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Nowadays, research has shown the emergence of the 3D printing method for printing a functionalized component. Graphene nanomaterial has an enormous conducting property that can compete with conducting materials like copper and silicon. This paper describes the electrical conductivity investigation of 3D-printed graphene nanomaterial in extrusion-based 3D printing methods. In extrusion, two different approaches of the 3D printing method were used to print the graphene-based structure: the fused deposition modeling (FDM) method and the direct ink writing (DIW) method. Both printing methods follow the two printing processes and select material forms. Selection of testing was made to analyze the characterization variations in the printed material, such as XRD, TGA, viscosity, Raman shift, and Scanning Electron Microscopy analyses, which shows the changes of effect in the conductivity due to various parameter differences in both the printing methods. A four-point probe technique was used to analyze the electrical conductivity of the two different methods. These analysis results prove that the characterization variations differ in the FDM and DIW printed models. [ABSTRACT FROM AUTHOR]

The hygroscopic properties of natural fibers tend to degrade the mechanical properties of composite materials. It is essential to investigate the influence of water absorption behavior on the mechanical properties of hybrid composite materials. In this study, hybrid laminate materials consisting of two different reinforcement materials, i.e., Kevlar fibers and jute fibers in the same layer, are considered. Hybrid laminates that have four different weaving patterns: plain weave, basket weave, twill weave, and the satin weave, are tested for their water absorption characteristics. The jute fiber is a naturally extracted fiber that is subjected to chemical treatment. A comparison of mechanical properties before and after treatment of the jute fibers is carried out. Mechanical properties such as tensile strength, compressive strength, flexural strength, impact strength, and hardness are tested. It is found that the mechanical properties improved after the treatment of the jute fibers. The twill weave pattern exhibited negligible defects compared to its counterparts. Chemical treatment of the jute fibers enabled less water being absorbed into the hybrid laminate materials. Mechanical properties improved after using chemically treated jute fibers as the reinforcement material in the hybrid laminate materials. It is concluded that the twill weave pattern and chemical treatment of the natural fibers improved the mechanical properties of the hybrid laminate materials. [ABSTRACT FROM AUTHOR]

Non-exhaust brake dust and pollution arising from metal, semi-metal, and ceramic brake pads have made recent research consider their replacement by potential natural fibers such as hemp, flax, sisal, etc. These natural fibers are lightweight, biodegradable, and cheap. This paper discusses the wear and friction analysis of hemp fiber reinforced polymer brake pad material. Three test specimens viz. HF4P20, HF5P20, and HF6P20 were prepared per ASTM G99 standards for the pin-on disc tribo-test. The test trials and validation were done using the Taguchi design of experiments and ANOVA. The optimum result showed a consistent coefficient of friction and lowered specific wear rate for HF6P20 brake pad material. Worn surface morphology was done using scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The attainment of intricate part profiles for composite laminates for end-use applications is one of the tedious tasks carried out through conventional machining processes. Therefore, the present work emphasized hybrid intelligent modeling and multi-response optimization of abrasive waterjet cutting (AWJC) of a novel fiber intermetallic laminate (FIL) fabricated through carbon/aramid fiber, reinforced with varying wt% of reduced graphene oxide (r-GO) filled epoxy resin and Nitinol shape memory alloy as the skin material. The AWJC experiments were performed by varying the wt% of r-GO (0, 1, and 2%), traverse speed (400, 500, and 600 mm/min), waterjet pressure (200, 250, and 300 MPa), and stand-off distance (2, 3, and 4 mm) as the input parameters, whereas kerf taper (Kt) and surface roughness (Ra) were considered as the quality responses. A hybrid approach of a parametric optimized adaptive neuro-fuzzy inference system (ANFIS) was adopted through three different metaheuristic algorithms such as particle swarm optimization, moth flame optimization, and dragonfly optimization. The prediction efficiency of the ANFIS network has been found to be significantly improved through the moth flame optimization algorithms in terms of minimized prediction errors, such as mean absolute percentage error and root mean square error. Further, multi-response optimization has been performed for optimized ANFIS response models through the salp swarm optimization (SSO) algorithm to identify the optimal AWJC parameters. The optimal set of parameters, such as 1.004 wt% of r-GO, 600 mm/min of traverse speed, 214 MPa of waterjet pressure, and 4 mm of stand-off distance, were obtained for improved quality characteristics. Moreover, the confirmation experiment results show that an average prediction error of 3.38% for Kt and 3.77% for Ra, respectively, were obtained for SSO, which demonstrates the prediction capability of the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]

The present research investigates the wear properties of a continuous carbon fiber-reinforced additively manufactured polymer composite under dry sliding conditions. The effect of load and fiber orientation is examined on polymer composite specimens. The wear test of the additively manufactured polymer composite specimens is conducted on pin-on-disk test equipment. The result shows that the applied load and fiber orientation significantly affect the composite specimen's wear properties. The wear and coefficient of friction (COF) increase with load. The minimum effect on wear and COF is observed for 0° fiber orientation, and the maximum effect is observed for 90° fiber orientation. Finally, morphological analysis is conducted using an optical micrograph of the worn-out surfaces to understand the failure type for different fiber orientations. [ABSTRACT FROM AUTHOR]

To meet the global requirements of the industry, there is a need for innovative light weight, low cost, eco-friendly, high quality engineering materials with superior performance at a wide range of temperatures. Aluminum Matrix Composites (AMCs) are lightweight materials with isotropic properties, a suitable choice for modern industry. Low-cost aluminum alloys reinforced with minerals have found a special place in the automotive industry for the manufacture of automobile parts. Rutile particles improve the mechanical properties of the aluminum matrix, making it attractive for structural applications as well as providing greater wear resistance to the composite during sliding. In the present studies, a rutile mineral reinforced LM27 aluminum alloy composite was developed through a stir casting route with 6, 9 and 12 wt.% reinforcements. To study the effect of particle size on the mechanical and tribological properties of composite samples reinforced with fine-sized (50–75 μm) and coarse-sized (106–125 μm) rutile particles were prepared From the results of the experiment, it was found that the hardness, compressive strength and wear resistance increase with increasing rutile wt.% addition. The worn surface and re-groove of the new surface are restored during sliding with the help of oxide films. The analysis of the fractured surface clearly indicates with the help of energy dispersive X-ray spectroscopy (EDS) that with the increase in the volume fraction of the reinforced particles, the porosity increases, which could be the main reason for the compression failure of the composite material. [ABSTRACT FROM AUTHOR]

This work addresses an evolutionary algorithmic approach to reduce the surplus pieces in selective assembly to increase success rates. A novel equal area amidst unequal bin numbers (EAUB) method is proposed for classifying the parts of the ball bearing assembly by considering the various tolerance ranges of parts. The L16 orthogonal array is used for identifying the effectiveness of the proposed EAUB method through varying the number of bins of the parts of an assembly. Because of qualities such as minimal setting parameters, ease of understanding and implementation, and rapid convergence, the moth–flame optimization (MFO) algorithm is put forward in this work for identifying the optimal combination of bins of the parts of an assembly toward maximizing the percentage of the success rate of making assemblies. Computational results showed a 5.78% improvement in the success rate through the proposed approach compared with the past literature. The usage of the MFO algorithm is justified by comparing the computational results with the harmony search algorithm. [ABSTRACT FROM AUTHOR]

Hybrid composites recently developed as highly effective, high-strength structural materials that are increasingly used. Aluminum matrix hybrid composites strengthened with ceramic particulates are commonly used in marine, aerospace, and defense applications because of their exceptional properties. Zirconia-reinforced composites are favored because these composites display high refractory properties, excellent abrasion resistance, and chemical resistance compared to composites of other reinforcements.For applications where lightweight and superior performance is paramount, such as parts for spacecraft, fighter aircraft, and racecars, graphite compositesare the material of choice. In this research work, an effort was made to combine the properties of zirconia and graphite by producing a unique metal matrix composite of LM5 aluminum alloy reinforced with 6% zirconium dioxide (zirconia), using the stir casting process by changing the percentage of the weight of graphite to 2%, 3%, and 4%. The test specimens were prepared and evaluated in compliance with ASTM standards to study micro- and macrohardness, and impact, tensile, and compressive strength. Microstructural studies of composites performed through optical microscopy and SEM expose the unvarying dispersal of particulates of ZrO2/graphite in the aluminum matrix. The hardness, impact, and compressive strength are enhanced due to the addition of reinforcement. [ABSTRACT FROM AUTHOR]

Exposure of the engine valve to high temperatures led to the degradation of the valve material due to microstructural instability and deteriorating mechanical properties. Performance enhancement and alteration in microstructures can be attained through the powder metallurgy route which is a viable method to produce near net shape components. In this current study, the development of austenitic stainless steel (21-4N) through the powder metallurgy route as an alternate material for engine valves was investigated. Mechanical alloying was carried out for the pre-alloyed mixtures and consolidated using vacuum hot pressing. Sintering parameters were fixed at 1200 °C, 50 MPa and at a vacuum level of 10-3 Torr. A scanning electron microscope was used to analyze the morphology of the milled powders. Densities for the hot pressed powders were compared with theoretical densities and found to be around 98–99%. Observations regarding grain size, the presence of austenitic grain, heterogeneous distribution of metal carbides and analysis of chemical composition along the metal matrix were determined using both optical and electron microscopes. X-ray diffraction was carried out for both the consolidated and powder samples. The hot pressed samples exhibited a hardness value of 410 ± 10 Hv. An isothermal compression test for the sintered samples was carried out at a temperature of 650 °C and strain rate of 0.001 s−1. It is showed that the compressive strength of 1380 MPa. An analysis between the room temperature yield strength obtained from hardness measurement and the strengthening mechanism based on the microstructure was conducted. Grain size, dislocation and solid solution are the major strengthening mechanisms which strengthen the material. Overall, the development of valve steel material through the powder metallurgy route exhibited improved metallurgical and mechanical properties in comparison to the corresponding cast product. [ABSTRACT FROM AUTHOR]