Vacuum Assisted Resin Transfer Molding Research Articles

Influence of MoS2 nano-filler additions on wear behavior of carbon fiber reinforced epoxy composites

In this research work, two body wear and three-body wear performance of carbon fabric reinforced HTR 212 epoxy resin(CF/Epoxy) composites are experimentally evaluated. Carbon fabric/epoxy resin composite panels with MoS2 nano-filler additions of 0.1, 0.2, 0.4 and 0.7 weight percentage are developed by Vacuum Assisted Resin Transfer Molding process. Two Body Wear test is conducted on the prepared specimen in accordance with ASTM G-99, whereas Three Body Abrasive wear test is conducted as per ASTM G-65. Experimental Tests are conducted for sliding and abrading distances in multiples of 250 m up to 1500 m. Results reveal that Carbon fabric/epoxy resin composites with 0.7 weight percent of MoS2 show 18% reduction in two body wear compared to a decrease of 35% in Three Body abrasive wear at 1500 m abrading distance. Scanning Electron Microscopy is used to study the surface morphology of the tested samples and to know the mode of damage at the surface.

A study on the optimal design of UAM seats

The objective of this study is to enhance the efficiency of urban air mobility (UAM) air transportation by determining the optimal design, materials, and processes of seven different manufactured fiber-reinforced plastics (FRP), and to confirm their applicability for next-generation UAM aircraft seats. Structural designs for the aircraft seat models were carried out using carbon fiber-reinforced plastic (CFRP), glass fiber-reinforced plastic (GFRP), and GFRP chop materials, employing Autoclave, Hot-press, and vacuum-assisted resin transfer molding (VaRTM) processes, resulting in a total of seven FRP configurations. It was confirmed that CFRP seats were 50% lower weight than aluminum models, while GFRP seats showed a 30% reduction. Although Autoclave processing resulted in the highest tensile strength at 985[Formula: see text]MPa, VaRTM processing also produced strength levels comparable to Autoclave processing. Structural integrity assessments of the seat models, utilizing the Korean aviation standards (KAS), confirmed that the designed seat models exhibited no failure or deformation under the conditions required by the technical standards. This study provides insights into the potential application of the seven types of FRP materials in the design of aircraft seats, offering weight reduction benefits and meeting the structural integrity requirements outlined by KAS.

Effects of core geometry, silica nanoparticles, and polyurethane foam on the mechanical properties of a novel circular-shaped core sandwich panels under compression test: Experimental study

For the first time in this paper, a composite sandwich panel with a novel circular-shaped core reinforced with silica nanoparticles (SNPs) is designed and fabricated using the vacuum-assisted resin transfer molding (VARTM) method. Carbon fibers and epoxy resin are utilized to construct the composite sandwich panels, followed by polyurethane foam injection. After fabrication, the sandwich panels undergo uniform compression testing to examine their mechanical behavior and properties. In this study, the effects of various parameters, such as core length, core height, weight percentage (wt.%) of SNPs, and polyurethane foam, on the compressive strength of the structure are evaluated. To validate the results, a finite element simulation of the sandwich panel compression test is performed using ABAQUS software, and the results obtained are compared with experimental data, showing good agreement. The results of this research demonstrate that adding SNPs within a specific range results in a considerable enhancement of the structural strength. Adding SNPs up to 3% leads to approximately a 19% increase in the compressive strength of the structure. However, adding 4 wt.% SNPs results in a decrease of about 12% in the strength of the sandwich panel. Additionally, the core’s geometry significantly influences the control of compressive strength and rigidity of the sandwich panel. In other words, by increasing the core length, the compressive strength increases by 38%, while increasing the core height decreases compressive strength by about 30%. Also, it is found that adding polyurethane foam to the sandwich panel, despite a slight increase in weight, leads to a significant increase in compressive strength by about 32% and postpones its ultimate failure. Eventually, the hybrid specimen exhibits a strength approximately 57% greater than that of the pure foamless sandwich panel.

Environmental Impact of an Innovative Aeronautic Carbon Composite Manufactured via Heated Vacuum-Assisted Resin Transfer Molding

The Vacuum-Assisted Resin Transfer Molding (VARTM) process has gained popularity as a reliable and cost-effective alternative to autoclave molding for high-performance composite production, which is especially interesting for aeronautics, where weight reduction is crucial. However, to date, the environmental impact of components produced through VARTM remains relatively unknown. To address this gap, this study applied the Life Cycle Assessment (LCA) methodology to estimate the environmental impact of a thermoset composite laminate produced through heated VARTM. Aiming to support the decision, the VARTM composite part’s production was compared to conventional autoclave manufacturing, and the influence of alternative end-of-life (EoL) scenarios and energy mixes was considered, through LCA. The study found that energy consumption represented the majority of the environmental impacts of the heated VARTM component (33%), followed by carbon fibers, resins, consumables, and wastes. In terms of the comparative analysis, the autoclave manufacturing process showed better environmental results. Regarding EoL management, supercritical hydrolysis (with heat recovery) recycling emerges as the most beneficial method, reducing the impacts of the VARTM-manufactured component by 25%. This study emphasizes the importance of sustainable practices, such as reducing energy consumption, using low-carbon energy mixes, and adopting recycling methods to improve VARTM composite’s environmental performance.

Analyzing the Tensile Strength of Carbon Fiber-Reinforced Epoxy Composites Using LabVIEW Virtual Instrument

Carbon fiber-reinforced polymer composites are widely used materials in the aircraft industry, automotive sector, marine applications, civil engineering, and daily consumer goods, due to their superior mechanical properties at a relatively low density compared to metallic materials. The studied composites are composed of an epoxy resin matrix in which three layers of carbon fiber fabric are embedded, oriented at 0 and 90 degrees. Carbon fiber-reinforced polymer composites were manufactured using the Vacuum Assisted Resin Transfer Molding technique. The tensile failure mechanism in carbon fiber-reinforced polymer composites is an extremely complex phenomenon influenced by numerous factors. This study aims to evaluate the mechanical behavior of carbon fiber-reinforced composites through tensile testing and to compare experimentally obtained results with those calculated using the mixture rule. Additionally, the behavior of the materials under tensile stress was analyzed using the digital image correlation method. Estimating mechanical properties based on the mixture rule is a common practice in the design phase of polymer composites. This study s novelty and originality lie in its anticipation of the tensile strength and modulus of elasticity of the studied composites. This anticipation was achieved using a virtual instrument developed in the LabVIEW graphical programming environment. The experimentally obtained results for the tensile characteristics of the studied materials are suitable for this type of composite. These results were compared with estimates derived from the mixture rule, and the absolute error was determined.

Development of hybrid green composites by dual natural fibers (jute/bamboo) reinforcement and investigation of their mechanical behavior

AbstractThis study aims to investigate the mechanical properties of natural fiber hybrid composites, specifically those based on jute and bamboo fibers. Jute fibers made in the form of highly scattered mesh and fine‐meshed bamboo mat were selected as reinforcing materials. The highly scattered meshed jute fabric composite showed poor mechanical properties owing to resin agglomeration, leading to the brittle fracture of the composite before elongation. In contrast, the randomly oriented fine‐meshed bamboo fabric performed better in terms of both mechanical properties and strain energy absorption under the same loading conditions. Hybridization with fine bamboo mesh fibers can be a solution to improve the mechanical properties of jute fabric composites. The tensile, flexural, and in‐plane shear properties of the composites are investigated in our study. We found that hybridizing a fine‐meshed bamboo mat with jute fabric resulted in an improved mechanical performance of the composite. Composite panels have been manufactured using vacuum assisted resin transfer molding (VARTM). Experimental and numerical methods have been used to investigate the flexural behavior. Of the stacking sequences considered, the (J/B4/J) stacking showed the highest flexural strength (141.1 Mpa) and the (B2/J2/B2) 2/2 stacking sequence showed the minimum flexural strength. The alternating stacking sequence (B/J/B/J/B/J) exhibited intermediate properties. The randomly oriented bamboo fabric near the neutral axis enhanced the properties of the hybridized composite. This was verified numerically using the ANSYS ACP software.Highlights Mechanical behavior of Hybrid composite of two natural fibers was investigated. Vacuum assisted resin transfer molding was used to manufacture composite panels. Tensile, in plane shear, 3 point flexural tests and SEM micro analysis were done. FEA was used to validate and compare the experimental and numerical results. Resin agglomeration was improved by fibers with better resin impregnation property.

Effect of Water Absorption and Stacking Sequences on the Tensile Properties and Damage Mechanisms of Hybrid Polyester/Glass/Jute Composites.

The aim of this work is to analyze the effect of water absorption on the mechanical properties and damage mechanisms of polyester/glass fiber/jute fiber hybrid composites obtained using the compression molding and vacuum-assisted resin transfer molding (VARTM) techniques with different stacking sequences. For this purpose, the mechanical behavior under tensile stress of the samples was evaluated before and after hygrothermal aging at different temperatures: TA, 50 °C, and 70 °C for a period of 696 h. The damage mechanism after the mechanical tests was evaluated using SEM analysis. The results showed a tendency for the mechanical properties of the composites to decrease with exposure to an aqueous ambient, regardless of the molding technique used to conform the composites. It was also observed that the stacking sequence had no significant influence on the dry composites. However, exposure to the aqueous ambient led to a reduction in mechanical properties, both for the molding technique and the stacking sequence. Damage such as delamination, fiber pull-out, fiber/matrix detachment, voids, and matrix removal were observed in the composites in the SEM analyses.

Vibration Response of Thermoplastic Veil Interleaved Carbon Fiber Reinforced Epoxy Composites

Plate composite structures are used in many sectors today. Therefore, the demand for these structures is increasing. Especially in the field of aerospace, layered composite structures attract more attention. These wide range of applications affect composite materials in various aspects such as dynamic and mechanical in terms of working environments. Time-dependent variable stresses, vibrations and fatigue that occur in structures subjected to dynamic loads adversely affect both the internal and external structure of composite materials. This situation reduces the safe service life of composite materials. It is an important problem to eliminate or minimize the parameters that negatively affect the economic service life of fiber reinforced layered composite structures. In order to overcome these problems, it is aimed to create new composite structures by adding two different thermoplastic veil layers between fiber fabrics, which are widely used on an industrial basis. In this study, carbon fiber was used as the fiber fabric and Polyamide (PA) and Polyether ether ketone (PEEK) veils were used as the thermoplastic veil layers. The productions were made by Vacuum Assisted Resin Transfer Molding (VARTM) method and dynamic (natural frequency and damping ratio) tests were performed according to the relevant ASTM standards. With the experimental results obtained, the dynamic properties of thermoplastic veil-layered carbon fiber/epoxy composites were comparatively investigated to determine the effect of both veil layers and different fiber contents.

3D woven tubular composites with bamboo‐structures for enhanced energy absorption: Designing, manufacturing and performance analysis

Abstract3D woven tubular composites (3D‐WTC), known for their lightweight and high‐strength characteristics, are widely used in various energy‐absorbing components. To enhance the energy absorption capacity of 3D‐WTC, this study conducted a mechanical analysis of bamboo tube structures and proposed concentric circular nested biomimetic structures with “single tube + double ribs” and “double tubes + double ribs.” 3D woven tubular composites with bamboo‐structures (3DWTC‐Bamboo) were fabricated using the vacuum‐assisted resin transfer molding (VARTM) process. Axial compression tests were conducted using a universal testing machine to reveal and discuss the energy absorption capacity and failure modes of 3DWTC‐Bamboo. The results showed that 3DWTC‐Bamboo with a “double tube + double ribs” concentric circular nested biomimetic structures performed exceptionally, with a peak load of 28.93KN and specific energy absorption of 7.74 J·g−1. The failure mode was a hybrid of “rib folding + tube wall buckling.” Finally, finite element analysis of the stress distribution during the compression of 3DWTC‐Bamboo was conducted using ABAQUS, which validated the experimental results. In summary, this work provides a reference for structural innovation in 3D‐WTC and further expands its application in the field of energy absorption.Highlights Propose “single tube + double ribs” and “double tubes + double ribs” structures. Introducing the “rib” structures to enhance the local strength/stiffness. Test results show that 3DWTC‐Bamboo has great potential in energy absorption. The “ribs” can increase the local strength/stiffness of the tube structures.

Interply hybridization of hollow glass fiber reinforced vascular composites

AbstractThe use of hybrid reinforcement in polymer composites has been getting attention due to its potential for weight and cost reduction while achieving improved design flexibility for mechanical and thermal properties. In this study, an interply hybridization of epoxy laminates was performed using layers of solid and hollow glass fibers. The structural and thermal performance of the resulting hybrid vascular composites was investigated. All composite parts were manufactured using vacuum‐assisted resin transfer molding (VARTM), following an interply hybridization plan for the stacking sequence of hollow and solid fiber layers. An expected decrease in flexural properties and thermal conductivity was observed for the laminates with completely hollow fibers. On the other hand, hybridization had a positive effect on the laminate properties. It was shown that hybrid vascular composites could be manufactured without a significant reduction in mechanical and thermal performance by a judicious hybridization plan. The optimum hybridization of the laminate achieved a 3.1% increase in the specific flexural strength and a 5.3% decrease in thermal conductivity while containing a vascular network that can be used for active thermal control.Highlights A vascular interply composite structure consisting of hollow and solid fibers was manufactured and characterized for the first time. The I4 composite, vascularized through the middle layers of the laminate, has almost as much flexural strength as solid composite and much more specific flexural strength. The thermal conductivity of the I4 composite is almost as much as that of the solid composite. Functional composites for thermal management and smart applications can be manufactured using hollow fibers without sacrificing flexural strength and thermal conductivity with interply vascularization.

Effects of various parameters on the mechanical properties of composite lozenge‐shaped core sandwich panels subjected to flat‐wise compression test

AbstractThis paper studied the compressive behavior of a composite sandwich panel with a lozenge‐shaped core reinforced with graphene nanoparticles (GNPs) under different conditions. The fabrication process involves the utilization of Kevlar fibers and epoxy resin to construct the sandwich panels, followed by introducing polyurethane (PU) foam through vacuum‐assisted resin transfer molding (VARTM). Flat‐wise compression testing is conducted to assess the mechanical properties and behavior of the sandwich panels. The study investigates the effect of various parameters, including core angle, core height, weight percentage (wt%) of GNPs, and PU foam, on the compressive strength of the structure. The experimental results are validated through finite element simulation using ABAQUS software, and a satisfactory agreement is observed between the simulated and experimental data. The research findings indicate that the inclusion of 3 wt% of GNPs in the structure leads to a notable 25% enhancement in the compressive strength of the sandwich panel. However, when the GNP content was further increased to 0.4 wt%, a contrasting trend was observed and the strength of the structure decreased by about 12%. Furthermore, an increase in the core angle is associated with a substantial 46% improvement in the sandwich panel's strength. Conversely, an increase in the core height is found to cause an 18% reduction in the sandwich panel's strength. Also, the addition of PU foam results in a significant increase of approximately 42% and 58% in the strength and energy absorption of the sandwich panel, respectively. This comprehensive parametric study offers valuable insights to engineers and designers seeking to construct sandwich panels with optimal strength against compressive loads.Highlights Adding GNPs modifies the mechanical properties of the sandwich panel. Adding 0.4% of GNPs leads to the reduction of the structure's strength. Increasing the core angle increases the sandwich panel's strength. Increasing the core height decreases the sandwich panel's strength. PU foam significantly increases the sandwich panel's strength.

Significant enhancement of mechanical properties for glass fiber fabric‐reinforced polyamide 6 composites by improving interfacial bonding

AbstractIn fiber‐reinforced composites, the interfacial bonding between fibers and the matrix is crucial for determining the material's performance. A vacuum‐assisted resin transfer molding (VARTM) process was utilized in this work to fabricate glass fiber fabric‐reinforced polyamide 6 (GFF/PA6) composites through in‐situ polymerization using caprolactam (CL) as the precursor. To enhance the fiber‐matrix interfacial bonding, polyethylene glycol (PEG) was incorporated into the polymerization system, improving the hydrogen bonding between the matrix and fibers. Morphological observations and interface layer analysis revealed that the introduction of PEG resulted in improved interfacial bonding and increased interface layer thickness. Molecular dynamics simulations indicated that the amino formate groups formed by the reaction with PEG exhibited more hydrogen bonds with the hydroxyl groups on the glass fiber surface, thereby promoting interfacial bonding between the matrix and fibers. When the PEG content was 10 wt%, the tensile strength and the elongation at break of the corresponding composite increased by 160% and 300% compared to GFF/PA6 composites without PEG. This study presents a promising strategy for enhancing the fiber‐matrix interfacial bonding by modifying the matrix, offering a prospective approach for developing high‐strength thermoplastic composites.Highlights GFF/PA6 composites were fabricated via the VARTM method. The addition of PEG for matrix modification improved the interfacial bonding. The modification enhances the hydrogen bonding between the matrix and fibers. Good interfacial bonding can greatly promote the crystallization of the matrix. The composites exhibited a significant increase in strength and toughness.

Impact of Process Technology on Properties of Large-Scale Wind Turbine Blade Composite Spar Cap

As wind turbine blade length increases, reconciling lightweight design with strength necessitates continuous advancements in process technology. The impact of three different process technologies–vacuum-assisted resin transfer moulding (VARTM), prepreg, and pultrusion–on the properties of wind turbine blade composite spar caps was investigated using scanning electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and static and fatigue testing. The results demonstrated that the fibre weight content and 0° tensile modulus of the VARTM and pultrusion composites increased as compared to those of the prepreg samples. Subsequently, the properties of a 94-m blade were analysed using the Ansys Composite PrepPost (ACP) and static structure modules in Ansys simulations, and the weights of the spar cap were compared with test data of materials under different process technologies. The results showed that the masses of the spar cap of a 94-m blade in the pultrusion, VARTM, and prepreg processes were 7965, 9170, and 9942 kg, respectively. The quantitative influence rules on the weight of the wind turbine blade spar cap prepared through different process technologies were formulated. The findings of this study are promising and are expected to aid the development of wind turbine blade process technologies.

Surface flame retardancy of clay mineral powder infused onto the top of the layer of vinyl ester/bamboo composites through a modified VARTM process

The mechanical properties of fire-resistant biocomposites are significantly compromised owing to the high amounts of flame retardants (FRs) required for satisfactory results and the limited interfacial interactions between flame retardants (FRs) and polymer/natural fibers. The study addresses these challenges by modifying the vacuum-assisted resin transfer molding (VARTM) process to include two inlets and two outlets, allowing for the simultaneous infusion of an FR-filled resin on the top layer and pure resin in the remaining layers. Vermiculite clay mineral (VCM) was employed as an FR additive in vinyl ester (VE) using mechanical mixing methods such as the three-roll mill and overhead stirring. Bamboo fabric (BF) was used as the reinforcement in fabricating of VC-VE/BF fire-resistant bio-composites. Microscopic and spectral analyses confirmed clay dispersion and interactions within the composites. The FR-loaded side exhibited superior flame resistance (with a peak heat release rate (pHRR) of 467.1 W/g) and a 44% increase in thermal stability compared to the remainder of the composite. The findings indicate improved thermal and mechanical properties. The study presents a novel design for eco-friendly, FR composites.

EXPLORING THE MECHANICAL PROPERTIES OF LEAF SPRINGS REINFORCED WITH FIBRE COMPOSITES

To determine whether eggshell particles can be used as a filler material to improve mechanical properties, this study examines the mechanical characteristics of a hybrid material made of eggshell particles and glass-fiber-reinforced polymer (GFRP). To obtain the appropriate particle size, the eggshells are cleaned, crushed, and sieved as part of the experimental approach. The eggshell fragments are then mixed with resin and glass fibres using a vacuum-assisted resin-transfer moulding process to create GFRP composites. The produced GFRP composites’ flexural strength, stiffness, fatigue stability, and other pertinent characteristics are evaluated with practical tests. Notably, certain qualities are enhanced with the inclusion of eggshell particles containing 110 % of the weight of fibroin. In comparison to conventional GFRP composites, which only consider fatigue life during the exhaustion testing phase, the results reveal a 15% increase in the enhancement rate. The findings imply that adding eggshell particles to GFRP composites has tremendous opportunities for progress, notably in automotive applications, and more specifically in the use of leaf springs. The hybrid material’s better mechanical characteristics suggest that it may be possible to improve the performance and longevity of leaf-spring applications. This study advances the investigation of low-cost, environmentally friendly materials for improving composite materials’ mechanical properties in the automobile sector. The application of eco-friendly and effective solutions in the production of automobiles may result from more study and development in this field.

Experimental investigation of physical, mechanical, and thermal behaviour of Bi-directional date palm fiber reinforced epoxy composite

The present study attempts to fabricate lightweight polymer composites with superior physical, mechanical, and insulating properties by vacuum-assisted resin transfer molding (VARTM) technique. This produces bidirectional woven palm fiber epoxy composites with four different fiber loading i.e. 27, 28, 29, and 30 Wt%. The epoxy composite processed with VARTM technique has been characterized by physical, mechanical, and thermal properties along with increasing fiber loading. The test results signified that the mechanical properties including tensile, interlaminar shear, hardness, and impact strength improve with fiber loading. The maximum tensile strength and tensile modulus were observed at a fiber loading of 30 wt%, resulting in values of 64.852 MPa and 3.74 GPa, respectively. The recorded ILSS values for the epoxy composites loaded with 30 wt% were found to be 7.28 MPa. The observed improvements in the mechanical characteristics of the composite produced by the VARTM technology can be attributed to the enhanced interfacial bonding between the matrix and discontinuous prepreg fiber (DPF). The identification of a superior composite, known as DPF-4, was achieved through the incorporation of 30 wt% of bi-directional palm fiber loading. This resulted in notable improvements in the mechanical properties of the composite, as a significant enhancement of 311% and 173% in tensile and impact strength, respectively. These mechanically strengthened epoxy composites could be used as low-grade housing, structural, and automobile component applications.

Assessment of thrust force, delamination and temperature during drilling of basalt fiber-reinforced composite with different drill geometries

Basalt fiber-reinforced composites (BFRC) are globally recognized for their superior mechanical properties, resistance to moisture absorption and corrosive substances and environments, which have led to their widespread use in industrial applications. Drilling of BFRC has fascinated researchers because of its non-homogeneous and anisotropic nature and various challenges associated with it. This research article explores the assessment of thrust force, delamination and temperature during drilling of BFRC made through the vacuum-assisted resin transfer molding (VARTM) process. Different feed rates (FR) (0.07, 0.17, 0.27 mm rev–1) and spindle speeds (SS) (1000, 3000, 5000 RPM) also drill geometries such as parabolic, twist, and center drill were considered for parametric study. The study employed a full factorial design (FFD) to evaluate thrust forces (TF), delamination factor (DF), and drilling temperature (DT). ANOVA was used to determine the contributions of drilling parameters, while multivariable regression analysis (MRA) was utilized to establish predictive empirical models. Scanning electron microscopy (SEM) analysis was also conducted through the drilled hole for understanding of drilling behaviour and surface morphology. Results have demonstrated that feed rate significantly influenced delamination (61.62%) and thrust force (62.73%), whereas drill geometry and spindle speed had the greatest impact on drilling temperature by 55.26% and 33.04%, respectively.

An unexpected hardening behaviour of carbon-fiber epoxy composites under flexural fatigue loading and its intensification by graphene nano-fillers

The fatigue performance of carbon fiber reinforced polymer (CFRP) composites under cyclic loading remains a significant concern in various engineering applications due to the complex damage mechanisms and uncertain failure modes associated with these materials. Despite their exceptional strength-to-weight ratio, CFRP composites are prone to progressive damage accumulation, leading to premature failure and reduced structural integrity. The present study investigates the flexural fatigue response of pristine CFRPs and CFRPs with added graphene nanoplatelets (GNPs), accompanied by in-situ microscopy for progressive damage analysis. Eight layers of carbon fibers fabric, both pristine and GNP coated were utilized to fabricate the composites using vacuum-assisted resin transfer molding (VARTM) technique. GNP-added composites exhibited significantly improved monotonic flexural strength, strain and fatigue life compared to pristine composites. The dissipated strain energy density (DSED) was also evaluated as a function of cycles and correlated with the damage that happened in the composite using in-situ optical imaging. While cycling at or below three-quarters of the maximum tensile stress, it was observed that the DSED decreased with the number of cycles in both composites. However, at higher loads, the DSED was found to increase progressively, ultimately shooting up during catastrophic failure. These composites that showed a decrease in DSED with cycles, did not fail even at one million cycles and had a higher residual strength than the original when they were forced to break under monotonic loading and the percentage increment was even higher when GNPs were used. Additionally, post-failure fracture surface examination using scanning electron microscopy (SEM) was conducted to understand the influence of GNP addition on damage evolution of CFRPs.

Investigation of the influence of Halloysite Nanotubes (HNTs) on the low-velocity impact behavior of carbon fiber-reinforced epoxy composites

This study explores the impact of incorporating Halloysite Nanotubes (HNTs) nanoparticles on the low-velocity impact (LVI) behavior of carbon fiber (CF) laminate epoxy nanocomposites. The objective of this investigation was to observe the effects of different nanotube loadings (0.5[Formula: see text]wt.% and 0.7[Formula: see text]wt.%) on CF composites and assess their impact resistance. To achieve this, the CF was subjected to Electrophoretic Deposition (EPD) process to introduce the HNTs. Vacuum-assisted Resin Transfer Molding (VaRTM) was employed to fabricate the CF-reinforced epoxy-based laminated nanocomposites with incorporated HNTs. LVI tests were conducted following the ASTM-D-7136 standard, utilizing impact energies of 10[Formula: see text]J and 15[Formula: see text]J. Subsequently, the damaged areas within the composites were examined using optical microscopy (OM) and scanning electron microscope (SEM). The findings of this investigation revealed a significant enhancement in impact damage resistance with the addition of HNTs. The highest damage resistance and minimal energy absorption were observed at a loading of 0.7[Formula: see text]wt.% HNTs. The results reveal that incorporating 0.7[Formula: see text]wt.% HNTs substantially reduces delamination damage, influenced by absorbed impact energy. As well it composite underscores enhanced interlaminar bonding through 0.5[Formula: see text]wt.% and 0.7[Formula: see text]wt.% HNTs modification. Hence, we confidently assert that the addition of HNTs nanoparticles to CF/epoxy composites has considerably influenced the impact response of the nanocomposites.

Mechanical performance of stitched foam-filled honeycomb sandwich panels

Foam-filled Honeycomb Sandwich panels (FHS) are widely used in various industrial applications due to their superior multifunctional properties. However, these sandwich panels fail in some extreme conditions due to interfacial failure between the face sheet and core. To overcome this issue, novel stitched foam-filled honeycomb sandwich panels (SFHS) were fabricated by integrating the top face sheet and bottom face sheet by the stitching technique. Stitching through the face sheet and core is to improve the interfacial strength and increases the mechanical properties of the sandwich panel. FHS and SFHS were prepared by the Vacuum Assisted Resin Transfer molding (VARTM). Flexural, flatwise, and edgewise compression analysis values for SFHS panels are 2.02, 1.28, and 1.25 times higher than for FHS panels. SFHS panel weight increased slightly but had superior mechanical properties than FHS. These innovative SFHS panels can be broadly used for applications including structural, flooring, and body panels.