Carbon Fiber Reinforced Polymer Matrix Research Articles

Stabilization of polyacrylonitrile-based fiber with a quasi-traveling microwave applicator

This study introduces a novel microwave applicator and optimized processing conditions to enhance the stability of Polyacrylonitrile (PAN)-based precursor fiber (PF). The innovative microwave applicator facilitates the propagation of the electromagnetic (EM) field akin to a quasi-traveling wave, thus circumventing standing wave nodes. This ensures a uniform thermal distribution and broadens the heating zone. Utilizing this applicator, the PF undergoes thermal stabilization in a streamlined two-step process, completing in just 13 min, a significant improvement over the conventional 90-min process. This not only saves manufacturing time, promoting energy efficient manufacturing but also aligns with the global trend towards green energy and lightweight carbon fiber-reinforced polymer matrix composites, potentially catalyzing rapid economic growth. Fiber characterization through Raman spectroscopy (RS), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and complex permittivity measurements reveals that the microwave-processed fiber meets the standard of commercial stabilization fiber (SF).

Evaluating shear capacity in reinforced concrete deep beams with web openings strengthened using fiber-reinforced polymer and fiber-reinforced cementitious matrix

This research systematically compares the effectiveness of Carbon Fiber-Reinforced Polymer (FRP) and Fabric-Reinforced Cementitious Matrix (FRCM) in shear strengthening of reinforced concrete (RC) deep beams featuring web openings. Through a comprehensive experimental program, six RC beams were subjected to shear tests, considering variations in the number of layers for both FRCM and FRP, employing a U-wrapping configuration. Recorded parameters include load-deflection curves, ultimate strength, cracking patterns, failure modes, and strains in steel bars, allowing a comprehensive comparison between strengthened and un-strengthened RC beams. The study compares observed shear strengths from experiments with shear capacities predicted by proposed models for RC beams strengthened with FRCM and FRP, following codes such as ACI 440.2R-17, CSA S806-12, Eurocode 2, and ACI 549.4R-20. Increasing layers enhanced shear strengths and post-elastic stiffness. The presence of substantial openings led to early shear cracks and reduced strength. CFRP improved shear strength by 13.99% (1-layer) and 18.12% (2-layer), while FRCM strengthened layers by 20.2% (1 layer) and 29.3% (2 layers). FRCM outperformed in strength and stiffness, while FRP excelled in ductility and concrete confinement. Experimental and calculated results varied based on ACI, CSA, and Eurocode, with ACI providing consistent and accurate results. CSA’s calculation surpassed experiments, emphasizing its consideration of effective fabric design strain.

Carbon fiber recovery from carbon fiber reinforced polymer matrix composite by microwave pyrolysis

The recovery of high-value carbon fibers (CFs) from carbon fiber-reinforced polymers (CFRP) is essential for advancing sustainability goals. In this study, CFs were extracted from CFRP using a microwave pyrolysis method known for its efficiency and environmental friendliness. The pyrolysis process was optimized through the response surface methodology to minimize carbon residue accumulation on the CFs' surface. The microwave pyrolysis of CFRP was simulated using COMSOL software to analyze temperature distribution patterns. The optimal parameters for microwave pyrolysis were determined as follows: a temperature of 543.7 °C, a holding time of 22.8 minutes, and a microwave power of 840.9 W, resulting in a residual carbon rate of only 3.7 %. Scanning electron microscopy (SEM) examination revealed no visible surface damage to the CFs. Analysis using X-ray diffraction (XRD) and Raman spectroscopy indicated a slight reduction in the crystallinity and graphitization level of the CFs due to the presence of deposited carbon. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) results suggested increased oxygen-containing functional groups. The comparative microstructural analysis between the pyrolyzed and pristine CFs showed no significant disparities. These results demonstrate the successful recovery of CFs through rapid resin pyrolysis in CFRP using microwave irradiation.

Comparison of Mechanical Property Simulations with Results of Limited Flexural Tests of Different Multi-Layer Carbon Fiber-Reinforced Polymer Composites.

This article is focused on the experimental study of flexural properties in different multi-layer carbon fiber-reinforced polymer (CFRP) composites and correlations with the results of finite element method (FEM) simulations of mechanical properties. The comparison of the results shows the possibility of reducing the number of experimental specimens for testing. The experimental study of flexural properties for four types of carbon fiber-reinforced polymer matrix composites with twill weaves (2 × 2) was carried out. As input materials, pre-impregnated carbon laminate GG 204 T and GG 630 T (prepreg) and two types of carbon fiber fabrics (GG 285 T and GG 300 T (fabric)) were used. Multi-layer samples were manufactured from two types of prepregs and two types of fabrics, which were hand-impregnated during sample preparation. The layers were stacked using same orientation. All specimens for flexural test were cut with the longer side in the weft direction. Pre-impregnated carbon laminates were further impregnated with resin DT 121H. Carbon fabrics were hand-impregnated with epoxy matrix LG 120 and hardener HG 700. To fulfill the aim of this research, finite element method (FEM)-based simulations of mechanical properties were performed. The FEM simulations and analysis were conducted in Hexagon's MSC Marc Mentat 2022.3 and Digimat 2022.4 software. This paper presents the results of actual experimental bending tests and the results of simulations of bending tests for different composite materials (mentioned previously). We created material models for simulations based on two methods-MF (Mean Field) and FE (Finite Element), and the comparative results show better agreement with the MF model. The composites (GG 285 T and GG 300 T) showed better flexural results than composites made from pre-impregnated carbon laminates (GG 204 T and GG 630 T). The difference in results for the hand-impregnated laminates was about 15% higher than for prepregs, but this is still within an acceptable tolerance as per the reported literature. The highest percentage difference of 14.25% between the simulation and the real experiment was found for the software tool Digimat FE 2022.4-GG 630 T composite. The lowest difference of 0.5% was found for the software tool Digimat MF 2022.4-GG 204 T composite. By comparing the results of the software tools with the results of the experimental measurements, it was found that the Digimat MF 2022.4 tool is closer to the results of the experimental measurements than the Digimat FE 2022.4 tool.

Erimiş Filament Üretim Yöntemi ile Üretilen Kompozit Yapılarda Yöne Bağlı Yüzey Özelliklerinin İncelenmesi ve İyileştirilmesi

Additive manufacturing methods, which have begun to be used in final product production beyond producing prototypes, are popular research topics today. The Fused Filament Fabrication (FFF) method, which has a wider usage area and user base, is the most well-known among these methods. The method in which the polymer is extruded in layers has advantages such as design freedom and topology optimization, as well as disadvantages such as surface roughness and low production speed. The number of materials that can be used in the FFF method is diversifying day by day, and polymeric composites can also be produced beyond pure polymers. The use of engineering polymers such as polyamide in this production method creates many new opportunities. In addition, the start of production of short fiber reinforced polymeric composites has paved the way to produce high-performance final products. In this study, the effects of parameters such as layer thickness and printing orientation on the surface roughness of samples produced using polyamide and short carbon fiber reinforced polymer matrix composite materials were examined. Chemical surface treatment was applied to the surfaces of 3D-printed samples to improve surface roughness. It was concluded that the increase in layer thickness increases the surface roughness, the -/+45 filling orientation creates higher roughness than the 0 and 90 orientations, and the surface quality can be increased by chemical surface modification.

Response of trigger type to crash box energy absorption performance

In this study, carbon fiber reinforced polymer matrix composites were produced to investigate the trigger effect on energy absorption performance. Production was carried out by vacuum infusion method. Three types of trigger geometry were opened on the composite crash boxes produced and a comparison sample without trigger was prepared. The quasi-static compression tests of these four different samples were carried out and the energy absorption performances of the samples were evaluated with the obtained data. In addition, the damages of the samples were examined, and it was revealed how they changed with the trigger. Accordingly, the sample described as S-2, and the triggered sample, which consists of four symmetrical slits downwards from its upper surface, exhibited the best performance.

Predicting Galvanic Corrosion of Aluminum Using Accelerated Laboratory Electrochemical Experiments

Aluminum (Al) alloys are the most commonly used non-ferrous metals (approximately 25 million tons per year) for various technical applications and is the second most commonly used metal alloy after steel. Al alloys are also used in combination with other metals or materials to get specific desirable properties for applications such as transportation, construction, electrical appliances, and consumer goods. However, a system of dissimilar materials can lead to potential corrosion problems such as galvanic and crevice corrosion. In this work, atmospheric galvanic corrosion of Al alloy was predicted by combining electrochemical techniques and accelerated laboratory corrosion tests. Three different galvanic couples were analyzed where 6061-T6 Al alloy was coupled with a passivating metal (304 stainless steel), noble metal (copper), and a carbon fiber-reinforced polymer matrix composite (CFR PMC). The galvanic current flowing between the anode and cathode was measured using the zero-resistance ammeter (ZRA) technique in the humidity-chamber setup, cyclic corrosion test chamber following a modified GM9540P cycle, and an outdoor exposure test site. Electrolytes with varying amounts of chloride contents were used to simulate different atmospheric conditions. Four separate equations based on Faraday's law were developed to calculate the corrosion rate in grams per meter square per day (gmd) by relating the time of wetness (TOW) to the galvanic current measured from the accelerated laboratory experiments. The total exposure time was divided into wet periods (Twet) and dry periods (Tdry). The surface morphology of Al samples from the galvanic couples was studied using a scanning electron microscope (SEM), and elemental surface analysis was conducted using energy-dispersive X-ray Spectroscopy (EDXA). Figure 1

Laser-induced heating, property changes, and damage modes in carbon fiber reinforced polymer matrix woven composites

Despite numerous efforts to understand mechanical damage in carbon fiber reinforced polymer matrix composites, there are minimal experimental and computational efforts that incorporate temperature effects on mechanical performance of composites. Recent studies have shown temperature changes can be readily monitored and predicted under relatively low heat fluxes. The present study augments such prior work by exploring effects of higher heat fluxes and increased heating rates. Plain-woven composites with T650 carbon fibers in a bismaleimide 5250-4 matrix were heated with a continuous wave laser (3.0 cm diameter flat-top beam profile at 1.0692 μm). Laser powers and durations were designed to reach temperatures near, and exceeding, matrix decomposition temperatures. Three duplicates of specimens were irradiated with four powers and two durations, yielding an irradiance range of 4.2 – 12.7 W/cm2. Resulting spatial and temporal temperature changes were measured with calibrated infrared cameras for both composite surfaces. Post-test surface photography and X‐ray CT scans were used to assess morphology changes and damage characteristics. Two key findings are reported herein: (i) delamination events dramatically impacted thermal transport, and (ii) TGA data and appropriate kinetic models can be used to account for temperature- / rate- dependent thermal responses and damage behaviors in the composites.

Biomimetic Design and Topology Optimization of Discontinuous Carbon Fiber-Reinforced Composite Lattice Structures

The ever-increasing requirements for structural performance drive the research and development of lighter, stronger, tougher, and multifunctional composite materials, especially, the lattice structures, heterogeneities, or hybrid compositions have attracted great interest from the materials research community. If it is pushed to the extreme, these concepts can consist of highly controlled lattice structures subject to biomimetic material design and topology optimization (TO). However, the strong coupling among the composition and the topology of the porous microstructure hinders the conventional trial-and-error approaches. In this work, discontinuous carbon fiber-reinforced polymer matrix composite materials were adopted for structural design. A three-dimensional (3D) periodic lattice block inspired by cuttlefish bone combined with computer modeling-based topology optimization was proposed. Through computer modeling, complex 3D periodic lattice blocks with various porosities were topologically optimized and realized, and the mechanical properties of the topology-optimized lattice structures were characterized by computer modeling. The results of this work were compared with other similar designs and experiments to validate the effectiveness of the proposed method. The proposed approach provides a design tool for more affordable and higher-performance structural materials.

Facile preparation, closed-loop recycling of multifunctional carbon fiber reinforced polymer composites

Recyclable carbon fiber reinforced polymer (CFRP) composites have attracted considerable attention in recent years due to the combined merits of excellent mechanical and thermal properties, recyclability and reprocessability. This paper reports on the successful preparation of closed-loop recyclable CFRP by in-situ polymerization and dynamic cross-linking (ISPDC) technology. The SEM, XPS and monofilament tensile curves were measured to investigate the morphology, chemical details, and mechanical properties of the recycled carbon fiber (CF); the chemical structure of the degraded resin was further characterized and analyzed according to the NMR and FTIR spectra. The obtained results show that under mild acidic conditions, the CFRP was degraded to high-quality recycled CF and linear polymer with methacrylic acid units, which can be used to prepare regenerated CFRP. In addition, due to the dynamic feature of the hemiacetal ester structure in the CFRP matrix, the CFRP also exhibited multiple functions, such as rapid welding, reprocessing, shape shifting, and self-healing, as well as the extremely long shelf life of composite prepregs. Our analysis of the recycling and dynamic exchange processes indicates that the strategy of embedding a releasable linker is dominant for the preparation of closed-loop recyclable and multifunctional CFRP.

Enhancing vertical thermal conductivity of carbon fiber reinforced polymer composites using cauliflower-shaped copper particles

Carbon fiber reinforced polymer (CFRP) composites are lightweight and mechanically robust, and therefore have received considerable attention with a wide range of applications from the aerospace to automotive industries. However, their low vertical thermal conductivity seriously limits the potential applicability of high-performance CFRPs in metal replacement. Herein, we propose a simple and effective, scalable strategy to fabricate thermally conductive and mechanically robust CFRP composites on the basis of formation of vertical heat transfer pathways using pressure-assisted thermal migration of cauliflower-shaped dendritic copper particles. A new type of CFRP composite was achieved by facile layer-by-layer coating of prepregs with dendritic coppers and subsequent pressure-assisted thermal processing under elevated temperature. The cauliflower-shaped dendritic copper particles efficiently infiltrated into the CFRP matrix and thereby provided an effective heat transfer pathway, resulting in a CFRP composite with an excellent vertical thermal conductivity of 2.321 W m−1 K−1, which is 155% higher than that of pristine CFRP. Moreover, the proposed CFRP composite afforded a high thermal diffusivity of 1.125 × 10−6 m2 s−1 and a low specific heat capacity of 1.267 J g−1 K−1, as well as an excellent flexural strength of about 2.4 GPa.

Simulation of tensile behaviour of carbon fiber reinforced polymer matrix composite

Simulation of tensile behaviour of carbon fiber reinforced polymer matrix composite

Mechanical and Tribological Properties of Polytetrafluoroethylene Modified with Combined Fillers: Carbon Fibers, Zirconium Dioxide, Silicon Dioxide and Boron Nitride.

The introduction of combined fillers can effectively improve the mechanical and tribological properties of polytetrafluoroethylene (PTFE). In this work, three different types of nanosized fillers (zirconium dioxide, silicon dioxide, and boron nitride) were introduced in a carbon fiber-reinforced polymer matrix for the development of polymer composite materials (PCM). Tensile and compressive testing were carried out, and the hardness of created PCM was evaluated. It is shown that the compressive strength of PCM increased by 30-70%, and the hardness, increased by 38-55% compared to the initial PTFE. The tribological properties of the developed PCM were evaluated under dry friction conditions. An analysis of the results of an experimental study of wear confirmed that the inclusion of combined fillers (two- and three-component) in PTFE significantly increased wear resistance compared to the polymer matrix with a slight increase in the coefficient of friction. It has been shown that the introduction of three-component fillers has an antagonistic effect on the wear resistance of PCMs compared to two-component fillers. The thermodynamic properties of the composites were analyzed by differential scanning calorimetry and a thermomechanical analyzer. The surface morphology of polymer composites after wear testing was studied by IR spectroscopy and scanning electron microscopy to investigate and suggest a possible mechanism for increasing the wear resistance of the developed composites.

Past, present and future prospective of global carbon fibre composite developments and applications

Carbon fibre and carbon fibre reinforced polymer matrix composites (CFRPs) are important lightweight materials for aerospace, automotive, rail transport, infrastructure, and renewable energy applications. This paper provides a comprehensive review on the history of carbon fibres and carbon fibre composites, the current global CFRPs consumption, and trends for future developments in the aerospace, wind turbine, automotive, pressure vessels, sports and leisure, and construction sectors. The history of carbon fibres and CFRPs is discussed over four representative periods including their early development (1950–60's), growth of carbon fibre composites industry (1970–80's), major adoption of carbon fibre composites (the first wave, 1990–2000's), and expanded use of carbon fibre composites (the second wave, 2010's and beyond). Despite a 37% decline of carbon fibre consumption in the aerospace industry in 2021 caused by COVID-19, the global CFRP demand was around 181 kt which more than doubled its value in 2014. There is tangible projected increase over the next five years and the demand for CFRPs is expected to reach 285 kt in 2025, mainly attributed from the fast expansion of non-aerospace industries such as the wind energy sector. Lower cost carbon fibres (e.g., large tow) and associated manufacturing technologies are continually evolving. Finally, the implications of emerging materials and manufacturing methods in conjunction with recycling and reuse for carbon fibre composites are discussed.

A novel embedded all-solid-state composite structural supercapacitor based on activated carbon fiber electrode and carbon fiber reinforced polymer matrix

Composite structural supercapacitors (CSSs), that provide both mechanical and electrochemical properties, have great potential for applications in electric vehicles, unmanned aerial vehicles and portable electronic devices with reduced overall system weight and volume. In this paper, a novel composite structural supercapacitor device is designed and fabricated, mainly consisting of energy storage units (flexible devices) and a structural unit (carbon fiber reinforced polymer, CFRP). KOH activated carbon cloth (ACC) and PVA-KOH gel electrolyte are selected as the electrode and electrolyte of the energy storage units, respectively. The specific capacitance, energy density and power density of 1:1 ACC-CSS reach 88 mF⋅g−1, 9.9 mWh⋅kg−1 and 445.5 mW⋅kg−1, respectively. Meanwhile, the flexural strength, flexural modulus and shear strength of 1:1 ACC-CSS achieve 230 MPa, 21 GPa and 8.75 MPa, respectively. In addition, the excellent stability of electrochemical performance of 1:1 ACC-CSS under various external loads is verified by electrochemical three-point bending, electrochemical tensile and electrochemical tensile fatigue tests as well. Experimental results show that even after mechanical failure, 1:1 ACC-CSS can still maintain its electrochemical performance. The combination of good electrochemical and mechanical properties of 1:1 ACC-CSS makes it a promising and competitive candidate for the development of composite structural energy storage devices.

Auxetic Composite Laminates with Through-Thickness Negative Poisson's Ratio for Mitigating Low Velocity Impact Damage: A Numerical Study.

Auxetic materials are those that exhibit negative Poisson’s ratios. Such a unique property was shown to improve the indentation and impact resistances. Angle-ply composite laminates can be designed to produce negative Poisson’s ratio at the laminate level due to the large anisotropicity of the individual layer and the strain mismatch between adjacent layers. This paper investigates the effect of through-thickness negative Poisson’s ratio on the low velocity impact behaviors of carbon fiber reinforced polymer matrix composite laminates, including the global impact behaviors, as well as the delamination, and the fiber and matrix damage. Results from numerical investigations show consistently reduced fiber and matrix tensile damage in the auxetic laminate in all plies, in comparison to the non-auxetic counterpart laminates (up to 40% on average). However, the auxetic laminate does not present a clear advantage on mitigating the delamination damage or the matrix compressive damage.

Effect of Nanofillers on the Mechanical Properties of Vinyl Ester Resin Used as a Carbon Fiber Reinforced Polymer Matrix

Effect of Nanofillers on the Mechanical Properties of Vinyl Ester Resin Used as a Carbon Fiber Reinforced Polymer Matrix

A Study on the In-Plane Shear-after-Impact Properties of CFRP Composite Laminates.

Impact loading on carbon fiber reinforced polymer matrix (CFRP) composite laminates can result in a significant reduction in their residual properties, and the (ShAI) properties of the composite material are essential to obtain the material allowable values of the shear dominated composite structures. In order to obtain the ShAI properties of the composite material in pure shear stress at a coupon level, this study presents theoretical, experimental, and numerical methods and analysis work on the in-plane shear and ShAI properties of the composite laminates. Theoretically, a method of sizing the composite specimen loading in shear is developed through comparing the load values due to buckling and the material failure. Following this, both impact tests using the drop-weight method and ShAI tests using the picture frame test method are conducted, and the influences of the impact energies on the impact damage and the residual ShAI values are evaluated. Moreover, a progressive failure finite element model based on the Hashin’s failure criterion and the cohesive zone model is developed, and a two-step dynamic analysis method is performed to simulate the failure process of the composite laminates under impact loading and ShAI loading. It is found that the impact damage with the cut-off energy, 50 J, causes a 26.8% reduction in the residual strength and the residual effective shear failure strain is about 0.0132. The primary reason of the shear failure is the propagation of both the matrix tensile failure and interlaminar delamination. It can be concluded that the proposed theoretical, experimental, and numerical methods are promising factors to study the ShAI properties of the composite materials.

Effects of midplane carbon nanotube sheet interleave on the strength and impact damage resistance of carbon fiber reinforced polymer composites

AbstractThe effects of embedding a midplane carbon nanotube (CNT) sheet on the impact damage resistance, tensile strength and propensity for interlaminar shear failure in a carbon fiber reinforced polymer matrix composite is experimentally evaluated. External and internal damage in the impacted composite laminates were characterized via surface profilometry and ultrasonic C‐scan, respectively. The external dent areas and dent depths were greater for impacted laminates without the CNT sheet interleave, while the planar internal damage areas were greater for the impacted laminates with the CNT sheet. Destructive evaluation of the impacted laminates showed significant delaminations and matrix cracks in the vicinity of the midplane for the laminates with the CNT sheet, while damage was more distributed through the thickness in the non‐CNT sheet ones. While a single CNT sheet interleave did not significantly affect the tensile strength of the laminate, residual strength after impact and the corresponding strain to failure was higher because of the CNT sheet interleave. The propensity for interlaminar shear failure was greater for laminates without the CNT sheet than those with the CNT sheet.

Debonding-on-demand adhesive film using internal Joule heating effect of the steel-aramid braided reinforcement

Carbon fiber-reinforced polymer (CFRP) composite materials are widely employed as lightweight and high-strength materials. Recently, interest in reuse has increased in terms of price and environmentally friendly. In this study, a novel adhesive film that can selectively control adhesive strength was studied. This debonding-on-demand (DOD) adhesive film is stitched by stainless steel fibers to be heated up to 239.3 °C in 5 min through Joule heating. The polymeric adhesive layer in the midst of the carbon plies is thermally damaged, and then it is successfully delaminated with no further damage to the carbon fiber or CFRP matrix materials. Thermal, optical, and mechanical testing were performed on the prepared DOD film. It is noted that the optimal structure of DOD film includes electrical insulation layers, and the number of stitch lines is carefully designed for reliable bonding and debonding performance.