Carbon fiber reinforced polymers (CFRP) are characterized by their impressive specific strength. These lightweight composites are increasingly replacing metals and glass fiber reinforced polymers (GFRP). Key advantage of CFRP is its inherent resistance property to environmental degradation, making them promising candidates for corrosion-resistant applications. Engineering structures frequently experience cyclic loading conditions, which can lead to their failure and damage. Numerous research findings indicate that the performance of CFRP composites under fatigue is significantly influenced by various factors such as material composition, environmental impact, and the applied cyclic loads. The nature of composite fatigue involves the complex process of crack initiation and propagation. The damage mechanism of CFRP composite is challenging due to the material inhomogeneity and variations in constituent materials, service and cyclic loading conditions. This review paper aims to present the most relevant data regarding CFRP’s fatigue behaviour.
Aluminium alloy 6063-T6 is a popular choice among different industrial sectors as it portrays various desirable properties like moderate strength, improved corrosion resistance, better weldability and formability etc. These advantages make AA6063-T6 a common choice for matrix in a metal matrix composite. Mostly conventional fusion welding methods like Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG) seem preferable options for welding aluminium and its alloys but it remains a challenge to use them to weld aluminium metal matrix composite. A modified version of MIG i.e. CMT welding, can be explored to overcome the challenges. In this study, an aluminium metal matrix composite has been fabricated with AA6063-T6 as matrix and two reinforcements −one organic, i.e., Eggshell (ES) and one inorganic, i.e., Boron Carbide (B4C), using the conventional stir casting method. CMT welding has been performed on plates cut out from the composites. Microstructure, hardness, tensile strength and residual stress of weld joint of composite have been observed. From micrographs, it is observed that a finer grain has been formed at the Fusion Zone (FZ) in comparison to the Heat Affected Zone (HAZ) and Parent Material (PM). XRD analysis at the fusion line has identified several intermetallic stoichiometric compounds (Al12Mg17, Mg2Si, CaMgSi, CaO, B2O3) and reinforcement B4C and CaCO3 within the matrix volume. The FZ exhibits higher hardness than the HAZ and the PM. Further, the tensile strength of the FZ exceeds that of the unwelded composite due to the presence of metastable strengthening phases of Mg2Si in the FZ, along with reinforcement (B4C and ES) particles. Residual stress analysis reveals tensile stress in the FZ and more compressive stress in the HAZ than in the PM.
While silicon-based electronic devices exhibit high performance, they lack the flexibility required for the development of flexible devices. The need for flexible devices has sparked research interest in organic semiconductors, primarily due to their lightweight nature, cost-effectiveness, and suitability for large-scale applications. Organic field-effect transistors (OFETs) are crucial in advancing the development of bendable smart cards, expansive displays, healthcare sensors, and various other applications. This study explores the structural and optical properties of the organic semiconductor layer, poly (3-hexylthiophene-2, 5-diyl) (P3HT), and the dielectric layer, graphene oxide (GO), with the aim to incorporating them into OFETs. Field Emission Scanning Electron Microscopy (FESEM) reveals the smooth surface morphology of both the P3HT and GO semiconductor layers, facilitating efficient charge transport at the dielectric-semiconductor interface. X-ray Diffraction (XRD) characterization indicates the amorphous nature of both the P3HT and GO layers. Furthermore, Raman spectra of GO demonstrate an ID/IG ratio of 0.91, indicating the presence of defects in the dielectric material. Additionally, the electrical characteristics of the fabricated device exhibit Schottky behaviour.
A cytocompatible silica-zinc catalyst from cow dung for photocatalytic reduction of Chromium (VI) to Chromium (III) was prepared by sol-gel method with zinc nitrate and the sodium silicate solution prepared from the cow dung ash. The catalyst was characterised by X-Ray Diffraction (XRD) analysis, which indicated the Opaline form (Opal-C) of silica. This result was further corroborated in the Infrared (IR) spectrum. Silicon, Sodium, and Zinc were confirmed using an energy-dispersive spectrum, and the surface morphology indicated agglomerated particles and hollow tubular structures of different dimensions in the Field emisson scanning electron microscopy (FE-SEM). The direct band gap of 4.9 eV was calculated from diffuse reflectance studies. The Chromium (VI) to Chromium (III) reduction was analysed by DPC complexation and absorbance at 540 nm in a UV–visible spectrophotometer. MTT assay test proved that the composite is cytocompatible with more than 50 % cell viability even at higher concentrations like 100 µg/mL.
This research paper presents a comprehensive study on the comparison of three distinct corner manufacturing techniques in sheet metal forming: close corner, open corner, and open corner with a corner relief notch. The investigation primarily focuses on assessing crack presence, crack propagation behaviour, and structural integrity of the corner samples through visual inspection and scanning electron microscope (SEM) analysis. Visual inspection revealed the presence of cracks in the close corner sample, whereas both open corner samples exhibited crack-free surfaces. SEM analysis uncovered micro cracks at the tip of the existing crack in the close corner sample, while the open corner sample showcased a micro crack at the lower fibre. Notably, the upper fibre of the close corner sample remained defect-free. In contrast, the open corner sample with a corner relief notch exhibited an absence of cracks altogether. To evaluate real-world application feasibility, a circuit breaker mounting pan for a switchboard was designed using the three corner types. Static analysis was conducted to assess the structural performance of each corner pan. Results indicated that the stresses in the close corner pan remained below the yield strength, ensuring structural stability. Conversely, stresses in both open corner pans, with and without a corner relief notch, exceeded the yield strength, posing concerns for their practical use. Interestingly, the open corner pan with a corner relief notch demonstrated stress patterns similar to its counterpart without the notch.
This study introduces a graphene oxide (GO)-based memristor, a unique device expanding the concept of a resistor to include memory functionality. Memristors possess exceptional qualities that make them ideal for non-volatile memory (NVM) applications. In this work, we present a memristor utilizing GO as the active layer, which can be effortlessly fabricated via a simple spin-coating method at room temperature. GO-based resistive memory devices offer several advantages over other oxide materials, such as ease of fabrication, scalability down to nanometer dimensions, and compatibility with diverse device applications. The research examines the structural properties of GO using X-ray Diffraction (XRD), revealing a broad peak between 20° to 25°, indicative of its relatively low crystallinity. Raman spectroscopy of GO shows a D-to-G intensity ratio of 0.947, suggesting defects and disorder in the deposited thin film. Furthermore, morphological analysis via Field Emission Scanning Electron Microscopy (FESEM) demonstrates a uniform distribution of the GO thin film. Remarkably, the fabricated device exhibits distinctive I-V characteristics, featuring resistive switching behavior with a read voltage of 2.3 V, power consumption of 0.171 mW and Ion/Ioff of 103, highlighting its potential for non-volatile memory applications.
The lead (Pb)-based perovskites have gathered the majority of research attention, but their toxicity and stability issues pose significant barrier to commercialization. In this context, the Pb-free perovskites may offer promising alternatives with reducedtoxicity and increased stability. This research focuses on analysing Pb-free perovskite material-based LEDs (PeLEDs) using TCAD simulation software, Silvaco. A systematic investigation of a Pb-free perovskite material (CsSn0.5Ge0.5I3)-based LEDs has been conducted to explore their luminescence power versus voltage (current), power spectral density and anode current–voltage (I-V) characteristics. Remarkably, we observed that luminescence power elevates almost linearly with the applied voltage once it surpasses the turn-on voltage of 1.1 V. Additionally, the power spectral density curve reveals a peak wavelength of 818 nm, and a peak power spectral density (PSD) 0.55 mW/cm-eV at an anode voltage of 10 V. The peak PSD is considerably affected by the applied voltage, while peak wavelength remains independent of the applied voltage. Moreover, analysis of the I-V curve demonstrates the presence of a potential barrier between the transport layer and the electrode and once the voltage becomes sufficiently high to overcome this barrier then the current follows the voltage exponentially. This study could aid in the design and fabrication of more efficient and environmentally sustainable PeLEDs.
In the present investigation an endeavor was made to synthesize Si3N4/ Gr reinforced Al7075 alloy hybrid composites using squeeze casting method and its microstructure, mechanical properties were analyzed for function applications. Observation shows that the microstructure of the synthesized composites exhibits a dendritic pattern of primary aluminium, accompanied by the presence of eutectic particles precipitated at the grain boundaries. ASTM standards was used to analyze its performance measures. The incorporation of high strength reinforcement, strong bonding between the matrix and reinforcement, and reduced grain size were found to significantly enhance the tensile (18.12 %) and compressive strength (19.71 %) of hybrid composites when compared to the as-cast alloy. On the other hand, the existence of stress concentration can serve as fracture initiation locations, resulting in early failure, and that this can greatly reduce the percentage of elongation of hybrid intermixture (12.23 %). The presence of Si3N4 serves as a buffering agent, thereby impeding the process of oxidation in aluminium alloys reinforced with silicon nitride.
Aluminium alloys continue to be an effective material for the aviation and automotive sectors in spite of the development of composites and other lightweight materials because of their sophisticated manufacturing techniques, strong durability against fatigue fracture propagation, and excellent impact endurance. As numerous holes are needed for creating rivets, drilling is the most difficult of all the machining operations. The primary problems with drilling these aluminium alloys are represented by a low hole quality, which increases the risk of airframe construction defects and lowers reliability. As a result, parts get discarded throughout the process of assembling, which affects the overall cost of production. To satisfy the needs of machined parts, the selection of Feed rate (F), Spindle Speed (S), Drill Material (D) and percentage of reinforcements (R) as well as drilling equipment, is necessary. The objective of this research work is to study the impact of cutting parameters on surface roughness (SR) and thrust force (TF) during drilling Hybrid MMCs, which were prepared by stir casting. The reinforcements used for fabrication were fly ash and boron carbide. A computer numerical control VMC with a cutting tool dynamometer for measuring TF was used for the experiments. The investigations used the L18 orthogonal array as their base of operation. The multi response optimization considering TF and SR was carried out using grey relational analysis (GRA) and the optimal level of cutting parameters like 'F', 'S', 'D' and 'R' were identified to obtain low TF and SR. The optimal machining parameters which give low TF and low SR are at 6 % reinforcement, coated carbide drill, S 3000 rpm and F 50 mm/min. Feed Rate (67.20 %) has the most significance on GRG trailed by S (15.88 %), Drill Material (6.39 %) and reinforcement percentage (3.65 %). Confirmation experiments demonstrated that grey relational analysis precisely optimized the process variables in drilling of hybrid MMCs.
Lead-free ceramic powder with composition 0.8BaTiO3-0.2Bi(Mg0.5Ti0.5)O3 [BT-BMT] was synthesized by sol–gel method. Two separate sets of free-standing polymer composite films were prepared by the simple and affordable solution casting method. The BT-BMT particles were dispersed into the individual polymer matrix: P(VDF-TrFE-CFE) terpolymer (TP) and P(VDF-TrFE) copolymer (CP). The filler content in both cases was maintained as 7 wt%. The synthesized ceramic powder, the raw polymer powder and the prepared polymer composite films were characterized by X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared(ATR-FTIR) and Raman spectroscopy techniques at room temperature.XRD results confirmed the phase formation in the polymer composite films, that exhibited the peaks from the two phases: perovskite phase (from the filler particles) with a strong (110) preferential orientation and the peaks associated with the respective polymer.The FTIR and Raman spectra revealed the polar β- and γ-phases of the PVDF. Besides, highly diffused peak associated with the nonpolar-α-phase was also observed.Dielectric and ferroelectric properties were studied that revealed relaxor behavior in the terpolymer based films.This research suggests a successful method to include oxide nanoparticles in the polymer matrix, which while maintaining the properties of the polymer and the fillers can lead to high-quality flexible free-standing polymer composite films that have the potential to be used in various applications such as energy storage, electrocaloric cooling, energy harvesting applications.
In order to meet the growing need for high-strength, light, and wear-resistant materials, further research and development in the field of suitable relative nanocomposite is necessary, even though advancements in the aviation and automotive industries in the manufacture of lighter materials have taken place in recent years. Especially the Al2O3 family of advanced nanomaterials is significant as it can satisfy the high-strength requirements of automobile and aerospace components. Therefore, it is essential to make extensive use of Al2O3 nanocompounds. The lightweight, affordable, heat-tolerant, machinable, and corrosion-resistant properties of 6061 alloys make them ideal for use as critical structural components in aircraft and automobile structures, including fuselages and wings, internal and external panels, gateways, chassis parts, and external and internal trunks. In this research using a Stir Casting (SC) furnace, Al2O3 nanoparticles reinforced with 2 %, 4 %, 6 %, and 8 % weight were utilised to overcome the low tensile strength and hardness of 6061 aluminum, resulting in the production of unique Al2O3 / Al6061 nanocomposites. The micrographs obtained by the FESEM showed that the main cause of the strength augmentation is the high degree of grain refinement, homogenous scattering, and low porosity that is produced by Al2O3 reinforcing. The highest strength and hardness of the Al2O3 reinforced material is 282.38 MPa and 98.41 BHN. This surpasses the basic alloy strength (282.38 MPa) and hardness (37.5 BHN) by 134 % and 162 % respectively.
This study investigates the flexural strength in cellular cold-formed steel by varying the hole diameter and beam thickness. The hole diameters, which range from 0 to 160 mm, and the beam thicknesses, which are 2 and 3 mm, determine the cross-sectional geometry variations. Three-point loading on the beam was assessed with ABAQUS, a finite element analysis. The mesh size, element type, and boundary conditions were simulated using the finite element analysis. The end condition supports are to be placed 100 mm from the beam’s ends. When the load deflection curves are plotted and compared with the various thicknesses and hole sizes of cold-formed steel beams, the result shows the bending capacity of the cellular beam. The cold-formed steel cellular beams’ distorted forms and failure modes were examined.
In the present study we performed Density Functional Theory (DFT) calculations to study the decorated Vanadium (V) on graphene sheet (Gr-V) as well. We adsorbed 6H2 molecules on V decorated graphene surface. The calculated total energy (Etotal) for pristine graphene and complex system Gr-V found –223.718 Ry and −368.95557 Ry respectively. After successive adsorption of molecular hydrogen, the total energy found in the range of −371.308 Ry to −382.523 Ry. We investigated the Fermi energy in increasing order within the range of 0.898 eV to 3.135 eV, The evaluated binding and Fermi energies confirms the Vanadium candidate is more suitable for hydrogen storage capacity of the studied system. On the basis of the extracted results, we can infer that the decorated hydrogen molecule (1H2-6H2) has the sufficient gravimetric capacity of V decorated graphene. The density of states (DOS) confirms the weak interaction between σ bonding electrons of H2 molecule (1H2-6H2) with the vanadium (V) decorated graphene complex system. Our reported complex system (Gr-V-1H2-6H2) is feasible for a promising material to store hydrogen molecules (H2) moreover.
The construction industry is a significant contributor to environmental degradation due to the extensive use of Portland cement, which is energy-intensive to produce and generates a substantial amount of carbon dioxide emissions. In recent years, there has been a growing concern to reduce the environmental impact of construction materials and processes. As a response to this concern, researchers and engineers have been exploring alternative binders and supplementary cementitious materials to partially replace Portland cement. One such alternative is the use of low environmental impact agglomerants, which offer the potential to mitigate the environmental footprint of construction materials. This study focuses on the evaluation of the compressive strength of pastes produced by partially replacing Portland cement with a low environmental impact agglomerant. The objective is to assess the feasibility of using these alternative materials for construction applications, considering both their environmental benefits and their mechanical performance.
The research focuses on the sustainable utilization of rice residue for lightweight biocomposites, emphasizing the importance of pre-treatment methods like NaOH interventions on cellulose, hemicellulose, and lignin in rice residue. The balance in pre-treatment timing is crucial for maintaining the structural integrity of these components. Rice Husk Ash (RHA) stands out for its low heavy metal content and high refractoriness, making it versatile for various applications. Rice straw (RS), another component of rice residue, offers abundant cellulose and low lignin, making it suitable for biocomposite matrices. The study delves into extracting cellulose and CNCs from RS for eco-friendly packaging, targeted drug delivery, and high-quality composites. It also explores how advanced farming practices can reduce waste and enhance crop yields.
Laser-directed energy deposition (LDED) is a newer way of making things that builds solid parts from metallic powder one layer at a time. The LDED process is more convenient compared to other metals synthesis processes because of its own merits such as minimum building time and greater powder deposition rate. The directed energy deposition machines can be programmed to use a specialized set of settings to process various grades of metallic powder. This process is mostly used for repairing metallic components. Inconel 718 is a superalloy used in high-temperature applications. In the present study, the LDED technique is used to synthesize the Inconel 718 superalloy. The experimental investigation examines the influence of powder feed rate and laser energy density on the geometry and quality of the single tracks deposition of Inconel 718 superalloy.
