Carbon Reinforcement Research Articles

Numerical Study on Coupling Beam Retrofitted Using CFRP and GFRP Sheets

One of the most useful way to resist against earthquake is using coupling beam of steel shear walls. The steel shear wall’s behavior depends on several factors such as stiffness, ductility, strength and so on. But, it has the shear cracks in coupling beam. In this paper, the effect of Carbon Reinforced Fiber Polymer (CFRP) on coupling beams has been evaluated to find out the improvement in ductility, stiffness and its strength. In order to do this research, the commercial edition of ABAQUS software is used. The results show that, using CFRP sheets can improve the load capacity of coupling beams.

Effect of Carbon Forms on Properties of Ag-C Composites Contact Materials

This paper presents the manufacturing method of silver based composite materials containing 3 % vol. carbon forms (nanotubes and graphene). The most significant challenge was to obtain good dispersion of carbon in the metallic matrix. The applying of suitable dispersants allows to get uniform distribution of carbon reinforcement. Triton X-100 and ultrasonic support were used in the powder mixing process. Ag-nanotubes and Ag-graphene contact tips were made using Spark Plasma Sintering process (SPS). The results of research into both physical and electrical properties of these composites are presented. It has been demonstrated that the form of introduced carbon exerts influence on the electrical characteristics of contacts, and particularly on arc erosion. Performed electrical test indicated that Ag-nanotubes contacts showed higher resistance to arc erosion than Ag‑graphene contacts. It can be explained by the better dispersion to individual carbon nanotubes their lower than for graphene edge defects density and due to this higher thermal and electrical conductivity.DOI: http://dx.doi.org/10.5755/j01.ms.24.1.17769

High strength injection molded thermoplastic composites

The use of injection molding to impregnate fabric reinforcements and produce carbon or glass reinforced thermoplastic composites opens the way for high volume mass production at reasonable cost, high strength, and lightweight products. Variable mold temperature together with non‐standard injection parameters allows the proper impregnation of woven carbon and glass reinforcements with standard low viscosity polymers. Testing of the injected composite parts showed a clear increase in mechanical strength. POLYM. ENG. SCI., 58:560–567, 2018. © 2018 Society of Plastics Engineers

Silica coating for interphase bond enhancement of carbon and AR-glass Textile Reinforced Mortar (TRM)

Abstract In this paper, we investigate the effect of silica nano-coating for interphase bond enhancement on the mechanical performance of Textile Reinforced Mortar (TRM) composite materials aimed at structural rehabilitation and strengthening. Alkali-resistant glass (ARG) and carbon fabric reinforcements are preliminarily treated via sol-gel deposition of SiO2 coating to promote bond formation capability with the mortar matrix. Optical and electron microscopy provide evidence of interphase bond enhancement. Mechanical performance is assessed both in traction, through uni-axial elongation of prismatic coupons, and in flexure, by three-point bending of laminated masonry bricks. Results are given in terms of mean strength curves, ultimate and design strength and strain values, cracked and uncracked moduli, mean crack spacing, mean crack width and energy dissipation. It is shown that mean absolute performance of silica coating offers a significant improvement over uncoated fabric, yet it is inferior to that of specimens which have been treated with a liquid partially-organic adhesion promoter (polymer coating). However, when design values are considered which incorporate the dispersion of experimental data, silica coating proves superior or at least equivalent to polymer coating, respectively for carbon and ARG fabric. These promising results describe the first application of silica nano-coating to fabric reinforced composite materials.

Studies on solvent based phenolic pre-pregs with various reinforcements

The Glass, rayon based carbon, PAN based carbon and high silica fabric reinforcements were impregnated with standard resole type phenolic resin in a vertical impregnating plant. The heating zones of prepreg plant converts resin impregnated fabric into partially polymerized state is called B-stage. The required volatile content and chang’s index are achieved by adjusting plant parameter based on online testing of prepreg, and it was noticed resin content varying depend on reinforcement used. The rayon carbon/phenolic prepregs had high wet resin content and glass/phenolic prepregs had low wet resin content

Stress-strain behaviour of pre-stressed slabs of off-shuttering formation reinforced by carbon fiber

The paper presents calculations result of an assembled reinforced concrete hollow core slab of off-shuttering formation which has been reinforced with pre-stressed wire in its top and bottom areas reinforced with carbon fiber, in their turn. The research also examines the existing practice of using carbon fiber as reinforcement elements of reinforced concrete structures, existing specification documents regulating carbon fiber application of carbon in the Russian Federation as well as specification documents containing information about carbon fiber strength and stress-strain properties. The article contains the information on the scheme of loading, conditions of the slab fastening, geometrical characteristics of floor slab panels, physical characteristics of concrete and reinforcement of the experimental sample; technical characteristics of carbon reinforcement elements. The research results are represented as graphs of variance of construction deflections under loading in operating conditions of a slab wIth and without cracks before its reinforcement, and also in the moment of reinforcement. The research shows that using of carbon fiber to reinforce flexural elements with preliminary stress allows to increase rigidity and crack resistance of reinforced concrete elements.

Thermal conductivity of textile reinforcements for composites

Thermal conductivity data for dry carbon fibre fabrics are required for modelling heat transfer during composites manufacturing processes; however, very few published data are available. This article reports in-plane and through-thickness thermal conductivities measured as a function of fibre volume fraction ( Vf) for non-crimp and twill carbon reinforcement fabrics, three-dimensional weaves and reinforcement stacks assembled with one-sided carbon stitch. Composites made from these reinforcements and glass fibre fabrics are also measured. Clear trends are observed and the effects of Vf, de-bulking and vacuum are quantified along with orthotropy ratios. Limited differences between the conductivity of dry glass and carbon fibre fabrics in the through-thickness direction are reported. An unexpected trend in the relationship between that quantity and Vf is explained summarily through simple simulations.

Experimental Analysis for the Effect of Impactor Geometry on Carbon Reinforced Composite Materials

For the last three decades, composites have become very preferable materials to be used in the automotive industry, structural parts of aircraft and military systems and spacecraft, due to their high strength and modulus. Composite materials are sometimes exposed to invisible or visible damage due to impact loading during their service life. In this study, the effect of impactor geometry with four different contact surfaces on woven carbon fibre-reinforced composite plates having three different thicknesses are investigated. In the first stage, composite plates were manufactured with the ply orientations of [45/-45/0/90/45/-45]2s, [45/-45/0/90/45/-45]3s, [45/-45/0/90/45/-45]4s based on conventional usage. In the second stage, carbon fibre-reinforced composite test panels were exposed to low velocity impact tests to obtain force-time, energy-time and force-displacement curves. Finally, semi and full penetration of composite panels and damage magnitude were determined. It was found that the impactor geometries with lower contact surfaces such as conical and ogive types were much more penetrative on composite plates than the other geometries, but they caused larger damage area in the vicinity of the impact point.

Multi-scaled carbon reinforcements in ternary epoxy composite materials: Dispersion and electrical impedance study

The following study, is focused on developing a ternary epoxy based composite material by the combined inclusion of two types of carbon fillers. The selected fillers (i.e. multi-walled carbon nano-tubes, MWCNTs and carbon black, CB), were dispersed using high speed shear mixing while the effect of dispersion duration, filler type and weight contents was studied using Impedance Spectroscopy (IS), fracture toughness tests and Dynamic Mechanical Thermal Analysis (DMTA). SEM was also employed in order to qualitatively assess the dispersion quality by means of mean agglomerate size and identify the fracture mechanisms. IS results indicated an inverse dependence between the magnitude of impedance and the dispersion duration. The decrease of the impedance with increasing dispersion duration was attributed to the formation of the conductive network. The synergistic effect between the two fillers was evident in the more rapid decrease in the maximum imaginary impedance values followed by a concurrent shift of the observed peaks towards higher frequencies with increasing dispersion duration. The synergy of the two fillers was also evident in the superior fracture toughness and thermomechanical performance of the ternary composites. The SEM micrographs revealed that the fracture surfaces of the ternary composites combined all the fracture mechanisms observed on the respective binary composites i.e. particle pull-out, crack bifurcation and pinning. DMTA revealed a significant increase in the storage modulus while glass transition temperature was marginally affected. Overall, the formation of the hybrid conductive network resulted in ternary composite materials with improved electric, mechanical and thermomechanical performance.

Nanostructured Nickel Film Deposition on Carbon Fibers for Improving Reinforcement-matrix Interface in Metal Matrix Composites

The issues in dispersing any form of carbon in metal matrix is the major problem in the field of metal matrix composites with carbon reinforcement (MMCcr). The low wettability of carbon in molten metals and the difference in density are some of the difficulties to obtain a good dispersion of carbon fibers in the matrix and, as a consequence, an improvement of some critical properties for metals in a wide range of application (mechanical properties, electrical properties, optical properties). For this reason, the aim of this work is to obtain a metallic coated carbon fiber to enhance the interaction between the reinforcement and the matrix. Moreover, also the density of carbon fibers could be adjusted depending on the thickness of the coating. Electroless Nickel-Phosphorus Plating (ENP) is one of the candidate to be a coating technique to improve the interaction between the carbon fibers and the metal matrix. Despite of its versatility in terms of complex geometry of the substrate and homogeneity and adhesion of the coating, the presence of the phosphorus in the alloy could create some problems with the metal matrix such as the formation of metal-phosphorus products that can drastically decrease the mechanical properties of the composite. For this reason, in this work, is presented a new way of Electroless Pure Nickel Plating (EPP) without any introduction of phosphorus in the nickel coating. The dependence of the coating thickness and the density of the coated fibers were studied under different plating parameters (temperature of the plating solution, deposition rate and plating solution composition). All the samples were characterized with SEM and XRD and the thickness, density and homogeneity were compared for all the samples obtained.

Effect of temperature on bending behavior of woven fabric-reinforced PPS-based composites

The flexural behavior of two kinds of PPS-based composites (carbon and glass fiber woven fabric reinforcements) from 23 to 200 °C was evaluated in terms of load–displacement curves, stiffness, strength and failure mechanisms. With the increase in temperature, the bending stiffness for carbon and glass fiber-reinforced thermoplastic composites decreased by 36.71 and 34.98%, and bending strength deceased by 68.44 and 61.23%, respectively. The failure mode shifted from a brittle fracture to a ductile manner with the increase in temperature owing to the enhanced plasticization of matrix. Dynamic mechanical analysis was performed to characterize the glass transition and decomposition processes of both PPS-based composites and to establish the relationship between temperature and mechanical properties . Compared with the different empirical models, a new simple and stable thermo-mechanical model was proposed to estimate the variation of flexural properties for both thermoplastic composites with temperature.

Fractographic and three body abrasion behaviour of Al-Garnet-C hybrid chill cast composites

Fractographic and tribological behaviour of hybrid composite of aluminum alloy LM13 matrix with garnet and carbon was investigated. Conventional stir casting technique was used to fabricate the composites with chill cast technique. Various chill materials like Copper, Steel, Iron and Silicon carbide were used to improve the directional solidification. The garnet being added ranges from 3 to 12 wt-% in steps of 3wt-% and constant 3wt-% of carbon. The experiment evaluates the mechanical, fractographic and three body abrasion behaviour of the hybrid composites for various parameters of load, garnet and chills. Microstructural characterization of the composite samples revealed a uniform distribution of reinforcements with minimum clustering. SEM was used for examine worn surfaces. The addition of garnet and carbon reinforcement decreases the wear rate of hybrid composites. Fracture behaviour showed the changes from ductile mode to brittle mode of failure. Further, directional chilling with copper chill improves the wear resistance of the composites.

Grafting of size-controlled graphene oxide sheets onto carbon fiber for reinforcement of carbon fiber/epoxy composite interfacial strength

It is widely accepted that the interfacial properties of carbon fiber (CF) reinforced composites tend to be weak due to the poor wettability and chemically inert surface of CF, which greatly limits the reinforcement effect of CF in composites. Here, size-controllable graphene oxide sheets (GO) were grafted on CF using Poly(oxypropylene) Diamines (D400) as the bridging agent to improve the interfacial properties of CF composites. It was found that the size and content of active functional groups on GO played important roles in controlling the surface morphology of GO grafted CF. Moreover, the interfacial shear strength (IFSS) of the middle sized GO sheets grafted CF/epoxy composites reached a maximum value of 82.2MPa, with an enhancement of 75.6% compared with untreated CF. That is to say, the strong mechanical interlocking between CF and epoxy resin and the improved wettability of resin on CF surface were responsible for the enhancement of IFSS. Instead of decaying of fiber tensile strength after treatment, the tensile strength of GO grafted CF increased from 4.73GPa to 5.02GPa. The reason for the enhancement may be due to that GO bridged the surface defects on CF. This hierarchical reinforcement was believed to have widely potential applications in high performance polymer matrix composites.

APPLICATION OF INNOVATIVE MATERIALS IN PRECAST CONCRETE STRUCTURES

Construction industry contributes essentially to Germany’s gross domestic product (GDP). In 2015 construction investments amounted around 300 billion Euro corresponding to a share of 10% of total GDP. Because of the essential importance of construction industry there are many activities aiming on reduction of construction costs and improvement of durability and sustainability. Recent tendencies in precast concrete industry include application of innovative materials like self-compacting concrete, fiber reinforced concrete, textile reinforced concrete, carbon concrete composite and strain hardening cementitious materials. The report describes the material developments and first applications for precast concrete members. By the application of non-metallic reinforcement, such as carbon meshes and carbon bars, there is no corrosion risk for the reinforcement resulting in an essentially lower concrete cover and depth of structural members. However, the use of carbon reinforcement requires new design concepts and new construction methods. By solving these problems there is a big chance for precast concrete industry to enhance their market share.

Toughening Fe-based Amorphous Coatings by Reinforcement of Amorphous Carbon

Toughening of Fe-based amorphous coatings meanwhile maintaining a good corrosion resistance remains challenging. This work reports a novel approach to improve the toughness of a FeCrMoCBY amorphous coating through in-situ formation of amorphous carbon reinforcement without reducing the corrosion resistance. The Fe-based composite coating was prepared by high velocity oxy-fuel (HVOF) thermal spraying using a pre-mixed Fe-based amorphous/nylon-11 polymer feedstock powders. The nylon-11 powders were in-situ carbonized to amorphous carbon phase during thermal spraying process, which homogeneously distributed in the amorphous matrix leading to significant enhancement of toughness of the coating. The mechanical properties, including hardness, impact resistance, bending and fatigue strength, were extensively studied by using a series of mechanical testing techniques. The results revealed that the composite coating reinforced by amorphous carbon phase exhibited enhanced impact resistance and nearly twice-higher fatigue strength than that of the monolithic amorphous coating. The enhancement of impact toughness and fatigue properties is owed to the dumping effect of the soft amorphous carbon phase, which alleviated stress concentration and decreased crack propagation driving force.

An investigation into the effects of fabric reinforcements in the bonding surface on failure response and transverse impact behavior of adhesively bonded dissimilar joints

Abstract The purpose of the current study is to evaluate the failure response and transverse impact behavior of adhesively bonded dissimilar single-lap composite joints fabricated by using fiber-reinforced polymer. The adherend materials utilized for the experimental tests were AA6082-T6 and glass fiber reinforced polymer (GFRP) in the form of thin sheets. The adhesive used was a warm to hot curing epoxy system (Araldite LY 1564 SP/Aradur 3487 BD) manufactured by Huntsman. In this study, some modifications were provided to enhance the failure response of single-lap composite joints. These modifications comprise the addition of different type and number of fabric reinforcements in the bonding surface. Based upon the test results, an increase of 33.6% in the failure load at room temperature is obtained for the joint fabricated by the addition of double-layer glass fabric reinforcement in the bonding surface. However, the failure load of all types of joint modifications decreases with the increasing tensile test temperature from room temperature to 75 °C. Similarly, tensile tests of the same specimen also resulted in double failure displacement by comparison with the adhesively bonded joint through only epoxy without any fabric reinforcement. The effect of low velocity impact on the failure response of the joints at the impact energy level of 2.5 J is also evaluated. From the tensile tests subsequent to impact treatment, it was found that the transverse impact significantly reduced the failure load of all types of joint modifications. However, the adopted modifications provided tensile failure loads over 1875 N and 1270 N for the joint fabricated by using double-layer carbon and glass fabric reinforcements, respectively.

Mineral-Based Coating of Plasma-Treated Carbon Fibre Rovings for Carbon Concrete Composites with Enhanced Mechanical Performance.

Surfaces of carbon fibre roving were modified by means of a low temperature plasma treatment to improve their bonding with mineral fines; the latter serving as an inorganic fibre coating for the improved mechanical performance of carbon reinforcement in concrete matrices. Variation of the plasma conditions, such as gas composition and treatment time, was accomplished to establish polar groups on the carbon fibres prior to contact with the suspension of mineral particles in water. Subsequently, the rovings were implemented in a fine concrete matrix and their pull-out performance was assessed. Every plasma treatment resulted in increased pull-out forces in comparison to the reference samples without plasma treatment, indicating a better bonding between the mineral coating material and the carbon fibres. Significant differences were found, depending on gas composition and treatment time. Microscopic investigations showed that the samples with the highest pull-out force exhibited carbon fibre surfaces with the largest areas of hydration products grown on them. Additionally, the coating material ingresses into the multifilament roving in these specimens, leading to better force transfer between individual carbon filaments and between the entire roving and surrounding matrix, thus explaining the superior mechanical performance of the specimens containing appropriately plasma-treated carbon roving.

The analysis of the properties of ablative composites with carbon and MMT nanofiller reinforcement

The analysis of the properties of ablative composites with carbon and MMT nanofiller reinforcement

A Review: Fiber Metal Laminates (FML’s) - Manufacturing, Test methods and Numerical modeling

Weight reduction of components is the main aim of different industrial sectors. This leads to increasing application areas of fiber composites for primary structural components. Aiming this objective, a new lightweight Fiber/Metal Laminate (FML) has been developed. Fiber metal laminate is one such material which is being widely investigated for its performance compared to existing material.. The most commercially available fiber metal laminates (FML’s) are ARALL (Aramid Reinforced Aluminium Laminate), based on aramid fibers, GLARE (Glass Reinforced Aluminium Laminate), based on high strength glass fibers and CARALL (Carbon Reinforced Aluminium Laminate), based on carbon fibers. The mechanical properties of FML show advantages over the properties of both aluminium alloys and composite materials individual. This paper reviews relevant literature which deals with different manufacturing techniques for FML’s with excellent properties under tensile, flexure and impact conditions. It also reviewed recent modeling techniques on FML’s. Modeling of tensile, flexure and impacts behavior on fiber metal laminates requires understanding the bonding between the metal and composite layer. Further research is necessary in the assessment of mechanical performance of complex structures in real world conditions.

Microwave Assisted Manufacturing and Repair of Carbon Reinforced Nanocomposites

We report a composite capable of advanced manufacturing and damage repair. Microwave energy is used to induce thermal reversible polymerization of the matrix allowing for microwave assisted composite welding and repair. Composites can be bonded together in just a few minutes through microwave welding. Lap shear testing demonstrates that microwave welded composites exhibit 40% bond strength relative to composites bonded with epoxy resin. Double cantilever beam testing shows 60% recovery in delamination strength after microwave assisted composite repair. The interfacial adhesion and composite repair after microwave exposure are examined by X-ray computed tomography. The microwave processing is shown to be reproducible and consistent. The ability to perform scalable manufacturing is demonstrated by the construction of a large structure from smaller components.