Increasing Carbon Fiber Content Research Articles

Mechanical Performance/Cost Ratio Analysis of Carbon/Glass Interlayer and Intralayer Hybrid Composites

Hybrid composites combining carbon and glass fibers are increasingly studied for their potential to enhance mechanical properties and cost efficiency. Understanding how different hybrid structures influence these properties is critical for optimizing material design and application. In this paper, the mechanical properties of carbon/glass (C/G) interlayer and intralayer hybrid composites, including tensile, compressive, and flexural properties, were tested, and the cost performances of hybrid composites were analyzed to assess the economic feasibility of different stacking configurations. It was revealed that the specific tensile, compressive, and flexural modulus/cost and strength/cost ratios of interlayer and intralayer hybrid composites decreased with increasing carbon fiber content, indicating that adding carbon fiber reduced cost performance. With the combined hybrid ratio and the interlayer structure with glass fiber sandwiching carbon fiber, the tensile and compressive properties were the most cost-effective. When the dispersion degree of the intralayer hybrid structure was 0, the tensile and compressive properties were the most cost-effective. Specifically, for intralayer hybrid composites with a dispersion degree of 0 and C:G = 1:4, the specific tensile strength/cost ratio was 6.7 × 104 N·m/USD, and the specific compressive modulus and strength/cost ratio was 3.8 × 106 N·m/USD and 4.7 × 103 N·m/USD, respectively. However, the flexural performance/cost ratio was found to be opposite to the tensile and compressive results. When carbon fiber was distributed in the bottom layer or used to sandwich the glass fiber, the flexural performance/cost ratio of interlayer hybrid composites was nearly as good as that of glass fiber. Moreover, by considering the working condition of composites, the cost performance of mechanical properties can be optimized and improved through careful design of hybrid ratios and stacking structures.

Experimental and numerical studies of the effects of micro/nano carbon fibers in the dynamic behavior of cement-based grouting materials for reinforcement of sand layers

Geological hazards of sand layers pose a serious threat to engineering safety. Grouting reinforcement technology is widely used in such conditions due to its convenience, economy, and effectiveness. To explore the reinforcement effect of carbon fiber (CF) modified cement-based grouting materials on sand layers, grouting solidified bodies (GSB) with CF contents of 0.0%, 0.5%, 1.0%, and 1.5% are selected for Split Hopkinson Pressure Bar (SHPB) impact tests, scanning electron microscope (SEM) scanning, and numerical simulation experiments. The mechanical properties of specimens under dynamic impact conditions and the reinforcement mechanism of CF are studied. Results show that GSB is a strain-rate-dependent material. With the increase of impact rate, peak stress, incident energy, transmitted energy, and dissipated energy of specimens gradually increase, while the integrity of specimens decreases. The CF content remarkably affects the mechanical properties of specimens. When the impact rate is constant, with the increase of CF content, the peak stress and transmitted energy of specimens show a decreasing–increasing– decreasing trend, and the performance of CF-1.0% specimens is optimal. The cement matrix is the main energy storage and release medium, accounting for 97.66% of the energy. When damaged, the cement matrix is mainly fractured. At the microcrack tip, CF influences the direction of crack propagation, reducing the radius of crack propagation, and the main failure mode of CF is debonding. CF can substantially improve the mechanical properties of specimens and reduce the number of cracks. Compared with CF-0.0%-cementitious material (CM) specimens, the peak stress of CF-1.0%-CM specimens is increased by 19.98%. The magnitude of CF force is related to the angle between crack and CF. As the angle increases from 0° to 90°, the CF force gradually increases, reaching the maximum at 90°, with an increase of 133.82%. At this angle, the anti-cracking effect of CF is most substantial. The research results can provide technical support for sand layer grouting reinforcement technology.

Study on mechanical properties and self-sensing properties of sprayed high-performance concrete containing glass aggregate

Using glass sand as a substitute for sand in high-performance concrete not only conserves resources but also helps protect the environment. This study replaced manufactured sand with glass sand and added carbon fiber to prepare high-performance shotcrete. Its mechanical and self-sensing properties were then tested separately. The findings suggest that with an increase in glass sand content, the compressive strength of high-performance shotcrete initially rises and subsequently declines. When the replacement ratio of glass sand is 75%, the compressive strength exhibits its maximum value, whereas an increase in the glass sand content leads to a reduction in both splitting tensile strength and flexural strength. Although increasing carbon fiber content does not significantly contribute to compressive strength, it significantly improves flexural strength and splitting tensile strength. In addition, when testing the self-sensing performance of the material, it was found that its self-sensing performance increased significantly with increasing carbon fiber content but decreased with increasing glass sand content. Finally, an Ansys APDL simulation using the relevant parameters of the optimal group of mechanical properties was performed to model a tunnel and verify its feasibility and validity. This study provides a theoretical and practical reference for future engineering applications.

Wind turbine blades with hybrid fiber composite: Tensile properties and numerical verification

Wind turbine blades are the main component of wind turbines to capture effective wind energy, and require good quality and reliable performance. Therefore, the manufacturing cost of wind turbine blades is much higher than that of other components of wind turbines. The blade is a slender elastomer prone to vibration. The wind turbine vibration always arises in the blade instability. At the same time, the blade is also a typical aerodynamic component. In the process of rotation, it will not only produce mechanical vibration but also bear aerodynamic force. In this paper, the mechanical properties and modal numerical simulation analysis of composite blades with different hybrid ratios of carbon fiber and glass fiber are analyzed, it is found that with the increase of carbon fiber content, the mechanical properties of the blade gradually increase, and the torsional vibration resistance of the blade become stronger. Therefore, the wind turbine blades of hybrid fiber composites have a longer service life, which can reduce material wastage and help protect the environment.

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

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

High temperature oxidation of additively manufactured silicon carbide/carbon fiber nanocomposites

An additive manufacturing process and subsequent pyrolysis cycle were used to fabricate SiC matrix/carbon fiber hybrid composites. The matrix was fabricated using a mixture of preceramic polymer and acrylate monomers, while polyacrylonitrile (PAN) precursor was used to fabricate fibers via electrospinning. The precursor matrix and reinforcing fibers at 0, 2, 5, or 10 wt% were printed using digital light processing, and both were simultaneously pyrolyzed to yield the final ceramic matrix composite structure. After pyrolysis, XRD and SEAD analysis proved the existence of SiC nanocrystals and turbostratic carbon structure in the matrix, while the reinforcement phase was shown to have a turbostratic carbon structure similar to commercial carbon fibers. Thermogravimetric analysis (TGA) in air up to 1400 °C was used to evaluate the oxidation resistance of this material. TGA results showed some weight loss due to oxidation of SiC and/or carbon up to about 900 °C, followed by weight gain to about 1200 °C due to the formation of a protective SiO2 layer. Although increasing carbon fiber content negatively impacted the total mass loss for the first heating cycle, exposure of the composite to second-run air revealed negligible weight loss. This is explained by SiO2 layer formation which acts as a protective film that prevents oxygen diffusion. Oxidation of SiC and the formation of a glassy layer has been proven to protect the sample from further oxidation, as well as provide healing of surface cracks and defects as revealed by SEM analysis.

Effect of fiber volume fraction on hybrid effects of tensile properties of unidirectional aramid/carbon fiber hybrid composites

AbstractAramid/carbon fiber hybrid reinforced polymer (A/CHFRP) composites were prepared via compression molding to obtain carbon‐fiber‐reinforced polymer (CFRP) composites with better toughness. Based on the existing theoretical model, the effects of the carbon fiber volume fraction on the properties of the A/CHFRP were studied using thermal gravimetric analysis (TGA), tensile tests, and scanning electron microscopy (SEM) analysis. According to the TGA results, the hybrid fiber improved the thermal stability of the CFRP. With increasing carbon fiber content, the thermal stability of the A/CHFRP composites also increased. The tensile results showed that the A/CHFRP composite with a carbon fiber volume fraction of 22.7% exhibited “pseudo‐ductility,” with the failure strain 54.09% higher than that of the CFRP composite. With increasing carbon fiber content, the ductility of the A/CHFRP composites decreased. The elastic modulus of the A/CHFRP composites conformed to the prediction model of the rule of mixtures (ROM). The strength was found to fall in the triangular area surrounded by the ROM and the bilinear ROM and exhibited a positive hybrid effect. The SEM results showed that the tensile failure modes of the A/CHFRP composites were mainly fiber and resin matrix debonding and fiber fracture. Brittle fracture of the carbon fibers was observed in the A/CHFRP composites, while aramid fibers appeared to peel off and silk crimp for ductile failure. Thus, this study provides a theoretical basis for toughening CFRPs.Highlights The volume ratio of the two fibers affects the hybrid effect of A/CHFRP. The thermal stability of A/CHFRP increases with increasing carbon fiber content. The carbon fiber volume ratio of 22.7% in A/CHFRP exhibited pseudo‐ductility. A/CHFRP exhibiting a failure strain 54.09% higher than that of the CFRP. The strength prediction of A/CHFRP depends on the failure mode.

Preparation of carbon fiber conductive concrete and study on its mechanical and heating properties

Carbon fiber conductive concrete demonstrates great potential for effectively removing ice and snow from road surfaces. This study investigates the electrical conductivity and electromagnetic heating effects of carbon fiber conductive concrete, considering different carbon fiber dosages and temperatures. Experimental and numerical simulation methods were employed to assess the material's performance. The results show that as the carbon fiber content increases to 0.38 % and 1.5 %, the compressive strength decreases by 19 % and 55 %, respectively, which is related to the introduction of more bubbles and the agglomeration of carbon fiber when the carbon fiber is added, making it easier to produce stress concentration when the concrete is compressed. However, when the content of carbon fiber is small, the tensile properties of carbon fiber itself can improve the overall splitting tensile strength of concrete. With the increase of carbon fiber content, carbon fiber gradually forms a conductive network in the concrete, and the overall resistivity of the concrete decreases, but there is a certain threshold. Overall, 0.75 % fiber is the best solution. In addition, the heating process is accurately simulated by numerical simulation method. The simulation results are in good agreement with the experimental results, showing that the heating rate decreases with the increase of energizing time until reaching the heat equilibrium state. And the precise temperature distribution and change process that can be obtained through simulation provides valuable insights for engineering design.

Dynamic mechanical properties of carbon fiber reinforced geopolymer concrete at different ages

In order to improve the strength and toughness of geopolymer concrete (GC) at different ages under impact load, using slag and fly ash as cementitious materials, NaOH and sodium silicate as alkaline activators, carbon fiber as reinforcement, carbon fiber reinforced geopolymer concrete (CFRGC) was prepared. The dynamic compression test of CFRGC was carried out by Φ 100 mm SHPB test system. The effects of age (3 d, 7 d, 28 d) and fiber content on the dynamic mechanical properties of CFRGC were studied, and the strengthening and toughening effects of carbon fiber on GC were analyzed. In addition, the strengthening and toughening effects of carbon fiber on GC and ordinary Portland cement based concrete (PC) were compared and analyzed. The results show that the performance indicators of CFRGC at different ages have strain rate effect under impact load, and the dynamic compressive strength and specific energy absorption of CFRGC increase approximately linearly with the strain rate. With the increase of age, the dynamic compressive strength and specific energy absorption of CFRGC increase, and the strain rate sensitivity of dynamic compressive strength and specific energy absorption also increases. With the increase of carbon fiber content, the dynamic compressive strength and specific energy absorption of CFRGC increase first and then decrease, and the strain rate sensitivity of dynamic compressive strength and specific energy absorption also increase first and then decrease. When the carbon fiber content is 0.2%, the dynamic mechanical properties of CFRGC are the best, and the strain rate sensitivity of performance indicators is the strongest. Carbon fiber has strengthening and toughening effects on GC and PC. When the fiber content is 0.2%, carbon fiber has the best strengthening and toughening effects on GC and PC. The strengthening and toughening effects of carbon fiber on GC is better than that of PC. Compared with 28 d, carbon fiber has better strengthening and toughening effects on GC at the ages of 3 d and 7 d.

Hydrothermal durability of unidirectional flax/carbon fiber hybrid composite plates

Hybrid carbon fiber/flax reinforced polymer composites (HFRPs) meet the requirements of high property to cost ratio for many structural applications. In the present study, HFRP plates produced with filament winding were studied on the property evolution subjected to 40 and 70 °C water immersion for eight-week. Water uptake and flexural properties of the HFRP samples were tested and analyzed in terms of the hybrid modes and fiber contents. The diffusion coefficient and equilibrium water absorption of fiber reinforced polymer composites increase and the performance deterioration intensifies with the increase in temperature. The equilibrium water absorption and the diffusion coefficient of the FFRPs are 7.6 and 3.8 times higher than those of the carbon fiber reinforced polymer composites (CFRPs), respectively. With the increase in the carbon fiber content, the hybrid samples showed a decrease in the water uptake and diffusion coefficient. HFRP with carbon fiber on the surface shows better hydrothermal resistance than other hybrid modes due to the barrier behavior of carbon fibers for water molecules. Fiber contents and hybrid modes also play a crucial role in the degradation of flexural properties. The flexural strength and modulus of HFRPs increase with increasing carbon fiber content but the nonlinear behavior becomes less obvious. The flexural strength and modulus of HFRPs with carbon fibers on the surfaces (CFC) are 3.59 and 7.96 times higher than those of the HFRP plates with flax on the surfaces (FCF) respectively. However, the significant water absorption in the flax layers deteriorates the stress transferring ability of the core flax layer, which causes the aging of CFC seriously.

Effect of carbon fiber on the properties of polymer cement based building sealant

AbstractThe working property, bond property, and mechanical property of five kinds of polymer cement based building sealant (PCBS) with different carbon fiber content were tested. The effect of carbon fiber on the properties of PCBS was discussed by analyzing the variation of the leveling performance, consistency, low temperature flexibility, surface dry time, elastic recovery rate, tensile mechanical property, and shear mechanical property of PCBS with carbon fiber content. And the modification mechanism of carbon fiber on PCBS was interpreted using scanning electron microscopy and mercury intrusion porosimetry techniques. The results shows that PCBS still has good working property and bonding property with carbon fiber addition. As the carbon fiber content increases, the leveling performance and low temperature flexibility of PCBS are unaltered., the consistency increases, while the surface drying time and elastic recovery rate decrease. The tensile and shear mechanical properties of PCBS can be improved by adding carbon fiber. With the increase of carbon fiber content, the strength performance indexes of PCBS increase, while the energy consumption performance indexes first increased followed by a decrease. When the carbon fiber content is 0.1%, the properties of PCBS is the best. The pore structure of PCBS gradually deteriorates, and the total porosity and the percentage of macropores increase with carbon fiber addition. Carbon fiber primarily exerts cracking resistance and internal deterioration effects in PCBS.

Negative permittivity behavior of carbon fibre/alumina ceramic composites prepared by hot-press sintering

Although metals are the most common conductive functional phase in metacomposites preparation, one-dimensional carbon fibre (CF) is an ideal alternative. In this paper, ceramic composites with CFs homogeneously dispersed in an alumina matrix were prepared using a hot press sintering process. The impact of CF contents on the microscopic morphology, electrical conductivity and negative permittivity behavior of the composites was systematically investigated. The conductivity of the composites increased with increasing CF contents, and their impedance modulus subsequently decreased. The conductivity mechanism of the composites transformed from a hopping conductivity to a metal-like conductivity. With the increase in CF contents above the percolation threshold, the composites showed a negative permittivity behavior at the frequency range from 1 kHz to 10 MHz. The negative permittivity of the metacomposites was attributed to the plasma oscillations of free electrons in the three-dimensional CF networks, and the corresponding dispersion characteristics were in agreement with the Drude model. The plasma oscillation frequencies of ceramic composites moved to higher frequencies with increasing CF content in the composites, and the absolute value of negative permittivity also increased. These findings can be useful for clarifying the realization and regulation mechanism of negative permittivity, which greatly facilitates the development of ceramic-based metacomposites.

Additive Manufacturing of Carbon Fiber Reinforced Plastic Composites: The Effect of Fiber Content on Compressive Properties

The additive manufacturing (AM) of carbon fiber reinforced plastic (CFRP) composites continue to grow due to the attractive strength-to-weight and modulus-to-weight ratios afforded by the composites combined with the ease of processibility achievable through the AM technique. Short fiber design factors such as fiber content effects have been shown to play determinant roles in the mechanical performance of AM fabricated CFRP composites. However, this has only been investigated for tensile and flexural properties, with no investigations to date on compressive properties effects of fiber content. This study examined the axial and transverse compressive properties of AM fabricated CFRP composites by testing CF-ABS with fiber contents from 0%, 10%, 20%, and 30% for samples printed in the axial and transverse build orientations, and for axial tensile in comparison to the axial compression properties. The results were that increasing carbon fiber content for the short-fiber thermoplastic CFRP composites slightly reduced compressive strength and modulus. However, it increased ductility and toughness. The 20% carbon fiber content provided the overall content with the most decent compressive properties for the 0–30% content studied. The AM fabricated composite demonstrates a generally higher compressive property than tensile property because of the higher plastic deformation ability which characterizes compression loaded parts, which were observed from the different failure modes.

Effect of Layering Methods on Microstructure and Bending Properties of BF/CF Composites

Five group of different layering methods of basalt/carbon fiber (BF/CF) hybrid reinforced resin matrix composites are prepared by vacuum infiltration hot-press forming process. The bending properties with different layering methods have obvious distinguishing, B5C1 (B-Basalt fiber, C-Carbon fiber) has the lowest bending strength of 283 MPa, and B1C5 has the highest bending strength of 404 MPa. The observation of microstructure shows that infiltration effect of composites is good, and matrix is fully and evenly distributed in fibers. The bending fracture morphology is also relatively ideal. Some of the fibers show brittle fracture morphology and others show pull-out morphology, further indicating that the fibers are tightly bound to the matrix. In addition, the ultimate bending strength of composite single-layer plate is calculated, and the formula for calculating the bending strength of the composite laminate is established based on the laminate principle. By modifying the calculation formula, more accurate results are obtained. The experimental results are in good agreement with the theoretical ones, and the reliability of the calculation method is verified. The results showed that carbon fiber enhanced the bending strength of hybrid laminates, but with the increase of carbon fiber content, the strengthening effect decreased

Study on preparation and mechanical properties of bionic carbon fiber reinforced epoxy resin composite with eagle feather structure

Inspired by the effect of angle between feather shaft and the feather vane on strength enhancement of feather structure, carbon fiber reinforced epoxy resin composites with eagle feather structure were prepared successfully. Based on liquid-phase oxidation, wettability of carbon fiber was improved, which enhanced bonding strength between reinforcement and matrix and built material base for mechanical strength of bionic composite. With the increase of carbon fiber content (0.1 wt.%, 0.2 wt.%, 0.3 wt.% and 0.4 wt.%), tensile strength and impact toughness of carbon fiber reinforced epoxy resin composites increased first and then decreased. Composites with 0.2 wt.% carbon fiber exhibited optimal mechanical properties, which was used for preparation of bionic composite. Compared with carbon fiber reinforced epoxy resin composite with the traditional vertically arranged structure, the composite material with the bionic structure owned higher tensile strength and impact toughness. The fracture and drawing out of carbon fiber and crack deflection were mechanical mechanism of bionic composite, which provided a new design and preparation method for carbon fiber reinforced epoxy resin composite.

Research on electromagnetic properties and microwave deicing performance of carbon fiber modified concrete

The electromagnetic properties of concrete have an important effect on the microwave deicing performance of concrete road. In this paper, the carbon fiber was added into the concrete matrix to prepare carbon fiber modified concrete (CMFC), aiming to improve the concrete’s microwave absorbing performance and enhance the efficiency of road microwave deicing. Moreover, a rectangular waveguide transmission/reflection method was used to test the electromagnetic properties of concrete, and a self-developed microwave deicing test system was employed to test the microwave deicing performance. The electromagnetic characteristics tests show that with the increase of carbon fiber content, the microwave energy storage performance of CFMC is firstly increased and then decreased, its performance of microwave energy loss increases gradually, and its reflection of microwave enhances gradually as well. When the microwave frequency is in the vicinity of 2.45 GHz, the real part of complex permittivity of CFMC with a carbon fiber content of 1‰ (CFMC-1), 3‰ (CFMC-2) and 5‰ (CFMC-3) are 1.59 times, 1.69 times and 0.94 times of that of plain concrete (PC), respectively. As for the imaginary part of complex permittivity, the ratios are 4.42 times, 36.38 times and 37.74 times, respectively. As for the reflection properties, CFMC-1 has the lowest reflectivity, which is −6.21 dB. In addition, the microwave deicing tests show that CFMC-3 has the fastest heating rate, which is 1.680 ℃/s, 4.46 times that of PC. However, considering the mechanical properties, deicing effect and economic cost, CFMC-1 has the best application prospects, whose heating rate is 1.289 ℃/s, 3.42 times that of PC. Above all, it can be concluded that the efficiency of concrete road microwave deicing can be effectively improved by adding carbon fiber, and the research in this paper can provide theoretical guidance for the road microwave deicing operations in some sense.

Experimental Study on Mechanics and Pressure Sensitivity of Carbon Fiber RPC

To study the mechanical properties and conductivity enhancement effect of carbon fiber (CF) on reactive powder concrete (RPC), this work systematically investigated the changes in the compressive strength, elastic modulus, Poisson’s ratio, and pressure sensitivity of RPC under standard curing system. With age, CF content, and pressure sensitivity as parameters, the micro-method for scanning mechanism was used to study the effect mechanism of CF content on RPC. The experimental results showed that with the increase of carbon fiber content, poisson's ratio and compressive strength of carbon fiber RPC tended to increase first and then decrease. The elastic modulus decreased first and then increased, and 0.75% was the turning point of fiber content. With the increase of carbon fiber content, the resistivity decreases gradually, while the resistivity change rate (FCR) shows a trend of increasing and decreasing first, and there is a strong corresponding relationship between strain and FCR.When the CF content is 0.75%, the maximum FCR is 38.8%, which is increased by 33%. the CF RPC with a CF content of 0.75% is the highest stress and strain sensitivity group, reaching 2.05%/Mpa and 513.7, respectively.

The influence of long carbon fiber and its orientation on the properties of three-dimensional needle-punched CF/PEEK composites

In this work, high performance composite materials with high mechanical strength and isotropic properties are expected to obtained. Long carbon fiber (40 mm) reinforced poly(ether ether ketone) (PEEK) composites were prepared by three-dimensional (3D) needle-punched method. Orthogonal test was used to optimize molding parameters of 3D needle-punched CF/PEEK (30/70) composites. The influence of carbon fiber content and its orientation on the mechanical properties, thermal properties, crystallization properties and microstructure of the composites were studied in the range of 30–60 wt %. The excellent mechanical properties were shown with the increase of fiber content, and the composites were approximately isotropic in-plane due to the random fiber orientation. With the increase of carbon fiber content, the melting point measured by differential scanning calorimetry (DSC) and 5% weight loss temperature tested by thermogravimetric analysis (TGA) of the composites increased slightly, however the heat deflection temperature (HDT) increased obviously. SEM observation showed that compared with traditional thermoplastic plate, 3D needle-punched CF/PEEK composites could provide multi-direction impregnation channel for PEEK melt resin to realize multi-point impregnation, as a result, carbon fiber had a better impregnation effect in PEEK resin matrix. It was found that the tensile modulus and flexural modulus of CF/PEEK were very close to those of human cortical bone. It would reduce the stress shielding effect and has great application value if it is applied to the orthopaedic bone plate.

A Study on Mechanical Properties of Short Carbon Fiber Reinforced Polycarbonate via an Injection Molding Process

This manuscript is dealt with the synthesis of short carbon fibers reinforced polycarbonate polymer composite by using injection modeling technique. Four different composite materials were obtained by varying the carbon fibers weight percentage of 10, 20, 30 and 40%. The synthesized carbon fibers/polycarbonate composites were characterized for their morphological, mechanical and thermal properties by means of scanning electron microscopy (SEM), universal testing machine (UTM) and IZOD strength test. The resultant carbon fibers/polycarbonate composites exhibited excellent interfacial adhesion between carbon fibers and polycarbonate resin. The tensile properties were observed to be monotonically increases with increasing carbon fiber content in the composite resin. The tensile strength of carbon fiber/polycarbonate composites with the carbon fiber content 40% were increased about 8 times than that of the pristine polycarbonate matrix. The carbon fibers/polycarbonate composites with 40 wt.% of short carbon fibers exhibited a high tensile strength and thermal conductivity. The incorporation of carbon fiber in to polycarbonate resin resulted in a significant enhancement in the mechanical and the thermal behavior. These studies suggested that the short carbon fiber incorporated polycarbonate composite matrix is a good candidate material for many technological applications.

Modelling and assessment of carbon fiber reinforced aluminum matrix composites and their laminate squeeze casting fabrication

The equibiaxial bend behavior of laminate carbon fiber fabric reinforced aluminum matrix composites is modelled and assessed. Analytical modelling and finite element analysis are comparatively investigated to study the mechanical properties, with particular focus on the elastic modulus and flexural strength. The investigation allows evaluating how far the experimental results deviate from idealized assumptions of the models, which provides insight into the composite quality and the effectiveness of the used laminate squeeze casting technique. Specifically, discrepancies shed light on the interlaminate and fiber-matrix interface bond as well as on the stability of the laminate layers during fabrication. The two model approaches are in good agreement with differences below 8%. Moreover, the models agree with experimental data in predicting an overall improvement in properties with increasing carbon fiber content up to 4.89 vol%. Overall, the composite samples outperform the model predictions, which indicates good interface bonding. However, microstructure investigations also indicate that the outperformance is partly caused by a shifting of the carbon fibers during squeeze casting closer to the later bend tensile loaded surface due to their lower density compared to aluminum. The result is higher load bearing capacity of the composites than estimated by the models that assume perfectly symmetrical composite structure. The experimental outperformance in ultimate flexural strength vanishes at higher carbon fiber contents. This is due to imperfect interlaminate and fiber-matrix interfaces where some defects such as pores, carbides and oxide particles tend to locate, leading to damage initiation and potentially interface failure.