Fiber Reinforced Epoxy Composite Materials Research Articles

Quasi-static punch shear behavior of glass/epoxy composite: Experimental and numerical study in artificial seawater environment

Enhancing the understanding of how fiber-reinforced polymer composites respond to high-speed impacts is crucial, particularly in comparison to Quasi-Static Punch Shear Test (QS-PST). While researchers have extensively investigated QS-PST in FRP composites through experimental and numerical approaches, there's a notable gap in studies addressing the aging effects through both experimental and numerical methods. In this study, the QS-PST was conducted on S2 glass fiber reinforced epoxy composite materials aged in an artificial seawater environment. Composite plates were fabricated using Vacuum-assisted resin transfer molding (VARTM). Test samples were subjected to aging for durations of 4, 8, and 12 months. Experimental QS-PST were performed on the samples, followed by Finite Element Analysis (FEA) using LS-DYNA and the MAT 162 material model. The mechanical properties of the composite material were incorporated into the FEA and aging effects were simulated with a maximum error of 8.08% by using the proposed material model. The results indicated that the aging process led to a reduction in the punch shear strength of the composite by up to 26.84%. These findings provide valuable insights into the degradation mechanisms of composite materials in marine environments, aiding in the development of strategies for enhanced durability and performance in such conditions.

NUMERICAL ANALYSIS OF TENSILE MECHANICAL PROPERTY OF GLASS FIBER REINFORCED EPOXY

In this paper a study has been carried out to find the characteristic relation between experimental and numerical analysis of tensile properties of glass fiber reinforced epoxy composite materials, which are subjected last before to tensile test using the universal testing machine. The numerical results obtained by finite element analysis were compared with available experimental data in literature for the tensile strength. The comparison shows that the results of tensile strength are in agreement with available experimental data published in literature. It was confirmed and enhancing validity of tensile properties of experimentally tested composite materials

Study on the inter-laminar shear properties of carbon fiber reinforced epoxy composite materials with different interface structures

To explore relationship between the inter-laminar shear properties and the interfacial structure of carbon fiber (CF) reinforced epoxy resin (EP) composite materials (CFRPs), four CFRPs with different interfacial structures were prepared through introducing polar groups on the surface of the CF and then combining the modified CF with the EP, including CF/EP (where no polar group was introduced), CF-COOH-EP (where carboxyl group –COOH was chemically introduced), CF-COOH/MXene /EP (where –COOH was chemically introduced while MXene was physically introduced and the MXene was non-covalently bonded to CF and to EP), and CF-CONH-MXene-EP (where both of –COOH and MXene were chemically introduced and the MXene was covalently bonded to CF and to EP). Results of inter-laminar shear strength (ILSS) of the materials and morphology of transverse and longitudinal cross-sections of the damaged materials show that with enhancing the interfacial interaction between CF and EP, the ILSS increases and the interlayer shear failure gradually changes from a single interface debonding (for CF/EP) to a combination of interface debonding and matrix fragmentation. The interfacial structure of CF-COONH-MXene-EP with higher interfacial interaction could bear more interlayer shear forces, being beneficial for improving the service life of CFRPs.

Structural Design and Analysis of a Booster Arm Made of a Carbon Fiber Reinforced Epoxy Composite Material

An analysis of a booster arm made of a carbon fiber reinforced epoxy composite material is conducted by means of a finite element analysis method. The mechanical properties are also determined through stretching and compression performance tests. It is found that the surface treatment of the fibers causes the silane coupling agent to undergo a chemical reaction on the surface of the glass fiber. The used material succeeds in producing significant vibrations damping (vibration attenuation effect is superior to that obtained with conventional alloy materials).

Strength of carbon fiber/epoxy in sea water

Abstract Composite materials are widely used in the marine industry. The marine environment, on the other hand, has a significant impact on the strength of composite materials. The tensile strength is adversely affected because the matrix material absorbs water. In this study, the effect of orientation, number of layers and different mediums over time on the tensile strength of the woven carbon fiber reinforced epoxy composite material was investigated experimentally from a comprehensive perspective. The findings of the experiments were subjected to variance analysis. The repeated tests and cross-results of the experimental parameters were found to be compatible with each other. Seawater reduces the tensile strength of composite materials in any case. The tensile strength increased with increasing the number of layers. However, it has been observed that the seawater medium reduces strength when the number of layers increases. At the same time, as orientation angle rises, the seawater medium’s negative effect on strength rises.

Investigation of Mechanical Properties of Silk and Epoxy Composite Materials

This research Investigates the new composite materials are fabricated of two or more materials raised. The fibers material from the sources of natural recycled materials provides certain benefits above synthetic strengthening material given that very less cost, equivalent strength, less density, and the slightest discarded difficulties. In the current experiments, silk and fiber-reinforced epoxy composite material is fabricated and the mechanical properties for the composite materials are assessed. New composite materials samples with the dissimilar fiber weight ratio were made utilizing the compression Molding processes with the pressure of 150 pa at a temperature of 80 °C. All samples were exposed to the mechanical test like a tensile test, impact loading, flexural hardness, and microscopy. The performing results are the maximum stress is 33.4MPa, elastic modulus for the new composite material is 1380 MPa, and hardness value is 20.64 Hv for the material resistance to scratch, SEM analysis of the microstructure of new composite materials with different angles of layers that are more strength use in industrial applications.

Performance Improvement of Carbon Fiber Reinforced Epoxy Composite Sports Equipment

This study is to explore the changes in the performance of sports equipment under the action of carbon fiber reinforced epoxy composites. This paper studies the effects of carbon fiber reinforced epoxy composites in pole vault, bicycle, and tennis. The research results show that the performance of sports equipment based on carbon fiber reinforced epoxy composite materials has been greatly improved, with outstanding effects in terms of thermal properties, interface properties, mechanical properties, and fatigue resistance. Carbon fiber reinforced epoxy composite material damage expansion is divided into five stages: matrix cracking, interfacial degumming, delamination, fiber fracture, fracture. Therefore, carbon fiber reinforced epoxy composite materials are comprehensive for the improvement of sports equipment, which has greatly promoted the further development of sports. Carbon fiber reinforced epoxy composite materials can be promoted in other fields, thereby obtaining greater progress with help of high technology. The study of carbon fiber reinforced epoxy composites in this paper has a positive effect on subsequent research.

Delamination assessment in drilling basalt/carbon fiber reinforced epoxy composite material

The present work aims at assessing the delamination damage occurring in a hybrid composite material during the drilling process. The hybrid composite selected for work comprises of basalt and carbon fibers as reinforcements and epoxy as the matrix. Process parameters quantified by speed, feed, and drill size are the selected input independent variables. The response variable, delamination factor (Fd), for each experimental combination, is determined using the simple Chen's one-dimensional equation. Taguchi's L27 orthogonal array (OA)-based experimental design with the ‘smaller-the-better’ approach forms the base for experimental runs and optimization in the present work. ANOVA is applied in the present work to investigate the significance of the linear, squared, and interaction effect of speed, feed, and drill diameter on the delamination damage. Besides, the regression prediction model is developed and validated through a set of confirmation experiments. The optimum process parameters in the drilling of hybrid composite concerning delamination are drill diameter (D) of 6mm, speed (N) of 1250rpm and feed rate (f) of 50mm/min. The regression model developed shows a high degree of fitness with both R-sq and R-sq (adj) values above 80%. The results of confirmation experiments show that the predicted model is highly adequate and there exists only an average prediction error of approximately 2%.

Mechanical Behaviour of Glass Fiber Reinforced Epoxy Composite Material

Mechanical Behaviour of Glass Fiber Reinforced Epoxy Composite Material

Failure mode analysis of ramie fiber reinforced composite material

This study aims to determine the failure mode of ramie fiber reinforced epoxy composite materials (RFRECM). The method used is testing the composite test sample that includes tensile test according to ASTM D 3039/D3039M, compression test according to ASTM D 695, simulation by using computer software, and morphology analysis by using Scanning Electron Microscope (SEM). The results show that RFRECM has SR ≥1 for failure criteria derived from stress theory, strain theory, and Tsai-Wu criteria, while having SR <1 only for the criteria of Tsai-Hill. Theoretically, the epoxy flax fiber composite has good strength in fiber or longitudinal direction (00) and decreases with the addition of the angle of the fiber. The failure mode of RFRECM is caused by voids, initial cracks, delimination and debonding occurring between 5-10% of the total area observed in the test sample. This condition can occur in all test samples as a result of imperfections of the fabrication process.

Optimization of Solid Particle Erosion by ZrN Coating Applied Fiber Reinforced Composites by Taguchi Method

In this study, ZrN coatings are applied on glass and carbon fiber reinforced epoxy composite materials by magnetron sputtering method to gain an improved understanding of the solid particle erosion (SPE) wear resistance. The tests were carried out by selecting two different impact velocities (34, 53 m/s), four different impingement angles (30°, 45°, 60°, 90°) and two different abrasive (SiO2) particle sizes (approximate 250, 500 m). The thickness of ZrN coating material was 0.15 m. Protective coatings produced by using Physical Vapor Deposition (PVD) method can increase the life time of the components. All test specimens regardless of their various parameter properties exhibit maximum erosion rates at 45 impingement angle and thus exhibiting similar behavior as that observed for semi ductile materials. Optic microscopic views were performed on the surfaces in order to characterize the erosion mechanism. The erodent particles of the both coating layer and composite matrix were found of main role in governing the wear progression. The measured erosion rates were sensitively correlated with the material removal process in order to explain the changes within the coated interfaces. Moreover, an erosion test facility at room temperature and Taguchi’s orthogonal arrays were used for experimentation. The expression derived from the results of Taguchi experimental design is proposed as a predictive equation for estimation of erosion rate of these composites. It is demonstrated that the predicted results from this equation are consistent with the experimental observations. Finally, an optimal parameter combination was determined, which led to minimization of erosion rate (ER).

Improvement of the mode I interlaminar fracture toughness of glass fiber/epoxy composites using polystyrene electrospun nanofibres

In this paper, the polystyrene nanofiber (PSnF) with diameter in range 40–80 nm were fabricated using electrospinning technique from solution of polystyrene in toluene and used as an effective filler for glass fiber reinforced epoxy composite materials (GF/EP) with contents in range from 0 to 0.1 wt%. GF/EP composites with absence and presence of PSnF were characterized by different techniques, namely; mode I interlaminar fracture toughness, tensile testing and scanning electron microscope. The bonding between GF and EP were also accessed by interfacial shear strength test (IFSS). The obtained results indicated that at 0.07 wt% of PSnF incorporation in epoxy matrix the stress intensity factor (KIC), initiation and propagation interlaminar fracture toughness in mode I were improved by 42.2% from 0.631 to 0.839 MPa m1/2, and 43% from 389.82 to 512.09 J/m2 and 47% from 401.38 to 545.34 J/m2, respectively, when compared to pristine epoxy resin as well as pristine composite material. The scanning electron microscopy (SEM) observation pointed out that fibers pull out during initiation delamination accounting for fracture toughness improvement the fracture surface of GF/EP.

Experimental investigation of fracture toughness for treated sisal epoxy composite

The aim of this work is to show the fracture toughness behavior of sisal reinforced epoxy composite using fracture toughness testing method by including most important fracture mechanics parameters which is called stress intensity factor K. The fracture toughness tests of chopped sisal fiber reinforced epoxy composite materials were carried out using test samples which were prepared according to the ASTM standard. The samples have been fabricated by using the epoxy resin (AY-105) as a matrix and the hardener (HY-951) and the chopped sisal fiber as a reinforcement material with the 15%, 25%, 30%, 35% and 40% fiber weight fraction, random oriented chopped fibers by using hand layup fabrication technique. The experimental results justify that the 30/70 composition of fiber and matrix has superior fracture characteristics with KIC of 5.54 MPa·m1/2 and critical strain energy release rate (GIC) of 13.72 MPa·mm and results of this study indicate that using chopped sisal fibers as reinforcement in polymer matrix could successfully develop a composite material in terms of high strength and rigidity for light weight material.

Mathematical modelling of water absorption behavior of bagasse fiber reinforced epoxy composite material

Natural fibers reinforced polymeric materials have drawn a considerable attention to academicians and researchers over last two decades. The environmental friendly nature, low cost and sustainability of these natural fibers are the main advantages. Among all advantages one issue that needs to be addressed is the hydrophilic tendency of these fibers which is highly undesirable and ultimately leads to the degradation of properties of these fiber reinforced polymer composites. The major cause of hydrophilic tendency is the presence of voids and non crystalline part of these fibers which affects the fiber and polymer matrix adhesion too. Therefore in order to maximize the potential of these natural fiber reinforced polymer composites, this issue should be overcome, therefore it is important to develop the proper mechanism and understanding the water or moisture absorption behavior of these composites. In the present work 1% sodium hydroxide followed by 1% acrylic acid is used for the treatment of bagasse fibers at room temperature in order to improve the bonding strength between the fiber-polymer and to suppress the water absorption. Mathematical investigation of water absorption behavior of Bagasse fiber reinforced epoxy composites at different fiber loadings (5%, 10%, 15%, and 20%) has been done and mechanism of kinetic behavior of water absorption is established.

Directional diffusion of moisture into unidirectional carbon fiber/epoxy Composites: Experiments and modeling

Water diffusion into composites in different directions was examined in this study with the aim of determining the best way of measuring diffusion coefficients and to provide values to compare with model predictions. Water absorption behavior of unreinforced epoxy resins and carbon fiber reinforced epoxy composite materials was investigated with long‐term exposure to different environmental conditions. Initial Fickian absorption was observed followed by a slower second stage that continues for at least 3.7 years. Fiber architecture was found to be an important aspect of controlling absorption, where water diffusion along fibers was observed to be about three times faster than across the fibers and about seven times faster than through the thickness. A three‐dimensional finite element computer model based on Fickian diffusion behavior was developed to predict the levels of moisture absorption under hot/humid environments. A multi‐scale modeling approach was used which allowed the results of simulations at the micro‐structural level to be used to predict the diffusivity in different directions. The modeled diffusion coefficients showed high dependency on the detailed micro‐structure. Experimental results provided a baseline for the validation of the model, and it was found that these data could be closely predicted using a reasonable micro‐structure characterization. POLYM. COMPOS., 39:E2305–E2315, 2018. © 2017 Society of Plastics Engineers

Numerical and experimental investigation of residual strength of a LVI damaged CFRP omega stiffened panel with a cut-out

The fibre-reinforced epoxy composite materials, thanks to their high specific strength, have found many applications in the last decades, especially in the transportation field. However, even though this great advantage allows having a lightweight and strong structure, their application is limited by many critical aspects. Some of these depend on the fact that the composite materials are prone to a large range of defects and damages if subjected to some types of loads. Such defects and damages can be very critical for composites structures, because they may be invisible and cause a significant decrease of the residual strength. In these circumstances, if a structure is not designed under a damage tolerance philosophy it might fail under an unexpected load value, also because the presence of defects can promote the arising of unexpected instability phenomena, as for example buckling under compressive loads. For this reason, one of the most critical aspects to consider during a design process is the structural behaviour of a component under compression load. In fact, fibre and matrix failures and delaminations could reduce the residual strength of a structural component and decrease the buckling load limit. So, defects and damages which could be due either to a critical phenomenon that has previously affected the structure, such as a Low Velocity Impact (LVI), or due to voids and defects caused by manufacturing and production processes, have to be taken into account during the design process. In particular, among different defects and damages, which can affect a composite material, both delamination and fibre failures are the most dangerous. In order to assess the residual strength of damaged composite structures, compression tests are usually performed on such structures. For example, compressive tests are experimentally carried out on damaged structural components, which have been affected to an LVI in a previous phase. With the aim of studying and better understanding the structural behaviour of composites panel under compressive loads, some experimental tests and the respective numerical simulations, based on finite elements theory, have been performed and presented in the paper. The compressive test is numerically reproduced by using the finite element code Abaqus®, which, thanks to its implemented algorithms, has allowed considering different failure modes. Moreover, the progressive damage of fibre reinforced composites has been modelled by using Hashin's criteria which allowed considering two different laws for damage initiation and propagation. In particular, the paper deals with structural behaviour of both undamaged and damaged aircraft panels, with omega stiffeners, made of fibre-reinforced composite materials subjected to static compression tests. A comparison between the structural behaviours of both types of panels has been performed and presented in the paper. Moreover, with numerical model validation purpose, also a correlation between numerical and experimental results has been performed and shown in the paper.

Heterogeneous Surface Wear Models for the Prediction of the Specific Wear Rate of Woven Carbon Fibre Reinforced Epoxy Composites

Heterogeneous surface wear (HSW) models have been derived to predict the specific wear rates of woven carbon fibre reinforced epoxy composite materials. The specific wear rates of unidirectional carbon fibre/epoxy composites, with fibres orientated both parallel and antiparallel to the direction of sliding, are used as input variables. The first model (EW mode) is based on an assumption of uniform thickness reduction during wear, but uneven surface pressure. The second model (EP mode) is based on an assumption of even surface pressure throughout the test. The specific wear rates of plain and 5HS woven composite panels were measured to validate the accuracy of the models. It was found that the EW model was able to accurately predict the specific wear rates of the two types of woven composites under mild abrasive conditions (120 grit sandpaper). However, under more severe abrasive conditions (36 grit sandpaper), the woven panels exhibited a new wear mechanism caused by tearing of the out-of-plane fibres at the crossover points of warp and weft fibres. This mechanism caused both models to under-predict the specific wear rates of the woven composites in severe abrasive conditions. However, the EW model can be used with confidence under less abrasive conditions, where the asperities do not have significant interactions with the out of plane fibres.

Tensile Strength of Banana Fiber Reinforced Epoxy Composites Materials

Indonesia is one of countries with the potential for abundant natural resources, especially natural fibers. The potential of Indonesian natural fibers abundant is not fully put to good use to increase social welfare. One of the natural fibers that have the potential to be developed is the banana fiber. Banana fiber has potential in abundance and can be developed as a biocomposite material that is strong, inexpensive, environmentally friendly, and can be recycled. This study aims to produce a tensile strength of Banana Fiber Reinforced Epoxy Composite Materials (BFRECM). Testing of the tensile strength refers to the ASTM D 3039 / D3039M. Based on the research results, obtained the tensile strength of BFRECM (62.3 ± 0.67) MPa and modulus of elasticity (8.72 ± 1.12) GPa. Tensile strength obtained will be referred for further study of natural fiber composites.

Drilling delamination and thermal damage of carbon nanotube/carbon fiber reinforced epoxy composites processed by microwave curing

The drilling-induced delamination and thermal damage of carbon fiber reinforced epoxy composite materials are serious problems especially for high value components of the aviation industry. To suppress the delamination and drilling ablation, an innovative approach was employed in this study. The multiwalled carbon nanotubes (MWCNTs) were introduced to the matrix resin to improve the interlaminar strength and thermal conductivity. The as-prepared composite was processed by microwave curing to enhance the interface strength between carbon fiber and the carbon nanotubes modified matrix. During the drilling processes, optical fiber Bragg grating sensors were utilized to precisely measure the drilling temperature. Experimental results indicated that the interlaminar fracture toughness was increased by more than 66% compared to that of the traditional thermal cured samples without MWCNTs. And the delamination factor was decreased by 16% according to the computerized tomography scanning results. The maximum drilling temperature of the MWCNTs reinforced composite was below the glass transition temperature of the matrix resin and declined by 23°C compared to traditional composites. With this novel method of carbon nanotube modification and microwave curing, we provide the capability of reducing the drilling delamination and thermal damage of carbon fiber composites simultaneously, and explored the possibility of manufacturing and machining integration.

Experimental Investigation and FE Analysis of CFRP Composites

Composites are one of the most advanced and adaptable engineering materials. The strength of any composite depends upon volume/weight fraction of reinforcement, L/D ratio of fibers, orientation angles and other factors like curing temperature etc. The present work focuses on mechanical properties of carbon fiber reinforced epoxy composite material. Tensile testing of specimens are prepared and tested according to ASTM 3039. Composite properties like Young's modulus (E1), transverse modulus (E2), poisons ratio (υ12), failure stress (σ1) and strain (ɛ1). The experiment is conducted on Computer controlled Universal testing machine with proper mounting of strain gauges and extension meters. Mechanical properties obtained from these samples are input to the FEM model to find the stress and strain distribution in each layer and at interface. Finally the numerical results are compared with experimental results. The variation between Experimental results and numerical results is less than 5%.