Carbon Fiber Samples Research Articles

On the physical-mechanical and tribotechnical properties of antifriction carbon fiber based on a modified thermosetting matrix

The physical-mechanical and tribological properties of anti-friction carbon fiber plastic UGET based on low-modulus carbon fabric “Ural T-15R” have been studied in order to increase the magnitude of the ultimate deformation and reduce the elastic modulus through the use of a modified thermosetting matrix ET-4 instead of the traditionally used ET-2.Modes of polymerization and of heat treatment of epoxy binders were selected considering the results of the experiments. Prototypes of prepregs were obtained by solution impregnation on the UPST-1000M line and then processed into PCM by hot pressing. Laboratory samples were made and physical and mechanical tests were carried out to determine the ultimate strength under compression, shear and bending stress under destruction, as well as Charpy impact strength. Steel 20Kh13 and oxidized titanium alloy PT-3V were used as counter body rollers to determine carbon fiber tribosets.It was shown that carbon fiber samples based on chemically modified binder ET-4 with two-stage polymerization and heat treatment mode in the range of 90°C to 180°C both have better physical-mechanical and tribotechnical properties, in contrast with the analogue with a three-stage mode and carbon fiber carbon heat at friction over 20Kh13 steel and oxidized titanium alloy PT-3V.

Experimental studies of sensors based on fiber Bragg gratings embedded in the internal structure of composite plates

The main purpose of this article is to study the structural characteristics of carbon fiber samples printed on a 3D printer, including embedded sensors, during 3D printing, through numerical and experimental studies. There is a widespread tendency to replace metals with modern composite materials. Various methods can be used to measure the destruction of the composite structure. Fiber Bragg array sensors are known as intelligent localized and global structural condition prediction devices for all kinds of structural applications, especially those using composite materials. In this work, we created control plates by impregnating a selected number of layers of carbon fabric with epoxy resin. Fiber-optic Bragg sensors were additionally located between the layers of carbon fabric. In the course of experimental studies, a fiber Bragg grating sensor was embedded in the middle of the sample, and a second sensor was attached to the finished surface of the sample. We conducted environmental tests to examine the durability of the additively manufactured standard’s components and the impact of integrated sensors on the composite sample. We applied the concept of equations, known as conjugate modes, and used the transition matrix method to solve them numerically. The scientific novelty of the work is the development of a new method and technology for measuring spatial deformation in composite materials using fiber-optic Bragg gratings.

Optimization of an Aerospace Bracket by Additive Manufacturing with Continuous Fiber Reinforced Plastics

Fused Deposition Modelling (FDM), one of the most widely used methods of Additive Manufacturing Technique known as 3D Printing, is a popular technique used to produce different engineering components using common engineering fibre. Carbon fibre filament. This study presents an experimental study examining the effect of printing parameters on the mechanical properties of components produced with Carbon fibre filaments. The effects of the printing parameters determined as infill pattern, infill density and nozzle temperature on the mechanical strength parameter determined as tensile strength and flexural strength of Carbon fibre samples produced in standard sizes were investigated experimentally. The experimental design was carried out in accordance with the Taguchi L9 orthogonal array, and the relationship between the printing parameters and the mechanical strength parameters was modelled mathematically. The predicted strength values calculated using mathematical models were compared with the experimental test results. The results showed that the tensile strength and flexural strength values were directly proportional to the infill density. Experiments have shown that the most effective 3D printing parameter on the mechanical strength parameters is the infill density parameter with a contribution ratio of 62.09% for tensile strength and 72.83% for flexural strength. As a result of the RSM optimization, it was determined that the infill density 60%, the nozzle temperature value 265 C° and the infill pattern type lines to maximize the flexural strength and tensile strength values. Key Words: Sustainable Material, 3D Printing Parameters, Mechanical Strength Optimization, Response Surface Methodology.

Thermomechanical Material Characterization of Polyethylene Terephthalate Glycol with 30% Carbon Fiber for Large-Format Additive Manufacturing of Polymer Structures.

Large-format additive manufacturing (LFAM) is used to print large-scale polymer structures. Understanding the thermal and mechanical properties of polymers suitable for large-scale extrusion is needed for design and production capabilities. An in-house-built LFAM printer was used to print polyethylene terephthalate glycol with 30% carbon fiber (PETG CF30%) samples for thermomechanical characterization. Thermogravimetric analysis (TGA) shows that the samples were 30% carbon fiber by weight. X-ray microscopy (XRM) and porosity studies find 25% voids/volume for undried material and 1.63% voids/volume for dry material. Differential scanning calorimetry (DSC) shows a glass transition temperature (Tg) of 66 °C, while dynamic mechanical analysis (DMA) found Tg as 82 °C. The rheology indicated that PETG CF30% is a good printing material at 220-250 °C. Bending experiments show an average of 48.5 MPa for flexure strength, while tensile experiments found an average tensile strength of 25.0 MPa at room temperature. Comparison with 3D-printed PLA and PETG from the literature demonstrated that LFAM-printed PETG CF30% had a comparative high Young's modulus and had similar tensile strength. For design purposes, prints from LFAM should consider both material choice and print parameters, especially when considering large layer heights.

Effect of sizing agents on tensile properties of carbon fiber filament wound structures

In order to evaluate the effects of sizing agents on the wettability, strength loss, and properties of final filament wound structures during filament winding of carbon fibers, three types of sizing agent based on epoxy, epoxy + polyester, and epoxy + polyurethane were used to treat carbon fibers, the surface properties of carbon fiber samples after treatment were evaluated using SEM, infrared spectroscopy, dynamic contact angle analysis, and interlaminar shear strength (ILSS) test, the strength loss caused by fiber damage during filament winding was quantitatively analyzed, and the strength properties of the filament wound structures were characterized by NOL ring test. The results showed that the sizing agent treatment only slightly improved the surface free energy and ILSS of carbon fibers, but it had obvious influence on the strength loss rate of carbon fiber bundles. Added polyester or polyurethane in epoxy-based sizing may improve its protective effect for carbon fiber, and thus decrease strength loss during winding process, result in better tensile properties of carbon fiber filament wound structures.

Macro- and micromechanical characteristics and energy evolution law of micro/nano carbon fibre grouting samples

This study comprehensively explores the macro- and micromechanical attributes and energy evolution dynamics of micro/nano carbon fiber (CF) specimens. The investigation centers on a graded sand gravel grouting specimen, aiming to determine the optimal CF content through uniaxial compression tests conducted on samples containing 0.0 %, 0.5 %, 1.0 %, and 1.5 % CF. Utilizing CT and PFC2D simulation analyses, we establish the interrelation between micro- and macromechanics. The findings reveal similar failure modes across CF samples with varying contents, predominantly marked by shear failure in the principal crack of the inclined section, accompanied by proximal secondary cracks. The post-peak stress–strain curves exhibit notable divergences. Specifically, with increasing CF content, the total strain energy, elastic strain energy, and dissipated energy of the CF samples initially decline, subsequently rise, and then diminish once more. Furthermore, the 1.0%CF sample demonstrates heightened dissipated energy, uniaxial compressive strength, and elastic modulus in contrast to the 0%CF sample, showcasing superior macroscopic mechanical properties and enhanced toughness. A staged microcrack evolution unfolds, delineating defect initiation, pore evolution, crack development, and crack penetration stages. The non-uniform distribution of CF and sand gravel profoundly influences the propagation trajectory of minute cracks. Additionally, the failure modes and energy evolution trends from both models closely mirror experimental outcomes. The reinforcing characteristics and crack-resistant attributes of CF usher the transition from brittle failure (0%CF) to ductile failure (1.0%CF). PFC simulations highlight hysteresis in the model's damage and failure, underscoring CF's role in restraining grouting sample failure and shifting it from brittle (0%CF) to ductile (1.0%CF) failure, thus accentuating CF's pivotal role in impeding crack propagation. These findings furnish invaluable theoretical insights for bolstering grouting reinforcement in fractured rock masses.

Solvent-free surface modification of milled carbon fiber using resonant acoustic mixing

Resonant Acoustic Mixing (RAM) is used to rapidly modify the surface of milled carbon fiber using diazonium salts in solvent free conditions. This novel method allows tuning of the surface properties of this material and reduces the environmental footprint usually associated with surface modification of carbon fiber (discontinuous or otherwise). As a proof of concept, fluorine-containing diazonium salts were successfully grafted as determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and an increase in water contact angle (WCA) of the milled carbon fiber samples (+15°). Atomic Force Microscopy (AFM) together with SEM revealed the surface structure and integrity of the milled carbon fibers could be maintained despite vigorous mixing conditions. Using RAM proved more efficient than positive controls produced under thermal conditions in solvent.

USING THE ACOUSTIC EMISSION METHOD, STRAIN GAUGE AND FRACTOGRAPHY TO ANALYZE THE PROCESSES OF DESTRUCTION OF SAMPLES FROM CARBON FIBER

Static loading of Torayca T800 carbon fiber samples to failure was carried out, during which defects were registered using a microprocessor-based diagnostic acoustic emission (AE) system. The location of AE signals began in the area of the stress concentrator at loads not exceeding 30 kN. The analysis of the destruction process of samples at negative (–50 C) and positive (+80 C) temperatures was carried out. During their heating and cooling, thermal chambers were used, located in the region of a stress concentrator with a diameter of 12 mm. In the process of testing at a temperature of T = –50 C, an active location of AE signals was observed, corresponding, as shown by fractography, to delamination and destruction of the upper monolayers of carbon fiber. During tests carried out at a temperature of T = +80 C, AE signals were localized, caused by lateral delaminations located at the edges of the samples. Using wavelet transforms, an analysis was made of the features of changes in the main informative parameters of AE signals, and their relationship with the growth of damage (matrix, fiber, delamination) of the carbon fiber material.

Synchrotron X-ray diffraction and radiography - Lattice strain characterization in thin-walled carbon fibre channel structures subjected to buckling

Carbon fibre composites are widely used in low specific stiffness and high strength structures such as airframes. Compressive loading of these assemblies can lead to buckling and localised deformation around defects and imperfections that can hinder performance and lead to overengineering via excessive safety factors. Synchrotron X-Ray Diffraction (SXRD) has recently been shown to be capable of performing lattice strain mapping within carbon fibre composites at the microscale, a previously unprecedented resolution. In this study SXRD and radiography was performed on carbon fibre composite columns produced via two different methods (standard lamination and half square) at a range of different load states: unbuckled, one-third of the buckling load and post buckling. The results provide quantitative insights into the impact of these different production methods on lattice strain and fibre orientation, as well as the influence these factors have on reducing buckling load (by up to 22%). As well as being the first use of SXRD on industrially representative full-size carbon fibre samples, these insights provide invaluable detail into the factors which limit performance and the origins of column failure; crucial factors required to optimise structural design, production and loading capability.

Inspection benchmarking of Fiber Reinforced Polymers produced by Additive Manufacturing

The production of Polymer Matrix Composites (PMCs) through Additive Manufacturing (AM) presents new defects, and the detection of these is crucial for proper functioning. Non-destructive testing (NDT) techniques such as terahertz (THz), air-coupled ultrasounds, and active thermography are fast, automatable, non-invasive, and noncontact inspection methods. The aim of this study is to investigate the use of NDT techniques for detecting defects in PMCs produced by AM. Six samples were produced using polylactic acid (PLA) as the base material and reinforced with continuous fibers of Kevlar, glass, and carbon. Two types of samples were created: one with a full-thickness reinforcement defect in a specific area and the other with a partial reinforcement defect, with a layer of fibers missing in the same area. The samples were then tested using three NDT techniques: THz, non-contact ultrasonic, and active thermography. The results showed that THz was only able to detect the defect in the carbon fiber sample with full-thickness reinforcement, ultrasonic testing was able to detect the defects in Kevlar and carbon fiber samples with missing three layers of fibers, and active thermography was the most reliable technique, detecting all samples with missing three layers of fibers as well as partial reinforcement defects.

Analysis of the destruction processes of carbon fiber samples using acoustic emission and tensometry

With samples made of carbon fiber, static tests were carried out to failure. Defects were controlled using acoustic emission and tensometry. Four wire strain gauges were glued to each sample in the area of the hole, and four piezoelectric gauges were installed along its edges, forming the working zone of control. Registration of signals associated with the destruction of the composite material of the samples, and their location was carried out by the acoustic emission system. In the process of testing, the tensometric system recorded loads and deformations, at which the process of destruction of carbon plastics began. The types of destruction were determined during the analysis of micro-glyphs, which were made from location zones. The main informative parameters (amplitude, dominant frequency, MARSE, structural coefficient) of acoustic emission signals were associated with the type of failure of carbon fiber reinforced plastics.

Analyzing the Processes of Carbon Fiber Sample Failure Using Acoustic Emission and Strain Gaging

Analyzing the Processes of Carbon Fiber Sample Failure Using Acoustic Emission and Strain Gaging

Cryogenic tensile performance of 3D printed onyx–continuous carbon fiber composites

PurposeThe aerospace, energy and automotive industries have seen wide use of composite materials because of their excellent mechanical properties, along with the benefit of weight reduction savings. As such, the purpose of this study is to provide an understanding of the mechanical performance of these materials under extreme operational conditions characteristic of in-service environments.Design/methodology/approachThis study is novel in that it has evaluated the tensile performance and fracture response of additively manufactured continuous carbon fiber embedded in an onyx matrix (i.e. nylon with chopped carbon fiber) at cryogenic and room temperatures, for specimens manufactured with an angle between the specimen lying plane and the working build plane of 0°, 45° and 90°.FindingsResearch findings reveal enhanced tensile properties (i.e. ultimate tensile strength and modulus of elasticity) by the 0° (X) built specimens, as compared with the 45° (XZ45) and 90° (Z) built specimens at cryogenic temperature. A reduction in ductility is observed at cryogenic temperature for all build orientations. Fractographic analysis reveals the presence of fiber pullout/elongation, pores within the onyx matrix and chopped carbon fiber near fracture zone of the onyx matrix.Research limitations/implicationsResearch findings present tensile properties (i.e. ultimate tensile strength, modulus of elasticity and elongation%) for three-dimensional (3D)-printed onyx with and without reinforcing continuous carbon fiber composites at cryogenic and room temperatures. Reinforcement of continuous carbon fibers and reduction to cryogenic temperatures appears to result, in general, in an increase in the tensile strength and modulus of elasticity, with a reduction in elongation% as compared with the onyx matrix tensile performance reported at room temperature. Fracture analysis reveals continuous carbon fiber pull out for onyx–carbon fiber samples tested at room temperature and cryogenic temperatures, suggesting weak onyx matrix–continuous carbon fiber adhesion.Originality/valueTo the best of the authors’ knowledge, this study is the first study to report on the cryogenic tensile properties and fracture response exhibited by 3D-printed onyx–continuous carbon fiber composites. Evaluating the viability of common commercial 3D printing techniques in producing composite parts to withstand cryogenic temperatures is of critical import, for aerospace applications.

Влияние компонентов гибридной матрицы на изменение ударной вязкости углепластиков в условиях экстремально низких температур Арктики

The results of tests to determine the impact strength of carbon fiber reinforced plastics based on an epoxy matrix and components that form an independent liquid phase in the composite structure (anaerobic polymer material (Loctite 638), silicone elastomer (Unisil-9628), synthetic wax) are presented. The tests were carried out after holding the samples at temperatures of 20±2 °C, –30 °C and –50 °C according to the Charpy method with the direction of an impact perpendicular to the plane. The use of an anaerobic polymer material as a component of the liquid phase of the hybrid matrix makes possible to obtain the highest impact strength among the compared types of carbon plastics and to ensure the stability of this characteristic after exposure at a temperature of –50°C. Synthetic wax in the structure of the composite matrix ensures the stability of impact strength after storage at a temperature of –30°C. Samples of carbon fiber reinforced plastics with silicone elastomer as part of the hybrid matrix have the lowest impact strength after holding under different temperature conditions.

Evaluation of Carbon Fiber and Titanium Surgical Implants for Proton and Photon Therapy

Impending and actual pathologic fractures secondary to metastatic bone disease, lymphoma, or multiple myeloma often require intramedullary fixation followed by radiation therapy. Because of carbon's low atomic number, there are reduced computed tomography (CT) imaging artifacts and dose perturbation when planning postoperative radiation for carbon fiber (CF) rods. Herein, we characterize the dosimetric properties of CF implants compared with titanium alloy (TA) for proton and photon. TA and CF samples were acquired from an implant manufacturer. Material characteristics were evaluated by CT scans with and without metal artifact reduction (MAR). Relative stopping power (RSP) was determined from the range pull-back of each sample in a 20-cm range proton beam. Photon transmission measurements were made in a solid water phantom and compared with the modeled dosimetry from the RayStation planning system. CF caused no visible CT artifacts, and MAR was not necessary for Hounsfield unit (HU) determination (median, 364 HU) or contouring, whereas TA (median, 3071 HU) caused substantial artifacts, which were improved, but not eliminated by MAR. The proton RSP was measured as 3.204 for TA and 1.414 for CF. For 6 MV photons, the measured transmission was 89.3% for TA and 98% for CF. CF RSP calculation and transmission from CT HU showed a physical density overestimate compared with measurements, which would cause a slight, but acceptable, dose uncertainty (<10% proton range or 1% photon transmission). With a density similar to bone, CF implants did not cause imaging artifacts and minimal dose perturbation compared with TA. Although the CF proton RSP is underestimated and the photon attenuation is overestimated by the HU, both effects are relatively small and may be most easily accounted for by planning with a 2-mm expansion around organs at risk beyond or in close proximity to the implant.

Novel 3D carbon fibers derived from Luffa wastes for oil/water separation

In this study, the 3D structure of carbon fibers (CFs) was prepared from Luffa sponge wastes by H3PO4 impregnation with various ratios and a low-temperature carbonization process at 500 °C in a nitrogen atmosphere. The H3PO4-treated Luffa sponge had higher thermal stability and carbonic yield (∼60–70%) than neat-Luffa (∼21%). Characterization analyses exposed that the synthesized CFs derived from H3PO4-treated Luffa exhibited oleophilic and hydrophobic carbonic nature with 3D sponge skeletal, reflecting an ideal structure for oil sorption. The engine oil sorption properties on the CFs were studied by varying the contact time. The engine oil sorption equilibrium data for 3D CFs samples was explained by the pseudo-second-order and intraparticle diffusion models. The equilibrium oil sorption capacities of 3D CFs were as large as 23.1 ± 0.4 g/g for engine oil, 23.7 ± 1.0 g/g for gasoline, 28.1 ± 1.0 g/g for almond oil, and 29.2 ± 0.8 g/g for pomegranate seed oil in 20 min. Moreover, the optimized 3D CFs can be selectively for oil/water separation applications, such as high capacities for various oils, fast kinetic sorption, and reusability (>6 cycles). This research presented a facile and cost-effective process for the 3D CFs through recycling Luffa sponge wastes for rapid oil sorption.

Assessment of the stress-strain state of machine structural elements made of polymer composite materials with a hybrid matrix by numerical simulation

The expansion of the fields of application of polymer composite materials (PCM) requires the development of their new compositions, structures, and molding methods. One of the most difficult tasks in the design of PCM products is the selection or development of a polymer matrix that meets a number of technological and operational requirements. The addition of components forming an independent conditionally liquid phase to the composition of the PCM matrix makes it possible to change the set of properties of the composite and ensure its high crack resistance. The paper presents the results of evaluating the stress-strain state of model samples of carbon fiber reinforced plastic with an organosilicon polymer material that forms a hybrid matrix with the base material of the binder. Modeling was carried out for cases of using organosilicon material with low and high modulus of elasticity. Also, modeling of a front-end loader bucket made using carbon fiber with the considered hybrid matrix was performed. The simulation results showed that the use of PCM with organosilicon material in the manufacture of a product can significantly reduce its weight and provide a sufficient margin of safety.

Evaluation of the Failure Mechanism in Polyamide Nanofibre Veil Toughened Hybrid Carbon/Glass Fibre Composites.

The interface of hybrid carbon/E-glass fibres composite is interlayered with Xantu.layr® polyamide 6,6 nanofibre veil to localise cracking to promote a gradual failure. The pseudo-ductile response of these novel stacking sequences examined under quasi-static three-point bending show a change to the failure mechanism. The change in failure mechanism due to the interfacial toughening is examined via SEM micrographs. The incorporation of veil toughening led to a change in the dominant failure mechanism, resulting in fibre yielding by localised kinking and reduced instances of buckling failure. In alternated carbon and glass fibre samples with glass fibre undertaking compression, a pseudo-ductile response with veil interlayering was observed. The localisation of the fibre failure, due to the inclusion of the veil, resulted in kink band formations which were found to be predictable in previous micro buckling models. The localisation of failure by the veil interlayer resulted in a pseudo-ductile response increasing the strain before failure by 24% compared with control samples.

A comprehensive experimental investigation on mechanical properties and fracture morphology of particulate composites via material extrusion-based 3D printing

Mechanical properties and fracture morphologies of Poly-Lactic acid (PLA) neat and composites (PLA reinforced with Aluminium, Copper, Carbon fibres and Brass) developed by Material Extrusion based Additive Manufacturing technique were studied to consolidate the comprehensive data for various applications. In the current study, printing parameters viz., layer height, print angle and print speed were varied to form the arrays of experimental trials to estimate the Tensile (Ultimate Tensile strength, young's moduli) and Flexural (Maximum bending strength) properties. Further, the study emphasized on fracture morphologies and categorized the types of fractures within the PLA neat and composite samples via Field Emission Scanning Electron Microscope (FESEM). An analytical model was adopted for a qualitative validation of results of micrographs for estimating the tensile and bending strengths.Results showed that the percentage improvement in the young's modulus was relatively higher for carbon fibre and brass reinforced composites in comparison to the other counterparts. It was conclusive from fracture morphology that the Intra-laminar type of fracture was prominent. However, PLA + Carbon Fibre (CF) samples exhibited Trans-laminar type of fracture, owing to their higher aspect ratio. Also, the composite samples exhibited better strengths during flexural test, in comparison to the tensile test. Optimization plots showed that the print angle was the most dominant factor influencing the strength values.

Influence of sodium and calcium contaminant in the growth of carbon nanotube on rayon-based carbon fibers

This study investigated the role of contaminants commonly found on rayon-based carbon fibers (CF) for the carbon nanotubes (CNT) synthesis. The most common contaminant found on CF is sodium. From the experimental results, sodium contaminant indeed performed as a catalyst, but with low efficiency. However, some CF samples also contained calcium as a contaminant, and Ca presence made higher density and better-quality CNT growth. Probably Ca acts as the reducing agent, keeping Na in metallic form along the entire growth process. XPS data suggests a new view of sodium oxide/hydroxide to sodium carbonate transition after CNT synthesis. On CF samples with calcium, sodium keeps activity and carbonate does not form, differently of the sample containing just Na. CF free of contaminants (PAN-based CF) helps set apart the effects and Raman Spectroscopy picked up sodium and calcium effects on the CNT crystalline quality. The sodium presence in rayon-based CF worsens CNT quality when growing from the foreign iron-cobalt catalyst. By another hand, calcium presence helps keeping iron-cobalt nanoparticles surface reduced. Images of Field Emission Gun Scanning Electron Microscopy (FEG-SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) also supported the analysis.