Carbon Fibre Reinforced Research Articles

Machinability of 3D printed peek reinforced with short carbon fiber

The new manufacturing technologies are advancing and developing rapidly, gradually causing some conventional processes used until now to become obsolete or relegated to second place. One of the challenges of emerging manufacturing processes is sustainability, decreasing raw materials and recycling used components. Additive manufacturing is among these new technologies, allowing the fabrication of complex geometries and the reduction of waste by producing parts close to their commissioning (i.e., net-shape or near-net-shape manufacturing) and the recycling of used components to develop raw material.One of the most widely used thermoplastic materials in manufacturing is polyether ether ketone (PEEK), mainly due to its good mechanical properties. The use of fibers as a means of reinforcement in polymeric materials has witnessed a significant surge in recent times to enhance mechanical properties. Recycling these fibers from other components after service life, giving a second life to these materials, would have a high impact in terms of sustainability. CFRPs have been widely used in different sectors in the last decades, providing a source of carbon fibers suitable for use as polymer reinforcement in additive manufacturing.Processing operations are often necessary to reach dimensional and joining (e.g., assembly) specifications. Despite its widespread use in the industry requiring certain postprocessing operations, just a few publications analyze the machinability of PEEK polymer. The addition of carbon fiber reinforcement influences the machinability of the polymer. This study uses orthogonal cutting tests to focus on the machinability of 3D printed PEEK with and without short carbon fiber reinforcement through orthogonal cutting tests.The additive process procedure is analyzed in terms of printing orientations. The effect of machining parameters (cutting speed and the depth of cut) on the force generation, the superficial damage, and the temperature reached in the samples are also analyzed and related with the addition of reinforcement.

Shape recovery and mechanical properties investigation of carbon fiber dispersed bisphenol-A based epoxy composite

Shape memory polymers (SMPs) are employed in a wide range of fields because to their appealing properties, which include low density, low production costs, and ease of processing. In the present work, SMP composites were developed using ultrasonic mixing of carbon fiber (CF) and amorphous epoxy to enhance the properties of epoxy and shape memory effect. The prepared composites were tested for mechanical and shape memory properties. Flexural strength and tensile strength of pristine epoxy enhanced after dispersing 1% CF which are about 12.7% and 16.2%, respectively, higher than pristine epoxy. Fracture toughness of epoxy improves after adding 1% CF which is about 94.05% higher compared to pristine epoxy. UV–vis-NIR showed reduction in energy bandgap. Shape fixity and shape recovery ratios for pristine epoxy was 98.49% and 93.40%, respectively. These ratios decrease to 90.52% and 87.86%, respectively with addition of 1.5 wt.% CF. However, recovery time improves from 57 s to 33 s with addition of 1.5 wt.% CF in epoxy. Shape recovery rate enhances with CF reinforcement in epoxy composite.

Solid particle erosion and scratch behavior of novel scrap carbon fiber/glass fabric/polyamide 6.6 hybrid composites

AbstractThis study investigated the tribological performance of hybrid composites composed of scrap carbon fiber (CF), glass fabric (GF), and polyamide 6.6 (PA6.6) through an innovative approach for reusing scrap CFs in high‐value composite structures. The experimental setup included CF/GF/PA6.6 hybrid composite laminates with varying CF contents and surface‐modified GFs, as well as PA6.6 sheets and GF/PA6.6 composite laminates. Solid particle erosion and scratch tests were conducted to assess the influence of scrap CF hybridization and GF surface modification on the tribological properties of the composites. The results demonstrated that neat PA6.6 sheets exhibited the lowest erosion rate, while the incorporation of CF and GF reinforcements had a detrimental effect on erosion resistance. The highest erosion rate was observed within the impact angle range of 15°–30° for pure PA6.6 sheets, whereas for composite laminates, it occurred within the range of 30°–45°. In contrast, CFs positively affected scratch hardness despite their negative impact on erosion resistance. Additionally, the silane treatment of GFs, which enhanced interfacial strength, improved the erosion resistance and scratch hardness of GF/PA6.6 composite laminates without CF. Profilometer‐based topographic analysis revealed a correlation between the average surface roughness of the eroded surfaces and the weight loss resulting from solid particle erosion.

Lower Carbon Footprint Concrete Using Recycled Carbon Fiber for Targeted Strength and Insulation.

The production of concrete leads to substantial carbon emissions (~8%) and includes reinforcing steel which is prone to corrosion and durability issues. Carbon-fiber-reinforced concrete is attractive for structural applications due to its light weight, high modulus, high strength, low density, and resistance to environmental degradation. Recycled/repurposed carbon fiber (rCF) is a promising alternative to traditional steel-fiber reinforcement for manufacturing lightweight and high-strength concrete. Additionally, rCF offers a sustainable, economical, and less energy-intensive solution for infrastructure applications. In this paper, structure-process-property relationships between the rheology of mix design, carbon fiber reinforcement type, thermal conductivity, and microstructural properties are investigated targeting strength and lighter weight using three types of concretes, namely, high-strength concrete, structural lightweight concrete, and ultra-lightweight concrete. The concrete mix designs were evaluated non-destructively using high-resolution X-ray computed tomography to investigate the microstructure of the voids and spatially correlate the porosity with the thermal conductivity properties and mechanical performance. Reinforced concrete structures with steel often suffer from durability issues due to corrosion. This paper presents advancements towards realizing concrete structures without steel reinforcement by providing required compression, adequate tension, flexural, and shear properties from recycled/repurposed carbon fibers and substantially reducing the carbon footprint for thermal and/or structural applications.

Coatings Made by Atomic Layer Deposition for the Protection of Materials from Atomic Oxygen in Space

Atomic Layer Deposition (ALD) has been investigated for the possible protection of various materials against atomic oxygen (ATOX) at ESTEC Materials and Electrical Components Laboratory facility. ALD is a conformal coating process, that can be used to apply ultra-thin films of metal oxides on various materials, that may have a sophisticated three-dimensional shape, such as the internal and external components of satellites. The challenge with metal oxides on soft and/or flexible surfaces arises from the brittle nature of these ceramic films if their thickness exceeds 30 nm. Different substrates, including silicon, Printed Circuitry Board (PCB), polyimide, and Carbon Fibre Reinforced Polymers (CFRP) were coated by ALD with 20 nm thick metal oxide films at 125 °C, then exposed to ATOX and characterized by photographing, reflectance measurement and scanning electron microscopy (SEM). The studies showed good performance of protective films prepared by ALD on polymer substrates, which suggests that the nanometer-scale coatings can improve the lifetime of these materials at low Earth orbit, where they are inevitably exposed to ATOX. In contrast, the uncoated substrates suffered near-surface damage after exposure to ATOX, which resulted in microscopic features on their surface that were visible in SEM. Damage caused by ATOX to the uncoated substrates was also visible in photographs and observable in reflectance studies. In the latter case, the changes in the reflectance spectrum were caused by the change of surface morphology and/or chemical and elemental composition due to corrosion by ATOX.

A focused review on the tribological behavior of C/SiC composites: Present status and future prospects

Silicon carbide-based ceramic matrix composites have received extensive attention in recent years. Many excellent reviews have reported on the tribological behavior of carbon fiber-reinforced carbon and silicon carbide dual matrix (C/C-SiC) composites. However, a systematic overview of the tribological properties of carbon fiber-reinforced silicon carbide (C/SiC) composites does not exist. This review focuses on C/SiC composites and summarizes the key factors, including internal factors (constituent content, graphitization process, material structure and fiber direction), and various test conditions (pressure and speed, dry and wet, temperature, and counterparts) that affect their tribological behavior. Their wear mechanisms under different conditions are elaborated. Finally, some potential future development directions for improving the performance of C/SiC composites are proposed to provide high-quality ceramic matrix composites for engineering applications. These directions include structural modification, matrix modification, coating technology, laser surface texturing, and material genome method.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

Exploration of a crucial mechanical property of gap-filling materials for restoration of deformed bronze and tentative application of carbon fiber reinforced composites

The fracture of a bronze object is usually accompanied by localized deformation. The deformed part often tends to spring back at an unpredictable moment after its shape is corrected. The reconstruction of the area adjacent to the damage should be sufficiently resistant to the stress derived from springback so that the whole structure can remain stable. However, the choice of gap-filling materials for bronze objects is typically based on personal experience, and there are few available studies on their pertinent properties. The present study focused on a typical situation of deformation, took the flexural modulus as a crucial parameter and explored the development of a protocol for selecting a gap-filling material for bronze restoration in terms of its mechanical property. The flexural modulus was measured for the main classes of materials in use, and the factors related to preparation that influenced performance were studied. Among the various materials tested, carbon fiber reinforced (CFR) materials exhibited an advantageous value of the modulus and notable operational convenience. Further tests were conducted to assess their chemical safety for application in a museum context, as well as their surface workability. After obtaining overall encouraging results, composites reinforced with CF cloth and chopped CF were applied to the reconstruction of different parts of an archaeological bronze vessel. Indications for future improvement in the experimental setup and some practical notes regarding the use of CFR materials were also provided in this paper.

Temperature‐dependent inter‐laminar fracture behavior of waste short carbon fiber embedded glass fiber/epoxy composites

AbstractDelamination is one of the life‐limiting failure modes for fiber reinforced polymer (FRP) composite composites resulting in poor damage tolerance, as this failure mode occurs at considerably lower loads. Owing to the enormous demand and mass production of FRP composites, a large amount of fiber waste is produced worldwide. This triggers concern about utilizing these fiber wastes for some valuable applications. The present study aims to improve the overall damage tolerance of laminated glass/epoxy composites via the introduction of waste short carbon fibers (SCFs) reinforcement in the epoxy matrix. The effect of various SCF contents (0.1, 0.3, and 0.5 wt%) in glass fiber/epoxy composites were evaluated experimentally for their interlaminar fracture toughness in terms of both crack development and propagation under mode I and II interlaminar fracture toughness tests, at elevated temperatures (30, 50, and 70°C). Based on the experimental results, glass/epoxy composite with 0.1 wt% of SCF revealed 13.49% and 20.45% increment in mode I and II interlaminar fracture toughness, respectively, at ambient temperature. A positive reinforcement effect could be noticed for GIC and GIIC values up to 50°C. However, due to residual interfacial stresses, interfacial debonding, and epoxy softening, a negative reinforcement effect could be noticed at 70°C. Delamination initiation and crack propagation mechanisms have been explored at elevated temperatures. Fractographic studies have been carried out using a scanning electron microscope to identify the failure mechanisms.

Comparative Cradle-to-Grave Carbon Footprint of a CFRP-Grid Reinforced Concrete Façade Panel

Due to climate change and current efforts to reduce emissions in the construction sector, this study evaluates and discusses the results of a comparative cradle-to-grave Life Cycle Assessment (LCA), with a main focus on Global Warming Potential for functionally equivalent carbon-reinforced concrete (CRC) and steel-reinforced concrete (SRC) façade panels for the first time. The novelty of this study is the focus on construction waste and, in particular, the worst-case application of non-recycled construction waste. The use of CRC requires a lower concrete thickness than SRC because the carbon fiber reinforcement does not corrode, in contrast to steel reinforcement. Façade panels of the same geometrical dimensions and structural performance were defined as functional units (FU). Assuming an End-of-Life (EoL) scenario of 50% landfill and 50% recycling, the Global Warming Potential (GWP, given in CO2 equivalent (CO2e)) of the CRC façade (411–496 kg CO2e) is shown to perform better than or equal to the SRC façade (492 kg CO2e). Changing the assumption of CRC to a worst-case scenario, going fully to landfill and not being recycled (single life cycle), turns the GWP results in favor of the SRC façade. Assuming a 50-year service life for the SRC façade panel and relativizing the emissions to the years, the more durable CRC façade performs much better. Finally, depending on the system boundary, the assumed EoL and lifetime, CRC can represent a lower-emission alternative to a functionally equivalent component made of SRC. The most important and “novel” result in this study, which also leads to future research opportunities, is that delicate adjustments (especially concerning EoL scenarios and expected service life) can lead to completely different recommendations for decision-makers. Only by combining the knowledge of LCA experts, structural engineers, and builders optimal decisions can be made regarding sustainable materials and building components.

Masonry Wall Reinforcement

Unreinforced masonry has been used as a construction material for thousands of years. Whilesome of these structures survive to this day, these tend to have massive walls and would be unpractical formodern use. Unreinforced masonry can be reinforced with proper masonry techniques. As a result,reinforced and confined types of masonry were developed to exploit the strength potential of masonry andto solve its lack of tensile strength, significantly improving not only resistance, but also ductility andenergy dissipation capacity.Fiber reinforced polymer composites have emerged as an effective means of reinforcing masonrystructures due to their high mechanical characteristics, low weight and durability. The role of FRPmaterials is to act as a tensile reinforcement which can be used to improve the ability of a wall against inplane shear and/or out-of-plane bending.This contribution, based on experimentation and numerical modelling, aims at a better understanding ofthe behaviour of structures in masonry. Multiple reinforcement techniques and methods are illustrated inthis summary, such as the reinforcement of masonry walls by composite materials like CFRP (CarbonFiber Reinforced Polymer) and glass fibre reinforced polymer (GFPR), also there are Near surfacemounted (NSM), carbon fibers reinforced polymer (CFRP) and other techniques are cited in this work.

MECHANICAL BEHAVIOUR OF CARBON AND JUTE FIBERS REINFORCED ALUMINIUM LAMINATES FABRICATED IN DIFFERENT STACKING SEQUENCES

In this research work, the mechanical properties of aluminium laminates having carbon fiber reinforcement and carbon-jute fibers reinforced aluminium laminates fabricated in different stacking sequences are studied. Here the fiber metal laminates are manufactured through the hand layup technique. A compression moulding machine was used to press the laminates during the production process. In this study, carbon and jute fibers along with thin aluminium sheets are used as reinforcement. Four different stacking sequences were selected. Each arrangement is symmetric and consists of ten layers of reinforcements. The fabricated laminates were subjected to tensile, compressive, flexural, hardness and impact tests. The test results show that the laminate L2 with outermost layers of carbon fibers revealed the highest tensile strength of 268 MPa, followed by L4 laminate with jute fibers outer layers having a tensile strength of 226 MPa. Whereas, the laminates L1 and L3 with outer layers of aluminium sheets show improved flexural and impact strength along with high hardness value. The flexural strengths are 246 MPa and 204 MPa respectively. Impact strength of 36 MPa, 32 MPa and hardness value of 64 HVN and 62 HVN respectively.

Hybrid reinforced effect of long carbon fiber and short glass fiber on polycarbonate foams

AbstractBecause of advantages such as remarkable mechanical properties and the ease of recycling, fiber‐reinforced thermoplastic polymer composites have been increasing in importance in industrial, transport, and sporting potential extraordinary applications. To fabricate polycarbonate (PC) components with lightweight and high mechanical properties, short glass fiber (SGF), long carbon fiber (LCF) reinforcement, and foaming technology were used in this study. The effects of SGF, LCF, and SGF/LCF on the mechanical properties and foaming quality of PC samples were carefully investigated and compared. The results show that SGF has a better foaming nucleation effect than LCF, and the mechanical enhancement effect of LCF is more significant than that of SGF. The combination of SGF and LCF can effectively improve the cell quality of foam samples and significantly enhance their mechanical properties. Therefore, a comprehensive application of the fiber‐reinforcement effect of PC resin is proposed.Highlights LCF and SGF reinforced PC foams have been successfully fabricated. Hybrid reinforced effect of LCF and SGF on PC foams was verified.

Deformation Behavior of Carbon Fiber/Al Composites with Corrugated Structure for Developing the Rolling Plate

Herein, a rolling strategy for carbon fiber (CF)/Al composites is proposed, that is, by constructing a corrugated structure of Sn‐protected CFs ([CF@Sn]≈Al composites), to realize the cooperative extension of woven CFs with Al matrix deformation in the rolling process. The matching extension feasibility and structural optimization of (CF@Sn]≈Al composites are calculated based on the designed 3D numerical model of rolling system. The [CF@Sn]≈Al composites have successfully combined excellent mechanical properties while meeting the extension design of the CF reinforcement. Mechanical testing of the samples indicates that the tensile strength of the [CF@Sn]≈Al composites increases by 18.6% while the bending strength is more than 23.2% higher than that of the rolled Al matrix. The present work provides an effective method for developing the deformed CF/Al composites as rolling plate in lightweight applications.

Fluorescent aggregate structure revealed in bisphenol F epoxy thermoset

Bisphenol F (BPF) epoxy resin is a prepolymer component of thermosets used in construction of reinforced carbon fiber composites (RCFC). The fluorescence of this resin can provide information about chemical and structural alterations of the thermoset from thermal or mechanical damage. While some work has investigated the fluorescence spectra of bisphenol A epoxy resin, a structural analog of BPF, none have studied BPF. The purpose of this study is to investigate the baseline fluorescence spectra of the BPF epoxy resin for features that could be utilized for monitoring damage and structural alterations. Bisphenol F epoxy resin was found to have two emission peaks with a broad peak centered at 410 nm and a sharp peak centered at 550 nm. The broad emission peak was identified as the fluorescence from BPF epoxy monomer while the sharp emission peak was found to be from an aggregate structure present in the epoxy resin. It is hypothesized that this structure is an H-aggregate based on the emission features and structural stability of the aggregate compared to the alternative J-aggregate which was determined via density functional theory calculations. The H-aggregate was found to persist into one of the cured thermoset formulations evaluated but was lost when exposed to elevated temperatures below thermal degradation of the thermoset. This loss of aggregate structure was due to polymer network rearrangement. This new fluorescence signature can be used as an indicator of polymer network rearrangement from thermal exposure which may alter the expected material performance and precede thermal degradation.

“Investigation of Lap Shear Strength on Hybrid FRP (Carbon / Glass) / Al6061 Single Lap Joint

The joining strength of three different layered composites made of carbon-glass-carbon-glass, carbonglass-glass-carbon, and glasscarbon-carbon-glass was investigated in the current work utilising a single lap joint. Composite materials containing carbon fibre and glass fibre reinforcement were bonded with 6 series aluminium alloy. As a joining method, adhesive joints, mechanical joints, and hybrid joints (a combination of adhesive and mechanical joints) were all employed. It was discovered that the mechanical and hybrid joints in the carbon-glass-glass-carbon layered composite performed better than those in other layered composites and adhesive bonding joints. The mechanical and hybrid joining of the carbon-glassglass-carbon layered composite was found to have the highest strength among all other combinations tested in this study, with maximum loads of 3.33 KN and 3.14 KN, respectively. The other combinations had maximum loads that were lower than 3.33 KN.

Effects of Abrasive Waterjet Machining on the Quality of the Surface Generated on a Carbon Fibre Reinforced Polymer Composite

The effect of the water pressure, traverse speed, and abrasive feed rate on the circularity, cylindricity, kerf taper, and surface roughness of holes produced by abrasive waterjet machining (AWJM) of a carbon-fibre-reinforced polymer (CFRP) composite was investigated in the current study. It was found that the circularity deviation decreased as the water pressure was increased. Cylindricity was affected by all three parameters, although the abrasive feed rate caused the largest deviations as it increased. The surface roughness was affected by all three, but a clear connection was not able to be concluded. The kerf taper ratio reduced with an increase in water pressure, while it increased with an increase in the abrasive feed rate and an increase in the traverse speed. To obtain optimum results, the water pressure should be increased, the traverse speed should be decreased, and the abrasive feed rate can remain constant but is recommended to be slightly reduced.

Novel zone-based hybrid laminate structures for high-velocity impact (HVI) in carbon fibre-reinforced polymer (CFRP) composites

We propose novel zone-based hybrid laminate concepts for improving the high-velocity impact (HVI) response of baseline carbon fibre-reinforced polymer (CFRP) composites while maintaining similar areal weights and retaining substantial in-plane mechanical properties by requiring that about 80% (by mass) of the baseline CFRP is kept in the hybrid concepts. We identify three zones along the thickness of the laminate according to their role during HVI and implemented tailored materials in these zones to improve the HVI response. We studied a wide range of materials, including: fibre reinforcements of carbon (thin- and thick-plies), glass, Zylon and ultra-high molecular weight polyethylene (UHMWPE); a shape memory alloy/carbon fabric; and ceramic, alumina and titanium sheets. All laminate concepts have similar areal weights for a meaningful comparison. After defining the various concepts, we manufactured and measured their specific dissipated energy under HVI, and finally carried out post-mortem analysis (including C-scan and microscopy). The results show up to 95% improvement in energy dissipation over the baseline quasi-isotropic (QI) CFRP configuration.

Model analysis of carbon fiber reinforcement properties for reinforced concrete beams to resist blast loads

Safety is paramount in Oil & Gas plants, and continuous monitoring and improvements ensure that all measures are taken to protect them. The purpose of this paper is to examine how composite materials can be used to improve the structural reinforcement of concrete beams. Concrete structural beams have been improved in the past by using varying Fiber Reinforced Properties (FRP). It has been investigated how Carbon Fiber Reinforced Properties (CFRP) composites perform under blast loads and how they behave, respond, and perform as reinforcement for reinforced concrete beams. The response of RC beams to blasts was analyzed using a software modelling program called ANSYS that can mimic RC beam properties when reinforced with CFRP in concrete structures. The reason CFRP was chosen was because its properties showed great potential and it is well suited for testing and analysis. As well as absorbing a lot of energy, this material is strong, elastomeric, and alkali-resistant. A numerical analysis and model analysis have been performed with the help of the ANSYS software program. In the experimental results, CFRP was found to increase the flexural and shear strength of RC beams. The RC beams reinforced with CFRP has outperformed RC beam (control beam) in factors such as in Deformation, Equivalent Stress, and Shear Stress by a minimum percentage difference of 0.784% and maximum of 7.09% depending on the layers of CFRP and load applied on the beams in each factor.

Influence of Carbon Fibre Reinforced Polymer and Recycled Carbon Fibres on the compressive behaviour of self-compacting high-performance fibre-reinforced concrete

Influence of Carbon Fibre Reinforced Polymer and Recycled Carbon Fibres on the compressive behaviour of self-compacting high-performance fibre-reinforced concrete