High Modulus Carbon Research Articles

Establishing interphase with “rigid-flexible coupling” crosslinked network by supramolecular structure to improve interfacial properties of high-modulus carbon fiber composites

Interfacial properties are a key factor influencing the overall performance of carbon fiber reinforced polymer composites (CFRPs). A novel interphase with “rigid-flexible coupling” crosslinked network is established by introducing supramolecule pseudopolyrotaxane (PPR) on the high modulus carbon fiber (HMCF) surface to improve interfacial properties of CFRPs. Our design utilizes the unique molecular necklace structure of PPR composed of β-cyclodextrin (β-CD) and polyetheramine (PEA). Here, hydroxyl-rich β-CD acts as crosslinking sites and catalyst to enhance interfacial crosslinking density and the mobile main chain PEA serves as an internal stress relaxant to dissipate stress, thereby simultaneously improving the stiffness and toughness of the interphase. The resultant CFRPs exhibit excellent interfacial properties with a 90 % rise in interfacial shear strength (IFSS) and 156 % enhancement in transverse fiber bundle test (TFBT) strength in comparison with desized HMCF composites. This work provides a new strategy for preparing carbon fiber reinforced polymer composites with excellent interfacial properties.

Flexible and lightweight carbon fiber/silicone resin composites with the “soft-rigid” structural interface for thermostable and antistatic applications

To avoid a large difference in modulus between carbon fiber (CF) and silicone resin (SR) and unstable thermal properties, the “soft-rigid” structural interface is constructed by coating polydopamine-polyethyleneimine@octaphenyl-silsesquioxane (PDA-PEI@octaphenyl-POSS) on the fiber surface. The tensile strength of the CF-AE@3P/SR composite was 24.35 % higher than that of the unmodified CF/SR. The mechanism of mechanical enhancement revealed that the rigid layer with nanoparticles effectively deflected the crack and prolonged the path, and the hydrogen bonds and van der Waals forces helped disperse the stress concentration at the interface. The defects in the soft–rigid structural interface were reduced, and the decomposition of the fibers and composites was effectively inhibited, thereby increasing the heat transmission in the composites. After heating for 20 s on the heating plate at 200 °C, the surface temperature of the CF-AE@3P/SR composite was 155.4 °C, which is higher than that of the unmodified CF/SR (131.4 °C). Therefore, the thermal stability of the CF-AE@3P/SR composites was significantly improved compared to that of unmodified CF/SR after holding at 350 °C for 3 h. Surface resistance analysis showed that the soft–rigid modification maintained the antistatic properties of the composites at room and high temperatures. It was also found that the CF-AE@P/SR composites exhibited good flexibility, lightweight, and hardness for application in sealing and electronic components. This work provides ideas for forming a seamless transition and effective bonding between high-modulus carbon fibers and a low-modulus elastomer matrix, increasing the thermal stability and mechanical properties, and maintaining the flexibility, stiffness, lightweight, and antistatic properties of composites at high temperatures.

The effect of the Weibull modulus on the shape of the stress–strain curves of thin-ply pseudo-ductile hybrid composites

This paper presents a numerical approach using ABAQUS CAE scripting to simulate the mechanical response of thin-ply pseudo-ductile hybrid composites. A parametric study demonstrates that interface critical fracture energy is essential for accurately modeling damage mechanisms and mechanical behavior. Correct shear strength identification enables the model to capture experimental observations, including fragmentation and the plateau region in the stress–strain curve. The analysis shows that the mechanical behavior of these composites is largely independent of fragmentation location patterns in the low-strain layer. Results emphasize the significant impact of the Weibull modulus on the stress–strain response, with careful selection leading to strong correlation with experimental data. Notable differences in best-fit Weibull moduli were observed for different materials, with higher values for high modulus carbon fibers.

Highly thermally conductive and shape-stabilized phase change materials with desirable solar/electric-to-thermal conversion performance based on high-modulus graphite/PVA foam

The widespread utilization of phase change materials (PCMs) has been impeded by challenges such as leakage, low thermal/electrical conductivity, and inadequate light absorption. Although constructing interconnected three-dimensional (3D) carbon networks within PCMs can mitigate these issues, their complex and energy-intensive fabrication processes, coupled with insufficient mechanical strength causing significant leakage and collapse of liquefied PCMs under external loads or impacts, hinder their practical application. Herein, we present a novel approach for the preparation of 3D graphite/polyvinyl alcohol foam (GPF) through a simple vacuum foaming combined with air-drying method. The obtained GPF-5 exhibits impressive compression strength (4.46 MPa) and compression modulus (93.1 MPa) at low density of 0.30 g/cm3. Upon impregnation with polyethylene glycol (PEG), GPF-5/PEG exhibits notable mechanical strength (7.62 MPa), contributing to its thermal shape stability and resistance to leakage. Even when subjected to temperatures above the melting point of PEG under external loads, GPF-5/PEG maintains its original shape without any liquid leakage. Due to the efficient construction of 3D thermal conductivity pathways within GPF, GPF-5/PEG demonstrates a high thermal conductivity of up to 3.48 W/m K−1 with graphite contents of 21.1 wt%, representing an increase of 136 % and 1640 % compared to graphite/PEG (with equivalent graphite content) and pure PEG, respectively. Additionally, GPF-5/PEG displays high latent heat of melting (136.8 J/g) and superior thermal cycling stability. Moreover, GPF-5/PEG demonstrates high solar-to-thermal and electric-to-thermal energy conversion capabilities, highlighting their potential for diverse applications. The work offers a rational strategy for fabricating high-modulus carbon foam, which can be used for PCMs-based multi energy conversion and storage systems with high thermo-mechanical properties.

Application of Computer-Aided Design Software to the Simulation and Analysis of Composite Material Properties in Housing Engineering Structures

Reinforced polymer composites are widely used in engineering applications due to their excellent mechanical properties, and this paper combines experiments and numerical simulations to fully examine the properties of the composites. The article takes the reinforced concrete structure of civil engineering as the basis for experimental testing on the basic properties of carbon fiber composites in its application. Subsequently, the intrinsic model of reinforced concrete and carbon fiber composites was constructed, and each finite element unit of the member was selected to simulate and finite element analysis the performance of the composites through ABAQUS computer-aided design software. The results show that increasing the diameter of carbon fibers will reduce the number of carbon fibers at the same time, which will reduce the toughness of the composite material, random and chaotic distribution of carbon fibers for the improvement of the compressive properties of concrete can achieve a relatively balanced effect, and the high elastic modulus carbon fibers for the improvement of uniaxial and cyclic compressive properties of concrete play a dominant role. In addition, the oriented elliptical fibers in the long-axis direction have a significant increase in the modulus of elasticity and strength of the material, and this phenomenon will become more and more obvious with the increase of the length-to-diameter ratio. The reasonable structural design may help to improve the performance of composites and enhance their adaptability for engineering applications.

Enhancement of the impact resistance of masonry walls using fiber-reinforced polymer composites

Many civilian structures are masonry ones. However, masonry walls are susceptible to impact loading. Despite the vulnerability, research on enhancing the impact resistance of masonry walls is substantially scarce, especially under high-velocity impact. Hence, in this study, the effect of fiber-reinforced polymer (FRP) composites on the impact resistance of masonry walls was numerically investigated, especially considering high-velocity impact loading. For this purpose, finite element analysis (FEA) was implemented deploying LS-DYNA. In modeling, the Add Erosion and the Smooth Particle Hydrodynamics options were employed to effectively represent impact behaviors of masonry walls subject high-velocity impact loading. Firstly, the developed masonry wall models were validated by comparing the numerical results with experimental ones. Using the verified numerical models, various parametric studies were performed. The main parameters were the directions and types of fiber, different velocities of an impactor, and the number of impactors. Based on the study, the near-surface-mounted (NSM) FRP method was found to be inefficient in improving the impact resistance of masonry walls. Although the externally-bonded (EB) FRP technique was more effective than the NSM FRP one, the impact behavior varied depending on the types and number of FRP. For instance, strengthening a masonry wall using one layer of high-modulus carbon FRP (HCFRP) EB sheet resulted in the perforation of the HCFRP sheet due to the low ultimate strain of HCFRP sheet. Although one layer of standard CFRP (SCFRP) EB sheet was effective to prevent a masonry wall from being perforated against one impactor, the strengthened masonry wall was penetrated by multiple impactors. It was found that two woven SCFRP EB sheets were optimum to evade the perforation of masonry walls subject to high-velocity impact loading. Furthermore, equations for correlations between the maximum impact force and impact energy are proposed.

Compressive strength and failure mechanism of high-modulus carbon fibers produced from polyacrylonitrile and mesophase pitch

Compressive strength and failure mechanism of high-modulus carbon fibers produced from polyacrylonitrile and mesophase pitch

MODERN APPROACHES TO THE USE OF COMPOSITE MATERIALS IN CONSTRUCTION

A review of the literature on scientific approaches in the development of composite materials and building structures made of composites is carried out. When creating and manufacturing traditional and new composite materials, for example, by additive manufacturing, and when creating structures and structures in engineering calculations, new techniques, finite element computational software systems, and neural network technologies are used, which are used in the creation of modern metal and composite materials, analysis of mechanical characteristics of materials, forecasting loads on the structure, optimization of structures and calculation of their construction characteristics. The distinctive features of modern composite materials are shown. The main types of composite materials are considered: talc, diatomite, calcium carbonate, gibbsite, barium sulfate, feldspar, nepheline, aragonite, calcium carbonate, wool, silk, cotton, linen, jute, wood pulp, asbestos, fiberglass, metal fibers, quartz fibers, basalt fibers, polyamide fibers, polyester fibers, polyvinyl alcohol fibers, carbon fibers, viscose fibers. The physical and mechanical characteristics of composite materials (based on epoxy, aluminum, carbon, magnesium, and nickel matrices) and traditional (steel, aluminum, brick, concrete) building materials are presented. The disadvantages of such composite materials as carbon fiber, fiberglass, organoplastics, textolite, carbon concrete, and polystyrene concrete are presented. Deformation diagrams of some types of fibers for composite materials are considered: high-modulus carbon fibers, high-strength carbon fibers, aramid fibers, glass fibers, and basalt fibers. The advantages of the system of external reinforcement of building structures with composite materials are described. Examples of reinforcement of building structures are considered: reinforced concrete reinforcement; reinforcement of floor slabs; reinforcement of columns; and reinforcement of brick walls.

Elucidating the enduring transformations in cellulose-based carbon nanofibers through prolonged isothermal treatment

This study investigates the conversion of highly acetylated sugarcane bagasse into high-modulus carbon nanofibers (CnNFs) with exceptional electrical conductivity. By electrospinning the bagasse into nanofibers with diameters ranging from 80 nm to 800 nm, a cost-effective CnNFs precursor is obtained. The study reveals the transformation of the cellulose crystalline structure into a stable antiparallel chain arrangement of cellulose II following prolonged isothermal treatment, leading to a remarkable 50 % increase in CnNFs recovery with carbon contents ranging from 80 % to 90 %. This surpasses the performance of any other reported biomass precursors. Furthermore, graphitization-induced shrinkage of CnNFs diameter results in significant growth of specific surface area and pore volume in the resulting samples. This, along with a highly ordered nanostructure and high crystallinity degree, contributes to an impressive tensile modulus of 9.592 GPa, surpassing that of most petroleum-based CnNFs documented in the literature. Additionally, the prolonged isothermal treatment influences the d002 value (measured at 0.414 nm) and CnNFs degree of crystallinity, leading to an enhancement in electrical conductivity. However, the study observes no size effect advantages on mechanical properties and electrical conductivity, possibly attributed to the potential presence of point defects in the ultrathin CnNFs. Overall, this research opens a promising and cost-effective pathway for converting sugarcane biomasses into high-modulus carbon nanofibers with outstanding electrical conductivity. These findings hold significant implications for the development of sustainable and high-performance materials for various applications, including electronics, energy storage, and composite reinforcement.

Raman spectroscopic stress mapping of single high modulus carbon fibre composite fragmentation in compression

Fragmentation of high modulus carbon fibres is relevant to the failure mechanisms of advanced polymer matrix composites in compression. In situ spatially-resolved Raman spectroscopy during the fragmentation of model single fibre composites is used to map local stress distributions during failure events. The characteristic graphitic band (the G band) located around 1580 cm−1 is associated with the in-plane carbon-carbon bonds; this band shifts its position, and can be calibrated, with the local axial stress in the fibre. The analysis maps the evolution of local stresses with increasing overall composite compression strain, identifying a series of critical events, including fibre fracture, interfacial debonding, and the formation of inter-fragment ‘wedges’. Fitting shear lag models provides interfacial shear strength values. Multiple failure maps of two examples of high modulus PAN carbon fibres (M46J and M55J) demonstrate the possibility of local fragment bending due to fragment end contact. A timeline of potential fragmentation events is proposed for carbon fibres undergoing compression.

High modulus carbon fiber based composite structural supercapacitors towards reducing internal resistance and improving multifunctional performance

Carbon fibers (CFs) based composite structural supercapacitors (CSSs) are promising multifunctional energy storage composites which can simultaneously realize load bearing and electricity storage. The device power is still low due to the high internal resistance of CSS. Herein, the CFs, electrolytes, monofunctional devices and multifunctional composite devices were investigated to show the attribution of the internal resistances. Both the normally used T300 CF and high modulus M55J CF fabrics were utilized. The electric in-plane and through-the-thickness resistances of CF fabric electrodes were characterized, respectively. The internal resistance of the monofunctional supercapacitor devices which were assembled using liquid electrolyte were evaluated considering the effects of CF sizing. The bicontinuous structural electrolytes (BSEs) composed of epoxy (EP) and ionic liquid (IL) were prepared as the multifunctional matrix of the CSSs. The chemical structure, thermal stability and ionic conductivity of the BSEs were assessed. The activated carbon (AC) loaded CFs and BSEs were used to fabricate the CSSs. Both the tensile and charge/discharge properties of the M55J CF CSSs were higher than those of the T300 CF CSSs. This work could provide new insights into the resistance attribution of CSS and how to simultaneously improve both mechanical and electrochemical performances of CSSs.

Enhanced interfacial, mechanical, and anti-hygrothermal properties of carbon fiber/cyanate ester composites with the catalytic sizing agents of titanium epoxy

The mechanical properties of composites are closely related to the interfacial behavior, especially under the hygrothermal circumstance. A catalytic sizing agent of titanium epoxy is designed to enhance interfacial, mechanical, and anti-hygrothermal properties of high modulus carbon fiber (HMCF)/cyanate ester composites simultaneously. The mechanisms of interface enhancement and low hygroscopicity of composites are investigated. The titanium epoxy is synthesized and its catalytic effect on the curing of cyanate ester is proved. The interfacial properties of HMCF composites with catalytic sizing agents are improved to 95.5 MPa, which is attributed to the interphase with high crosslinking density and sufficient triazine rings and oxazolidinone structure due to preferential curing induced by interfacial catalysis, stimulating the smooth transition of interphase modulus. Further, the formed interphase exhibits few interface defects and low content of hydroxyl groups, which changes the moisture diffusion path and reduces saturated water absorption of composites to only 0.36 %, resulting in the release of interfacial wet stress concentration and high retention of mechanical properties in hygrothermal environment. The resultant composites with high stiffness, excellent temperature resistance, superior dimensional stability and low moisture absorption are expected to be applied to high-orbit space, aerospace, precision instruments.

Study on the mechanical properties and optimization methods of high-strength high-modulus carbon fibre composite with the cap structure

The application of high-strength, high-modulus carbon fiber with excellent properties such as high modulus, conductivity, and thermal conductivity has been increasingly widespread in aerospace flight, deep space exploration, and near-space vehicles. In recent years, with the continuous enhancement of functional requirements for products in these domains, there is a growing need to optimize the typical structure of such carbon fibers to enhance their load-bearing capacity. Therefore, in this study, we first conducted basic mechanical performance tests on specimens of T1100/5405 composite materials to obtain fundamental mechanical performance parameters of the material. Subsequently, compression and bending performance tests were performed on a typical hat-shaped structure to understand its actual load-bearing capacity and failure modes. The results indicate that the compressive failure load and bending failure load of the hat-shaped structure are 474.44 kN and 27.365 kN, respectively. Additionally, by combining the fundamental mechanical performance parameters of the composite material, the mechanical performance of the hat-shaped structure was simulated and verified using finite element analysis software, with the model validated using experimental data. Finally, layering parameters of the established finite element model were optimized, resulting in an increase of the structure’s load-bearing capacity under compression and bending loads to 662.629 kN and 31.9059 kN, respectively. In conclusion, the optimization approach presented in this paper for the T1100/5405 composite material’s hat-shaped structure is efficient. It yields noticeable improvements, significantly enhancing the load-bearing capacity of the typical structure in various application scenarios.

Сравнительный анализ термоупругих характеристик керамоматричных композиционных материалов, определенных по различным модельным представлениям структурно фазового состава матричного материала

A comparative analysis of thermoelastic characteristics of ceramic matrix composite materials (CMC) obtained by liquid and gas phase technologies, reinforced with two types of carbon fibers (CF), is carried out based on different model structural phase composition of the obtained matrix material. It is noted that when implementing the liquid phase siliconizing and using high modulus carbon fibers with high negative values of the absolute value of the coefficients of linear thermal expansion (CLTE), a simplified model of the matrix material consisting of only one SiC phase can be correctly used. When implementing PIP and CVI technologies, CMC with low modulus CF and CF with low negative CLTE values show the greatest sensitivity to an increase in matrix porosity. For CMC based on CF T800, the change in the longitudinal CLTE was about 66% with a porosity of 20%. An increase in porosity leads to a decrease in all elastic characteristics of the CMC, to the greatest extent for the transverse modulus of elasticity and the shear modulus.

Compressive strength and failure mechanism of high-modulus carbon fibers produced from polyacrylonitrile and mesophase pitch

Compressive strength and failure mechanism of high-modulus carbon fibers produced from polyacrylonitrile and mesophase pitch

The Non-Linear Elasticity of Unidirectional Continuous Carbon Fibre-Reinforced Composites and of Carbon Fibres.

A database of non-linear elastic parameters in axial tension and compression is provided for continuous carbon fibre polymer composites and carbon fibres of different stiffnesses. Composite laminates manufactured by conventional or automated processes are tested in bending, and parameters are extracted for strains of less than 0.5%. While fibre composites with fibres of standard and intermediate moduli exhibit a stiffening of ∼15 GPa/% (of strain) and a softening of ∼20 GPa/%, those with high-modulus carbon fibres exhibit much higher values of ∼50 GPa/% for both. This database is useful for designing composite structures in a stiffness-based design and for correlating the processing of carbon fibres with their nanostructure and induced properties. The latter is discussed in terms of reorientation of crystallites of graphene sheets vis-à-vis the carbon fibre axis during loading.

Femtosecond laser drill high modulus CFRP multidirectional laminates with a segmented arc-based concentric scanning method

High modulus carbon fiber reinforced plastic multidirectional laminates (HM-CFRP-MDL) are widely employed in the aerospace industry as crucial structural materials for satellites, rockets, and aircraft. However, it is difficult for the femtosecond laser to drill holes on HM-CFRP-MDL with the traditional concentric scanning method (CSM). To improve drilling quality and precision, this study proposes a segmented arc-based concentric scanning method (SAB-CSM) and investigates the interaction mechanisms between femtosecond lasers and CFRP. By adopting the proposed scanning method with optimized parameters, the overall average HAZ width can be decreased to 10 μm in different regions on the surface of the drilled hole, the hole taper can be reduced significantly, and the consistency across different layers can be improved. Compared to CSM, the HAZ width can be decreased by 40.8 % (12.597 μm to 7.464 μm) and 50.3 % (15.585 μm to 7.748 μm) in the regions where the angles between fiber direction and scanning direction are 45° and 90° respectively, and the taper can be reduced by 34.5 % (0.084 to 0.055). Moreover, the SAB-CSM approach effectively decreases quality discrepancies between different layers, and substantially reduces those defects which results in smooth and uniform hole walls, facilitating synergistic removal of multidirectional carbon fibers and resin matrix.

Analysis of fracture state and fatigue life of high modulus carbon fiber wrapped composite barrel

High-modulus Carbon Fiber-reinforced Polymer composites are widely used in critical industries due to their exceptional mechanical properties. However, the fatigue and fracture of high modulus carbon fiber materials are currently poorly studied. For this purpose, the NOL ring fatigue tensile testing is referenced and improved to investigate the performance and service life of high-modulus carbon fiber wound barrels. NOL ring specimens, made of M40 carbon fiber material, are subjected to quasi-static tensile and fatigue tests. The fracture state and characteristics of high modulus materials during fatigue are analyzed. Two-parameter Weibull distribution function is used to analysis statistically the fatigue life results of composite samples. Then, the life curve is drawn for different stress amplitudes. Additionally, the fiber fracture surface is observed under a high-power microscope. The fiber fracture model under brittle fracture is established. The results indicate that the fracture characteristics and mechanisms of high-modulus materials differ from those of high-strength materials, necessitating different fatigue life assessment methods. The fatigue failure of high modulus fibers exhibits brittle fracture similar to quasi-static loss, with flat fracture surfaces and minimal cumulative damage. The failure mechanism is accompanied by brittle fractures with a small amount of fiber pulled out.

Compressive Performance of Longitudinal Steel-FRP Composite Bars in Concrete Cylinders Confined by Different Type of FRP Composites.

This paper presents an experimental study on the compressive performance of longitudinal steel-fiber-reinforced polymer composite bars (SFCBs) in concrete cylinders confined by different type of fiber-reinforced polymer (FRP) composites. Three types of concrete cylinders reinforced with (or without) longitudinal SFCBs and different transverse FRP confinements were tested under monotonic compression. The results showed that the post-yield stiffness of SFCBs is higher when confined with high elastic modulus carbon fiber-reinforced polymer (CFRP) composite than with low elastic modulus basalt fiber-reinforced polymer (BFRP) composite. Decreasing confinement spacing did not significantly improve the compressive strength of SFCBs in concrete cylinders. The compressive failure strain of SFCBs could possibly reach 88% of its tensile peak strain in concrete cylinders confined by CFRP sheets, which is significantly higher than the value (around 50%) in previous studies. Existing design equations, which applied a strength reduction factor or a maximum compressive strain of concrete to consider the compressive contributions of SFCBs in concrete members, underestimate the load-carrying capacity of SFCB-reinforced concrete cylinders. The design equation that considers the actual compressive stress of SFCBs gives the most accurate prediction; however, its applicability and accuracy need to be verified with more experimental data.

Preparation and characterization of silk hybridizing carbon fiber/polybutylene succinate composite

AbstractCarbon fiber‐reinforced composites (CFRPs) offer numerous benefits due to their exceptional strength and modulus, making them extensively utilized in various applications. However, the disadvantage of poor impact resistance also limits their application in some aspects. In this study, silk fabric is used to hybridize CFRPs, and the silk/carbon fiber‐reinforced polybutylene succinate (PBS) composites were fabricated by combining the film stacking technique with the hot‐pressing method. The mechanical, thermal, and thermodynamic properties of the composites were assessed using various techniques, including tensile testing, scanning electron microscope, flexural testing, Charpy impact test, low‐velocity impact test, differential scanning calorimetry, and dynamic mechanical thermal analysis, and the optimal preparation process conditions (140°C/15 min) for the composites were obtained. Additionally, the mechanical properties of silk fiber/PBS, carbon fiber/PBS, and hybrid composite materials are comprehensively compared and evaluated. This work indicates that the synergistic toughening of silk and PBS significantly improves the impact resistance of CFRPs, and the impact strength of sample 5 (140°C/15 min) (54.97 kJ/m2) is higher than many reported values for CFRPs.Highlights High strength, high modulus carbon fiber, and high toughness silk were rarely combined as reinforcing phases for PBS composites. A hybrid composite material with a balanced combination of stiffness, strength, and toughness was prepared. Compared with similar studies, it was found that the hybrid composite prepared by this work exhibited relatively balanced mechanical properties, especially, its impact strength higher than many reported values.