Carbon Fibre Reinforced Research Articles

Assessment of two quasi-static approaches to mimic repeated impact response and damage behaviour of CFRP laminates

Full impact damage tolerance assessment requires the ability to properly mimic the repeated impact response and damage behaviour of composite materials using quasi-static approximations. To this aim, this paper reports an experimental investigation evaluating two quasi-static methods for mimicking repeated impact response and damage behaviour of Carbon Fibre Reinforced Polymer (CFRP) composite laminates. In this study, an 8.45-J single impact was repeated 225 times and mimicked with 225 times 6.51-J quasi-static (energy equivalent) indentations and with 225 quasi-static (force equivalent) indentations following the recorded impact peak force variation. Results show that the loading rate and the inertial effect are the two major factors affecting the responses of the composite laminates under out-of-plane concentrated loading. Both the energy- and force-equivalent quasi-static indentations failed to reproduce the impact responses greatly associated with high loading rate and inertial effect. The force-equivalent quasi-static indentations were performed in a semi-automatic way and induced damage states more similar to those of the repeated impacts than those of the energy-equivalent quasi-static indentations, whereas the latter can be better automated and has better reproducibility compared to that of the repeated impact responses, as it is less dependent on high loading rate and inertial effect.

Tensile Response of Fibre-Reinforced Plastics Produced by Additive Manufacturing for Marine Applications

The present study makes a consistent attempt to evaluate promising additive manufacturing (AM) processes and materials for marine structural applications, paving the way for the development of additively manufactured light-weight composites. The main objective is to analyse the structural performances of fibre-reinforced plastics (FRP) produced by AM for marine applications. In particular, the tensile response of chopped and continuous carbon-fibre-reinforced thermoplastics have been investigated through destructive and non-destructive testing, considering the influence of AM process settings and thermal post-manufacturing treatments. The results demonstrate that continuous fibre-reinforced thermoplastics produced by AM are potentially suited to marine structural applications, since their tensile capacity is superior to the minimum imposed by the Classification Society Rules. However, the mechanical properties of additively manufactured FRP are currently lower than conventional composites. The continuous carbon fibre reinforcement is far more effective than the chopped one, and the additive manufacturing deposition pattern significantly influences the structural capacity. The annealing post-manufacturing treatment enhances the mechanical properties by approximately 10%, decreasing material ductility and manufacturing defects.

Investigation of Carbon Fibres Reclamation by Pyrolysis Process for Their Reuse Potential.

During Carbon Fibre Reinforced Polymers (CFRPs) manufacturing, large quantities of scrap are being produced and usually disposed to landfill or incinerated, resulting in a high environmental impact. Furthermore, CFRP parts that have been damaged or reached their end-of-life, follow the same disposal route and because of this, not only the environment is affected, but also high added-value materials, such as carbon fibres (CFs) are lost without further valorisation. Several recycling technologies have been suggested, such as pyrolysis, to retrieve the CF reinforcement from the CFRPs. However, pyrolysis produces CFs that have residual resin and pyrolytic carbon at their surface. In order to retrieve clean long fibres, oxidation treatment in high temperatures is required. The oxidation treatment, however, has a high impact on the mechanical properties of the reclaimed CFs; therefore, an optimised pyrolysis procedure of CFRPs and post-pyrolysis treatment of reclaimed fibres (rCFs) is required. In this study, CFRPs have been subjected to pyrolysis to investigate the reclamation of CF fabrics in their primal form. The temperature of 550 °C was selected as the optimum processing temperature for the investigated composites. A parametric study on the post-pyrolysis treatment was performed in order to remove the residues from the fabrics and at the same time to investigate the CFs reusability, in terms of their mechanical and surface properties.

CARBON FIBRE-REINFORCED PEEK AS BIOMATERIAL IN A ROTATING HINGE KNEE DESIGN: BIOTRIBOLOGICAL TESTING IN COMPARISON WITH RETRIEVAL FINDINGS

Total knee arthroplasty with a rotating hinge knee with carbon-fibre-reinforced (CFR)-PEEK as an alternative bushing material with enhanced creep, wear and fatigue behaviour has been clinically established [1–4]. The objective of our study was to compare results from in vitro biotribological characterisation to ex vivo findings on a retrievals.A modified in vitro wear simulation based on ISO 14243-1 was performed for 5 million cycles on rotating hinge knee (RHK) designs (EnduRo®) out of cobalt-chromium and ZrN-multilayer ceramic coating. The rotational & flexion axles-bushings and the flanges are made of CFR-PEEK with 30% polyacrylonitrile fibre content.Analysis of 12 retrieved EnduRo® RHK systems in cobalt-chromium and ZrN-multilayer in regard to loosening torques, microscopic surface analysis, distinction between different wear modes and classification with a modified HOOD-score has been performed.For the RHK design with the polyethylene gliding surface and bushings and flanges made out of CFR-PEEK, a cumulative volumetric wear was measured to be 12.9±3.95 mm3 in articulation to cobalt-chromium and 1.3±0.21 mm3 to ZrN-multilayer coating - a significant 9.9-fold decrease (p=0.0072).For the CFR-PEEK flexion bushing and flanges the volumetric wear rates were 2.3±0.48 mm3/million cycles (cobalt-chromium) and 0.21±0.02 mm3/million cycles (ZrN-multilayer) (p=0.0016). The 5 million cycles of in vitro wear testing reflect a mean in vivo service life of 2.9 years, which is in accordance to the time in vivo of 12-60 months of the retrieved RHK components [5]. The main wear modes were comparable between retrievals and in vitro specimens, whereby the size of affected area on the retrieved components showed a higher variation.For the EnduRo® RHK design the findings on retrieved implants demonstrate the high suitability of CFR-PEEK as a biomaterial for highly loaded bearings, such as RHK bushings and flanges in articulation to cobalt-chromium and to a ZrN-multilayer coating.

Numerical modeling of mechanical behavior of a reinf orced concrete column-short corbel assembly strengthened by bonding a CFRF

In this study a numerical simulation is developed using finite element (FE) software Abaqus, to assess and simulate the structural behavior of reinforced concrete column - short corbel assembly strengthened by bonding composite materials The objective of the presented simulation is to reproduce the behavior of the considered structure as the displacements, strain, the mode of damages, the cracks propagation, the ultimate force, and the behavior of the main reinforcements, obtained from the experimental study. “Concrete Damage Plasticity” (CDP) has been used for modeling concrete. It combines the damage and the plasticity models and it reproduces failure modes that are based on tensile cracking and compression crushing. The perfectly plastic elastic behavior of steel was introduced in this study. Carbon Fibre Reinforced Fabrics (CFRF) was assumed as a linear elastic orthotropic material. The mechanical behavior of the composite material, in the elastic stage, was defined as “Lamina” and the properties were obtained by the “Rule of mixture”. The “Hashin Damage” failure criteria were also used for composite materials. The surface contact between the concrete and the composite material was developed through the cohesive zone model. The loading of the structure was done by displacement control for all developed models. This allows us to go further and study the influence of various parameters on the behavior such as the number of layers of bonding reinforcement, and the type of composite material. The optimal reinforcement is obtained by the wrapping of three layers of unidirectional carbon fiber fabrics.

Assessment of tensile behaviour of plain weave fabric CFRP composites using acoustic emission technique and deep learning

The applications of Carbon Fibre Reinforced Plastic (CFRP) composites in aerospace applications have increased exponentially in the last decade. CFRP composites are now replacing conventional materials used in high temperature applications. Different types and strategies of reinforcements are used in these composites to improve their applicability to high temperature applications. One of the reinforcement strategies that has been used frequently in the recent years is the plain weave fabric configuration of reinforcing fibres in polymer matrix. A comprehensive damage assessment is essential to evaluate the characteristics of these composites at elevated temperatures. The Acoustic Emission (AE) signals generated during the damage evolution stages are used for studying the damage evolution stages when the plain weave fabric composites are tested at temperatures close to their glass transition state. A new information-theoretic parameter, Lempel-Ziv (LZ) complexity and the deep learning neural network is used for understanding the damage evolution stages. Furthermore, the neural network is used for validating the utilization of LZ complexity as a potential AE parameter for damage classification applications. The results are promising with the damage classification strategy using LZ complexity exhibits an accuracy of 85.1% which is validated through the neural network.

Mechanical properties of carbon fiber reinforced with carbon nanotubes and graphene filled epoxy composites: experimental and numerical investigations

The mechanical properties of carbon fiber-reinforced epoxy composites were identified by adding carbon-based nano-reinforcements, such as multi-wall carbon nanotubes (CNTs) and graphene platelets (GP), into the epoxy matrix by conducting suitable experiments. The main focus of this study is to compare the tensile modulus, tensile strength, flexural modulus, flexural strength, and thermal conductivity of carbon fiber-reinforced epoxy composites with nanoparticle reinforcement. The results revealed that adding CNTs and GP nanoparticles improved the mechanical properties compared to a pure carbon fiber-reinforced plastic composite. However, compared to CNTs, the GP’s addition has increased the mechanical properties of the CFRP composite. In addition, scanning electron microscopy (SEM) images were presented to explore the microstructural characterization of carbon fiber-reinforced nanoparticle-reinforced composites. Further, using numerical studies, the transverse modulus, major and minor Poisson’s ratio of the carbon fibre reinforced with CNT and GP particle reinforcement were estimated. The current study is applied to the efficient design of nanoparticle reinforced carbon fibre reinforced composites.

Rheological Test of Flowability and Diffusion Behavior of Carbon Fibre Reinforced Polyamide

Various materials have been produced to be used as feeder material in 3D printing application to obtain the level of mechanical properties and physical properties of a product. Before to its usage as a 3D printing feed material, polyamide-reinforced carbon fibre composites were investigated for flowability and diffusion behaviour. Using a heated nozzle to transform polymer filament into a semi-liquid that is extruded to create a structure layer-by-layer, the primary issue to prevent is delamination. For the success of this study, there are 2 main methods, namely to study the physical properties of carbon fibre reinforced polyamide composites against the composition of 20 wt.% carbon fibre and to study the temperature and rheological load on the rheological properties. Rheological test analysis found that the material flowability of 20 wt.% CF/PA at temperature parameters 210 °C, 230 °C and 250 °C against rheological loads (40, 60, 80) N recorded a range of viscosity values between 48.80 Pa.s to 97.88 Pa.s and shear rate value range between 19700 s<sup>-1</sup> to 20270 s<sup>-1</sup>. Parameter optimization analysis using Taguchi method found that the largest factor contributing to the viscosity of CF/PA composite feed material was the addition of load applied. Moreover, the microstructural results of CF/PA composites show that smoother surfaces and good polymer structural bonding occur at an extrusion temperature of 250 °C. As a result, the rheology-derived flow rate may be used to tackle the problem of delamination and layer separation in 3D printing.

Influence of the Temperature-Dependent Characteristics of CFRP Mechanical Properties on the Critical Axial Force of Drilling Delamination.

Previous studies have often assumed that the mechanical properties of Carbon Fibre Reinforced Plastics (CFRP) remain unchanged during drilling. In fact, due to the increase in drilling temperature, the mechanical properties of the composites change greatly, and this then affects the critical force. In addition, previous studies have often assumed that the failure mode of CFRP drilling was a type I crack failure. In fact, due to the complexity of the CFRP drilling process, the failure modes are often coupled with different failure modes, so type I cracks alone cannot reflect the actual cracking situation. Therefore, a three-dimensional drilling Finite Element Modeling (FEM) was established to analyze the failure modes of CFRP drilling delamination, and the I/III mode was determined; then, a new drilling critical force mechanics model, which considers the temperature dependence of CFRP mechanical properties and the failure modes of CFRP drilling delamination, was established based on the classical drilling critical force mechanics model; the results of the mechanics model were validated by drilling critical force experiments under different temperatures. The effects of the temperature dependence of CFRP mechanical properties on the drilling critical force were investigated and analyzed.

Rehabilitation of defective connections between two precast concrete segments (experimental and analytical study)

Connections in precast concrete elements are essential for improving the structures' utilization, cost, and quality control. Moment connection in beams was one of the easiest ways to achieve good performance of the structures by eliminating the plastic hinges zone. Due to constructing precast elements, some of them can be defective. This paper presents an experimental and analytical study to rehabilitate defective connections between two precast concrete segments. Six simply supported beams with beam-to-beam connections and one simply supported beam without connections, each with dimensions of 200 × 400 × 1600 mm, were fabricated and loaded to failure with a four-point load. The main variables parameters were a) the type of concrete mix in the splice region, two types of concrete were employed: Normal Strength Concrete (NSC) and High Strength Concrete (HSC) b) effect of rehabilitation techniques with using NSC in the connection zone such as; using warped fiber sheets around splice region or Carbon Fiber Reinforcement Polymer CFRP laminates at the tension surface of the tested beams c) effect of rehabilitation techniques with using HSC in the connection zone. Also, a new model was proposed based on some codes and guidelines of beams strengthened with Externally Bonded FRP Systems to calculate the flexure capacity for rehabilitating the beam-to-beam connections. The results indicate that neither casting NSC nor the HSC at the connection region has any effect on increasing the beam's capacity and cannot be used only as a rehabilitation technique in beam-to-beam connection. The fiber sheet warped around the splice region constructed from either NSC or HSC did not significantly increase the beam's capacity compared to rehabilitated beams with casting concrete only in the connection region. The load capacity of the rehabilitated beam with CFRP laminates and warped fiber sheets is increased significantly by about 122 % and 209 % compared to rehabilitated beams with splice regions constructed from NSC and HSC, respectively. The proposed model based on CNR-DT 200 R1/2013 equation gave a good prediction of the capacity of the rehabilitation connection for rehabilitated beams with CFRP laminates and warped fiber sheets.

Computational Fluid Dynamic Analysis on Carbon Fibre Reinforced Polymer Wrapped on Defected Oil and Gas Piping System Using Solidwork Flow Simulation

Utilising Carbon Fibre Reinforced Polymer (CFRP) as a wrapping structure on defected piping system is not a very new approach in maintaining the defected pipe structure. But simulating the entire approach using computational simulation technique makes this research to be unique. This composite material was regarded as a one-of-a-kind wrapping material since it might have the combined properties of the element or significantly different properties than the constituents individually. Computational Fluid Dynamic (CFD) analysis is needed to make sure that the proposed wrapping structure doesn’t disrupt the fluid flow after the repair is done. The research is keen to fully utilise Solidwork flow simulation in evaluating the capability of proposed CFRP wrapping structure without any leaks or opening. Based on simulated data, this technique provides a preliminary analysis and visual deformations in selecting the suitable optimised lamination orientation of CFRP in real-world applications. Furthermore, the flow simulation study in SolidWorks has identified areas where possible fluid accumulation could occur after the repair has been done. This approach may prevent two primary failure modes by achieving the right lamination orientation and thickness which is CFRP overloading due to excessive thickness and CFRP delamination of the composite laminate from the substrate.

Mineral-impregnated carbon-fiber (MCF) composites made with differently sized fly-ash geopolymers for durable light weight and high temperature applications

For a wide application of carbon-fiber reinforcement in large-scaled, lightweight construction, mineral-impregnated carbon-fiber (MCF) composites provide a promising alternative to rebar or reinforcement made of non-metallic fibers and polymer matrix. The penetration ability of the aluminosilicate particles is a key factor for a stable, reproducible impregnation and the maximal reinforcing efficiency of continuous fiber geopolymer composites.The work at hand focuses on the influence of the particle sizes of geopolymer precursors on the processing quality, microstructural development and final composite performance regarding the flexural, tensile and pullout behavior. Three differently sized fly ash (FA) sources were used to impregnate a carbon fiber heavy tow before curing at 75 °C. FA particles in the same size range as the filament diameter proved to be the most efficient, enhancing both mechanical properties of MCF and its bond to concrete matrix, well beyond the effects induced by other, coarser precursors. The results of the microscopic investigation, μCT, thermal gravimetric analyzes and mercury intrusion porosimetry measurements show that the use of this particle fraction resulted in the best fiber-matrix distribution over the cross-section, densest microstructure and highest fiber volume fraction in the impregnated yarn. Furthermore, the geopolymerization kinetics of all FAs at ambient temperature and at 75 °C were determined by isothermal calorimeter, showing an increase in the reaction rate with elevated curing temperature and higher particle finesse.

Experimental and numerical investigation of 800 MPa HSS welded T-section column strengthened with CFRP

Carbon Fiber Reinforcement Polymer (CFRP) has been widely utilized in repairing and retrofitting engineering. The purpose of this work is to study the buckling behavior of high strength steel (HSS) welded T-section column strengthened with CFRP using experimental and numerical method. The experiment of six specimens of 800 MPa HSS welded T-section column strengthened with CFRP under axial compression is performed. The influences of three main parameters (i.e., the number of CFRP layers, the slenderness of columns, and the width-to-thickness of plates) are observed in this work. All columns fail by the debonding of CFRP layers and the flexural–torsional buckling of specimens. CFRP layer can effectively delay the local buckling of plate or the torsional buckling of specimen. CFRP layer and slenderness has significant influences on the bearing capacity of specimens. The flexural and torsional displacement of columns strengthened with CFRP is much smaller than that of columns without CFRP. A finite element (FE) method for estimating the bearing capacity of HSS welded T-section column strengthened with CFRP is developed using ANSYS software. It is found that the confining effect of CFRP is more effective for stub columns. A more accurate model modified from Cadei et al.’s model for estimating the bearing capacity of 800 MPa HSS welded T-section column strengthened with CFRP under compression is proposed.

Effect of surface profiling on the mechanical properties and bond behaviour of mineral-impregnated, carbon-fibre (MCF) reinforcement based on geopolymer

Mineral-impregnated, carbon-fibre composites (MCF) are a new and promising reinforcement type to become substitutes for conventional steel reinforcements or fibre-reinforced polymers. To enhance this reinforcement’s shape stability and load transfer capability to concrete matrices, a surface profiling of this novel material needs to be developed. To this end the automatic, auxiliary helical winding of a thread was implemented to produce semi-finished MCF based on geopolymer (GP) with defined geometrical features. Subsequently, a rapid solidification process was conducted by means of thermally activated geopolymerization of various durations.The results showed that applied surface profiling densified the matrix microstructure of the MCFs and improved shape stability during processing. However, flexural and tensile properties were slightly negatively impaired due to the stress concentrations induced. Furthermore, curing prolonged from 2 to 8 h enhanced the geopolymerization of the matrix gradually and therewith the mechanical performance of the MCFs in their entirety, as confirmed by morphological investigation. Uniaxial tension tests demonstrated that the strengths of all rod variants were in the same range as that of conventional CFRP. Enhanced bond properties were found for MCF with the profiling technology as developed, enabling defined load-bearing behaviour for subsequent application.

Investigation of cycloaliphatic amine-cured bisphenol-A epoxy resin under quenching treatment and the effect on its carbon fiber composite lamination strength

AbstractThermosetting epoxy resin polymer with cycloaliphatic amines curing agent has been widely used for a composite matrix with carbon fiber reinforcement. The utilization was increased due to the superior performance of this epoxy resin compared to other polymers. However, a changing operational environment has potentially reduced composite performance, which most likely begins with matrix degradation. This research applies thermal treatment by the quenching process sequence to the epoxy resin matrix and its reinforced carbon fiber composite (CFRP). The composite is made by epoxy resin diglycidyl ether bisphenol-A, curing with cycloaliphatic amine as matrix and strengthening carbon fiber mat/woven. Three times quenching treatment was performed by heating the specimen around the glass transition temperature and then dipped immediately in fresh water. After quenching treatment, the epoxy resin shows a reduction in tensile strength and elongation. Under infrared observation, epoxy resin does not significantly show changes in functional groups. Investigation under X-ray refraction also indicates no difference in a crystalline structure; this epoxy resin stays in an amorphous form before and after quenching. In contrast to the matrix, the quenching treatment of the CFRP composite above the epoxy resin s glass transition temperature revealed an increase in the interlaminar shear strength (ILSS). The matrix ductility reduction after quenching should be carefully considered for application in the form of epoxy resin sheets or CFRP composite construction materials.

A Review of Self-Sensing in Carbon Fiber Structural Composite Materials

Sensing is a basic ability of smart structures. Self-sensing involves the structural material sensing itself. No device incorporation is needed, thus resulting in cost reduction, durability enhancement, sensing volume increase and absence of mechanical property diminution. Carbon fiber renders electrical conductivity to a composite material. The effect of strain/damage on the electrical conductivity enables self-sensing. This review addresses self-sensing in structural composite materials that contain carbon fiber reinforcement. The composites include polymer-matrix composites with continuous carbon fiber reinforcement (relevant to aircraft and other lightweight structures) and cement–matrix composites with short carbon fiber reinforcement (relevant to the civil infrastructure). The sensing mechanisms differ for these two types of composite materials, due to the difference in structures, which affects the electrical and electromechanical behaviors. For the polymer–matrix composites with continuous carbon fiber reinforcement, the longitudinal resistivity in the fiber direction decreases upon uniaxial tension, due to the fiber residual compressive stress reduction, while the through-thickness resistivity increases, due to the fiber waviness reduction; upon flexure, the tension surface resistance increases, because of the reduction in the current penetration from the surface, while the compression surface resistance decreases. These strain effects are reversible. The through-thickness resistance, oblique resistance and interlaminar interfacial resistivity increase irreversibly upon fiber fracture, delamination or subtle irreversible change in the microstructure. For the cement–matrix composites with short carbon fiber reinforcement, the resistivity increases upon tension, due to the fiber–matrix interface weakening, and decreases upon compression; upon flexure, the tension surface resistance increases, while the compression surface resistance decreases. Strain and damage cause reversible and irreversible resistance changes, respectively. The incorporation of carbon nanofiber or nanotube to these composites adds to the costs, while the sensing performance is improved marginally, if any. The self-sensing involves resistance or capacitance measurement. Strain and damage cause reversible and irreversible capacitance changes, respectively. The fringing electric field that bows out of the coplanar electrodes serves as a probe, with the capacitance decreased when the fringing field encounters an imperfection. For the cement-based materials, a conductive admixture is not required for capacitance-based self-sensing.

Comparative analysis of methods for calculating the physico-mechanical characteristics of multi-layered composite materials

The paper presents a comparative analysis of methods and results of calculating the physical and mechanical characteristics of single-layered and multi-layered polymer composite materials (PCM). The object of the study is a polymer composite which consists of epoxy binder and carbon fiber reinforcements. The principle of multiscale modelling is applied to determine the physical and mechanical characteristics of the composite. Within the framework of this study, a representative volume element (RVE), the structure of which corresponds the characteristics of real materials, is used. The initial data for the calculation in this case are physical and mechanical characteristics of anisotropic fibers (carbon fabric) and an isotropic binder, as well as the geometric model of the RVE. As a result of the calculation, the effective characteristics of a quasi-homogeneous anisotropic material suitable for numerical analysis of the composite structures are determined. A comparison of the results of determining the physical and mechanical characteristics of the polymer composite using ANSYS Material Designer and MSC Digimat software packages for various size of RVE model is carried out and ANSYS Workbench software is also used to perform the stress-strain conditions of RVE model to determine the physico-mechanical characteristics of polymer composites.

Influence of the carbon fiber reinforcement scheme on the change of physical and mechanical properties under the influence of a microwave electromagnetic field

Influence of the carbon fiber reinforcement scheme on the change of physical and mechanical properties under the influence of a microwave electromagnetic field

Effect of carbon fiber reinforcement on dimensional variations of 3D printed polyamide-6 composites: A simulation study.

Due to material design and fabrication flexibility, additive manufacturing (AM) or 3D printing (3DP) processes and polymer composites have paved their way into several industrial sectors. The quality of 3D printed polymer composites is highly dependent on the reinforcement content of polymers and 3DP process parameters. Several experimental studies are performed to optimize the reinforcement contents and process parameters; however, exploring the numerical modeling and simulation techniques is vital to lower the research and development costs. In the study, the numerical simulations for the 3DP process were performed using Digimat® software for carbon fiber-reinforced polyamide-6 (PA6) composites fabricated via the fused filament fabrication (FFF) process to evaluate the effect of reinforcement content on deflections, warpages, and process-induced residual stresses. The FFF process simulations were performed to fabricate tensile testing coupons with pure PA6 and 10%-28% CF-reinforced PA6 composites. A significant impact of CF-reinforcement was observed on the deflections, warpages, and residual stresses. The maximum displacement of 4.518 mm and critical warpage of 3.012 was observed for pure PA6 material. However, with the addition of CF reinforcement, a maximum deflection of 3.369 mm and critical warpage of 2.246 was achieved for PA6 reinforced with 28% CF (PA6-CF28). The improved 3D printed specimen quality was acquired at the cost of increased residual stresses of 14.53 MPa compared to 11.75 MPa in pure PA6 specimen. The CF reinforcement significantly improved the 3DP manufacturing performance of PA6/CF composites, reducing deflections and warpages.

OPTIMIZATION OF NANO FILLERS CONTENT TO FABRICATE ELECTRICALLY CONDUCTIVE CARBON FIBER REINFORCED POLYMER FOR SPACE USE

Carbon fiber reinforced polymer (CFRP) composites are used in aerospace sector due to their high specific stiffness and light weight, and are a better alternative for aluminum, Invar, and Kovar alloys. However, lower electrical and thermal conductivity of CFRP was the main restriction for extensive use in aerospace sector as compared to aluminum alloys. High aspect ratio, high mechanical stability, high electrical as well as thermal conductivity of carbon nanotubes (CNTs) makes them excellent filler material in CFRP to enhance its electrical, mechanical, and thermal properties. CNTs add synergetic effect to CFRP giving improved CNT-CFRP composites in terms of electrical and mechanical properties. Single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) are used as filler for fabricating conductive CFRP. Selection of type of CNT (SW/MW-CNT), percentage of CNTs to be used as filler, extent of dispersion in thermosetting resin and carbon fiber layers, governs the properties of CNT-CFRP composites. Objective of the current study was to find optimum percentage of SWCNT and MWCNT to get highly electrically conductive CNT-CFRP composites with ease of manufacturing.