Mechanical Properties Of Carbon Fibers Research Articles

Polymer/Carbon Fiber Co-modification: Dynamic Compressive Mechanical Properties of Carbon Fiber Modified Polymer Reinforced Concrete

Polymer/Carbon Fiber Co-modification: Dynamic Compressive Mechanical Properties of Carbon Fiber Modified Polymer Reinforced Concrete

Insight into the structural variation mechanism of highly spinnable isotropic pitch prepared by halogenated model aromatic compounds

This study developed a novel method for synthesis highly spinnable pitch through thermal polymerization of halogenated polycyclic aromatic hydrocarbons (PAH-X) and anthracene oil (AO). The characteristics, average molecular model, and polymerization mechanism of the as-prepared pitches were systematically elucidated. Results show that the thermal cleavage of C-X bonds of the PAHs-X could generate large number of free radicals that greatly facilitate the cross-linking reaction of the active fragments. Namely, the formation of benzyl radicals with high reactivity of the raw materials made it possible to synthesize pitches at lower temperature. The softening point of the as-prepared pitches showed a decreasing trend with increasing of AO proportion due to the abundant carbon content and lower reactivity of AO. Higher temperature could elevate the polymerization activity of aromatic fragments, thus significantly promoted the formation of macromolecular aromatic structures to obtain the spinnable pitch with suitable softening point. The average models validated by calculating the NMR spectra was successfully constructed to demonstrate the condensation degree, which was found be conducive to probe the spinnability of the pitches. Further, the average molecular models could well describe the correlation of the molecular structure, spinnability of pitches, as well as the mechanical properties of carbon fiber.

Study on the regulation mechanism of interfacial mechanical properties of carbon fiber reinforced aluminum foam sandwich interface

Carbon fiber (CF) is often used to enhance the interfacial properties of porous metal sandwich panel, however, the regulation mechanism on the mechanical properties of the reinforced interface is not clear, which affects its guidance in application. In this study, the regulation mechanism of CF on the mechanical properties of aluminum foam sandwich (AFS) interface was studied from the perspectives of morphology and chemistry. Results showed the effects of CF modification time, modification temperature and content on the interface properties were synergistic. The interfacial strength increased and decreased afterwards as the modification time or temperature or content increased. Fibers aggregation caused by excessive fiber addition could decrease the interface strength. Self-locking and fiber bridging were the dominant reinforced modes and their effects increased as appropriate addition content increased. Guided by the results, the shear strength of AFS interface increased by 79.18 %, the energy absorption increased by more than four times.

Effect of polyphenylene sulfide sulfone sizing agent on interfacial, thermal, and mechanical properties of carbon fiber

AbstractPolyphenylene sulfide sulfone (PPSS) was synthesized by one‐step method and utilized as a sizing agent for carbon fibers. The effects of various monomer ratios, reaction time, and reaction temperature were investigated on the molecular weight of PPSS. The thermal analysis revealed that the product PPSS exhibited a glass transition temperature exceeding 215.5°C, indicating exceptional thermal stability. After PPSS sizing treatment, the grooves on the surface of carbon fibers were filled, resulting in a substantial enhancement of the microinterface properties. The surface energy was increased by 8.2%, while the maximum weight loss temperature was 27.8% higher than that of the commercial carbon fiber. The tensile strength of the carbon fiber after heat treatment reached 2196 MPa, representing a 45.9% increase over that of the commercial carbon fiber.

The Effect of Carbon-Based Nanofillers on Cryogenic Temperature Mechanical Properties of CFRPs.

In the present work, the effects of carbon-based nanofillers (0.5 wt%), i.e., graphene nanoplatelets (GNPs), carbon nanofibers (CNFs), and carbon nanotubes (CNTs), on the cryogenic temperature (77 K) mechanical properties of carbon fiber reinforced polymers (CFRPs) were investigated. The study utilized an ex situ conditioning method for cryogenic tests. The nanofillers were mixed with the epoxy matrix by a solvent-free fluidized bed mixing technique (FBM), while unidirectional carbon fibers were impregnated with the resulting nanocomposites to manufacture CFRP samples. Optical microscopy was employed to analyze the dispersion of the carbon-based fillers within the matrix, revealing a homogeneous distribution in nanocomposites containing GNPs and CNFs. Fracture toughness tests confirmed the homogeneity of the GNP-loaded systems, showing an improvement in the stress intensity factor (KC) by 13.2% and 14.7% compared to the unmodified matrix at RT (25 °C) and 77 K, respectively; moreover, flexural tests demonstrated a general increase in flexural strength with the presence of carbon-based nanofillers at both temperature levels (RT and 77 K). Additionally, interlaminar shear strength (ILSS) tests were performed and analyzed using the same ex situ conditioning method.

Effect of plant short fibers on the mechanical properties of carbon fiber reinforced epoxy matrix by using FEM based numerical homogenization technique

In this study, we utilized the material design library in Ansys Product 2022 R1 to analyze the impact of short plant fibers on the mechanical properties of epoxy resin. We employed the representative volume element (RVE) approach and examined different volume fractions up to 50%. The technique employed in this study was multi-scale modeling based on the finite element method (FEM) for numerical homogenization. Subsequently, we used the same software to develop a five-layer laminated composite. The samples were based on epoxy resin enriched with short plant fibers at fractions of 20% and 30%, as well as pure epoxy resin. The laminated composites were reinforced with carbon fibers. The objective of this study was to analyze the mechanical response of each sample during a tensile test, focusing on multiple parameters. The sought-after results included total deformation, directional deformation, equivalent and elastic stress (Von-mises). The samples containing epoxy resin enriched with 30% of short hemp fibers exhibited remarkable mechanical strength compared to the other samples. These results suggest that the incorporation of short hemp fibers into the matrix led to a significant improvement in the mechanical strength of the composite.

Multiscale simulation and prediction of mechanical properties for carbon fiber reinforced polymer orthotropic laminate

AbstractA multiscale analysis method based on numerical homogenization is presented for predicting the mechanical properties of carbon fiber reinforced polymer (CFRP) orthogonally symmetric laminate. Initially, based on the structural characteristics of CFRP orthotropic symmetric laminate, the relational equations for calculating the mechanical engineering constants from the stiffness coefficient are proposed. Subsequently, the finite element model (FEM) of orthotropic laminate is established. Corresponding subroutines are developed through ABAQUS‐Python to extract and compute the simulation results and obtain the mechanical properties of the laminate. Next, the macroscale mechanical properties are estimated by combining the micro‐scale mechanical model, classical laminate theory (CLT), and volume averaging method. Ultimately, the accuracy of the proposed equations and the feasibility of the numerical homogenization method are demonstrated by comparing the results of numerical simulation predictions, theoretical predictions, and experiments.Highlights Present the relational equations for calculating the mechanical engineering constants of CFRP orthotropic symmetric laminate from the stiffness coefficient. Establish the FEM of orthotropic laminate and develop corresponding subroutines to obtain the mechanical properties of the laminate. Analyze the mechanical properties of orthotropic laminate through microscopic modeling and CLT.

Effect of carbon nanotubes on thermoset curing and mechanical properties of carbon fiber reinforced epoxy resin laminates fabricated by self‐resistance electric heating

AbstractSelf‐resistance electric (SRE) heating for the curing of carbon fiber reinforced plastic (CFRP) offers the benefits of saving energy consumption and reducing investment in equipment. In this work, the investigation was carried out to illustrate the effect of carbon nanotubes (CNTs) addition (0.5, 1.0, and 1.5 wt%) on the thermoset curing and mechanical properties of carbon fiber‐reinforced epoxy laminates fabricated by SRE heating method. The results show that adding CNTs can improve the temperature uniformity and interlayer‐resin flow during the SRE heating process and have a limited influence on the curing degree of CFRP composites. The tensile strength in the longitudinal direction of the composites increased with the increase of CNT addition. Meanwhile, the flexural strength and interlaminar shear strength had the maximum value with the CNTs content of 0.5 wt% and decreased significantly at the CNTs content of 1.5 wt%. It concludes that the appropriate content of CNTs addition has the potential to improve the thermoset curing performance and mechanical properties of the CFRP laminate composites fabricated by SRE heating.Highlights This study focuses on the effect of CNT addition on SRE heating for CFRP. The addition of CNTs improved the temperature uniformity during SRE heating. The addition of CNTs can reduce the voids of SRE‐cured CFRP composites. Threshold value of CNTs affected the mechanical performance of SRE‐cured CFRP.

Nanomaterial-Enhanced Sizings: Design and Optimisation of a Pilot-Scale Fibre Sizing Line

This study focuses on the development of a pilot-scale sizing line, including its initial design and installation, operational phases, and optimization of key process parameters. The primary objective is the identification of critical parameters for achieving a uniform sizing onto the fibres and the determination of optimal conditions for maximum production efficiency. This investigation focused on adjusting the furnace desizing temperature for the removal of commercial sizing, adjusting the drying temperature, as well as optimizing the corresponding residence time of carbon fibres passing through the furnaces. The highest production rate, reaching 1 m sized carbon fibres per minute, was achieved by employing a desizing temperature of 550 °C, a drying temperature of 250 °C, and a residence time of 1 min. Furthermore, a range of sizing solutions was investigated and formulated, exploring carbon-based nanomaterial types with different surface functionalizations and concentrations, to evaluate their impact on the surface morphology and mechanical properties of carbon fibres. In-depth analyses, including scanning electron microscopy and contact angle goniometry, revealed the achievement of a uniform coating on the carbon fibre surface, leading to an enhanced affinity between fibres and the polymeric epoxy matrix. The incorporation of nanomaterials, specifically N2-plasma-functionalized carbon nanotubes and few-layer graphene, demonstrated notable improvements in the interfacial shear properties (90% increase), verified by mechanical and push-out tests.

One‐step in‐situ growth of CNTs on oxidized carbon fiber: Effects of catalyst concentration and growth time on mechanical properties of carbon fiber

AbstractChemical vapor deposition (CVD) method was performed to grow carbon nanotubes (CNTs) on oxidized carbon fiber (CF). First, CF was oxidized by a simple and gentle way to increase the number of active groups and the optimal treatment time was determined. Then, effects of catalyst concentration and growth time on morphologies and loading amount of CNTs, the properties of CF/CNTs reinforcements, and the interlayer properties of CF/CNTs composites were explored. When the catalyst concentration and growth time were controlled at a reasonable level, CNTs can be uniformly grown on the CF surface. The interlaminar shear strength (ILSS) was characterized and the fracture surfaces of CF/CNTs composites were observed. The results demonstrated that when the catalyst precursor was kept at 0.05 mol/L and the growth time was controlled at 10 min, CNTs had the best strength effect and the ILSS increased by 30.25% compared to that of composites without CNTs. The fracture surface showed that CNTs can penetrate the matrix at the interface and enhance the interface through mechanical interlocking effect. The CNTs‐induced interphase allows the stress inside the composites to propagate continuously between resin and fibers, thereby heightening the load carrying capacity.Highlights A simple and gentle way was performed to activate CF without strength reduction. The influence mechanism of various parameters was revealed in detail. The mechanism of CNTs enhancing the interface was revealed.

Effect of voltage on mechanical properties of carbon fiber reinforced concrete

Under various voltages, the performance variations and compressive and flexural failure modes of carbon fiber concrete were investigated. The findings indicate that while the general concrete will display a cone upon failure, the compressive carbon fiber concrete specimen maintains its integrity under the influence of voltage, displaying a state of surface cracking with similar-sized crack spacing. With an increase in voltage level, the compressive strength of carbon fiber reinforced concrete first rises and then falls. The compressive strength of carbon fiber concrete at a voltage level of 15V is 66% higher than that of carbon fiber concrete without voltage. Similar to the flexural strength test phenomenon of uncharged carbon fiber concrete, the flexural strength test phenomenon of concrete beams when applying voltage is immediate fracture. The maximum strength of carbon fiber reinforced concrete is only 10% higher, and the flexural strength is only marginally improved, fluctuating.

Synergism of non‐covalent interaction and ZIF‐8@GO to improve tribological and mechanical properties of carbon fiber reinforced recyclable indole‐based poly(hexahydrotriazine) composites

AbstractExisting research on interfacial interactions of recyclable carbon fiber reinforced poly(hexahydrotriazine) (PHT) composites has mainly focused on the study of reinforcing fibers, ignoring the wide range of applications of matrix in advanced friction materials. Herein, polyhedral ZIF‐8 was grown in‐situ on the GO surface (named as ZIF‐8@GO) to improve the load‐bearing capacity of GO nanosheets. The ZIF‐8@GO with zinc ions and imidazole ions were embedded as interlaminar reinforcement into matrix to construct a non‐covalent cation‐π interaction with indole‐based PHT (In‐PHT) matrix, which significantly enhanced the toughness and tensile strength (reached 215.5 MPa) of composites. With the incorporation of armor‐shaped ZIF‐8@GO reinforcement, compared with the composite without ZIF‐8@GO, the wear track width was significantly decreased by 50%. Moreover, the worn surface lubricated by this composite exhibited efficient self‐healing property due to the introduction of the polyethylene wax (PEW), and the healed average friction coefficient showed slight changes. Extensive analyses verify that the ZIF‐8@GO structure and cation‐π interactions across multiscale interfaces can enhance both mechanical strength and wear resistance of recyclable carbon fiber reinforced In‐PHT composites (In‐PHT‐CFRPs).Highlights ZIF‐8@GO was embedded as interlayer reinforcement to improve wear resistance. Cation‐π interaction across interface enhances interface carrying capacity. Due to strong cation‐π bonding, IPEZGC exhibits outstanding tensile strength. PEW was embedded as healing agent to obtain self‐healing property.

Improved mechanical properties of carbon fiber/epoxy composites via fiber surface grafting of rigid-flexible chain structure

The surface topography and interface characteristics play a significant role in determining the mechanical properties of carbon fiber reinforced polymer (CFRP) composites. These features are primarily influenced by the surface chemical structures and their interactions with the matrix resin. Here, we developed a rigid-flexible coating consisting of polyetheramine (PEA) and polydopamine (PDA) on the fiber surface to control the interface and improve the mechanical properties of CFRPs. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrum (FT-IR) results validated the successful introduction of polymeric chains and fiber surface characteristics including rough surfaces, slim polymer layers and uniform dots were examined by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Contact angle tests indicate that the functionalized coating noticeably enhances the interaction force between carbon fibers, promoting improved wettability by the matrix resin. The bending and interlaminar shear strength of CFRP prepared by functional carbon fiber are increased by 45.76 % and 47.63 %, respectively. The drop weight impact (DWI) test confirms the positive effect of improved interfacial properties on the out-of-plane impact resistance of CFRPs.

Interfacial microstructure evolution and mechanical properties of carbon fiber reinforced Al-matrix composites fabricated by a pressureless infiltration process

In this study, unidirectional carbon fiber reinforced aluminum-matrix (CF/Al) composites were successfully fabricated by using a pressureless infiltration process to infiltrate Ni-coated CFs with Al. The evolution of the interfacial microstructure was investigated. The results showed that the Al–Ni reaction provided the main driving force for infiltration of Al melt into CF bundles by the significantly improving wettability. As the infiltration time increased from 0 min to 8 min, the infiltration behavior gradually improved with fewer defects and better fiber dispersion. Furthermore, the Al–Ni intermetallic compounds (IMCs) transformed from the large-sized primary Al3Ni phase to fine Al3Ni phase with eutectic structure, and were uniformly distributed around the CFs, which was beneficial for transferring the load and preventing the crack propagation. However, the harmful Al4C3 phase grew up at the interface. The ultimate tensile strength (UTS) of the CF/Al composites with the optimal infiltration time of 6 min was 135 ± 4 MPa, which was 121.3 % higher than that of the Al matrix.

Effects of CNT microstructural characteristics on the interfacial enhancement mechanism of carbon fiber reinforced epoxy composites via molecular dynamics simulations

Numerous studies have concentrated on improving the mechanical properties of carbon fiber reinforced polymer composite (CFRP) through the modification of carbon fiber (CF) with carbon nanotubes (CNTs). However, most of them were confined to describing experimental phenomena. In this study, molecular dynamics (MD) simulation was used to systematically reveal the effect of CNT nanostructures on the interfacial reinforcement of CF/epoxy. An all-atom modeling method was used to provide a quantitative description of the CF-CNT/polymer interface characteristic structure. Computational results indicate that nanotubes can protect the intra- and intermolecular interactions of epoxy segments from being destroyed, thereby preventing the initiation and propagation of micro-defects during interfacial deterioration. The mechanical competition between the interface and polymer bulk leads to different failure mechanisms, and the strengthened interface region has fewer atoms leaving the equilibrium state during tensile deformation. The insertion of CNTs on the fiber surface, specifically increasing their length, diameter, distribution density, or orientation, can improve interfacial tensile strength (up to +62.11 %) and delay the detachment of epoxy molecules from the CF. Additionally, MD outcomes were verified by synthesizing CNTs onto CF using an electric field-assisted flame synthesis approach, leading to improvement in IFSS (+62.67 %) and ILSS (+27.78 %).

Effect of CNF in-situ growth on microstructure and mechanical properties evolution of RMI-deriver C/C–SiC composites

The present paper investigates the effect of carbon nanofibers (CNFs) on the microstructure and mechanical properties of Carbon fiber reinforced carbon and silicon carbide binary matrix (C/C–SiC) composite prepared by using the reactive melt infiltration technique. The CNFs used in this paper were generated through in-situ reaction in the pores of C/C preforms using the chemical vapor deposition. Results indicate introducing additional carbon sources in the form of CNFs in the C/C preform can remarkably improve the permeability of molten Si, resulting in higher density and more uniform microstructure of the RMI-deriver C/C–SiC composites. Consequently, the in-situ formation of CNFs reduces the residual Si content by 64.71% and increases the mechanical strength and modulus at room temperature by [22.31% and 17.89%] and after heat treatment at 1500 °C by [35.6% and 47.48%] with respect to no-CNF containing composites due to a lower amount of residual Si content and additional reinforcement effect of the unreacted CNFs.

SiO nanoparticle modified CFRP composites effecting on mechanical and vibration damping properties

AbstractSiO nanoparticle inclusion effects on vibration‐damping and mechanical properties of carbon fiber reinforced plastic composites (CFRP) were experimentally investigated by incorporating the NS particles into the epoxy resin system. The nanoparticles in the SiO form were incorporated into the epoxy resin at different ratios (0.5%, 1%, 1.5%, 2%, and 3%) in weight to produce the modified CFRP samples. In addition, the effects of cutout with two different types (edgewise semicircular and central circular) on the vibration response of SiO modified CFRP test samples were determined for different SiO particle incorporation ratios. In this way, variation of both mechanical and vibration properties was experimentally determined in terms of cutout weakening of the composite in the middle while incorporating the SiO particle modification of the CFRP composites. It was seen from this study that the incorporation SiO nanoparticles into CFRP composites were provided the increasing trend in the vibration‐damping and mechanical properties and the highest mechanical and vibration properties were obtained for the addition of 1.5 wt% SiO nanoparticles. On the other hand, further SiO nanoparticle addition, more than 1.5–2 wt%, decreased in mechanical and vibration properties of the composite test samples.Highlights SiO nanoparticle effects on mechanical properties of CFRP composite laminates. SiO nanoparticle effects on vibration damping of CFRP composite laminates. Central cutout effects on vibration characteristics of CFRP composite laminates. Fracture characteristics of CFRP composite laminates with SiO nanoparticle incorporation.

Effects of heat treatment on the microstructure and flexural mechanical properties of carbon fiber reinforced composite cured by electron beam

Carbon fiber (CF)-reinforced composite materials are attracting attention in the automobile and aerospace industries based on their light weight and excellent mechanical properties. Electron beam curing technology is replacing the thermal curing process and can improve productivity by shortening the curing time of CF-reinforced composite materials to minutes. However, the electron beam-cured CF-reinforced composite materials have weak flexural strength. We have found that the deterioration of flexural strength of electron beam-cured CF-reinforced composites can be solved by heat treatment in a vacuum bag prior to the electron beam curing process. Through heat treatment under vacuum, the viscosity of the matrix resin was lowered, and voids between the laminated surfaces of the CF prepregs could be removed. Through this approach, the flexural strength of the electron beam cured composite material reached 1.6 GPa, which was approximately 65% improved compared to the non-heat treated material. In addition, the energy distribution transmitted when the composite material is irradiated with an electron beam was simulated using the Geant4 code. It was confirmed that the nonlinear distribution of energy transmitted to the inside of the specimen according to the electron beam energy should be carefully considered in the design of the product shape and when setting the electron beam irradiation conditions.

Influence of carbon fiber nickel electroplating on the electromagnetic interference shielding and mechanical properties of carbon fiber reinforced polyamide 6 composites

AbstractThis article investigates the use of nickel electroplated carbon fiber (Ni‐CF) fabric to enhance the electromagnetic interference (EMI) shielding capability of carbon fiber reinforced thermoplastics (CFRTs), particularly for automotive and aerospace applications. The study examines the influence of nickel electroplating parameters of carbon fiber on the morphologies of carbon fiber fabrics. Ni‐CF reinforced polyamide 6 (Ni‐CF/PA 6) was prepared by the film‐stacking method. The flexural properties analysis demonstrates a 21.1% increase in flexural strength for Ni‐CF/PA 6 composites compared to as‐received carbon fiber reinforced PA 6 (CF/PA 6) composites. Additionally, the introduction of nickel layer significantly improves the EMI shielding efficiency of CF/PA 6 composites, with the average shielding efficiency increasing from 23.5 to 31.6 dB within the X‐band and Ku‐band frequency ranges. Scanning electron microscope (SEM) analysis confirms that the nickel layer enhances the interfacial bonding between the PA 6 matrix and the Ni‐CF, which is attributed to the micro cone‐shaped structures of the nickel layer. Overall, the electroplating method effectively modifies the carbon fiber surface, resulting in composite laminates with enhanced mechanical properties and superior EMI shielding efficiency. These findings provide valuable insights for the development of advanced carbon fiber reinforced composites with improved functionalities in various applications.Highlights The electroplating method is used to process the nickel electroplated carbon fiber fabrics. The introduction of micro cone‐shaped structure nickel on the fiber surface by electroplating provides the mechanical interlocking between carbon fiber and matrix. The nickel electroplated carbon fiber can significantly increase electromagnetic interference shielding capability of carbon fiber reinforced thermoplastic composites.

Effect of SiC and graphene nanoparticles on the mechanical properties of carbon fiber‐reinforced epoxy composites

AbstractThis study experimentally investigates the mechanical properties of carbon fiber reinforced epoxy composites (CFRECs) filled with Graphene (Gr) and Silicon Carbide (SiC) nanoparticles. Gr and SiC nanoparticle filled CFREC plates at 0%, 0.5%, 1%, and 2% weight ratios were fabricated using a vacuum infusion technique from unidirectional carbon fiber fabric with both 0 and 90° fiber orientation. According to ASTM standards, tensile, compression, and three point bending tests were performed to determine the effects of additive type and weight ratios. CFRECs with Gr additive exhibit improved tensile properties compared to the unfilled composites, especially at higher filler contents and at specific fiber orientations. Also, the Gr additive showed a better improvement in the tensile behavior of the CFRECs than the SiC additive. In general, it was found that the elastic modulus values of nanoparticle additive samples were higher than that of the unfilled composite material in both fiber orientations. Except for the 0.5% SiC ratio with 0° fiber orientation, the particle added nanocomposites did not exceed the value of the unfilled composite and did not make a positive effect on the compressive strength. It has been observed that Gr additives give more positive results on the bending strength of CFRECs than SiC, especially at a 2% weight ratio.Highlights Effects of nanoparticle types on mechanical properties of CFRECs were compared. Weight ratio effects on the properties of nanoparticle‐filled CFRECs were studied. The load‐bearing capacity decreased as the additive ratio increased. Additives and ratios should be carefully selected for the intended applications. Overall, presence Gr resulted in enhanced properties much prominently for composites.