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Rice husk biochar was added to polylactic acid (PLA) to create a biocomposite filament suitable for the extrusion-based 3D printing process of fused deposition modelling (FDM). Taguchi L16 was used for experiment design, and the significance of process parameters was determined using variance analysis (ANOVA). For a 0.3-mm layer thickness, the addition of 5 wt.% biochar resulted in ultimate tensile strength and a modulus of elasticity of 36 MPa and 1103 MPa, respectively. The addition of biochar had a negative influence on flexural strength. The maximum flexural modulus was obtained with 3 % biochar, 100 % infill density, and 0.1 mm layer thickness. Particularly, 1 % biochar resulted in a considerable increase in impact strength, while a subsequent rise in biochar resulted in a decrease, probably due to the agglomeration effect. For 3D printed neat PLA, the average tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength observed were 19 MPa, 550 MPa, 54 MPa, 1981 MPa, and 25 KJ/m2, respectively. Additionally, considering the output of each test, a multicriteria decision-making model, namely, TOPSIS, has been utilized for ranking the mechanical performance. In order to optimise the mechanical properties of three-dimensional printed objects, the study suggests a layer thickness of 0.2 mm, an infill density of 100 %, and raster angle of 0° as the FDM process parameters.

Natural fiber composites (NFC) exhibit good specific mechanical properties in comparison to synthetic fiber composites (SFC). The study investigates interlaminar glass (G) fiber hybridized jute (J) and flax (F) reinforced epoxy composites designated as JGGJ, GJJG, FGGF, and GFFG along with their virgin counterparts. Composite laminates of four plies are manufactured by hand-layup followed by compression molding to investigate tensile, flexural, and interlaminar shear properties. Further the effect of hybridization is also investigated for modal frequencies and damping ratio obtained from experimental modal analysis. Glass fiber hybridization as extreme layers shows significant improvement in flexural and shear properties as compared to tensile. Glass fiber reinforcement, as core layers improve the damping by 155.55% and 101.31% for JGGJ and FGGF, respectively, over pure glass epoxy. However with increase in bending stiffness of GJJG and GFFG, the bending modal frequency is improved. Also, the modal frequency and damping ratio increases following a power-law variation with a decrease in the free length. Finite element and analytical validations are presented to the experimental frequencies and flexural modulus, respectively. These studied hybrid composites can serve as semi-structural members like interior trim panels in automotive applications that possess significant strength and dissipate in-service vibrations effectively.

Over the last couple of decades, there is an increasing demand to control interior noise occurring in aircraft, automobiles, railways, and construction works. Interior noise could impair people’s health, affecting passenger comfort and active safety performance. One of the contemporary noise control technologies is the use of sound-absorbing materials. Traditionally, mineral fibers, foams, and composites are used as sound-absorbing materials. However, they are expensive and energy consumptive as they add to the structure’s weight and affect structural integrity. Natural fibers could contribute to the replacement of conventional mineral fibers with decreased environmental impact, carbon neutrality, and improved sound-absorbing qualities. Also, previous research proved that sound-absorbing materials having natural fiber possess better acoustic properties comparable to those of synthetic fibers. However, high water absorption, termite attack, low fire resistance, and low strength are some of the issues restricting natural fibers usage. Here, an attempt is made to present the potential of natural fibers for acoustic absorbers by understanding the benefits of their inherent porous and tortuous structure. This paper involves a review study of experimental methods and parameters used to regulate the acoustic performance of natural fibers. Natural fibers seem a proven alternative as an acoustic absorber, thereby reducing sustainability concerns related to synthetic materials in acoustics applications.

Lightweight elastomer nanocomposites have several uses in the automotive and aerospace industries. There ought to be no compromises in terms of efficiency, durability, or performance when it comes to new technological products. This results in the ongoing quest for innovative materials. This study contributes to the development of graphene-reinforced silicone rubber by evaluating its mechanical and tribological properties. The two-roll mill mixing process, followed by the moulding step, is utilised in commercial nanocomposites preparation. As a result, the man-made composite can be justified financially. The moulding process was carried out at 170 °C, and the final curing took place at 200 °C for 4 h. Testing is done using filler weight percentages of 0, 1, 3, 5, and 7% graphene to determine the optimal filler weight %. The mechanical performance of silicon rubber was enhanced by over 213% when the graphene weight percentage was increased. With increasing load, the coefficient of friction decreases, with the lowest value found at 3% graphene by weight. The coefficient of friction and the specific wear rate were discovered to vary with sliding speed.

This work focuses on optimization of abrasive machining parameters of the natural fiber reinforced sandwich composite, which is rarely reported in the literature. A sandwich made of vegetable fiber composite skins and polyvinyl chloride (PVC) foam of 80 gsm was machined for optimal conditions. The design of experiment and analysis were adopted to confirm the influence of machining parameters. The machining characters of bio-sandwich were compared with synthetic and hybrid sandwich panels to optimize the machinability of the target. The panels were manufactured through vacuum infusion bagging. The machining studies were done using the abrasive water jet cutting machine. The machining characteristics were optimized for the parameters and L18 Taguchi technique was employed in parameter optimization. Three controlled levels of machining parameters were chosen to be optimized: standoff distance (SOD), abrasive water jet pressure (JP), and nozzle traverse rate (TR). The response of kerf taper (KT), surface roughness (SR), and material removal rate (MRR) were investigated. It is observed that highest levels of these parameters gave minimum kerf taper and lowest levels produce lower surface roughness. The surface roughness and damage on the surface was observed using scanning electron microscopy (SEM). It Shows that flowing abrasive particle’s directional distortion noted at the foam regions due to their higher damping nature. The prediction model shows a good agreement with the experimental value.

Due to their superior advantage of strength-to-weight ratio, composite materials are mostly preferred over conventional materials. However, machining composite materials is a big challenge to industries due to their extreme heterogeneity. Several machining operations are required when the composites are brought to service; among all, drilling is one of the primary processes often required during assembling. Several researchers have done process parameter optimizations to attain improved quality drilling on composite materials. The experimental investigation involves a lot of effort, in terms of time and money, in the manufacturing and testing of the composites. With the invent of high-performance computing and its easy availability, in the recent past, researchers have started to work on the numerical simulation of the drilling process. The present review gives a comprehensive review of numerical modeling using finite element analysis of the drilling process for polymer composites. Numerical study on conventional and non-conventional drilling as well as orthogonal cutting with the effect of material, tool geometry, speed/feed, and temperature are reviewed. This will help the researchers to get a one-stop solution to learn different techniques used in numerical modeling of composite machining.

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.

Nanocomposite made by blending nano-montmorillonite (MMT) and Silicon Rubber (SR) for mechanical and tribological performance is explored in this work. Different configurations of MMT/SR nanocomposite, with 0, 0.5, 2 and 5 wt % of MMT are manufactured by two roll mixing methods. Noticeable improvement in the mechanical and tribological performance is observed, which is also justified by a morphological study of fractured and wear surfaces through SEM. Two percent of MMT loading is found to be the optimum content that shows excellent performance compared to other compositions. The performance improvement can be linked to the good interfacial interaction between the MMT and SR. Statistical modeling through ANOVA is carried out for tribological performance, which reveals the influence of load on the coefficient of friction (COF) and the influence of sliding distance on the wear rate.