Carbon Fiber Composite Materials Research Articles

Color carbon fiber and its discoloration response

Carbon fibers have been manufactured industrially for several decades and are widely used in the construction of aircraft, racing cars or sports appliances et al. However, carbon fiber showing no response and adaptation to environmental stimulation has prevented the widespread use of this excellent mechanical reinforcement as functional material. Here, we demonstrate that carbon fibers have not only excellent mechanical properties but also intelligent properties with color responsiveness. We coated graphene oxide (GO) on carbon fiber surface, where the two-dimensional GO orderly stack together and self-assemble as a lamellar stacked structure. Such self-assemble GO film exhibits structural color since the stacked structure is analogous to one-dimensional photonic crystals. Specifically, color carbon fiber with GO one-dimensional photonic crystal coating (colored-CF) is realized for the first time by uniformly surface depositing with vacuum filtration method. We further investigated the colored-CF's intelligent color response and associated coloring mechanism, as well as its microstructure, tensile mechanical properties. The results show that GO coating can repair the surface defects of carbon fiber and improve its specific tensile strength and modulus. Moreover, we found that the colored-CF has interesting characteristics of color response under different solvents, temperature and stress. Our approach gives inspiration for a future design of intelligent responsive carbon fiber composite materials.

An innovative fuzzy-inference system for predicting the mechanical behavior of 3D printing thermoset carbon fiber composite materials

An innovative fuzzy-inference system for predicting the mechanical behavior of 3D printing thermoset carbon fiber composite materials

Optimal Material Selection for Manufacturing Prosthetic Foot

The foot is an essential part of the components of the prosthesis. Therefore, the selected materials’ mechanical properties, cost, and weight must be considered when manufacturing the prosthetic foot. This study studied the mechanical properties of selected materials used for prosthetic feet. The material chosen is Carbon Fiber, Glass fiber, and hybrid composite material. This study aims to simulate chosen materials to find the optimal material selection for manufacturing prosthetic feet by assuming boundary conditions, reaction forces, design consideration, and application. The simulation was done by the finite element analysis ANSYS-14.5 program. The result of the force plate test shows the ground reaction force equal to 750N at heel strike,700N at mid-stance, and 650N at the toe-off stage. The finite element result shows the maximum Von-Misses stress equal to 119MPa at the toe-off stage, and the hybrid composite material has the maximum safety factor. Furthermore, the results showed that the mechanical properties of the hybrid composite materials are the best, as the yield stress is 560MPa, the ultimate stress is 678MPa, and the modulus of elasticity is 6.2GPa. The result shows that the Hybrid composite material has excellent improvement in mechanical properties such as lightweight, stiffness, high mechanical properties, and cost-efficiency. Hence by considering the body weight of the amputee, gait cycle, and analyzing the material properties, the hybrid composite material is the best suitable should be selected to manufacture foot prostheses.

Artificial neural network for predicting the mechanical performance of additive manufacturing thermoset carbon fiber composite materials

Abstract Composites have been evolved rapidly due to their unique performance in comparison with other conventional materials, such as metals. Although additive manufacturing (AM) has attracted considerable attention in recent years to produce reinforced complex composite structures as in reinforced carbon fiber composites, it is difficult to control the fiber content concentration within the composites to obtain tailored materials properties, especially at high loads of fibers. In fact, high load of fibers usually leads to technical issues, such as nozzle clogging and fiber agglomeration that hinder the 3D printing process. Therefore, a customized artificial neural network (ANN) system was developed in this work to predict the mechanical characteristics of 3D printing thermoset carbon fiber composites at any carbon fiber concentration. The developed ANN system was consisting of three model techniques for predicting the bending stress as well as the flexural modulus of the thermoset carbon fiber composites, even when handling small experimental datasets. The system architecture contained connected artificial neurons governed by non-linear activation functions to enhance precise predictions. Various schemes of ANN models were utilized namely: 1-4-1, 1-4-8-1, and 1-4-8-12-1 models. The developed models have revealed various accuracy levels. However, the 1-4-8-12-1 model has demonstrated a very high level of predictions for the mechanical performance of the AM epoxy/carbon fiber composites. This would enhance predicting the performance of such composites in 3D printing with very minimal experimental work to optimize the fiber content for the desired overall mechanical performance.

Study of self-healing capability of composite material with phase changing paraffin wax and graphene

The main aim of this research work was to conduct an experimental study of self-healing capability of the composite material by using phase changing material. The phase changing material utilized was “paraffin wax” for healing the material made up of the carbon fiber and epoxy. Three combinations of carbon fiber reinforced epoxy with phase changing materials were prepared i.e., plain carbon fiber epoxy without any phase changing material, carbon fiber epoxy with paraffin wax and carbon fiber epoxy with paraffin wax nano graphene. The fabrication of the carbon fiber composite material inside the capsulation has been done by keeping the 3d model. To identify the structural properties of the material some tests were done i.e., the tensile test and flexural test at normal room temperature and pressure. Damage was produced at the center of each specimen with the help of a Barcol hardness test machine. The Specimens were tested without indentation damage, immediately after indentation damage and after 48 hours of producing damage.

Analytical Model of Piezoresistivity for an Inner-Adhesive-Type Carbon Fibre Reinforced Plastic Tunnel Reinforcement.

Cracks in a tunnel lining often emerge under the coupling action of earth and water pressures in a complex stratum environment, and accidents often occur in the process of repairing cracks. In this study, we used the force-sensitive properties of embedded carbon fibre to conduct early-warning research on lining reinforcement to prevent secondary damage during tunnel lining reinforcement. According to the earth load characteristics, a bond stress–slip model of the embedded carbon fibre under bidirectional earth pressure was established on the basis of the thick-walled cylinder theory and the semi-inverse method in elastic theory. The length change of a single fibre was obtained on the basis of the principle that the volume of a single carbon fibre is constant during the deformation process. The resistance and strain model of the single carbon fibre under the action of an external force was then established following the relationship between the resistance, the length change and the volume change of the single carbon fibre. The resistance of carbon fibre composite materials, according to their production technology and unidirectional force properties, was assumed to be a mixture of the series and parallel resistances of the single carbon fibre, and a piezoresistive model of carbon fibre composite materials was formed by using the multidimensional Taylor series expansion and the idea of the average equivalent. The comparison between the theoretical and monitoring values of the piezoresistive model in a tunnel project in Tibet, China revealed that the resistance of various types of carbon fibres increases with the radius of the lining reinforcement and earth pressure and decreases with an increase in the lining reinforcement thickness. Meanwhile, the angles at different positions of the lining reinforcement also have certain effects on the resistance value of the carbon fibre. The variation curve of the piezoresistive model was exponential in both deeply and shallowly buried tunnels, which verifies the rationality of the model.

Comparative study of the mechanical properties of carbon fiber composite materials for the development of aeronautical structural elements

Comparative study of the mechanical properties of carbon fiber composite materials for the development of aeronautical structural elements

Experimental investigation of aluminum nitride/carbon fiber‐modified composite phase change materials for battery thermal management

The phase change material is currently being regarded as an effective cooling media to be applied in the thermal management of lithium batteries-powered vehicles, in which the inorganic hydrate phase change material is desirable and widely investigated due to the high thermal conductivity, latent heat value, and low cost. However, when applied to thermal energy storage applications, supercooling and phase separation are problematic. To effectively circumvent this issue, this work considers utilizing the disodium hydrogen phosphate dodecahydrate as the matrix of the composite phase change material, as the phase transition temperature is suitable for the battery's operating temperature range. Meanwhile, the nucleating agent sodium metasilicate nonahydrate with similar lattice parameters and the thickener carboxymethyl cellulose are used to suppress the supercooling and eliminate the phase separation, respectively. Effects of nucleating agent, surface modified aluminum nitride, and short-cut carbon fiber on the supercooling degree, and thermal conductivity and curing performance in the phase change material are evaluated and discussed in detail to determine the optimal preparation scheme for Na2HPO4·12H2O/modified AlN/CF inorganic composite phase change materials. Experimental results show that the addition of 4 wt% Na2SiO3·9H2O, 4 wt% CMC, 12 wt% modified AlN, and 6 wt% CF reduces the supercooling degree of the composite phase change material to 1.9°C and increases the thermal conductivity to 1.86 W/(m·K). The composite phase change material is found to have a suitable phase change temperature (35°C), high latent heat (249 J/g), excellent shaping effect, and electrical safety performance. In addition, the composite phase change material battery module can effectively control the battery's temperature, with the maximum temperature reduced by 40.9°C at 3C discharge rate and 30°C ambient temperature compared with the natural cooling battery module. The maximum temperature difference of the composite phase change material battery module is shown to be reduced to the minimum value of 0.9°C. Highlights A novel disodium hydrogen phosphate dodecahydrate—modified aluminum nitride—carbon fiber composite phase change material is designed and prepared for battery thermal management systems. The antiwater modification scheme of AlN is proposed and assessed. The effects of AlN before and after modification on the thermal properties of CPCM are compared. The joint use of nucleating agent sodium metasilicate nonahydrate and thermal conductive filler AlN contributes to significantly inhibiting the supercooling of hydrate salt. The addition of CF can effectively increase the thermal conductivity of CPCM and prevent its leakage. CPCM has suitable phase change temperature, high thermal conductivity and latent heat value, excellent electrical safety, and stable curing performance. The battery test bench is constructed and the discharge test of the CPCM battery module is carried out. The results show that the CPCM battery module has excellent cooling performance and temperature uniformity.

Defect imaging in carbon fiber composites by acoustic shearography

Carbon fiber reinforced polymer (CFRP) composites are increasingly used in aerospace, automobile, marine and power industries due to its good mechanical strength and low material density. The defect detection in CFRP has been challenging because of their complex material configuration and various types of defects. In this paper, we reported the use of acoustic shearography imaging for defect detection in carbon fiber composite materials. CFRP specimens with different levels of defects were prepared by open-hole compression tests according to ASTM standard. These specimens were subsequently tested with acoustic shearography imaging method. It is found that acoustic shearography can successfully image various defects efficiently. By synchronizing the stroboscopic laser with the ultrasonic wave frequency, the defect imaging quality can be significantly improved. Comparison with X-ray computed tomography results shows that acoustic shearography can provide sufficiently good defect imaging results with significantly reduced imaging time.

Characterizing Carbon Fiber Conductivity for Structural Antenna Applications

This study explores the potential applications of carbon fiber composite material for structural antennas. Carbon fiber composite materials provide excellent specific strength and stiffness, however, their electrical properties such as conductivity are not well established, especially in the very high frequency range. Knowledge of a material’s conductivity is required for electrical performance estimation through simulations. Through combined experimental and simulated analysis of multiple carbon fiber antennas, the effective conductivity for a biaxial weave carbon fiber composite was determined to be between 7,000-13,000 S/m in the very high frequency spectrum. Carbon fiber antenna performance is found to be particularly sensitive to the contact between the carbon fibers and the copper feed; however, radiation efficiencies of carbon fiber composite antennas are found to be within 2-10% of a geometrically identical copper antenna, and their bandwidths are nearly identical. The electrical performance of carbon fiber composite antennas demonstrates significant promise for structural antenna applications in the very high frequency range.

Retracted] Preparation and Performance Study of Carbon Fiber Composite Electroplated Carbon Badminton Racket

Driven by the slogan of “Fitness for All”, more and more people are participating in sports, which also promotes the popularity of the sports equipment market, of which badminton rackets are an important part. With the improvement of people’s economic level, there are higher requirements for the materials of various sports equipment. It is expected that badminton rackets will not only be light, but also bearable, and the electroplated carbon in carbon fiber composites has such properties. Therefore, the purpose of this paper is to study the preparation of badminton rackets by electroplating carbon with carbon fiber composite materials and to study its performance. In this paper, the properties of carbon fiber composites are tested and analyzed, and the relevant chemical formulas are used to explain them. The experimental results of this paper show that after using the same pressure to conduct experiments on wooden, iron, steel, steel‐aluminum, carbon‐aluminum, and carbon bats, it is found that the bearing capacity of wooden bats is only 28%, the damage degree of badminton racket is 54%, while the bearing capacity of carbon racket is 89%, and the damage degree of badminton racket is 12%. This fully shows that the badminton racket made of electroplated carbon material not only has a much higher bearing capacity than badminton rackets of other materials, but also has a much lower damage degree than badminton rackets of other materials. Therefore, badminton rackets made of electroplated carbon are more durable and more popular.

Study on Lifting Up and Unloading Work Support with Ankle Foot Orthotics Using Carbon Fiber Composite Material

To prevent back pain during load lifting, assist suits have been developed to reduce physical load by assisting human motion. There are two methods of lifting heavy objects: the stoop method and the squat method. Assistive suits to facilitate the squat method, which reduces the burden on the lower back, have not yet been put to practical use. Therefore, there is a need to develop assistive suits that are lightweight and do not require power. In this study, we developed a short leg orthosis using a leaf spring made of carbon fiber reinforced plastic (CFRP), and conducted lifting and unloading experiments of heavy objects while wearing the orthosis. We then investigated the work support effects of wearing the orthosis based on measurements of lower limb joint power using a three-dimensional motion analysis system and surface electromyography measurements. The results showed that joint angles and power at the ankle and knee joints during lifting was reduced, and joint angles at the ankle and knee joints and power at the knee joint during unloading was reduced by using the orthosis. In both lifting up and unloading, muscle use of the rectus femoris and gastrocnemius muscles decreased, while spinal muscles showed an increasing trend. In addition, muscle synergy analysis revealed two muscle synergies in both lifting up and unloading, indicating that wearing the orthosis reduced lower limb strain during lifting up, and reduced lower back and lower limb strain during unloading and standing up.

STRENGTHENING OF REINFORCED CONCRETE BEAMS IN A DAMAGED BUILDING USING CARBON FIBER MATERIALS

This article discusses modern methods for calculating various methods for checking the bearing capacity of a beam after its strengthening in a multi-story commercial building (on the example of the Al-Salam Commercial complex), located at the address: Iraq, Ramadi, St. Alcinama. The building was damaged by the war, necessitating a study to determine the best and most cost-effective way to strengthen concrete beams using carbon fiber composite materials as the external strengthening. Based on the data obtained as a result of the strength assessment, recommendations were given on the method of strengthening reinforced concrete beams.

Finite element analysis and energy recovery calculation of carbon fiber composite based on ANSYS software.

To study the response under impact load of carbon fiber reinforced composite materials that have excellent mechanical properties. Finite element analysis of unidirectional plates was conducted under unsymmetrical impact load based on drop weight impact test. At the macroscopic scale, a finite element model was built on ANSYS/LS-DYNA, which took the impact response of carbon fiber unidirectional plates as unknown quantity. The model considered the macroscopic response of carbon fiber unidirectional plates under different initial conditions, from the aspects of stress, strain, energy change and deformation degree of unidirectional plates. Finally, a mathematical model of energy recovery of carbon fiber composite materials under partial impact load was established, and the energy recovery amount under different fiber orientations was calculated on MATLAB. The impact energy absorbed by the unidirectional plate is the largest when the fiber orientation is 30°. To improve the impact resistance of unidirectional plates under unsymmetrical impact load, laying schemes should be avoided at fiber orientations of 0°, 15° and 60°, and be recommended at 30°, 45°, and 75°. For impact velocity, 4.71 and 7.54 m/s should be avoided, while 2 m/s is recommended. For the impact weight, 50 and 250 kg weights should be avoided, and 150 and 200 kg weights are recommended. This model not only provides reference for similar impact resistance research, but also predicts the impact response of unidirectional plates under different initial loads in the future. It can also provide reference for the structure using carbon fiber composite materials to achieve lightweight.

Basic guidelines for choosing autoclave curing tool material to make composite parts. CFRP vs INVAR36

The correct selection of a curing tool, to make Carbon Fiber composite (CFRP) parts, is key to the success of a project. The trend in the Aeronautical industry is the reduction of costs and structural weights. The required curing tools are getting bigger and complex, which is a challenge for the manufacturers of the parts and tools. The high temperature autoclave curing cycles present a serious drawback to the use of conventional tooling materials, which has forced the development of molds made of materials with a low coefficient of thermal expansion to solve the problems arising from the different behavior of parts and molds during cycles and to ensure the tight geometric tolerances required. INVAR 36 and CFRP material with high performance resin have become standards for the manufacture of molds. The objective of the study is the comparison of properties and performance of this type of materials, as well as an estimation of the costs associated with each one, with the aim of helping the selection of the most appropriate for use in an industrial environment of high production rates. The method used consisted in the compilation of the technical characteristics of the materials that affect the performance of the tools, as well as the results of research projects and experience of the behavior in service. In addition, a simulation of costs associated with the development, manufacture, putting into production and maintenance of the molds was carried out. The results allow to evaluate qualitatively the performance of the molds manufactured with these materials as well as to have basic guidelines for the correct evaluation of them.

Allowables Evaluation for the Design of a Thermoplastic Fuselage

Carbon fibre reinforced polymers are commonly used in the primary and secondary structures of aircraft, mainly due to their excellent specific mechanical properties. Currently, there is a growing interest in the use of carbon fibre and thermoplastic resin composite materials in aeronautical applications, since they offer multiple advantages compared to thermosetting equivalents. This study presents the results of the mechanical tests carried out at the coupon and element levels for the characterization of the properties of a thermoplastic composite that will form a fuselage panel. In addition to standardized tests, tests are carried out to evaluate the behaviour of critical areas of the panel, such as the radius of the frames, the stringers, and the joint between the frame and the skin around the stringers (mouse-hole). In these latest tests, experimental procedures are developed for their execution, including the design of the necessary tools to reproduce the representative boundary conditions. As a result of this research, the allowables have been obtained for the design of the curved thermoplastic fuselage panel. This work is developed as part of the European project DELTA, within the framework of the Clean Sky 2 JU program. The objective of this project is to develop and execute innovative experimental test procedures that allow the validation of thermoplastic composite aircraft fuselage panels, in order to apply these solutions in medium and long-range aircraft (LPA). The ultimate goal of this project will be achieved through the execution of a curved thermoplastic fuselage panel test under representative load conditions.

Surface Quality in Dry Machining of CFRP Composite/Ti6Al4V Stack Laminate

The present work deals with the effect of drilling parameters on the surface quality of CFRP composite/Ti6Al4V stacks. The assembly of the carbon fiber composite and metallic materials is often carried out by means of the adhesive and autoclave joining. To analyze the effect of the composite/metallic interface on the surface quality, several drilling experiments have been performed for different drilling conditions; spindle speed, feed rate and drilling sequence are particularly investigated. Surface integrity, delamination process and cutting forces were considered as the main output responses to analyze the machining quality. SEM images and 3D topography of the machined surfaces were carried to assess the surface quality of specimens. Thus, this study aims to provide in-depth understanding of drilling and the effect of assembly method on the machinability of CFRP/Ti stacks.

New advanced manufacturing process for rear fuselage sections of highly integrated aerospace structures

CS2-LPA-IADP-WP1.2.5. Advanced Rear End Manufacturing is an European project, inside of the CleanSky2 research program of the European Union Horizon 2020 (Grant Agreement nº 945583). This work package focuses on design, manufacturing and testing of new technologies for the manufacturing of aeronautical structures, integrating different elements, at the rear end of an aircraft. The work presented here shows the manufacturing process developed to obtain a full-scale demonstrator of a rear end section of the fuselage in prepreg carbon fiber composite material, integrating stiffeners, contour frames and skin in one-shot. The omega section stiffeners are made by automatic lay-up and forming, integrate them fresh into the demonstrator. The contour frames are also automatically lay-up and formed, carrying out a semi-curing cycle (for which a manufacturing test campaign has been necessary and different curing degree studies). The integration of these semi-cured frames in the demonstrator combines the advantages of a cobonded integration (without rivets) and the simplification of the tools respect to fresh elementals, since the final thickness has already been consolidated. The automatic lay-up of the skin is carried out on a tool where the fresh stiffeners and the semi-cured frames are located. Finally, the curing cyle is done in the autoclave, obtaining the full-scale highly integrated fuselage demonstrator. All the technologies developed in this demonstrator allow automation within an industrial environment with high production rates. 

Preparation and Properties of Magnetic Carbon Fiber Composite Wave-Absorbing Materials Modified by Carbon/Magnetic Heterogeneous Coating

Preparation and Properties of Magnetic Carbon Fiber Composite Wave-Absorbing Materials Modified by Carbon/Magnetic Heterogeneous Coating

Influence of covalently-bound graphene oxide on the mechanical properties of carbon fiber composite materials

Graphene was used as an additive in fiber-reinforced plastics. The apparent interfacial shear strength (IFSS) was improved by grafting graphene onto the fibers. In this study, the effect of graphene grafted onto carbon fiber via chemical covalent bonding on the mechanical properties of the fibers was evaluated. This method was used to link graphene and carbon fibers via ester linkages, which are stronger than physical adsorption interactions and cause little damage to the fiber strength. Before grafting through an ester linkage, an electrophoretic deposition was conducted to uniformly coat graphene onto the carbon fibers. The purpose of this study was to establish a fabrication method that could control the density and thickness of the graphene layer covalently bound to the fibers. In addition, the optimal production process and composite form of the reinforced fibers were determined by evaluating the fiber strength and IFSS of various graphene-reinforced fibers. Ultimately, it was determined that graphene could be grafted onto carbon fibers relatively uniformly, and that the graphene layer thickness affected their interfacial shear strength. In terms of optimizing the IFSS, a thin and uniform graphene layer was best, and the IFSS was improved by 42.1% compared with untreated fibers containing sizing agents.