strength and stiffness which makes the composite suitable for railcar applications. This work bring about the development of carbon fibre reinforced polymer and the determination of its mechanical properties for railcar applications.

Graphene oxide modified carbon fiber reinforced epoxy composites

Abstract The interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.