Carbon Fiber Filament Research Articles

Hierarchical aerospace epoxy composites of carbon fiber and hyperbranched filler: toughening behavior from nanocomposites to composites

In this work the effect of a glassy hyperbranched polymer (G_HBP), characterized by a Tg higher than room temperature (∼77 °C), on the mechanical properties of a patented epoxy resin was investigated. To define an optimized filler concentration, three different G_HBP contents were prepared by a solvent-free technique and improvements of fracture toughness compared to the neat matrix (ΔKC ∼ 16 % and ΔGC ∼ 39 %) and to the corresponding laboratory solvent-based procedure. The solvent-free procedure and the found optimal filler content were considered to manufactured long carbon fiber composite samples of both neat and G_HBP loaded matrix later tested and compared in terms of tensile and flexural properties, as well as fracture toughness performance. Mode I and II interlaminar fracture toughness tests were carried out, revealing remarkable increase of both onset and propagation (ΔGIConset ∼ 29 % and ΔGICprop ∼ 53 %) and preserving the GIIC value (ΔGIIC∼+ 6 %). Validation tests in compression after impact were also performed and analyzed.

Design of adjustable prosthetic pylon for children amputees: Numerical analysis case study

AbstractThe pylon is an essential part of lower limb prosthetics. It is usually made of titanium, aluminum, and steel. However, it is expensive and difficult to be available in developing countries, especially for children who suffer from amputation. Moreover, they constantly need new pylon pieces during close periods due to the growth and increase in the child's length.PurposeThis study aims to design an adjustable pylon that can change in length to suit the increase in the length of the healthy leg of the child without the need for a new pylon and reduce the economic cost.Design/methodology/approachIn this study, an adjustable pylon model was designed using the CAD software (Solid work) and work to manufacture the pylon from low-cost materials (carbon fiber filament) capable of bearing the amputee's weight, and manufacturing printed parts by using additive manufacturing technical (CREALITY CR20 3D printer).FindingsThe results showed that the pylon is successful in design and strength as it bears the patient's weight without any failure or buckling, and the proof that the maximum amount of stress generated is 27.8 MPa, which is far from the value of the yield stress.Originality/valueThe design of the adjustable pylon prototype offers good strength and ability to bear the patient weight, reducing the cost and time of manufacturing.

Analytical method for deformation and stress calculation of bell-and-spigot joints in PVC-U pipes

The stable operation of water supply pipelines relies significantly on the structural safety of pipe joints. A novel analytical pipe joint structural calculation method based on the Novozhilov thin shell theory was proposed to calculate the deformation and stress of bell-and-spigot joints in unplasticized polyvinyl chloride (PVC-U) pipes under internal pressure. An equivalent stress index was established to investigate and evaluate the safety performance of pipe joints. The effects of various factors, including spigot insertion depth, the clearance between the bell and spigot, internal pressure, and different pipe nominal outside diameter (DN) and nominal pressure (PN) series, on the maximum equivalent stress of pipe joints, were thoroughly analyzed. The results indicate that the maximum equivalent stress under nominal pressure is located on the inner surface of the bell and consistently exceeds the design stress. The influence of spigot insertion depth on the maximum equivalent stress is minimal. However, as the clearance value between the bell and spigot decreases and the internal pressure increases, the maximum equivalent stress increases significantly. Pipes with smaller DN and PN series result in a higher maximum equivalent stress at the joint. The analytical method indicates that increasing pipe thickness and reinforcing the bell with continuous carbon fiber filament winding are two potentially effective methods to enhance the mechanical performance of the joint and reduce the maximum equivalent stress. This study's findings offer valuable theoretical support for designing and selecting joints in PVC-U pipelines.

Hygrothermal resistance of large tow carbon fiber and its reinforced polymer composites

AbstractLarge tow carbon fiber reinforced polymer (CFRP) has been used to reinforce structures serving in hygrothermal conditions, which can be greatly affected by hygrothermal conditions. In this study, the hygrothermal resistance of 48K and 12K carbon fibers and their CFRPs immersed in deionized water at 25, 40, and 60°C were analyzed and compared. The sizing agent on the carbon fiber surface was deboned or hydrolyzed after immersion, resulting in a reduction in the tensile strength, an increase in dispersion, and a decrease in surface activity for carbon fibers. The retention rate of tensile strength of 48K CFRP was higher than 89.7% but was less than that of 12K CFRP due to the higher dispersion of 48K fiber filaments. The interlaminar shear strength (ILSS) and Mode I interlaminar fracture toughness of 48K CFRP was greater than 12K CFRP due to the higher fiber surface activity of 48K carbon fibers and the stronger obstructing effect of 48K fiber tows on the diffusion of water. The degrees of post‐curing and hydrolysis of CFRP were less than 10%. The degradation of the fiber‐matrix interface and a decrease in the strength and elastic modulus of the matrix led to the degradation of the tensile properties, ILSS, and Mode I interlaminar fracture toughness of CFRP.Highlights Debonding of sizing agent reduced the strength of the carbon fiber filaments. Degrees of hydrolysis and post‐curing of the matrix caused by immersion were low. Retentions of ILSS and fracture toughness of 48K CFRP were higher than 12K CFRP. 48K fiber tow possessed a stronger obstructing effect on water diffusion.

Analisis Kekuatan Tarik dan Regangan Filamen Carbon Fiber Hasil 3D Print dengan Variasi Fill Density

Mechanical properties problems that are closely related to the strength of 3D printed products generally occur during the development of 3D printing machines, In which several components used are the results of additive manufacturing technology. The damages generally occur in the components that receive force and the damage is in the form of cracks and fractures. The focus of this study is to determine the effects of increasing the value of fill density on mechanical properties, especially tensile strength and strain with carbon fiber filament material. This study used an experimental method using two types of filament material: nylon carbon fiber and PLA carbon fiber with a diameter of 1.75 mm for each filament and a recommended printing temperature of 190-260°C. Both types of filaments were printed using a direct extruder type 3D printing machine with a build size of 180 mm x 180 mm x 180 mm and printing was carried out at atmospheric pressure and a horizontal printing area. The Universal Testing Machine carried out mechanical properties testing implementation related to tensile strength and strain. Based on the results of experiments and tests that have been carried out, the strain values ​​are 16.970 – 26.681% and the tensile strength is 19.244 – 23.899 MPa for nylon carbon fiber filament material. Whereas the PLA carbon fiber filament material, the strain value is 7.673 – 15.546%, and the tensile strength is 18.580 – 24.552 MPa. Therefore, based on the test results, it is known that the fill density parameter value has an influence on the strain value and tensile strength so that it can be used as a reference in setting machining parameters.

Usage of 3D printing technology in centrifugal pumps and material selection

The fused deposition modeling (FDM) technique which is one of the 3D printing technologies was used to produce a centrifugal pump impeller. The fabrication and investigation of the impeller were preferred because of its complex geometry and the difficulties encountered in its production. The most commonly used ABS, HIPS, PLA, and carbon fiber filaments were preferred to compare and determine the most suitable material for the production of the impellers. Firstly, mechanical test specimens from four different materials were printed in the 3D printer according to standards. Then the tensile tests and quasi-static punch shear tests (QS-PST) were applied to determine the mechanical properties of the 3D printed parts. Also, the mechanical tests were repeated to some specimen with the different fillings to define the optimum fill rates. Secondly, the impellers were fabricated from four materials by using the 3D printer in determined fill rates. Then, these impellers were mounted in the actual pump system, and pump performance tests were performed. In the pump performance tests, the head, pump efficiency, and electric power parameters were measured against the flow rate for each impeller. Finally, the mechanical properties and pump performance of the impellers compared with the GG25 cast iron impeller which is produced by traditional technique. As a result, PLA was selected as the most appropriate material for the production of the impellers. Furthermore, PLA showed superior performance compared to others when price, production time, and product weight parameters were considered.

COMPOSITE MIXTURES BASED ON SYNTHETIC POLYMERS AND FILLERS AND EQUIPMENT FOR 3D PRINTING WITH THEM

The article states that the use of composite materials instead of traditional materials allows you to significantly reduce the weight of the product, while not changing the strength characteristics of this material. It was determined that polymer composite materials based on metal powders, high-strength organic (aramid) and carbon fiber fillers with a polymer matrix are promising for use as structural materials. Fillers are used to improve the operational properties of the composite material (strength, stiffness, heat resistance), give them various specific properties and reduce the cost. The classification of polymer composite materials by matrix and filler is presented. It is noted that the greatest variety of properties can be obtained using solid fillers of different nature (metals, ceramics, polymers) and structures. It has been established that both the type of filler and the shape and size of the particles are important when forming certain properties of polymer composite materials. It was determined that composite materials are used in additive technologies, in particular in 3D printing. Examples of the production of composite filaments by various companies, including various types of fillers, are given. The developed technology of printing with a mixture of polymer connector and filler using a 3D printer, which includes certain stages, is presented. Polymer materials and solid fillers of various nature were selected as the matrix for experimental research and their properties were described. The classification of equipment for forced mixing of materials is described. The developed extruder that prints with granules or composite mixtures of polymer materials and the 3D printer on which it is installed are presented. Composite mixtures for conducting experimental studies are given. The parameters of the printed samples to be examined are specified.

Effect of Short Carbon Fiber Reinforcement on Mechanical Properties of 3D-Printed Acrylonitrile Butadiene Styrene.

The effect of short carbon fiber (SCF) filler on the mechanical properties of 3D-printed acrylonitrile butadiene styrene (ABS) was investigated. The fused filament fabrication (FFF) method was used for the manufacturing of samples. Elastic properties and strength characteristics of samples made of conventional ABS and SCF-reinforced ABS were compared in tensile and bending tests. Fracture toughness and critical strain energy release rate were also determined. In addition, 3D-printed monofilament SCF-reinforced samples were fabricated, the internal structure of which was analyzed using microcomputed tomography (micro-CT). Based on the tomography data, finite-element (FE) models of representative volume elements (RVEs) of the reinforced material were created and used for the numerical calculation of effective characteristics. Numerical and experimental results for the effective elastic properties were compared with the Mori-Tanaka homogenization technique. The ABS samples filled with SCF showed considerably higher mechanical characteristics than those of the conventional ABS. Finally, the dependence between the strength characteristics and elastic properties of the samples on the diameter of the nozzle used for 3D printing was established. 3D-printed ABS reinforced with SCF demonstrated a gain in tensile strength and fracture toughness by 30% and 20%, respectively. Interlayer adhesion strength in flexure tests showed an increase of 28% compared to pure ABS samples.

Optimisation of recycling process parameters of carbon fibre in epoxy matrix composites

In order to improve the mechanical properties of recycled carbon fibres, this article adopted the centre composite design method to conduct high-temperature pyrolysis recycling experiments on carbon fibre filaments. The experimental results revealed the influence of the residual resin content in the recycled carbon fibre bundles and the degree of fibre oxidation on the tensile properties. On the basis, the process parameters were further optimised for the high temperature pyrolysis recycling process of resin-matrix carbon fibre composites through multi-island genetic algorithm. The results suggest that (1) in the process of pyrolysis and oxidation, the temperature has the greatest influence on the properties of the fibres, and a small amount of resin residue helps improving the tensile strength of the recycled carbon fibres; (2) when the temperature is at a constant value in the range of 400–520 ℃, the pyrolysis time has a parabolic relationship with the tensile strength of recycled carbon fibres; (3) the tensile strength of the recycled carbon fibres reaches 80 % with 5.6 % resin residue remained in the recycled carbon fibre bundle after continuous pyrolysis at 428 °C for 4.0 h, and such a strength meets the mechanical performance requirements of recycled carbon fibre.

3D printed carbon-fiber filament density effects on mechanical properties

AbstractThis study aims to select the suitable density of the material according to the mechanical properties needed by the 3D-printing application in which it will be used. 3D-printed carbon fiber filaments with different printing densities have been tensile, and a fatigue test was experimented with to find the mechanical properties. Furthermore, the modulus of elasticity, yield stress, and ultimate tensile strength of the material was determined by analyzing the stress-strain curves. The result shows that the parts printed with a high infill density give better mechanical properties, more time to build the object, more strength, and heavier weight than those printed with low infill density.

Electromagnetic wave absorbing and bending properties of 3D gradient structured woven composites: experiment and simulation

In order to prepare 3D structural composites with electromagnetic wave absorption and load-bearing, 3D gradient structured woven fabrics were woven with basalt fiber filament yarn and carbon fiber filament yarn as raw materials on a common loom with rational design. After that, the three-dimensional gradient structured woven fabric was used as the reinforcing material, epoxy resin was used as the matrix, and carbonyl iron powder (CIP) and carbon black (CB), the electromagnetic wave absorbers, were added. In this paper, a vacuum-assisted resin transfer molding method was used to fabricate composite materials with three-dimensional structures. Finally, the experimental and simulation analysis techniques were used to analyze the absorbing and mechanical properties of the 3D gradient structured woven composites. The results show that the error value of the peak reflection loss is 10.6% in the simulation of electromagnetic wave absorption performance, and the error value of the maximum bending load is 2.37% in the simulation of mechanical performance. The theoretical simulation results and experimental results were in good agreement, which proved the validity of the electromagnetic wave absorbing model and finite element model. The experimental and simulation analyses revealed the material’s electromagnetic wave absorbing mechanism and bending damage mechanism and provided some theoretical guidance for designing 3D gradient structured woven composites with integrated load-bearing and electromagnetic wave absorbing functions.

Evaluation of manufacturing defects in 3D printed carbon fiber reinforced cylindrical composite structure based on laser ultrasonic testing

Additive manufacturing (AM), also known as three-dimensional (3D) printing technology, has the advantages of rapid modeling of complex shapes and flexibility in design. Nowadays, 3D printing of continuous carbon fiber filaments based on material extrusion (ME) is drawing more attention owing to its advantages in shortening the traditional composite manufacturing process. However, in the 3D printing process, inherent defects occur owing to limitations of the ME-based 3D printing process itself. Because manufacturing defects can deteriorate structural performance, methods for visualizing and minimizing defects are required. In this study, defects in 3D printed cylindrical carbon fiber-reinforced plastic (CFRP) specimens were evaluated using laser ultrasonic testing (LUT) based on the rotational scanning method. From the inspection results of two cylindrical specimens, it was verified that the LUT inspection system and the proposed method are suitable for detecting defects that occur inside the specimen. The process parameters affecting the occurrence of defects are identified through visualization and quantization of inspection results. Research on process parameters that minimize defects can be applied to the continuous fiber 3D printing of complex structures beyond cylindrical structures.

Increasing Adhesion of Carbon Fiber Filler to Polymer by Sizing – a Review

Increasing Adhesion of Carbon Fiber Filler to Polymer by Sizing – a Review

The Effect of Thermal Exposure to Carbon Fiber Filament in the Thermoreceptor Area on the Physiological Response of Hypothermic Baby Rabbits.

The body has a thermoregulation setting where when it gets hot, the body responds by dilating blood vessels or vasodilation, otherwise it gets a cold response, which causes narrowing of blood vessels or vasoconstriction. The thermal conditioning system is a system that can influence the baby in terms of its thermal quality. So that the baby can feel a comfortable environment or not. Skin temperature is a fundamental factor in heat exchange between the body and its environment. The purpose of this study was to analyze the effect of thermal exposure to carbon fiber filaments in the thermoreceptor area on the physiological response of hypothermic baby rabbits to changes in body temperature, to analyze the time needed for physiological adaptation of the body's skin to occur and to analyze the response of the thermoreceptor area on the head, neck, chest, arms, wrists, soles of the feet, to changes in each local area of the body. The research method used is pure experimental or laboratory experimental, with a post-test only control group design approach that uses experimental animals as experimental objects. The treatment in this study was using baby rabbits. The Sampling of test animals was carried out using simple random sampling. Statistical analysis was performed using IBM SPSS Statistics version 20. The confidence level was set at 95% by one way ANOVA test. The results showed that the response of the thermoreceptor area to thermal exposure on the neck was the highest with an average of 39.77'. Based on the results of the analysis, it was concluded that there was an effect of thermal exposure to carbon fiber filaments in the thermoreceptor area on the physiological response of hypothermic baby rabbit models to changes in body temperature.

Strength and its variability in 3D printing of polymer composites with continuous fibers

Additive manufacturing (AM) of polymer composites with continuous fibers could play a major role in the future of aerospace and beyond but will require printed materials to achieve new levels of reliability. This study characterized the strength distribution of selected thermoplastic matrix composites as a function of printing via fused filament fabrication (FFF). Experimental and commercial composite filaments of continuous carbon or Kevlar fibers were printed with volume fraction (Vf) ranging from approximately 28 to 56 %. The strength was evaluated under uniaxial tension after specific stages of printing and Weibull statistics were applied to characterize the strength distribution. There was a significant reduction in strength of the printed material with respect to the unprinted condition, regardless of reinforcement type, fiber volume fraction or printer used. Damage introduced by feed extrusion of the filament, and fiber failures induced at material deposition were most detrimental. For carbon fiber filaments, the reduction ranged from approximately 10 % for an experimental material to over 60 % for a commercial filament. There was no correlation in the strength degradation or variability with Vf. The prevention of process-related fiber damage is key to advancing AM for continuous fiber composite and application to designs intended for stress-critical applications.

Monitoring inner temperature change of carbon fiber in additive manufacturing process using fiber optic sensors

This study presents a systematic investigation of the effect of infill density values on inner temperature change of carbon fiber filament in additive manufacturing process. Five groups of additive manufacturing experiments were carried out using carbon fiber filament, and the considered infill density values were 20%, 40%, 60%, 80%, and 100%, respectively. Fiber Bragg grating (FBG) sensors were selected as measurement sensors to monitor internal temperature change of all prototypes during additive manufacturing process. Monitoring tests indicate that fabrication of carbon fiber filament in additive manufacturing method leads to a significant temperature rise of FBG sensors. The obtained relationship of temperature change against printing time is characterized by three different typical phases including an initial temperature rise in the first stage, a gradual temperature reduction in the second stage, and a temperature decrease after printing is finished in the third stage. It is found that the peak value of temperature raised from 5.0 ℃ to 12.6 ℃ in the second stage when infill densities increased from 20% to 100%. The maximum peak value of temperature raised about 9.7 ℃ to 19.8 ℃ in the third stage. The obtained decrease rates of inner temperature change were -0.289℃/layer, -0.334℃/layer, -0.304℃/layer, -0.303℃/layer, and -0.294℃/layer, respectively. The monitoring test data provide a better understanding of temperature change of carbon fiber filament and therefore can be further used to indicate thermal expansion and contraction during additive manufacturing process. • Effect of infill density on inner temperature change of carbon fiber filament. • FBG sensors were selected to monitor internal temperature change. • The maximum peak value of inner temperature raised about 9.7 ℃ to 19.8 ℃. • The inner temperature change rose with infill density values.

Potentiality of MWCNT on 3D-printed bio-inspired spherical-roof cubic core under quasi-static loading

Sandwich panel is increasingly used as lightweight energy absorbing components, which provides excellent crashworthiness performance with the three-dimensional periodic core. This paper investigates 3D-printed bio-inspired spherical-roof cubic cores with multi-walled carbon nanotubes (MWCNT) and foam-filled cores under quasi-static loading. The proposed bio-inspired spherical-roof cubic cores with 1.5 mm wall thickness were manufactured using the fused filament fabrication process, which used 70% polylactic acid (PLA) and 30% carbon fiber filament. Moreover, four groups of 3D-printed bio-inspired spherical-roof cubic cores were compared and analyzed on compressive properties and failure behavior. Experimental results were shown that foam-filled double bio-inspired spherical-roof cubic core with MWCNT was the maximum Fpeak with 1.92 kN, which provided a much more stable plateau load and better energy-absorbing characteristics. In addition, it is conducted that a double bio-inspired spherical-roof cubic core with four notches core is considered as the potential energy-absorbing core.

Mechanical performance of marine concrete filled CFRP-aluminum alloy tube columns under axial compression: Experiment and finite element analysis

This study presents the mechanical performance of marine concrete filled carbon fiber reinforced polymer (CFRP)-Aluminum alloy tube columns (CFRP-CFAT) through axial compression experiment and finite element analysis. 18 specimens were tested including 3 marine concrete filled aluminum alloy tubes (CFAT) and 15 CFRP-CFATs. The effects of the CFRP pasting position (outer and inner CFRP) and the number of CFRP layers were investigated. The typical failure pattern of specimens without inner CFRP was waist drum failure of aluminum alloy tube and concrete crushed, aluminum tube and concrete of specimens with inner CFRP were shear failure, the CFRP of all specimens was fractured. CFRP and aluminum alloy tube have fine deformation coordination performance. With the confinement of CFRP, the ultimate bearing capacity and energy absorption capacity of CFRP-CFATs were increased by up to 60.0% and 37.3%, respectively, also effectively inhibited the damage development of specimens. Moreover, a finite element model was developed, a parametric study was carried and a model for calculating the ultimate bearing capacity of CFRP-CFAT was proposed. The simulated results and calculated results were consistent with experimental results.

Study on compressive-torsional behaviour of square concrete filled CFRP-steel tube (S-CF-CFRP-ST)

Concrete filled carbon fiber reinforced polymer confined steel tube (CF-CFRP-ST) columns are having promising utilization in offshore structures such as tower columns of offshore fans and curved beam bridges, which are usually subjected to the combination of axial compressive loading and torsional loading. To reveal the compressive-torsional behaviour of square concrete filled CFRP-steel tube (S-CF-CFRP-ST), total 8 specimens were designed and tested under compressive-torsional load. Principal factors of test are the confinement factor of transverse CFRP, strengthening factor of longitudinal CFRP, axial compression ratio and the compressive strength of cubic concrete as principal factors. Based on the tests, a numerical simulation method is firstly proposed to estimate the compressive-torsional performance of S-CF-CFRP-ST, and then validated against the representative tests results, such as the failure modes, torque-rotation angle curves, and torque-shear strain curves. The test results reveal that the CFRP sheets are all under tension during loading and can cooperate well with steel tube as strains measured on CFRPs. The failure mode of S-CF-CFRP-ST belongs to ductile failure. Additionally, the compressive-torsional deformation of S-CF-CFRP-ST is in line with plane section assumption before the specimen gets into plastic stage. The good consistence between numerical results and experimental ones reveals that the proposed simulation method can predict the torsional behaviour of S-CF-CFRP-ST reasonably and accurately. Using this verified numerical models, parametric study is conducted to explore the influence of principle factors (e.g. CFPR layers, strength of concrete and steel, and steel ratio) on compressive-torsional behaviour of S-CF-CFRP-ST. It is found that the compressive-torsional bearing capacity of S-CF-CFRP-ST is slightly improved with the increase of CFRP layers and significantly affected by the strength of the used square steel tube. Additionally, the increase of steel ratio for CF-CFRP-ST member enhances not only the torsional strength but also the initial stiffness. Finally, an expression for calculation of torsional bearing capacity of S-CF-CFRP-ST is proposed based on the result of test and numerical simulation.

Development of a Test Bench for the Investigation of Thermoplastic-Thermoset Material Combinations in Additive Manufacturing

To enhance the mechanical properties of fused filament fabricated parts, the process integrates continuous fibers. Currently, fibers are impregnated either with thermoplastics or with thermoset material, which is completely cured before printing and later combined with thermoplastic filament during the coextrusion process. A major problem about using cured thermoset matrix for the fibers is an insufficient bond between the fiber matrix and the thermoplastic material. A new approach proposed by the authors combine uncured thermoset matrices with thermoplastic filaments to form a substance-to-substance bond. To investigate the material and bonding behavior, a test bench is constructed. Its main purpose is to replicate the coextrusion of thermoplastic filament and thermoset impregnated continuous fibers. Parameters, such as temperature, tension and extrusion speed can be adjusted within the setup to accurately simulate the additive manufacturing process. Aluminum blocks including heater cartridges and thermocouples act as hot ends and impregnation units. Heated blocks compact the fiber strands. We tested different heating blocks containing flat and curved geometries including actual additive manufacturing nozzles to evaluate the impregnation behavior of the dry carbon fiber filaments. Approaches with additive manufacturing nozzles show the most promising results regarding fiber impregnation with thermoplastic material.