Carbon Fiber Yarns Research Articles

Hygrothermal aging effect on static and fatigue behavior of three-dimensional five-directional hybrid braided composites under tension

This paper attempts to study the hygrothermal aging effect on static and fatigue behavior of carbon/glass fiber three-dimensional five-directional (3D5D) hybrid braided composites under tension. Firstly, moisture absorption tests and micro-CT scanning analysis were conducted on the composite specimens. The results show that the moisture absorption behavior follows the Fickian diffusion law well and the aging damage is dominated by matrix cracks/pores and interfacial debonding which is more severe in the braiding glass fiber yarn and surrounding regions than the axial carbon fiber yarn and surrounding regions. Then tensile tests and fatigue tests were performed on the unaged and aged composite specimens. It was found that hygrothermal aging has significant detrimental influence on the static tensile and tension-tension fatigue behavior of the composites. From experimental observations and failure analysis, it was also concluded that hygrothermal aging has impact on the failure mechanisms of the composites under both static tensile and fatigue loading owing to the extensively existed aging damage and deteriorated material properties in the aged composites.

A microscale modeling method for predicting the compressive behavior of 3D needled nonwoven fiber preforms

The through-thickness compressive mechanism of 3D needled nonwoven fiber preforms is complicated due to the complex fiber structure and enormous fiber-to-fiber contacts. This work developed a microscale modeling method to predict compressive behavior of carbon fiber nonwoven preforms. A newly-developed virtual fiber is proposed based on the generalized beam elements, for which the low bending stiffness of the fiber is calibrated by experimental data and decoupled from the high tensile stiffness. The feasibility of the proposed virtual fiber method is demonstrated through a simulation example of three-point bending of 6 k carbon fiber yarn. Influence of modeling parameters including amount of virtual fibers in the yarn and the element length of virtual fibers on the simulations is analyzed. High precision model of 3D needled preform is then generated using the proposed virtual fiber method. Through-thickness and axial compressive deformations of the preform are simulated. The predicted load–displacement curves agreed well with the experimental results.

Research on the upper limit of constant strain rates and dynamic fracture behavior for hybrid woven composite

Based on the analysis of stress wave propagation at both ends of the specimen, a formula for the upper limit of the constant strain rate is derived. The upper limit of constant strain rate is applicable to all the ratios of wave impedance, providing a broader applicability. The in-plane dynamic compressive behavior was obtained for 2D plain weave carbon/aramid hybrid composites at strain rates ranging from 195 to 790 s−1. The results validate the prediction of the upper limit of the constant strain rate. The strength exhibited sensitive to strain rate. A nonlinear constitutive model described the dynamic constitutive relationship effectively under different strain rates. The distribution of delamination failure significantly influenced the final failure shape of the specimens. Microscopic observations indicated that carbon fiber yarns and aramid fiber yarns exhibited different fracture modes.

Micro contact modeling of electrical current conduction behavior between carbon fiber yarns

Electrical contact conduction between carbon fiber yarns is one of the important current conduction paths inside carbon fiber composites and is easily affected with fabric reinforcement structure and manufacturing process. Here we proposed a micro contact model to predict the contact resistance and to reveal the current conduction behavior between carbon fiber yarns. The model takes into account tunneling effect and yarn geometric structure. The fiber contact probability between yarns was determined based on the statistical characteristic of the fiber height on the yarn surface. The relationship between the yarn contact resistance in plain weave fabric and out-of-plane force was measured and the experimental results agree well with the model. We found that the current conduction between yarns depends on contact conduction between fibers and the contribution of tunneling conduction is negligible. The proposed micro contact model provides insight into the current conduction behavior between carbon fiber yarns and is meaningful for the electrical conductivity design of carbon fiber composites.

MoS2 decorated carbon fiber yarn hybrids for the development of freestanding flexible supercapacitors

Academic and industrial efforts have focused on developing energy storage devices for wearable and portable electronics using low-cost, scalable, and sustainable materials and approaches. In this work, commercially available stretch-broken carbon fiber yarns (SBCFYs) were hybridized with mixed phases of 1 T and 2H MoS2 nanosheets via conventional and microwave-assisted heating (CAH, MAH) without the use of binders to fabricate symmetric freestanding 1D fiber-shaped supercapacitors (FSCs). Electrochemical characterization performed in a three-electrode configuration showed promising results with specific capacitance values of 184.41 and 180.02 F·g−1, at 1 mV·s−1 for CAH and MAH, respectively. Furthermore, after performing 3000 CV cycles at 100 mV·s−1, the capacitance retention was 79.5% and 95.7%, respectively. Using these results as a reference, symmetric 1D FSCs were fabricated by pairing hybridized SBCFYs with MoS2 by MAH. The devices exhibited specific capacitances of approximately 58.60 ± 3.06 F·g−1 at 1 mV·s−1 and 54.81 ± 7.34 F·g−1 at 0.2 A·g−1 with the highest power density achieved being 15.17 W·g−1 and energy density of 5.06×10–4 Wh·g−1. In addition, five 1D FSCs were hand-stitched and connected in series onto a cotton fabric. These supercapacitors could power a temperature and humidity sensor for up to six minutes, demonstrating the practicality and versatility of the prepared 1D FSCs for powering future electronic systems.

Study on the wear characteristics of carbon fiber yarns under the influence of multifactor coupling on braiding carriers

AbstractReducing the wear of carbon fibers on braiding carriers is the key to manufacturing high‐performance carbon fiber composite prefabricated parts. In this study, a new analytical model is developed to describe the local friction behavior of yarns on braiding carriers. The degree of yarn wear is characterized by calculating the gray value of carbon fiber hairiness and observing the micro‐surface morphology of carbon fibers. The wear characteristics of carbon fiber yarns under the multi‐factor coupling influences of yarn tension, unwinding speed, and guiding element characteristics were considered. The results show that increases in unwinding angle and unwinding speed both increase the wear of carbon fiber yarns. Eliminating the effect of unwinding angle can reduce the yarn hairiness by more than 60%, alleviate the yarn tension fluctuation by more than 70%, and improve the yarn tension stability by more than 75%. Meanwhile, the relationship between the wrapping angle between the yarn and the yarn bobbin, the unwinding angle, and the yarn tension was established according to the Capstan Equation. A method is proposed to improve the characteristics and spatial position of the guiding elements to obtain more intact yarn and low‐damage yarn surfaces.Highlights A new analytical model for local friction of carbon fibers is developed. The friction‐wear‐fracture mechanism of carbon fiber yarns is constructed. Characterize the degree of yarn wear from a macro and micro perspective. Wear characteristics of carbon fiber yarns under multi‐factor coupling.

Structure, Thermal, and Mechanical Behavior of the Polysulfone Solution Impregnated Unidirectional Carbon Fiber Yarns.

The paper is devoted to the study of thermal and mechanical behavior and structural features of the polysulfone solution impregnated unidirectional carbon fiber yarns depending on fabrication conditions and appearance for optimum production method of the composites. The effect of producing conditions, such as polysulfone solution concentration, drying and post-heating temperatures, and the residual solvent content on the structure, mechanical, and thermal properties of the carbon fiber-reinforced composites was studied. The polysulfone solution impregnated carbon fiber yarns show relatively high mechanical properties, realizing up to 80% of the carbon fibers' tensile strength, which can be attributed to good wettability and uniform polymer matrix distribution throughout the entire volume of the composites. It was found that the composites impregnated with 40 wt.% of the polysulfone solution showed lower porosity and higher mechanical properties. The results of a dynamic mechanical analysis indicate that residual solvent has a significant effect on the composites' thermal behavior. The composites heated to 350 °C for a 30 min showed higher thermal stability compared to ones dried at 110 °C due to removal of residual solvent during heating. The impregnated carbon fiber yarns can be used for the further producing bulk unidirectional composites by compression molding and the proposed method can be easily transformed to continuous filament production, for example for further use in 3-D printing technology.

Excellent performance of pH sensitive artificial muscles under large loading

The pH-responsive artificial muscle is a chemical-driven actuator without external power input. However, the low work density and adequate stability limit their practical applications. Herein, we combine the porous pH-responsive polymer with carbon fiber bundles for obtaining the coiled hybrid fiber. The coiled carbon fiber (CNF) yarn enhances the strength of hybrid fiber, and the swelling pH sensitive polymer limited to CNF provide a large stroke for hybrid fiber untwisting, resulting in an excellent work capacity and a high cycle life. When the load weight is 600 times the weight of the fiber itself, its work density reaches 287 kJ/m3. In addition, the hybrid fiber can reach a maximum stretching and contraction of 47% at a load of 400 times its own weight. The breaking stress of the obtained artificial muscle can reach more than 100 MPa. At the same time, the constructed porous polymer hydrogels improve the response rate of the artificial muscle, the response time is shortened to 10 min and do not decay in hundreds of cycles, which is further shown that the limiting effect of carbon fiber on the polymer improve the stability of the artificial muscle. It is indicated that the pH-responsive composite fibers have a high potential for use in artificial muscles, pH sensors and mechanical system.

Mineral-impregnated carbon-fiber based reinforcing grids as thermal energy harvesters: A proof-of-concept study towards multifunctional building materials

This proof-of-concept study demonstrates for the first time the fabrication of a multifunctional reinforcing grid-building material within a thermoelectric element generator (TEG) configuration. Commercially available carbon fiber yarns, which possess inherent Seebeck coefficient (S) values of −2.5 μV/K (n-type) and +7.4 μV/K (p-type), were thoroughly investigated prior to their impregnation with a geopolymer (GP)-based suspension. The resulting hardened mineral-impregnated carbon-fiber (MCF) reinforcements were subsequently tested regarding their physicochemical and mechanical properties. Afterward, individual MCFs were employed as n-/p-type thermoelements to assemble a grid-like TEG consisting of five serially interconnected junctions. The TEG-enabled reinforcing grid exhibited a voltage output of 1.8 mV, corresponding to a generated power of 22.3 nW upon exposure to an in-plane temperature difference (ΔT) of 50 K. Multifunctional building materials are envisaged to exploit thermal gradients on a large-scale during their service lifetime, contributing towards zero energy consumption constructions.

Improving the structural integrity of foam-core sandwich composites using continuous carbon fiber stitching

This study aims to improve the structural integrity of foam-core sandwich structures by embedding carbon-fiber/epoxy stitched reinforcements with fiber-volume fraction (Vf) as high as 55 %. Sandwich panels with 1.5 mm thick carbon fiber skins and 30 mm thick PVC foam-core were stitched with 0, 12 k and 24 k carbon fiber yarns. X-ray computed tomography (CT) was utilized to determine the “as-manufactured” quality of the stitched panels. Flatwise-, edgewise-compression and 3-point bending tests were conducted with in-situ 3D Digital Image Correlation (DIC) to record the deformation and analyze the structure’s mechanical response. It was observed that compared to non-stitched samples - under flatwise compression loading, the reinforced samples with a stitch Vf of 0.34 and 0.55 showed an increase in stiffness and strength by 130 % and 163 %, and 29 % and 53 %, respectively. For edgewise-compression and 3-point bending loading cases, stiffness and strength of stitched samples showed an increase of ∼20 % over the benchmark. Using DIC, X-ray CT and a fractography analysis, the external and internal damage as well as failure mechanisms were evaluated. Analytical solution was employed to understand the parametric influence of the stitch Vf and stitch density per unit area in pursuit of an optimized sandwich structure.

Damage Monitoring of Braided Composites Using CNT Yarn Sensor Based on Artificial Fish Swarm Algorithm.

This study aims to enable intelligent structural health monitoring of internal damage in aerospace structural components, providing a crucial means of assuring safety and reliability in the aerospace field. To address the limitations and assumptions of traditional monitoring methods, carbon nanotube (CNT) yarn sensors are used as key elements. These sensors are woven with carbon fiber yarns using a three-dimensional six-way braiding process and cured with resin composites. To optimize the sensor configuration, an artificial fish swarm algorithm (AFSA) is introduced, simulating the foraging behavior of fish to determine the best position and number of CNT yarn sensors. Experimental simulations are conducted on 3D braided composites of varying sizes, including penetration hole damage, line damage, and folded wire-mounted damage, to analyze the changes in the resistance data of carbon nanosensors within the damaged material. The results demonstrate that the optimized configuration of CNT yarn sensors based on AFSA is suitable for damage monitoring in 3D woven composites. The experimental positioning errors range from 0.224 to 0.510 mm, with all error values being less than 1 mm, thus achieving minimum sensor coverage for a maximum area. This result not only effectively reduces the cost of the monitoring system, but also improves the accuracy and reliability of the monitoring process.

Biomimetic construction of 3D needle‐punched CF/PEEK composites based on ladybug forewing structure for directional reinforcement

Abstract3D needle‐punched CF/PEEK composites are a kind of composites with promising applications in multiple fields, such as implant materials, but their mechanical properties in the Z‐axis and interlaminar are still weak at present. In this study, a bio‐inspired reinforcement structure based on ladybug forewing was developed to achieve directed reinforcement of 3D needle‐punched CF/PEEK composites. Carbon fiber yarns were stitched into the 3D needle‐punched CF/PEEK preforms according to the set structure, and the bio‐inspired CF/PEEK composites were obtained after hot pressing. The interlaminar and in‐plane mechanical properties of the composites were investigated at different stitch lengths. The results showed that the addition of the bio‐inspired structure greatly improved the interlaminar shear strength of the composites, reaching 111.30 MPa, an enhancement of 95.06%. The in‐plane mechanical properties, including tensile, flexural, and compression, were also significantly improved to different degrees. The “structure‐effect” relationship in the bio‐inspired CF/PEEK composites was investigated, and the effectiveness of such a bio‐inspired reinforcement structure was demonstrated. This new reinforcement strategy provides a new idea for the improvement of the mechanical properties of multi‐stage carbon fiber‐reinforced thermoplastic resin matrix composites.Highlights The in‐plane and interlaminar mechanical properties of composites were simultaneously improved. Up to 95.06% improvement in interlaminar shear strength. A novel bionic strategy of directional reinforcement was developed. The “structure‐effect” relationship in the composites was investigated.

Tensile Experiment and Numerical Simulation of Carbon Fiber and Polyvinyl Alcohol Fiber Helical Auxetic Yarns

Tensile Experiment and Numerical Simulation of Carbon Fiber and Polyvinyl Alcohol Fiber Helical Auxetic Yarns

Short carbon nanotubes: From matrix toughening to interlaminar toughening of CFRP composites

Carbon nanotubes (CNTs) are widely used for strengthening and toughening of resin matrix. However, the improvement of resin matrix toughness can't be effectively transferred to carbon fiber reinforced polymer (CFRP) composites due to the “fiber filtration effect”. Here, short carbon nanotubes (SCNTs, average length <2 μm) were added to the epoxy resin and then used as the matrix of CFRP. The test results showed that 0.5 wt% SCNTs is the optimal mass fraction for matrix toughening, which enhanced the maximum strain, maximum stress and toughness of the epoxy resin by 43.3%, 10.1% and 65.9%, respectively, and the mode I interlaminar fracture toughness of resultant CFRPs was increased by as much as 86.7%. The superior interlaminar toughening efficiency of SCNTs can be ascribed to their smaller size, which enables them to penetrate into the tiny gaps of carbon fiber yarns, thus not only effectively avoiding the “fiber filtration effect” and making them evenly distributed in the matrix, but also strengthening the interfaces between epoxy resin and carbon fibers.

Yarn tension model and vibration analysis during unwinding of carbon fiber bobbins

A low-quality unwinding process of the unwinding machine can lead to downtime of the knitting machine and loss of fabric quality. To address this issue, we studied the tension and vibration of carbon fiber yarns during unwinding. Based on the theory of axially moving strings, the dynamic model of carbon fiber yarn was established during the unwinding process, bringing the parameters into the simulation. According to the simulation results, the yarn tension in the unwinding process is closely related to the spring preload, which needs control within a certain range. When the unwinding speed increases, the fluctuation amplitude, lateral vibration amplitude, and axial vibration amplitude of the yarn tension gradually increase, causing friction and wear of the carbon fiber yarn. By controlling factors such as spring preload, unwinding speed, and the number of bobbins unwound simultaneously, one can effectively control the yarn’s vibration and improve the quality of the yarn.

On the Pressure and Rate of Infiltration Made by a Carbon Fiber Yarn with an Aluminum Melt during Ultrasonic Treatment

The effect of the infiltration time of a carbon fiber yarn in the range of 6 to 13.6 s on the infiltrated volume under the cavitation of an aluminum melt has been studied. When the infiltration time was more than 10 s, the carbon fiber was completely infiltrated with the matrix melt, and a decrease in the infiltration time led to a monotonous decrease in the fraction of the infiltrated volume. Based on the experimental data, the infiltration rate and the pressure necessary to infiltrate a carbon fiber yarn with an aluminum melt were estimated. The infiltration rate was 20.9 cm3/s and was independent of the infiltration depth. The calculated pressure necessary for the complete infiltration of a carbon fiber yarn at this rate was about 270 Pa. A comparison of the pressure values calculated according to Darcy’s and Forchheimer’s laws showed that the difference between them did not exceed 0.01%. This indicates that a simpler Darcy’s law could be used to estimate pressure.

A flexible all-solid-state symmetric supercapacitor with 1.6 V high voltage window was designed by in situ growth of α-FeOOH based on carbon fiber yarn

A flexible all-solid-state symmetric supercapacitor with 1.6 V high voltage window was designed by in situ growth of α-FeOOH based on carbon fiber yarn

Carbon-Yarn-Based Supercapacitors with In Situ Regenerated Cellulose Hydrogel for Sustainable Wearable Electronics.

Developing sustainable options for energy storage in textiles is needed to power future wearable “Internet of Things” (IoT) electronics. This process must consider disruptive alternatives that address questions of sustainability, reuse, repair, or even a second life application. Herein, we pair stretch-broken carbon fiber yarns (SBCFYs), as current collectors, and an in situ regenerated cellulose-based ionic hydrogel (RCIH), as an electrolyte, to fabricate 1D fiber-shaped supercapacitors (FSCs). The areal specific capacitance reaches 433.02 μF·cm–2 at 5 μA·cm–2, while the specific energy density is 1.73 × 10–2 μWh·cm–2. The maximum achieved specific power density is 5.33 × 10–1 mW·cm–2 at 1 mA·cm–2. The 1D FSCs possess a long-life cycle and 92% capacitance retention after 10 000 consecutive voltammetry cycles, higher than similar ones using the reference PVA/H3PO4 gel electrolyte. Additionally, the feasibility and reproducibility of the produced devices were demonstrated by connecting three devices in series and parallel, showing a small variation of the current density in flat and bent positions. An environmentally responsible approach was implemented by recovering the active materials from the 1D FSCs and reusing or recycling them without compromising the electrochemical performance, thus ensuring a circular economy path.

Effect of bonded length on the load response and failure mode of pull-out tests of GFRP bars embedded in concrete

• The stress transfer mechanism occurs within the superficial layer of resin. • The free end of the bar slips prior to attaining the peak load. • Load when the free end starts to slip and bond strength depend on bonded length. • Oscillations in the load are associated with the presence of a carbon fiber yarn. • Peak load versus bonded length is compared with the ACI 440.1R-15 formula. In this paper, the experimental results of pull-out tests of glass fiber-reinforced polymer (GFRP) bars embedded in concrete are presented and discussed. The experimental work is designed to investigate the effect of the bonded length on the bond behavior of the bars. Five bonded lengths are considered. The first bonded length is equal to 5 times the bar diameter ( d b ), which is the bonded length recommended in ASTM D7913. The other four bonded lengths are equal to 10 d b , 20 d b , 30 d b , and 40 d b . Loaded-end displacement is obtained from the measurements of three linear variable displacement transformers (LVDTs). Pull-out tests are performed in displacement control. For some specimens, the free-end displacement is measured by two additional LVDTs. The load responses in terms of applied load versus machine stroke, loaded-end slip, and free-end slip are plotted and compared for the different bonded lengths. The average shear stress is plotted versus the bonded length. Finally, the maximum axial stress in pull-out tests is plotted versus the bonded length and compared with the prediction of ACI 440.1R-15.

Preparation and characterization of a novel carbon/PAN/PPy@Zn yarn electrode

To fulfill the growing demand for durable and deformable flexible wearables, this study proposes a fibrous zinc ion battery negative electrode that is low-cost, easy to prepare, and similar to the flexible yarn. We have constructed a new type of carbon fiber/polyacrylonitrile(PAN)/polypyrrole(PPy) Zn electrode (CPP@Zn yarn electrode). Based on carbon fiber yarn, PAN wrapped carbon yarn (CP yarn) was prepared by electrospinning. PPy nanoparticles were deposited on CP yarn by in-situ polymerization to get the highly conductive yarn (CPP yarn). Finally, Zn is deposited on the CPP yarn by electrodeposition to obtain the CPP@Zn yarn electrode. When the deposition voltage is 1 V and the time is 30 min, the flexibility and the Zn crystal morphology of the CPP@Zn yarn electrode are the best, the specific capacity is the highest. When the current density is 0.04 A·cm−1, the specific capacity can reach 981.3 mF·cm−1 and the energy density is 0.18 W·h·cm−1. After cyclic charge and discharge repeated 300 times, 87.76% of the original specific capacity can still be maintained. After bending the CPP@Zn yarn electrode for 500 times, the specific capacitance can still maintain 86.13% of the original specific capacitance. The yarn electrode has excellent electrochemical stability and flexibility, and it has broad application prospects in wearable smart textiles.