Effect Of Carbon Fiber Research Articles

Experimental and numerical analysis on the thermal degradation of reinforced silicone-based composites: Effect of carbon fibres and silicon carbide powder contents

Silicone-based composites material as Thermal Protection System (TPS) found a large use in the aerospace industry to protect wall structures from severe heating (airframe or propulsion parts, including ramjet type). The matrix of the composite material is often reinforced with fillers, such as Carbon Fibres (CFs) and Silicon Carbide Powder (SCP). This formulation aims to improve the thermomechanical properties which leads to significant impact on the thermophysical parameters (λ, ρ, cp). The present work consists of studying the effect of the CFs and SCP contents on the thermophysical properties evolution. For this purpose, three samples of silicone-based composites, referenced as M1, M2 and M3, are prepared by MBDA–France. The difference among the three samples is in the CFs and SCP contents in each sample. Firstly, some experimental studies were conducted to determine the thermophysical properties (λ, ρ, cp) in a temperature range from room temperature to 1000 °C. Dedicated experimental apparatus are used: dilatometry for density measurement, Calvet calorimeter combined with Differential Scanning Calorimetry (DSC) experiments for specific heat capacity determination, and finally laser flash analysis for thermal diffusivity measurement leading to the thermal conductivity calculation. Secondly, the measured thermophysical properties are used in a 1D numerical procedure using Amaryllis modulus of the SAMCEF™ finite element code in order to investigate the thermal efficiency of the materials as TPS. The comparison of the results confirms that the three silicone-based composites, M1, M2, M3, behave as efficient thermal barriers when exposed to severe heat fluxes. The lower the amount of CF, the higher the thermal efficiency. To a lesser extent, an increase in the amount of SCP tends to improve the insulation efficiency.

Effects of short carbon fiber on the macro-properties, mechanical performance and microstructure of SiSiC composite fabricated by selective laser sintering

Selective laser sintering was combined with reactive melt infiltration to fabricate SiSiC part, and the effects of carbon fiber (Cf) on the properties of the SLS green body, the carbonized and final SiSiC sample were investigated. Results show that the addition of an appropriate amount of Cf (1.59 wt%~2.97 wt%) can increase the bulk density and geometric precision of the sample at all stages, and improve the mechanical properties of green and carbonized samples. The main phases composed of the SiSiC composite were free Si, a-SiC, β-SiC, plus a very small amount of Al–Si alloy. With 1.59 wt% Cf addition, a relatively comprehensive favorable macro-properties of both the green sample and carbonized sample was achieved, and the homogeneous microstructure of the latter favored the decreased free Si content and increased β-SiC content of the final composite. The evolution mechanism of Cf added to the raw material is inferred to be the mutual diffusion of [C] and [Si] that occurred at the Cf/Si melt boundary leading to the formation of the siliconized Cf with relatively large diameter size (24.3 μm) and high aspect ratio (>30). Amorphous C, which derived from the pyrolysis of epoxy resin E12, undergone a dissolution-precipitation mechanism with the formation of fine-grain β-SiC.

Laboratory investigations on fracture toughness of asphalt concretes reinforced with carbon and kenaf fibers

This paper investigates the fracture toughness of asphalt concretes reinforced with carbon and kenaf fibers. Pure mode I, pure mode II and mixed mode I/II fracture toughness of reinforced asphalt concretes are measured through SCB (semi-circular bend) tests at a low temperature of −15 °C. Three different lengths (i.e., 4 mm, 8 mm and 12 mm) with three different dosages (i.e., 0.1, 0.2 and 0.3% by mixture weight) of fibers are used to prepare asphalt concretes. Results exhibit that both the carbon and kenaf fibers contribute to the enhancement of the fracture toughness of asphalt concrete, particularly when the proportion of mode I relative to mode II is dominant. However, the effect of carbon fibers is found to be superior to that of the kenaf fibers. Compared to the unreinforced asphalt concretes, the carbon fiber reinforced asphalt concrete shows up to 42% increase in the mode I fracture toughness. Furthermore, as the proportion of shear mode at the crack front of the specimen increases, the positive effect of the carbon and kenaf fibers diminishes. Meanwhile, 8 mm kenaf fibers and 4 mm carbon fibers with the dosages of 0.3% are finally found to be more effective in increasing the fracture toughness of asphalt concrete compared to their counterparts with other lengths and dosages.

Experimental Study on Material Properties of Bearing Bush of Water Lubricated Bearing

Water lubricated bearings are commonly used equipment in ship and other fields. The friction factors and other parameters of bearing materials have great influence on the performance of Water lubricated bearings. In this paper, a comprehensive bearing test platform was established, the slurry wear test of bearing material was carried out on the MPH corrosion wear tester, and the effects of wear time, sliding speed and load on the friction performance of bearing material were obtained. And then the effects of different additives on the optimization and improvement of the wear resistance and friction coefficient of bearing bushes have been systematically analyzed. The results show that the friction coefficient increases when glass fiber is added into PTFE matrix, but the effect of carbon fiber is not significant. The material composed of PTFE matrix and graphite not only improves the wear resistance, but also reduces the friction coefficient. Rigid additives increase the hardness of PTFE matrix, while soft additives decrease the hardness of PTFE matrix. Almost all kinds of additives can reduce the impact strength of PTFE matrix.

Mechanical Properties of Nano SiO2 and Carbon Fiber Reinforced Concrete after Exposure to High Temperatures

This study presents the key mechanical and residual properties after high-temperature of different Nano SiO2 carbon fiber-reinforced concrete (NSCFRC) mixtures. A total of seven NSCFRC mixtures incorporating 0%–0.35% of carbon fiber by volume of concrete and 0%–2% Nano SiO2 by weight of the binder were studied. The key mechanical properties such as compressive strength, tensile strength, and flexural strength of NSCFRC with 0.25% carbon fiber and 1% NS were 6.8%, 20.3%, and 11.7% higher than PC (0% CFs, 0% NS), respectively. Scanning Electron Microscopy (SEM) shows that Nano SiO2 reduced the internal porosity and increased the compactness of the concrete matrix. Furthermore, the experimental result demonstrates that NSCFRC can improve the mechanical properties of concrete after high-temperature and equations were obtained to describe the evolution of residual properties at elevated temperatures. Results suggested that the effect of carbon fibers on the residual properties of concrete after high-temperature is less than steel fiber and polypropylene fiber. It was also indicated that adding appropriate Nano SiO2 to concrete is an effective means to improve the residual performance after high-temperature.

Effect of carbon fibre on reinforcement of thermoplastics using FDM and RSM

Continuous fibre-reinforced composites have significant industrial importance and usage. However, they are limited by design considerations and high-cost manufacturing operations. This article presents a way forward to utilize Fused Deposition Modelling – a 3D printing technique – to manufacture continuous carbon fibre-reinforced thermoplastics. Several parameters including number of reinforced layers, material impact and interlayer gap have been investigated and optimized using response surface method. Successful incorporation of modified novel nozzle design in a dual nozzle setup resulted in the realization of controlled manufacturing of continuously reinforced composites leading to reinforced yet smooth surface finished samples. Several samples were made, and mechanical testing, parameter optimization, strength calculations and fracture analysis were carried out. For polylactic acid (PLA), tensile strength of 112 MPa and flexural strength of 164 MPA were achieved – an almost 3 times increase from pure PLA printing. The approach presented in this article can forward continuous fibre-reinforced composites for industrial usage with its controlled fibre layup and programmable thread orientation features.

Effect of Carbon Fiber Addition on the Microstructure and Wear Resistance of Laser Cladding Composite Coatings

In this study, the effect of carbon fibers (CFs) on the microstructure and wear resistance of Fe-based alloy coating produced by laser cladding was investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and wear tester. The results indicated that with the addition of CFs, the microstructure of the composite coating mainly transformed from α-Fe cellular dendrites and γ-Fe/(Cr, Fe)7C3/CrB eutectics to bulk-like (Cr, Fe)7C3, nano-size B4C, and γ-(Fe, Ni)/(Cr, Fe)23C6 lamellar eutectics. Additionally, the microhardness and wear resistance of the composite coating compared with the original coating both increased by approximately two times. The original coating showed the dominant wear mechanisms of micro-cutting and serious brittle spalling, while the composite coating with CFs showed the main wear mechanism of slight scratching.

Effects of Carbon Fiber on Mechanical Behaviour of Al2O3 Porous Ceramics

Effects of Carbon Fiber on Mechanical Behaviour of Al2O3 Porous Ceramics

Effect of carbon fiber on the tribo-mechanical properties of boron carbide: Comparison with carbon nanotube reinforcement

Composites with boron carbide (B4C) as the matrix and short carbon fiber (Cf) as reinforcement in 2, 5 and 10 vol% were fabricated by hot pressing route. Microstructural analysis by scanning electron microscopy reveled that Cf got aligned perpendicular to the hot press direction. Agglomeration of Cf was observed at 10 vol% Cf. The addition of Cf improved the flexural strength of B4C-Cf composite and was superior to that of B4C-CNT composite. On other hand, the hardness and fracture toughness of B4C-Cf composite were inferior to that of B4C-CNT composite. The tribological studies revealed that B4C-CNT had superior wear resistance. Both B4C-Cf and B4C-CNT had lower coefficient of friction than monolithic B4C. The possible reasons for deviation of properties due to change in length scale of carbon reinforcement has been analyzed.

Effect of carbon fiber on mechanical properties and dimensional stability of concrete incorporated with granulated-blast furnace slag

Concretes with binary and ternary blends of Portland cement, granulated-blast furnace slag (GGBS), and carbon fiber (CF) were prepared to investigate their effects on mechanical performance, drying shrinkage and creep behaviors. Nine types of concrete mixtures were prepared and tests were conducted during a long testing period which was up to 180 days. Research showed that GGBS and CF played a detriment effect on short-term compressive strength. GGBS could improve the workability of concretes, while CF presented an opposite effect. Concrete with the addition of CF showed superior drying shrinkage resistance and creep resistance, while GGBS increased the drying shrinkage and creep potentials. The coupling effect of GGBS and CF on the drying shrinkage and creep performance highly depended on the relative content of GGBS and CF. Analysis of variance (ANOVA) was performed to analyze the importance of GGBS and CF on the drying shrinkage and creep performance. Results showed that test period, content of GGBS, and content of CF were all significant factors in influencing the drying shrinkage and creep behaviors. Models to predict the drying shrinkage strain and creep coefficient were proposed by considering different proportions of cement, GGBS, and CF, and the models give promising results. Besides, the cost-benefit analysis and the environmental impact were also quantitively studied, and results showed that concretes incorporated with 20% GGBS in mass and 0.1% or 0.2% CF in volume presented both good cost-benefit effectiveness and low environmental impact. • Concrete incorporated with GGBS and carbon fiber CF was prepared. • The mechanical, drying shrinkage and creep behaviors were investigated. • Analysis of variance (ANOVA) was conducted. • Models were established to predict the shrinkage strain and creep coefficient. • Cost-benefit and environmental impact analysis were performed.

Interfacial adhesion between carbon fibers and nylon 6: Effect of fiber surface chemistry and grafting of nano-SiO2

In this study, the effect of carbon fiber (CF) surface chemistry and grafting of nano-SiO2 on CF surface with respect to the interfacial adhesion of CF-reinforced nylon 6 composites was investigated. CFs were oxidized and reacted with poly(oxypropylene) diamines to modify the surface chemistry. The oxidized CFs were modified with 3-aminopropyltriethoxysilane and then grafted with SiO2 nanoparticles. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microcopy (SEM), and atomic force microscopy (AFM) were used to characterize the chemistry and topographies of the CF surface. The transverse fiber bundle strength of CF oxidized and grafted nano-SiO2 increased to 31.92 MPa and 39.35 MPa, respectively, from 12.57 MPa for untreated CF. The results indicated that the reaction between the carboxyl group and nylon 6 led to chemical bonding at the interface and it meanwhile was strengthened and toughened by uniformly distributed SiO2 nanoparticles on the CF surface.

Energy generation by membraneless microfluidic fuel cell using acidic wastewater as a fuel

ABSTRACT A simple and novel membraneless paper-based microfluidic fuel cell was presented in this study. The occurrence of laminar flow was employed to ensure no mixing of the fuel and oxidant fluids along the bath of reaction. The acidic wastewater was used as a fuel. It was an air-breathing cell, so air and tab water were used as oxidants. Both the fuel and tab water flowed continuously under gravity. Whatman filter paper was used for preparation of the fuel cell channel and two carbon fibre electrodes were used and firmed on the edges of the cell. The performance of the cell was examined over three consecutive days. The results indicated that the present cell has the potential to generate electric power, but an extensive study is required to harvest better results. Also, the effect of carbon fibres used as electrodes in the cell was investigated.

Electrical conductivities of high‐density polyethylene composites reinforced with carbon fiber and nanometer carbon black

The effect of carbon fiber (CF) content on the electric conductive behavior of high‐density polyethylene composites filled with 10 wt% nanometer carbon black (CB) was investigated. It was found that the influence of the CF and CB on the resistivity was not the sum of these two fillers; the resistivity varied slightly and irregularly when the CF weight fraction was lower than 6 wt%, and then decreased quickly. The intensity of positive temperature coefficient (PTC) increased first and then decreased with increasing the CF weight fraction; when the CF weight fraction increased to 12 wt% from 8 wt%, the PTC intensity of the composite systems increased to 6.6 from 3.4; when the CF weight fraction increased to 15 wt% from 12 wt%, the PTC intensity of the composites decreased to 4.8 from 6.6. This could be attributed to the aggregation of the conductive filler in the matrix in this case. POLYM. COMPOS., 40:E1801–E1807, 2019. © 2018 Society of Plastics Engineers

Effect of carbon fiber and nanosilica on shear properties of silty soil and the mechanisms

In this study, the effects of carbon fiber and nanosilica on properties of silty soil including physical, microstructural characteristics and shear resistance were investigated. Soil samples treated with different contents of carbon fiber and nanosilica were prepared and studied. The samples were tested by direct shear method under different normal pressure levels. Besides, SEM (scanning electron microscopy) tests were performed to examine the microstructural changes. The test results indicated that the shear strength of treated soil samples was significantly improved compared with the untreated soil samples. Carbon fiber was found effective in improving internal friction angle and cohesion thanked to the interface friction between fiber and soil. On the other hand, nanosilica could improve cohesion effectively due to full filling of the pores between soil particles. The results also showed that the combination of 2 wt% carbon fiber and 3 wt% nanosilica could improve the shear stiffness and particularly the residual shear strength, which was increased significantly by 128.3% compared with the untreated soil sample at a normal stress of 100 kPa. The results demonstrated that the use of carbon fibers and nanosilica can be an effective method to improve silty soil in lieu of traditional cement grouting in mitigating geotechnical engineering disasters.

Effects of Pitch-Based Short Carbon Fibers on the Workability, Unit Weight, and Air Content of Mortar Composite

Pitch is a viscoelastic polymer material consisting of aromatic hydrocarbons. It is used to produce carbon fibers with sheet-like crystal structures. The aim of the work presented in this paper was to evaluate the effects of pitch-based short carbon fibers on the workability, unit weight, and air content of freshly mixed mortar composite. Experimental investigation was carried out on five different types of mortar composite, including a control mortar. Four mortar composites were prepared including pitch-based short carbon fibers with 1–4% volume contents. The fresh mortar composites were tested to determine their slump, inverted slump cone flow (flow time, mass flow, and volume flow), unit weight, and air content. In addition, the correlation between the slump and flow time of various mortar composites was determined. It was found that the slump decreased with the increasing volume content of carbon fibers. The flow time of mortar composite increased, and therefore its mass flow and volume flow decreased with a greater volume content of carbon fibers. The slump was strongly correlated with the flow time, with a correlation coefficient of 0.9782. Furthermore, the unit weight of the fresh mortar composite decreased due to the incorporation of carbon fibers. However, amongst the different carbon fiber reinforced mortar composites, the mortar with 3% fiber volume content provided the highest unit weight. The air content results were consistent with the unit weight results. The change in air content of various mortar composites followed a trend reciprocal to that of unit weights. When the overall effects of carbon fibers were compared, it was observed that the fiber volume content higher than 3% resulted in a significantly low workability and provided a much lower unit weight with greater entrapped air content.

Effect of carbon fiber as secondary filler on the electrical, thermal and rheological properties of carbon fiber/polypropylene composites

Abstract In this study, hybrid composites based on carbon fiber (CF) and polypropylene (PP) were fabricated by melt mixing techniques. The composite with optimum fiber length (8 mm) was chosen as a reference material, and to it, CF of various lengths (6 mm, 100 μm, 60 μm and 100 nm) were added as secondary filler. To understand the synergism effect of these fibers, electrical, rheological, thermal and morphological properties of composites were studied. The surface resistivity of the neat PP is in the order of 1017 ohm/square. It is observed that surface resistivity of a single fiber filled composite is in the range of 104 ohm/square, while it further decreased by three-fold (101 ohm/square) in the case of secondary fiber filled composites, indicating that the electrical network remains intact. Thermal analysis shows variation in crystallization of hybrid composites that can correlate to the lengths of secondary fibers. The rheological analysis shows that the frequency dependence of storage modulus (G′) and loss modulus (G″) in the lower frequency region indicates an elastic solid like behavior of these composites. The morphological behavior showed that the CFs are well dispersed and form a good adhesion with the polymer matrix.

Effects of carbon fiber on mechanical and electrical properties of fly ash geopolymer composite

High calcium fly ash geopolymer composite was prepared by incorporating short carbon fiber in the geopolymer matrix. The carbon fiber (CF) content was varied from 0 to 1%, the liquid to ash ratio was controlled at 0.5. The workability, mechanical and electrical properties of the geopolymer composites were examined. The result showed that the incorporation of 0.5%CF and above resulted in the ductile failure of specimen. The increasing CF content also resulted in decreasing workability and mechanical strength. The electrical resistivity was also reduced and was more stable to the curing age and temperature. The cyclic voltammetry (CV) curve of 60°C curing provided less peaks than that of 25°C.

Study of the flame retardant properties of short carbon fiber–reinforced epoxy composites

Short carbon fiber–reinforced epoxy composites (SCFRPs) are attracting increasing attention because of their excellent mechanical properties and simple molding process. However, their mechanical, magnetic, and electrical performances have been the main concern, while their flame retardant performance has not been comprehensively studied. In this article, short carbon fiber–reinforced epoxy resin composites were prepared via the method of solution blending. The effects of carbon fiber on the flame retardancy and thermal stability of epoxy resin composites were studied by a UL-94 horizontal combustion test, a cone calorimetry test, and thermogravimetry analysis. The results showed that when the short carbon fiber was 0.7 wt%, the combustion level of the material increased from FH-1 to FH-2; the peak values of the heat release rate and total heat release were reduced by 31.6% and 11.36%, respectively. Thermogravimetry analysis showed that the temperature at the maximum decomposition rate was improved by 9°C, and the decomposition rate was decreased simultaneously. The mechanical properties of the composites were improved as well.

Biobased epoxy/carbon fiber composites: Effect on mechanical, thermo-mechanical and morphological properties

ABSTRACTBiobased epoxy was synthesized from diglycidyl ether of bisphenol A (DGEBA) and epoxidized castor oil (ECO) at a ratio of 80:20. Carbon fiber (CF) was used as a reinforcing agent to fabricate composites using biobased epoxy as matrix. Mechanical, Thermal and morphological properties of neat epoxy and biobased epoxy composites were investigated. Mechanical test results revealed that the composites prepared using five plies were higher than those with three plies and one ply respectively. This phenomenon revealed the effective reinforcing effect of carbon fiber due to its higher strength and higher crosslinking density. The composites also demonstrate high damping behavior as compared with neat epoxy and biobased epoxy blend. With increasing number of plies the composites thermal properties also shows an improvement. The SEM micrographs of the composites depicted that the biobased epoxy was fully adhered to the carbon fiber, thus representing a strong interface between CF/epoxy matrix.

Effect of carbon fiber and gamma irradiation on acrylonitrile butadiene styrene/high density polyethylene composites

In this study, the effect of carbon fiber and gamma irradiation on acrylonitrile butadiene styrene (ABS)/high density polyethylene matrix was investigated. The ternary composites with short carbon fiber of concentrations 15, 30, and 45 wt % were irradiated with doses of 100 and 300 kGy. In order to characterize the physical and morphological properties of all reinforced composites, wide X-ray diffraction, differential scanning calorimetry, thermo gravimetric analysis, and scanning electron microscopy were performed.