Growing environmental awareness and the depletion of fossil fuel sources have propelled the development of sustainable, bio-based composite materials as competitive options to traditional synthetic composites. This review offers a detailed examination of recent advances in their classification, manufacturing processes, properties, and applications. The combination of natural fibers with biodegradable matrices, along with innovative manufacturing methods such as compression molding, injection molding, and automated fiber placement, has significantly improved the mechanical and structural qualities of bio-based composites. Their environmental advantages are assessed through life cycle analyses, highlighting lower carbon footprints and biodegradability. Various uses of sustainable bio-composites are also explored. Despite notable progress, challenges such as moisture absorption, mechanical variability, and raw material consistency remain. The review concludes with emerging developments in hybrid composites, nanomaterial integration, and future prospects to enhance scalability, performance, and alignment with circular economy principles.

Thermoplastic composites have emerged as advanced engineering materials due to their superior recyclability, damage tolerance, and processing versatility compared with conventional thermoset systems. This review provides a comprehensive assessment of recent advances in thermoplastic composite materials, with particular emphasis on matrix and reinforcement selection, advanced processing technologies, recyclability, and performance-related challenges. Key manufacturing approaches such as compression molding, thermoforming, automated tape placement, and in-situ consolidation are critically discussed, highlighting their advantages, limitations, and influence on microstructural integrity and mechanical performance. The review further examines sustainability aspects through life cycle assessment, renewable feedstocks, and end-of-life management strategies, positioning thermoplastic composites as promising candidates for circular economy-driven applications. Despite these advantages, long-term durability issues remain significant, particularly under dynamic loading, environmental exposure, and hygrothermal conditions. Challenges related to viscoelastic damage evolution, interfacial bonding, moisture sensitivity, and residual stress development are also discussed. Finally, the review identifies existing research gaps and outlines future directions focused on interfacial engineering, advanced process control, data-driven modeling, and sustainable material design to enable reliable large-scale adoption of thermoplastic composites in automotive, aerospace, marine, and construction sectors.

This study aims to develop a reliable artificial neural network (ANN) framework for predicting the tensile strength of polypropylene/carbon nanotube (PP/CNT) and low-density polyethylene/carbon nanotube (LDPE/CNT) nanocomposites fabricated using microwave-assisted processing. Four key input parameters, i.e., CNT concentration, microwave power, applied pressure, and exposure time, were used to train and validate the ANN model. The predictive performance of the models was evaluated using Mean Squared Error (MSE), Root Mean Squared Error (RMSE), Mean Absolute Error (MAE), and coefficient of determination (R2). The results demonstrate that both ANN models successfully captured the nonlinear relationships between processing variables and tensile strength. While the PP/CNT model exhibited stable prediction capability, the LDPE/CNT model achieved superior fitting accuracy, lower prediction errors, and improved generalization, with MSE, RMSE, MAE, and R2 deviations of 7.05

The airborne debris of the brake pad composite pollutes the air and makes the environment hazardous. Researchers develop organic and natural materials to replace such crucial materials without compromising the performance. Therefore, this research delves into the critical parameters of friction material: pressure, temperature fade, and breakaway torque conditions. The unique aspect of this study is the comprehensive analysis of Allium sativum's impact on the frictional performance of brake pads. The friction composites were scrutinized for their pressure and temperature fade at 5, 10, and 15 bar pressure at a constant speed of 660 ± 10 RPM and 100°C–200°C, 200°C–300°C, and 300°C–400°C temperature at a constant pressure of 11.7 bar in a Krauss test machine for 25 drag braking applications. Further breakaway torque tests (the low speed at 1 rpm at a constant pressure of 11.7 bar) for 100 drag braking applications were conducted and analyzed. The morphological changes were extensively studied using SEM & EDAX analysis, and 3D microscopy was employed to analyze the brake pads’ surface topography and surface roughness.

The current research has focused on developing epoxy-based glass fiber composites reinforced with boron carbide (B4C) and graphene (Gr) particles processed through a compression moulding process for enhanced tribological performance. Through Taguchi's L-32 experimental design, the experimental layout has been prepared by varying material configuration, sliding speed, normal load, and sliding time to observe their effect on wear rate and coefficient of friction. To address the multi-response problem, criteria weighting have been evaluated through Shannon's entropy and CRITIC techniques integrated with TOPSIS and CoCoSo MCDM methods. Both methods have identified the optimal condition for minimizing wear and CoF as the hybrid filler composite tested at 600 rpm, 20 N, and 4 min. Sensitivity analysis across the four weighting combinations indicated a strong correlation (approximate to 0.9) between the CRITIC TOPSIS and CRITIC CoCoSo rankings. Multivariate ANOVA has ensured and emphasized the strong interaction of material configuration and speed over both the responses studied. The AdaBoost algorithm has exhibited superior predictive accuracy, with an R-2 of 0.99 among the machine learning models. SEM analysis revealed fiber breakage, matrix cracking, void formation, and debris formation. The findings establish the potential of composites developed with hybrid fillers for applications demanding good tribological performance.

Traditional 3D-printed composites often rely on short or randomly oriented natural fibers, which limit the full exploitation of their reinforcing potential. In this context, the present study introduces a novel approach by strategically incorporating continuous Agave sisalana fibers as an interleaved core within 3D-printed polylactic acid (PLA) biocomposites. This architecture aims to overcome existing limitations by enhancing fiber alignment, interfacial bonding, and mechanical performance, while maintaining the lightweight benefits of PLA. NaOH treatment improved fiber–matrix adhesion, as confirmed by Scanning Electron Microscopy (SEM). Mechanical testing revealed significant improvements in the treated fiber-interleaved composites compared to its neat counterpart: tensile strength increased by 36.19

This study investigates the combined influence of carbon lamina interleaving, co-curing, and multiwalled carbon nanotubes (MWCNTs)-modified adhesives on the mechanical performance of flax fibre-reinforced composite joints. These composite joints were fabricated via hand lay-up and co-cured to enhance interfacial bonding. Shear and flexural tests were conducted to evaluate the effect of hybridisation and nano-modification. Interleaving carbon laminae significantly improved joint performance, increasing shear and flexural strength compared with co-cured neat flax fibre composite joints. Additional improvements were achieved using MWCNTs-modified adhesives, where 0.25 wt.

The rapid industrial revolution has led to increased use of synthetic materials in various automotive panel applications, resulting in environmental concerns due to their non-biodegradability. To address these issues, natural fiber composites have been explored as sustainable alternatives; however, their mechanical performance often falls short compared to synthetic counterparts. In the present study, hybrid natural/synthetic fiber composites were developed using pineapple and hemp mat fabrics with intermediate glass fiber mats to enhance performance characteristics. The composites were fabricated using the vacuum infusion technique with varied stacking sequences of hemp and pineapple fibers, hybridized with glass fiber mats for improved mechanical strength and durability. Comprehensive mechanical, thermal, viscoelastic, and low-velocity impact analyses were conducted to evaluate the composites' performance. Fracture morphology was examined using scanning electron microscopy. Mechanical results revealed that the pure hemp composite with intermediate glass layers exhibited the highest tensile and flexural strengths, at 58.24 MPa and 98.35 MPa, respectively. Viscoelastic analysis indicated that the pure pineapple fiber composite demonstrated the highest storage modulus of 2875.51 MPa, consistent with the observed flexural modulus trend. However, this configuration also exhibited a higher thermal expansion, with a coefficient of thermal expansion of 215.66 ppm/°C, attributed to the fiber-matrix interfacial bonding and chemical composition. A low-velocity impact analysis showed that hybrid composites with varied stacking sequences offered superior impact resistance. Overall, the results confirm that the properties of these hybrid composites can be tailored based on specific application requirements, making them promising candidates for lightweight, high-performance automotive panel applications.

This research paper presents the drilling performance of novel Carbon-Innegra (CI) fiber–reinforced polymer composites. CI fiber–reinforced composites are manufactured by the compression molding technique. Drilling experiments on CI composites were conducted based on Taguchi’s experimental design involving sixteen different combinations of machining trials. CI composites were drilled with different parameters such as speed 750 rpm, 1500 rpm, 2250 rpm, and 3000 rpm; feed rate 30 mm/rev, 60 mm/rev, 90 mm/rev, and 120 mm/rev, and with the solid carbide drill tool of 8 mm diameter. Drilling performance of the CI composites is estimated from the five different measured responses, such as thrust force, torque, delamination (at the entry and exit), and surface roughness. Optimal drilling parameter combinations of the CI composites are determined based on Entropy-TOPSIS, a hybrid multi-attribute decision-making methodology (MADM). The weights of each of the five machining responses are estimated by the Entropy technique, and further, the optimal solution is determined from the TOPSIS methodology. From the optimization methodology, it is determined that the experimental trial 8 with speed 1500 rpm and feed rate 120 mm/rev exhibits the best results with good surface quality, minimum delamination around the hole surface, and the nominal values of thrust force and torque. The confirmatory tests performed with the determined optimal solution agree well with the experiments, with lesser variation of 0.124

The present work investigates the influence of direct energy deposition (DED) based additive manufacturing (AM) parameters on the high strain rate and mechanical properties of Inconel 718-SS316L bimetallic structures fabricated at different processing conditions. The bimetallic structures were fabricated based on the box-behnken design methodology by varying the most significant DED parameters such as laser power (300-500 W), scanning speed (300-500 mm/min) and powder feedrate (3-4 g/min). Influence of these parameters on the high strain rate behaviour and microhardness were assessed through statistical analysis using analysis of variance (ANOVA) and three-dimensional response surface plots. Optimal DED parameters for improved response characteristics were attained through a metaheuristic-based hummingbird algorithm. The microstructural investigations including metallographic analysis, scanning electron microscope (SEM) with elemental dispersive spectroscopy (EDS) analysis and electron backscattered diffraction (EBSD) analysis were performed at the intermetallic regions of bimetallic samples which were fabricated at optimal processing conditions and the mechanical fractured surfaces. This study reveals the insights into the development of bimetallic structures through DED process with their microstructures, process-property relationship and multi-response optimization through metaheuristic algorithms concerning the improved high strain rate and mechanical characteristics.

In response to the growing demand for sustainable and copper-free friction materials, this study investigates the development of eco-friendly brake pad composites reinforced with calcium sulphate fibers. Three copper and asbestos-free brake pad formulations, Calcium Sulphate Fiber (CSF)-CSFA01, CSFB02, and CSFC03, were developed with 10 wt.% Calcium Sulphate Fibers of varying aspect ratios compared against a commercial brake pad (COMD04). Tribological properties were characterized using the SAE J661 Standard Chase test, while mechanical integrity and wear behavior were further examined using a Scanning Electron Microscope. Among the tested formulations, CSFC03 demonstrated a 20% lower wear loss, 3.6% higher recovery coefficient of friction, and 15% reduction in fade compared to COMD04. The coefficient of friction remained stable between 0.381 and 0.402 across all test regimes, reaffirming the composite's thermal and mechanical stability for demanding braking applications. The surface morphology also revealed better fiber-matrix interaction and wear resistance. Four Multi-Criteria Decision-Making techniques-Analytic Hierarchy Process-Extension Evaluation Method, Complex Proportional Assessment, Technique for Order of Preference by Similarity to Ideal Solution, and Multi-Objective Optimization on the Basis of ratio analysis-were applied to rank the formulations, all consistently identifying the CSFC03 composite as the top-performing green alternative. These results highlight the potential of calcium sulphate fibers as a sustainable, cost-effective reinforcement for next-generation eco-friendly brake friction materials.