Use Of Carbon Fiber Research Articles

Development and material properties of reinforced plywood using carbon fiber and waste rubber powder

This article reports on the use of carbon fiber (CF) and waste rubber (WR) as reinforcing agents for plywood. The aim of this study was to determine the effects of three variable parameters: CF content, WR content, and CF length, on the mechanical and physical properties of the plywood. The properties evaluated were mechanical properties in terms of modulus of rupture (MOR), modulus of elasticity (MOE), and impact strength (IS), and physical properties including water absorption (WA) and thickness swelling (TS). Beech (Fagus orientalis) veneers having 1.8‐mm thickness were used in the production of 7‐ply plywoods. The CF and WR layers were used in the middle (core) layer of plywood samples. Bonding of the wood layers was done using urea‐formaldehyde resin (160 g/m2), and to form the CF and WR layers and bond them to wood veneers, methylene diphenyl isocyanate resin (150 g/m2) were used. Based on the results, the CF was found to have significant effect on the mechanical properties at 99% confidence level. In addition, both the mechanical and physical performances of plywoods improved with increase in the CF content and length. At a certain amount of the CF, the panels with longer (18 cm) CF showed superior mechanical properties. As it expected, the MOR values considerably reduced with the addition of WR, while the MOE, IS, WA, and TS of the specimens improved when compared with the control. The IS of the samples increased as much as 32.5% with the addition of 30 wt% of the WR. POLYM. COMPOS., 39:675–680, 2018. © 2016 Society of Plastics Engineers

Experimental analysis of reinforced concrete beams strengthened in bending with carbon fiber reinforced polymer

The use of carbon fiber reinforced polymer (CFRP) has been widely used for the reinforcement of concrete structures due to its practicality and versatility in application, low weight, high tensile strength and corrosion resistance. Some construction companies use CFRP in flexural strengthening of reinforced concrete beams, but without anchor systems. Therefore, the aim of this study is analyze, through an experimental program, the structural behavior of reinforced concrete beams flexural strengthened by CFRP without anchor fibers, varying steel reinforcement and the amount of carbon fibers reinforcement layers. Thus, two groups of reinforced concrete beams were produced with the same geometric feature but with different steel reinforcement. Each group had five beams: one that is not reinforced with CFRP (reference) and other reinforced with two, three, four and five layers of carbon fibers. Beams were designed using a computational routine developed in MAPLE software and subsequently tested in 4-point points flexural test up to collapse. Experimental tests have confirmed the effectiveness of the reinforcement, ratifying that beams collapse at higher loads and lower deformation as the amount of fibers in the reinforcing layers increased. However, the increase in the number of layers did not provide a significant increase in the performance of strengthened beams, indicating that it was not possible to take full advantage of strengthening applied due to the occurrence of premature failure mode in the strengthened beams for pullout of the cover that could have been avoided through the use of a suitable anchoring system for CFRP.

High Precision Coulometry of Commercial PAN-Based Carbon Fibers as Electrodes in Structural Batteries

Carbon fibers have the combined mechanical and electrochemical properties needed to make them particularly well suited for usage as electrodes in a structural lithium-ion battery, a material that simultaneously works as a battery and a structural composite. Presented in this paper is an evaluation of commercial polyacrylonitrile-based carbon fibers in terms of capacity and coulombic efficiency, as well as a microstructural and surface evaluation. Some polyacrylonitrile based carbon fibers intercalate lithium ions, resulting in a similar capacity as state-of-the-art graphite based electrodes, presently the most commonly used negative electrode material. Using high precision coulometry, we found a capacity of around 250–350 mAh/g and a very high coulombic efficiency of over 99.9% after ten cycles, which is even higher than a commercial state-of-the art graphitic electrode evaluated as reference. The high coulombic efficiency is attributed to the very low surface area of the carbon fibers, resulting in a small and stable solid-electrolyte interface layer. A highly graphitized ultra high modulus carbon fiber was evaluated as well and, compared to the other fibers, less lithium was inserted (corresponding to approximately 150 mAh/g). We show that the use of carbon fibers as an electrode material in a structural composite battery is indeed viable.

Mechanical behavior of fiber/matrix interfaces in CFRP sheets subjected to plastic deformation

The use of Carbon Fiber Reinforced Plastic (CFRP) is increasing markedly, partially in the aviation industry, but it has been considered that CFRP sheets cannot be formed by press-forming techniques owing to the low ductility of CFRP. Since the mechanical characteristics of CFRP are dominated by the microscale structure, it is possible to improve its formability by optimizing the material structure. Therefore, to improve the formability, the interaction between the carbon fibers and the matrix must be clarified. In this study, microscale analyses were conducted by a finite-element model with cohesive zone elements.

CFRTP直接通電抵抗加熱溶着の接合強度に及ぼす炭素繊維表面へのCNT析出の影響

The use of Carbon Fiber Reinforced Thermoplastics (CFRTP) is expected to achieve lightening in mass-produced products. Although composite materials have the advantage that the complex structure can be integrated when being molded, many joints exist for real products. We have been developing a new welding technology in which carbon fiber itself was used for the heating elements, however further improvement of bonding strength is needed. Grafting carbon nanotubes (CNT) on the surface of carbon fibers was reported to improve the fiber matrix interfacial properties. In this study, CNT grafted carbon fibers were used for the heating element of resistant welding, and the effect of carbon nanotube grafting on resistance welded strength of CFRTP was discussed. Welded properties of CFRTP were evaluated by the tensile shear test and the higher welded strength by using carbon nanotube grafted carbon fibers was obtained.

Use of CFRP to Maintain Composite Action for Continuous Steel–Concrete Composite Girders

AbstractThe loss of composite action at the negative moment region for a continuous composite girder reduces the girder’s strength and stiffness. This paper presents an experimental investigation into the use of carbon fiber–reinforced polymer (CFRP) to maintain the composite action at the negative moment region of continuous composite girders. This is achieved by bonding CFRP sheets to the top of a concrete slab at the negative moment region. Six two-span continuous composite girders were tested. CFRP sheet thickness was varied to assess its effect on girder behavior. The girders were designed to have full composite action between the concrete slab and the steel girder. Moment capacity at the positive and negative moment regions was evaluated experimentally and theoretically. A plastic analysis was conducted to evaluate the ultimate capacity of the girders. Finite-element modeling evaluated girder performance numerically. The experimental results confirmed the effectiveness of CFRP sheets in maintaining ...

APPLICATION AS AN EXTERNAL CARBON FIBER REINFORCEMENT FOR INCREASE CAPACITY CONCRETE SPAN RAILWAY BRIDGES

Purpose. The study of the effectiveness of carbon fiber as an external reinforcement to enhance the capacity of reinforced concrete spans railway bridges that are in operation for a long time. Methodology. To achieve this goal fulfilled determining carrying capacity of reinforced concrete spans railway bridges by classification. To increase derived classes as external reinforcement used carbon fiber and made UAH. Findings. As a result of the study received classes of reinforced concrete spans railway bridges after amplification of carbon fiber and established the effectiveness of the reinforcement. Originality. Obtained in the results reflect the effectiveness of the carbon fiber reinforcement for reinforced concrete spans of railway bridges and engineering structures, operating under conditions of variable loads. Practical value. The issues discussed in the article, allow more effective use of carbon fiber to strengthen spans railway bridges in the performance of major repairs or reconstruction and thus enhance the capacity of structures that are in use for a long time.

Comparison of experimental and modeling results for cure induced curvature of a carbon fiber laminate

The use of carbon fiber laminated structures has steadily grown in industrial use during recent decades where the part performance is a function of both the manufacturing process and the underlying constitutive materials. This work presents an approach to predict the part geometry and internal stress state from experimentally characterized constitutive properties due to the manufacturing cure cycle. Our predicted results for the internal stress state are in agreement with that of previous published works, and the predicted part deformations agree with the experimental results for both of the fiber packing densities investigated. The uniqueness of this work is in the aspect of using basic micromechanical models to determine the dependence of the lamina behavior on the structural and thermal constitutive properties of an individual fiber and the surrounding polymer matrix. A full three‐dimensional (3D) FEA model is constructed with spatially varying properties obtained from the predicted lamina properties. The study models the cooling aspect of part fabrication after cure has been completed and the furnace temperature has dropped below the polymer's glass transition temperature. A discussion is provided at the end for the limitations of the approach and also where additional work would be needed to extend this approach to a physical system that does not follow the epoxy system investigated. POLYM. COMPOS., 38:2488–2500, 2017. © 2015 Society of Plastics Engineers

Wybrane zagadnienia z badań nad zastosowaniem włókien węglowych jako elektrod narzędziowych w mikroobróbce elektroerozyjnej

Wybrane zagadnienia z badań nad zastosowaniem włókien węglowych jako elektrod narzędziowych w mikroobróbce elektroerozyjnej

Fundamental Study of Deicing Pavement System Using Conductive Materials

PURPOSES : The purpose of this study is to develop a deicing pavement system using carbon fiber or graphite with high electrical conductivity and thermal conductivity. METHODS: Based on literature reviews, in general, conventional concrete does not exhibit electrical and thermal conductivity. In order to achieve a new physical property, experiments were conducted by adding graphite and carbon fiber to a mortar specimen. RESULTS: The result of the laboratory experiment indicates that the addition of graphite can significantly reduce the compressive strength and improve the thermal conductivity of concrete. In the case of carbon fiber, however, the compressive strength of the concrete is slightly increased, whereas, the thermal conductivity is slightly decreased against the plain mortar irrespective of the length of the carbon fiber. In addition, a mixture of the graphite and carbon fiber can greatly improve the degree of heating test. CONCLUSIONS : Various properties of cement mortar change with the use of carbon fiber or graphite. To enhance the conductivity of concrete for deicing during winter, both carbon fiber and graphite are required to be used simultaneously.

Experimental and Theoretical Analysis of Hollow Steel Columns Strengthening by CFRP

The need for strengthening and retrofitting is well known and extensive research is progressing in this field. The reasons for strengthening and retrofitting are numerous: increased loads, changes in use, deterioration, and so on. In recent years, the use of carbon fiber reinforced polymer (CFRP) for strengthening has shown to be a competitive method, both regarding structural performance, and economical aspects. Extensive research has been carried out in this field. However, most of the research has been undertaken on concrete structures and for confinement, flexural, and shear strengthening. Limited research has been carried out on steel structures strengthened with CFRP. This paper presents axially loaded steel columns strengthened for increased load. The topic is studied theoretically and through laboratory tests. The theory covers analytical methods. Carbon fiber reinforced polymers has been used to strengthen the columns. The tests have been undertaken on full scale specimens, non-strengthened for reference, partially strengthened and fully strengthened

Development of carbon fibre/polyamide 6,6 commingled hybrid yarn for textile-reinforced thermoplastic composites

With increased use of carbon fibre (CF)-based textile-reinforced thermoplastic composites, the demand of hybrid yarns consisting of carbon filament yarns (CFYs) and thermoplastic filament yarns with improved properties is also high. Hybrid yarn manufacturing using commingling process by means of compressed air shows some distinct advantages over other hybrid yarn manufacturing processes. However, the potential of commingling process for the production of CF-based thermoplastic hybrid yarns is not yet fully explored. In this article, extensive investigations have been carried out for the development of commingled hybrid yarns manufactured from CFY and polyamide 6,6 (PA 6,6) filament yarns with improved adhesion properties between CFY and matrix in composites. Hybrid yarns are manufactured by varying air pressure and keeping overfeeds and delivery speed constant. Moreover, an additional heat treatment on CFY is done online for a better opening of CFY prior to the mixing with PA 6,6 filament yarn. The tensile properties of hybrid yarns as well as different mechanical properties of unidirectional composite, such as tensile, flexural, impact and interlaminar shear strength are investigated. The results show good potential for the development of hybrid yarns produced from CFY and thermoplastic filament yarns with improved adhesion properties for their application in textile-reinforced thermoplastic composites.

Effects of cross-linking methods for polyethylene-based carbon fibers: review

In recent decades, there has been an increasing interest in the use of carbon fiber reinforced plastic (CFRP) in aerospace, renewable energy and other industries, due to its low weight and relatively good mechanical properties compared with traditional metals. However, due to the high cost of petroleum-based precursors and their associated processing costs, CF remains a specialty product and as such has been limited to use in high-end aerospace, sporting goods, automotive, and specialist industrial applications. The high cost of CF is a problem in various applications and the use of CFRP has been impeded by the high cost of CF in various applications. This paper presents an overview of research related to the fabrication of low cost CF using polyethylene (PE) control technology, and identifies areas requiring additional research and development. It critically reviews the results of cross-linked PE control technology studies, and the development of promising control technologies, including acid, peroxide, radiation and silane cross-linking methods.

Flexural reinforcement of glulam beams with CFRP plates

In recent years the use of fiber reinforced polymer composites for strengthening and repairing structural elements has significantly increased. This paper shows an experimental study carried out in order to demonstrate the effective use of carbon fiber reinforced polymer (CFRP) plates as flexural reinforcement of glulam beams. Altogether 20 reinforced beams and 8 unreinforced control beams were tested up to failure in a four-point bending configuration. Three different reinforcement schemes were considered. The bending behaviour of beams was analysed through their load–deflection relationship, failure mode, ultimate load capacity, stiffness and strain profile distribution. The addition of CFRP reinforcement to tension zone of glulam beams resulted in improvement in the strength, stiffness as well as ductility. The distance of the CFRP plate from the centre of cross section proved to have a very high impact on the effect of reinforcement.

FABRICATION AND TENSILE PROPERTY ANALYSIS OF A COMPOSITE LAMINATE WITH DIFFERENT DIAMETER HOLES

Composites play a vital role in aerospace, land transportation and consumer goods due to their high specific strength and stiffness leading to reduction in the mass of moving objects. Some of the important aerospace hardware such as rocket motor casing makes extensive use of carbon fiber reinforced polymer(CFRP). In this present investigation E-Glass epoxy laminates were used. The tensile properties for various Diameter holes were determined and compared with the actual strength of the material without any hole. Results indicate that because of the increase in diameter of the hole the tensile strength of the material is decreasing.

Recycling carbon fiber composites using microwave irradiation: Reinforcement study of the recycled fiber in new composites

ABSTRACTWith increasing use of carbon fiber reinforced polymer (CFRP) composites in transportation, sports, and many other industries, recycling of the scrap and end‐of‐life composites has presented both great challenges and opportunities. In this work, we report our study on reclaiming carbon fibers from CFRP using energy efficient microwave irradiation. Different irradiation conditions were used and the optimal conditions were determined based on the surface morphology of the recycled fiber. Polypropylene (PP) and Nylon, representing nonpolar and polar polymers, respectively, were reinforced using the recycled fiber through extrusion and injection molding. For comparison, PP and Nylon reinforced by virgin carbon fiber were also prepared using the same processing conditions. Tensile, flexural, and impact test results showed that, while both carbon fibers could improve these properties, they exhibited different reinforcing effects on the two polymers. The recycled fiber outperformed the virgin fiber in reinforcing PP whereas the virgin fiber performed better in Nylon. This was due to the differences in surface roughness, surface bonding, and fiber aspect ratio between the two fibers. This study shows the great potential of recycled carbon fiber and microwave irradiation as an effective recycling technique. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42658.

A comparative study of a self strain-monitoring carbon nanotube film and carbon fibers under flexural loading by electrical resistance changes

With the increased use of composites for load-carrying structures, the ability to obtain strain and damage information is critical to maintain reliable structures in the field. A promising class of multifunctional composites with the ability to self-sense strain and/or damage is possible through the use of carbon fibers and carbon nanotubes. This paper presents a comparative study of two sensors for fiber-reinforced polymer composites: the sensors are the carbon fibers themselves, and a non-structural carbon nanotube (CNT) film applied through spray deposition. The changes in resistance of the sensors are compared under monotonic and cyclic flexural loading. Within the limits of this study and the current CNT sensor configuration, the carbon fibers are shown to have a higher sensitivity for strain and damage sensing. However, the CNT film appears to track the performance of GFRPs reasonably well for tensile strains.

Mechanical and tribological properties of self-lubricating bio-based carbon-fabric epoxy composites made using liquid composite molding

Polymer composites reinforced with fibrous materials are used in several tribological and mechanical applications. In this study, the effect of carbon fiber as a reinforcement on the mechanical and tribological properties of a bio-based epoxy composite was investigated. The level of cure was investigated using DSC and the tribo-surfaces were studied using SEM micrographs. Use of carbon fibers with epoxy composites expectedly enhanced the bending strength and modulus of the composite. More importantly, the use of carbon fibers improved the tribological properties. Taguchi technique was employed in order to extract the data in a controlled situation in the experiments. Through the regression analysis equations, it was possible to predict the COF and volume loss as a function of these parameters.

Characterization of the major reactions during conversion of lignin to carbon fiber

Lightweight design is an essential part of the overall Volkswagen strategy for reducing the CO2 emissions. The use of carbon fiber offers an enormous lightweight potential. In comparison to steel enabling a mass reduction of up to 70% in automotive parts without a degradation of the functionalities is possible. Today, the use of carbon fiber is limited in mass series applications of the automotive industry by the cost of the conventional C-fiber precursor polyacrylonitrile (PAN). 50% of the cost of a conventional carbon fiber already belongs to the cost of the PAN precursor. Lignin as a precursor for carbon fiber production can realize enormous savings in cost. For qualifying lignin-based carbon fiber for automotive mass production a detailed characterization of this new material is necessary. Therefore, nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy are used. Using the results of these experiments, the major reactions during conversion of lignin to carbon fiber are proposed.

Lignin – an alternative precursor for sustainable and cost-effective automotive carbon fiber

Lightweight design is an essential part of the overall Volkswagen strategy for reducing the CO2 emission. The use of carbon fiber reinforced polymers (CFRP) offers an enormous lightweight potential in comparison to aluminum, enabling a weight reduction, if a load-adapted (unidirectional) CFRP-design is used, of up to 60% in automobile parts without a degradation of the functionalities. Today, the use of CFRP is limited in mass series applications of the automotive industry by the cost of the conventional carbon fiber precursor Poly-Acrylic-Nitrile (PAN). Fifty percent of the cost of a conventional carbon fiber already belongs to the cost of the PAN precursor.The analysis of lignin as an alternative precursor shows clearly a significant reduction in the cost of CFRP and reduction of CO2 emission during carbon fiber production. This fact is essential to make carbon fibers ready for a mainstream use within the automotive industry. Key aspects are: the examination and quantification of lignin as an alternative precursor, the optimization of the manufacturing processes, the characterization and quantification of the properties of the novel carbon fibers within an established material pre-validation process and a final economic efficiency and sustainability analysis.Furthermore, the process ability and demonstrators as well as the suitability for high volume production of the developed processes are main issues for successful implementation in future lightweight vehicle concepts.