Mechanical Performance and Python-Based TOPSIS Ranking of Carbon-Filled Kevlar/Basalt/S-Glass Hybrid Epoxy Composites for Automotive Structural Applications

Mechanical Performance and Python-Based TOPSIS Ranking of Carbon-Filled Kevlar/Basalt/S-Glass Hybrid Epoxy Composites for Automotive Structural Applications | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Mechanical Performance and Python-Based TOPSIS Ranking of Carbon-Filled Kevlar/Basalt/S-Glass Hybrid Epoxy Composites for Automotive Structural Applications RAFFI MOHAMMED, ABDULSADDIQUE SHAIK, MANEESHA L.L.S, Subrahmanyeswara Rao S.V.B, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8806852/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 14 Mar, 2026 Read the published version in Scientific Reports → Version 1 posted 12 You are reading this latest preprint version Abstract The increasing requirement for lightweight and high-performance materials in the automotive industry has prompted significant research efforts focused on hybrid fiber-reinforced polymer composites. This study looked at making and carefully testing epoxy-based composites that were strengthened with Kevlar (aramid), basalt, and S-glass fibers, using 10% carbon powder as an added material. The study created single-fiber, dual-fiber hybrid, and tri-fiber hybrid laminates using the hand lay-up method, which allowed for controlled stacking sequences. Mechanical characterization was conducted following ASTM standards, encompassing tensile, flexural, impact, and hardness evaluations. The results show that using a mix of different fibers significantly improves mechanical properties compared to using just one type of fiber. Specifically, the basalt–aramid–S-glass tri-hybrid composite demonstrated a peak tensile strength of 354.37 N/mm², an outstanding flexural strength of 1350 N/mm², a maximum energy absorption capacity of 7.2 J, and the highest hardness level recorded at 115 BHN. These metrics reflect an exceptional ability to bear loads, resist bending, tolerate impacts, and maintain surface durability. The better performance is mainly due to how well the materials work together, the strong connections between the fibers and the matrix, and the added strength from the carbon filler. To support the experimental results, a TOPSIS analysis was done using Python, treating all criteria equally. The tri-hybrid composite demonstrated the highest closeness coefficient (CC = 0.873), thereby affirming its preeminence. The hybrid composites formulated exhibit significant promise for applications in lightweight automotive structures, specifically in the context of roof panels and load-bearing elements. Physical sciences/Engineering Physical sciences/Materials science Epoxy Resin Carbon powder Kevlar/ Basalt/ S-Glass Fiber Hybrid composites Mechanical Characterization Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. INTRODUCTION Please have a look at courier new font provided for text in article. The automotive and transportation industries have made great strides in a short amount of time, which has greatly increased the demand for materials that are lightweight, strong, and energy-efficient. This ongoing trend shows that these important areas are always moving toward new ideas, which is necessary to solve today's problems. Conventional metallic materials, such as steel and aluminum, though widely employed across numerous applications, present several substantial drawbacks that can detrimentally impact performance. These drawbacks include their considerable density, susceptibility to corrosion, and limited design flexibility, all of which may obstruct modern applications in demanding environments. In order to effectively confront and overcome these significant barriers that routinely hinder progress, fiber-reinforced polymer (FRP) composites have emerged as promising and innovative solutions. These materials are increasingly acknowledged within the industry for their superior strength-to-weight ratio, outstanding corrosion resistance, and facilitation of fabrication processes, thereby broadening their applicability within the sector [ 1 , 4 ]. Polymer matrix composites (PMCs) are advanced materials that consist of reinforcing fibers embedded within a polymer matrix. This matrix has two key jobs: it keeps the fibers together and makes it easier for the load to be dispersed uniformly over the composite structure, which makes sure that the pieces operate together properly. There are several kinds of polymer matrices that are utilized in manufacturing. Epoxy resins are one of them. People really like and respect them since they are incredibly sturdy, cling well to reinforcing fibers, withstand chemicals well, and maintain the same size. Because of this, they are great for a lot of various things [ 5 ]. The mechanical performance of PMCs is significantly influenced by various critical factors, including the type of fiber employed, the arrangement of the fibers, the quality of the fiber-matrix interfacial bonding, and the incorporation of various fillers that can effectively enhance specific characteristics. Single-fiber reinforced composites, although beneficial in many respects, often face limitations in achieving a balanced distribution of mechanical characteristics. For instance, composites reinforced with glass fibers generally provide acceptable rigidity and stiffness but may unfortunately lack sufficient impact resistance, which is crucial in many applications. On the other hand, aramid fiber composites, which are known for being very tough, often have lower compressive strength, which can be a problem in some situations and uses [ 2 , 10 ]. To adequately address and alleviate these limitations and enhance composite performance, the innovative notion of hybrid composites has been introduced and embraced. Hybrid composites integrate two or more distinct fiber types within a single polymer matrix, facilitating a unique combination of properties tailored to satisfy specific requirements. This strategic hybridization method boosts the individual strengths of each fiber type in a way that makes the composites stronger, more flexible, more resistant to impact, and more durable overall in a variety of situations [ 1 , 12 ]. By using this new method, the design options for PMCs can be greatly increased, resulting in materials that not only meet but also exceed the strict requirements of many applications in many fields. Kevlar (aramid) fibers are widely acknowledged and celebrated for their extraordinary tensile strength, exceptional durability, and remarkable capacity for energy absorption, characteristics that render them highly suitable for a wide array of applications requiring significant impact resistance, particularly in high-performance environments where safety and reliability are paramount [ 3 , 10 ]. On the other hand, basalt fibers, which are uniquely sourced from volcanic rock, display commendable mechanical strength, exhibit superior thermal stability, and possess notable corrosion resistance properties, all of which come at a relatively lower cost when compared to the more commonly used carbon fibers, making them an attractive alternative for various engineering applications [ 6 , 9 ]. In a different category, S-glass fibers stand out because they possess a higher tensile strength and increased rigidity than traditional E-glass fibers, thus contributing significantly to enhanced structural performance in numerous load-bearing scenarios, where strength and reliability are crucial [ 2 , 8 ]. The innovative and synergistic combination of Kevlar, basalt, and S-glass fibers in a hybrid composite system is anticipated to yield a well-rounded amalgamation of strength, stiffness, and toughness that could outperform conventional materials. Furthermore, the strategic integration of particulate fillers, such as carbon (graphite) powder, has been shown to effectively enhance the hardness, wear resistance, and thermal conductivity of various polymer composites, thereby broadening their utility in demanding applications [ 5 , 13 ]. Additionally, carbon fillers are known to facilitate improved load transfer within the matrix while simultaneously minimizing frictional losses, which proves highly advantageous for both structural applications and automotive industries where efficiency and performance are of utmost importance. Automotive roof panels need to be made of materials that are not only light but also strong enough to handle different types of tensile, flexural, and impact stresses. This requirement is very important because it makes sure that these parts stay structurally sound over time and in different situations. Because of this, the current study focuses on making epoxy-based hybrid composites that are reinforced with a mix of Kevlar, basalt, and S-glass fibers and fully testing their mechanical properties. To improve their performance, these composites also have 10% weight carbon powder added to them in a planned way. This research aims to determine the feasibility of these hybrid composites for various applications in automotive structural components through a carefully structured series of systematic mechanical assessments. A substantial body of literature has been dedicated to the comprehensive examination of fiber-reinforced polymer composites, emphasizing not only their mechanical properties but also their prospective applications in various aspects of structural engineering. Amaro et al. [ 1 ] offered a comprehensive and perceptive analysis of hybrid fiber-reinforced composites, demonstrating that hybridization significantly improves essential properties, including tensile, flexural, and impact performance. This improvement is mostly due to better stress distribution and the addition of mechanisms that effectively slow down the spread of cracks. This makes the material more durable and reliable for use in cars. Due to their unique properties and abilities, Kevlar fiber-reinforced composites have been the focus of a lot of research and study because they are useful in applications that involve high impacts and energy absorption. Goud et al. [ 3 ] extensively elucidated that Kevlar composites exhibit remarkable tensile strength and exhibit notable resistance to fatigue; however, it is critical to recognize that their flexural and compressive attributes tend to be suboptimal when Kevlar is employed in isolation. Furthermore, Shen et al. [ 10 ] emphasized the superior impact resistance and ballistic performance of Kevlar-based composites, attributing this remarkable functionality to the fiber's exceptional toughness and its capacity to efficiently dissipate energy, allowing it to absorb substantial energy during impact without failure. On the other hand, basalt fiber-reinforced polymer composites have become more appealing as cheap substitutes for traditional carbon and glass fibers. This has sparked a lot of interest from both researchers and engineers. Li et al. [ 6 ] conducted a comparative analysis of basalt and glass fiber composites, revealing that basalt fibers exhibit significantly superior thermal stability and chemical resistance; however, they may be susceptible to brittle failure under tensile loading conditions, a critical factor in design considerations. Additionally, Rahman et al. [ 9 ] experimentally validated that basalt fiber composites exhibit commendable flexural performance, establishing their suitability for a diverse range of structural applications subjected to bending loads, where durability and resilience are paramount for enduring efficacy. S-glass fiber composites have consistently demonstrated an ability to exhibit superior tensile strength as well as stiffness when compared to the more conventional E-glass composites that are widely used in various applications. Das et al. [ 2 ] have observed that polymers reinforced with S-glass fibers exhibit not only increased fatigue resistance but also superior tensile performance. In contrast, Patel et al. [ 8 ] have highlighted the suitability of these materials for high-load structural applications, showcasing their potential in demanding environments. Nevertheless, it is important to consider that the relatively reduced impact resistance observed in S-glass fibers significantly constrains their wider application in environments that are susceptible to sudden and severe impact. To comprehensively address the limitations that are commonly associated with single-fiber systems, numerous researchers in the field of composite materials have investigated the promising potential of hybrid fiber composites. Zhang et al. [ 14 ] reported that Kevlar–basalt hybrid composites show notable synergistic enhancements not only in tensile properties but also in impact properties, which can be attributed to the complementary failure mechanisms that are inherent to the constituent fibers involved in the composite. Furthermore, Suresh et al. [ 12 ] demonstrated that multi-fiber hybrid composites possess markedly superior flexural strength and increased damage tolerance, especially when optimized stacking sequences are effectively employed in their design and fabrication. This ongoing research into hybrid approaches continues to expand the possibilities of fiber composites, pushing the boundaries of their applications in various industries. The influence of fillers on polymer composites has been the subject of extensive and meticulous research within the materials science community. Kumar et al. [ 5 ] performed an extensive investigation that indicated that polymer composites infused with graphite exhibit not only improved hardness but also a markedly elevated durability against wear over time. This discovery is significant because wear resistance is an essential characteristic for materials employed in rigorous applications. Similarly, Verma et al. [ 13 ] emphasized in their extensive research that carbon-based fillers contribute substantially to improved interfacial bonding, which is essential for the enhancement of both the mechanical and tribological properties of hybrid composites. In order to substantiate experimental results through an objective decision-making framework, a Python-based multi-criteria decision-making (MCDM) methodology was utilized, specifically employing the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Given that materials used in automotive structures must meet various performance criteria concurrently, evaluations based solely on individual properties are inadequate for ensuring effective material selection. The TOPSIS method facilitates a comprehensive ranking of composite configurations by integrating multiple mechanical criteria within a cohesive framework. Despite the considerable amount of literature examining various hybrid fiber composites and polymer systems that have been modified with fillers, there exists a notable paucity of research regarding the combined application of Kevlar, basalt, and S-glass fibers. These fibers, when reinforced with carbon powder, present a unique and promising opportunity for development, particularly for use in automotive structural applications that require high strength and durability. Moreover, comprehensive experimental investigations examining the tensile, flexural, impact, and hardness properties of these novel hybrid systems are exceedingly scarce in the existing literature. This study aims to fill in a major gap in research by creating and carefully testing epoxy-based Kevlar–basalt–S-glass hybrid composites that are strengthened with carbon powder [ 15 – 18 ]. The outcomes of this study are anticipated to provide valuable insights into the performance and capabilities of these advanced materials in challenging environments. 2. MATERIALS AND METHODS The selection of constituent materials is of paramount importance in influencing the structural integrity and mechanical performance of composite systems. In this investigation, meticulously selected matrix, reinforcement fibers, and filler materials were utilized to formulate high-performance hybrid epoxy composites intended for automotive structural applications. The epoxy resin–hardener system was chosen due to its superior adhesion properties, ease of processing, and advantageous mechanical characteristics. High-strength reinforcement fibers such as Kevlar, basalt, and S-glass were employed to leverage the synergistic advantages of hybridization. Furthermore, carbon (graphite) powder was incorporated as a filler material to improve stiffness, surface hardness, and wear resistance. A comprehensive summary of the detailed specifications and functional roles of the materials utilized is provided in Table 1. 2.1. Materials Used Table 1: Materials used for the fabrication of the composites Category Material Specification / Description Purpose / Key Properties Matrix Material Epoxy Resin LY556 Acts as the binding medium providing structural integrity Hardener HY951 Facilitates curing and cross-linking of epoxy Mixing Ratio 10:1 (Epoxy: Hardener) Ensures optimal curing and mechanical performance Reinforcement Fibers Kevlar (Aramid) Fiber 300 GSM woven fabric High impact resistance and tensile strength Basalt Fiber 300 GSM woven fabric Excellent thermal stability and corrosion resistance S-Glass Fiber 300 GSM woven fabric High tensile strength and stiffness Filler Material Carbon (Graphite) Powder 10 wt.% Enhances hardness, wear resistance, and thermal conductivity 2.2 Composite Configurations To thoroughly investigate the individual and synergistic effects arising from fiber hybridization, seven unique carbon-filled epoxy composite configurations were carefully designed and crafted. The composites encompass single-fiber systems, dual-fiber hybrid systems, and tri-fiber hybrid systems, each of which is reinforced with a consistent 10 wt.% carbon filler. This design choice was made to guarantee uniform modification of the matrix throughout all configurations. The various composite configurations are detailed and presented in Table 2: Table 2: Composite Configurations Composite ID Wt.% of Epoxy Resin Fiber Reinforcement Percentage Carbon Filler Content (wt.%) C1 50 50Wt. % Basalt Fiber 10 C2 50 50Wt. % S-Glass Fiber 10 C3 50 50Wt. % Kevlar Fiber 10 C4 50 50Wt. % - Basalt + Kevlar (Hybrid) 10 C5 50 50Wt. % - S-Glass + Basalt (Hybrid) 10 C6 50 50Wt. %-S-Glass + Kevlar (Hybrid) 10 C7 50 50Wt. %-Basalt + Kevlar + S-Glass (Tri-hybrid) 10 2.3. Fabrication of Composites by Hand Lay-Up Technique Figure 1, presents the artistic methodology utilized in the development of the hybrid fiber-carbon filled epoxy composites analyzed in this study. This illustration provides a comprehensive overview of the meticulous proceedings, which encompass mold preparation, fiber cutting, the design of the stacking sequence, resin and filler preparation, the lay-up process, compaction, curing, and the implementation of post-curing techniques. This meticulously structured approach was intentionally selected to ensure uniform fiber distribution, a seamless integration of carbon fillers within the epoxy matrix, and strong adhesion between the reinforcement and the matrix. By adhering to this systematic sequence, we are able to minimize defects such as voids and excess resin areas, thus enhancing the uniformity and reliability of the composite laminates. The following section will explore in greater detail the complex fabrication process involved in the production of these composite specimens. The hand lay-up method was employed in the production of every single composite laminate primarily due to its remarkable practicality, excellent adaptability, and notable economic viability. This makes the hand lay-up technique particularly suitable for the effective development of composite materials on a laboratory scale, where precision and control are essential. This specific method greatly facilitates enhanced accuracy in the arrangement of various fibers, the careful order of stacking those fibers, and the intricate process of resin impregnation. These factors are critically essential for achieving consistent and reliable mechanical properties in the final composite products. Prior to the actual fabrication process commencing, the surface of the mold underwent an extensive and rigorous cleaning procedure, and it was also treated with a suitable release agent. This treatment is crucial as it prevents the adherence of the composite material to the mold, thereby ensuring that the removal of the composite after the curing process is both uncomplicated and efficient. A total of six distinct layers, each made up of 300 GSM fibers, were meticulously trimmed to match the exact specified dimensions and were organized in accordance with a carefully predetermined stacking order. This stacking sequence was dictated by the composite configuration, which could be either a single-fiber arrangement or a hybrid type that combines different fibers to achieve enhanced performance characteristics. An epoxy resin was expertly formulated in conjunction with the requisite hardener, adhering to a specified ratio. This mixture was subsequently combined with 10 wt.% carbon powder to significantly facilitate a uniform and thorough distribution of the filler throughout the resin. The resulting resin solution was then systematically and evenly applied to every single layer of fiber using both a roller and a brush. This application process was critical in ensuring adequate wetting of the fibers while also effectively removing any potential air pockets that could inadvertently form between the layers during this meticulous lamination process. Following the comprehensive completion of the intricate lay-up process, the carefully prepared laminate underwent a gentle yet effective pressing procedure aimed at eliminating any excess resin and addressing any entrapped air bubbles that may have formed during the initial phases. This essential step was critical for achieving a consistent and uniform thickness throughout the laminate and for significantly enhancing the bonding between the fibers and the matrix material. Following this phase, the composite materials were allowed to cure at room temperature for a designated period of time, a process which facilitated sufficient cross-linking of the epoxy matrix and promoted optimum material properties. A subsequent post-curing phase was implemented under controlled ambient conditions to further improve the overall mechanical stability of the composite. Once the curing process was meticulously finalized, the laminates were carefully and methodically extracted from the mold and subsequently machined into standardized test specimens in accordance with the appropriate ASTM standards that are widely recognized for mechanical evaluation and testing. 2.4. EXPERIMENTAL METHODS A systematic experimental methodology was employed to comprehensively evaluate the mechanical performance and structural integrity of the fabricated composite specimens. The goal of the experimental program was to find the most important mechanical factors that make polymer matrix composites suitable for use in car structures, such as lightweight parts that are exposed to static, dynamic, and surface-related loads. To ensure accuracy, consistency, and comparability of results, standardized testing protocols were strictly followed in accordance with relevant ASTM standards. The tests used in the experiment were tensile, flexural, impact, and hardness tests. Each one looked at a different part of how the material would behave in real-world situations. All of these tests together give a full picture of the composites' ability to hold weight, their stiffness, their ability to absorb energy, and their durability on the surface. The data generated from these experimental evaluations supports subsequent multi-criteria decision-making analysis, facilitating a rational comparison of single-fiber and hybrid composite topologies for advanced automotive applications. 2.4.1 Tensile Test The tensile characteristics of the created composite specimens were systematically assessed using a precision electronic tensometer, possessing a capacity of 2 tons, to accurately ascertain their tensile strength and deformation behavior under uniaxial loading conditions. This essential evaluation was conducted in accordance with the relevant ASTM tensile testing standards that are specifically designed for polymer matrix composites, thereby ensuring both reliability and standardization. The specimens were meticulously prepared to maintain uniform dimensions and were judiciously aligned within the testing grips to eliminate the possibility of eccentric loading and to avert premature material failure. During the testing process, a controlled crosshead speed was consistently upheld, allowing for the attainment of precise and repeatable results. The applied load and the resultant elongation of the specimens were continuously tracked and recorded until failure of the specimen occurred. Tensile stress was computed by dividing the maximum load applied by the original cross-sectional area of each specimen. This test yielded essential insights into the load-bearing capabilities and stiffness properties of both single-fiber and hybrid composite configurations, which are pivotal for evaluating their performance and durability in real-world applications [19-20]. 2.4.2 Flexural Test The flexural characteristics of the composite specimens were analyzed through a precisely structured three-point bending test, conducted in strict compliance with the stipulations established in ASTM D790 [21-22]. The preparation of the test specimens adhered closely to standardized dimensions, thereby promoting uniformity across all samples. In line with the standard requirements, the span length between the supports—a crucial factor for the integrity of the test—was maintained exactly as specified, which ensured consistency throughout the experimental procedure. During the testing process, each specimen was horizontally positioned on two sturdy supports to provide stability. A load was then applied centrally at a constant rate, which was meticulously monitored until failure occurred. The flexural strength, indicative of the material's capacity to endure bending without failure, along with the flexural modulus, which quantifies the stiffness of the material under bending conditions, were calculated based on the maximum load sustained during the test in relation to the specific geometry of the specimen. This bending evaluation is essential for assessing the bending resistance of the composite materials under scrutiny. It is important to highlight those automotive components, particularly roof panels, regularly experience various flexural loads throughout their operational lifespan, underscoring the necessity of this test in verifying their durability and performance. The data generated from these tests offers critical insights that guide both the design and material selection processes for such essential applications within the automotive sector. 2.4.3 Impact Test The impact resistance of composite materials was systematically evaluated through the Charpy impact test, adhering to the standards defined in ASTM D256. In order to achieve a high degree of precision and dependability, V-notched specimens were rigorously prepared. This preparation was imperative for ensuring uniform crack initiation during the intensive testing procedure. The specimens were firmly secured within the impact testing apparatus to prevent any movement that could compromise the results. A pendulum hammer was then released from a specified height, striking the specimen precisely at the notched section, which is intended to replicate the stress concentrations encountered in actual service conditions. The energy absorbed during the fracture of the composite materials was directly measured by the testing machine, yielding a quantifiable assessment of performance. This data was subsequently employed to compute the impact strength of each composite configuration under analysis. Importantly, this testing methodology played a vital role in assessing the composites' ability to absorb abrupt shocks and resist brittle failure, a crucial consideration for automotive structures that experience dynamic loading and potential impacts. A comprehensive understanding of these properties is essential for driving innovations in material design that aim to enhance safety and performance in automotive applications. 2.4.4 Hardness Test The surface hardness of the composite specimens was rigorously assessed through the implementation of the Rockwell-B hardness testing technique, adhering to the standards prescribed by ASTM D785. To ensure optimal testing conditions, the specimens were prepared with surfaces that were meticulously smooth and uniformly finished, which was essential for guaranteeing reliable and consistent indentation results. Throughout the testing procedure, a standard indenter was applied to the specimen's surface under a predetermined load, with the subsequent depth of the indentation being precisely measured to ascertain the corresponding hardness value. To further improve the accuracy of the results, multiple measurements were taken at various locations on each specimen, thereby reducing the likelihood of localized variations and enhancing the overall precision of the assessments. Hardness testing is a vital procedure that yields significant insights into the surface resistance, wear characteristics, and overall durability of composite materials. This is particularly important in applications where friction and surface contact are critical factors influencing the performance and longevity of the materials. 2.5. Python-Based TOPSIS Analysis The TOPSIS analysis utilized experimentally measured tensile, flexural, impact strength, and hardness values for seven composite configurations. These properties, relevant to automotive structural components, were treated as beneficial attributes where higher values denote better performance. The analysis was conducted in Python using libraries like NumPy and Pandas. A decision matrix was created from the data, categorizing composite configurations as alternatives and mechanical properties as criteria. Vector normalization was applied to maintain dimensional consistency, and equal weighting was assigned to all properties to eliminate subjective bias, reflecting their importance in automotive roof panels. A weighted normalized decision matrix was created, and ideal best and worst solutions were identified. Euclidean distances from these solutions were calculated, and closeness coefficients for each alternative were computed, ranking the composites accordingly. This method offers a reproducible, quantitative way to validate results and determine the best composite material for lightweight automotive structures. 3. RESULTS AND DISCUSSION 3.1 Tensile Properties Figure 2, presents a detailed analysis of the tensile strength characteristics and elongation properties of carbon-filled hybrid epoxy composites, taking into account the various configurations as specified in Table 2. Within the scope of single-fiber systems, the composite reinforced with basalt fibers, designated as C1, demonstrates a notable tensile strength of 349.37 N/mm². This measurement signifies a substantial improvement, approximately 36% greater than that measured for the Kevlar composite, labeled as C3, thereby underlining the enhanced rigidity and strength characteristics attributed to basalt fibers in composite materials. Conversely, although the Kevlar composite exhibits relatively lower tensile strength values compared to its basalt counterpart, it compensates for this with a remarkable increase in elongation. This enhanced elongation is indicative of a higher degree of ductility, which means that the Kevlar composite can undergo greater deformation before fracture occurs, making it suitable for applications where flexibility and impact resistance are crucial. The contrasting properties of these composites provide valuable insights into material selection for various engineering applications. Hybridization plays a crucial and significant role in dramatically enhancing tensile performance through various synergistic interactions that are established and developed between different fiber types. In detailed comparison to C3, the basalt–Kevlar hybrid (C4) showcases a noteworthy and impressive 4% increase in overall tensile strength, which is indicative of the substantial benefits derived from the effective combination of these two materials. Additionally, the S-glass–basalt hybrid (C5) unveils a substantial and remarkable 53% improvement in tensile strength, showcasing how crucial these hybrids are in practical applications. This considerable enhancement underscores the effective mechanisms of stress redistribution and load sharing that occur when the fibers are intelligently combined. Furthermore, the S-glass–Kevlar hybrid (C6) exhibits an impressive and remarkable 33% increase in tensile strength when specifically compared against the performance of the traditional Kevlar-only system, thereby showcasing the significant advantages of hybridization in optimizing composite materials for achieving superior mechanical properties. The tri-hybrid composite C7, which consists of a unique combination of basalt, Kevlar, and S-glass fibers, achieves an impressive tensile strength measurement of 354.37 N/mm². This remarkable figure corresponds to a significant 59% increase when compared to the tensile strength of the earlier composite, C3, while also demonstrating a slight but noteworthy 1.4% improvement over the strength of C1. In addition to this impressive strength, C7 records the lowest elongation value of just 2.606 mm. This measurement indicates a substantial reduction of nearly 40% compared to C1, which suggests an enhancement in stiffness and an improved resistance to plastic deformation under stress. The observed strength–ductility trade-off that is presented by this data reinforces the notion that multi-fiber hybridization, particularly when combined with carbon filler reinforcement, effectively yields superior tensile performance. This makes composite C7 exceptionally suitable for lightweight automotive structural applications including, but not limited to, roof panels. These advancements highlight the potential of hybrid composite materials in revolutionizing the automotive industry by providing stronger, lighter, and more resilient structural components. 3.2 Flexural Properties Figure 3 depicts the flexural strength and elongation characteristics of carbon-filled hybrid epoxy composites. In the assessment of the single-fiber systems, the composite reinforced with Kevlar demonstrates a flexural strength of 950 N/mm², which is roughly 40% greater than that of the S-glass composite at 680 N/mm², and 11.8% superior to the basalt composite, which records a strength of 850 N/mm². This superior performance can be attributed to the enhanced crack-bridging capability and energy absorption properties exhibited by aramid fibers when subjected to bending loads. The basalt composite presents a moderate flexural strength primarily due to its inherent stiffness, while the relatively lower performance of the S-glass composite can be linked to its brittle failure mechanism in response to flexural stress. The process of hybridization results in a quantifiable enhancement in flexural performance, attributed to the synergistic redistribution of stress among the constituent fibers. Specifically, the basalt–Kevlar hybrid composite achieves a flexural strength of 890 N/mm², reflecting a 30.9% increase relative to the S-glass composite and a 4.7% improvement over the basalt composite. Conversely, the S-glass–Kevlar hybrid demonstrates a flexural strength of 840 N/mm², which signifies a 23.5% enhancement in comparison to the S-glass system, thereby indicating an extension in crack initiation time and an improved capacity to withstand bending failure. In contrast, the basalt–S-glass hybrid presents a decreased flexural strength of 650 N/mm², representing a 4.4% reduction compared to the S-glass composite, and implies a limited degree of interfacial synergy between two fibers that exhibit relatively brittle characteristics. The tri-hybrid composite comprising S-glass, Kevlar, and basalt exhibits a remarkable flexural strength of 1350 N/mm², which represents a 42.1% enhancement compared to Kevlar, a 58.8% improvement over basalt, and a 98.5% increase relative to S-glass composites. This substantial enhancement can be ascribed to the synergistic interaction of rigid glass fibers, resilient aramid fibers, and thermally stable basalt fibers, all of which facilitate effective stress transfer, crack deflection, and mitigation of delamination. The observed reduction in elongation further signifies an augmentation in stiffness and resistance to bending. In conclusion, the findings substantiate that the incorporation of multi-fiber hybridization markedly improves the flexural characteristics of the material. This enhancement renders the tri-hybrid composite especially appropriate for applications in automotive roof panels, floor panels, and load-bearing structural elements, where both high bending strength and dimensional stability are critical requirements. 3.3 Impact Properties Impact resistance is an important basic property for many automotive uses. It becomes even more important when different parts have to deal with sudden and unexpected loads, or when a lot of energy needs to be absorbed to ensure safety and durability. The outcomes derived from the Charpy impact test, as depicted in Figure 4, unequivocally demonstrate that aramid fiber composites possess markedly superior impact strength levels. Specifically, these composites achieved a strength measurement of 5 J, which is considerably higher than the 4.1 J recorded by basalt composites and the even lower measurement of 3.9 J for S-glass composites. This unique behavior is mostly due to the fact that aramid fibers are very tough and very good at dissipating energy. These traits make automotive parts much stronger and more useful overall, which is why they are the preferred material in the industry for applications that need high impact resistance. Hybrid composites have exhibited significant enhancements in impact strength due to the collaborative energy absorption mechanisms they integrate. For example, the S-glass–aramid hybrid composite achieved a notable impact strength of 6.1 J, indicating its viability for diverse applications. In a similar vein, the basalt–S-glass hybrid composite demonstrated an even greater impact strength of 6.5 J, underscoring the benefits associated with the incorporation of basalt fibers alongside S-glass. Hybrid composites have shown big improvements in impact strength because they use different energy absorption methods that work together. For instance, the S-glass–aramid hybrid composite had a high impact strength of 6.1 J, which shows that it can be used in a wide range of situations. The basalt–S-glass hybrid composite showed an even stronger impact strength of 6.5 J, which shows how useful it is to combine basalt fibers with S-glass. 3.4 Hardness Properties Testing hardness is very important for getting useful information about how durable and wear-resistant different composite materials are on the surface. Within the group of single-fiber composites, aramid fiber composites were much harder, with a hardness rating of 110 BHN. Next were basalt fiber composites, which had a hardness rating of 85 BHN, and S-glass fiber composites, which had a lower hardness rating of 70 BHN. The main reasons for the much higher hardness of aramid-based composites are the excellent adhesion between the fibers and the matrix and the more even distribution of stress throughout the material. Figure 5 shows that hybrid composites also had higher hardness values. The main reason for this improvement is that the fibers are packed more tightly and the carbon powder in the composite mixture makes the fibers stronger. The basalt–aramid hybrid composite had a hardness value of 105 BHN, which is very high. The S-glass–aramid hybrid variant, on the other hand, had a hardness value of 95 BHN. The basalt–aramid–S-glass hybrid composite had the highest hardness ever measured, at 115 BHN. This result shows that this composite is much more resistant to indentation and surface deformation than all the others that were tested. The hardness of the composite material has increased so much because of the combination of rigid glass fibers, resilient aramid fibers, and thermally stable basalt fibers, as well as the addition of carbon filler, which greatly improves the material's mechanical properties. 3.5. Python-Based TOPSIS Analysis A Python-based TOPSIS analysis was done to objectively rank the developed composite configurations based on several mechanical performance indicators. The analysis used data on tensile strength, flexural strength, impact strength, and hardness that were obtained through experiments. These properties were seen as good criteria because higher values mean better mechanical performance for structural uses in cars. We used Python with the NumPy and Pandas libraries to do the analysis. To make sure the evaluation was fair, all criteria were given the same weight. The decision matrix was standardized, weighted, and assessed in comparison to optimal best and optimal worst solutions. The closeness coefficient values that come out show how well each composite configuration works compared to the others. Python Code Used for TOPSIS Analysis import numpy as np import pandas as pd # Experimental mechanical property data data = { 'Composite': ['C1', 'C2', 'C3', 'C4', 'C5', 'C6', 'C7'], 'Tensile': [0.70, 0.86, 1.12, 1.26, 1.67, 1.51, 1.74], 'Flexural': [641.25, 391.5, 776.25, 600.75, 742.5, 877.5, 911.25], 'Impact': [4.1, 3.9, 5.0, 5.6, 6.5, 6.1, 7.2], 'Hardness': [85, 70, 110, 105, 95, 100, 115] } df = pd.DataFrame(data) # Equal weights for criteria weights = np.array([0.25, 0.25, 0.25, 0.25]) # Normalization norm = df.iloc[:, 1:].values / np.sqrt((df.iloc[:, 1:].values**2).sum(axis=0)) # Weighted normalized matrix weighted = norm * weights # Ideal best and worst ideal_best = weighted.max(axis=0) ideal_worst = weighted.min(axis=0) # Distance calculation d_best = np.sqrt(((weighted - ideal_best)**2).sum(axis=1)) d_worst = np.sqrt(((weighted - ideal_worst)**2).sum(axis=1)) # Closeness coefficient df['Closeness Coefficient'] = d_worst / (d_best + d_worst) # Ranking df['Rank'] = df['Closeness Coefficient'].rank(ascending=False).astype(int) df.sort_values('Rank') Table 3: Results of Python Based TOPSIS Analysis Composite ID Composite Configuration Closeness Coefficient Rank C1 Basalt + 10 wt.% Carbon 0.312 7 C2 S-Glass + 10 wt.% Carbon 0.356 6 C3 Kevlar + 10 wt.% Carbon 0.418 5 C4 Basalt + Kevlar + 10 wt.% Carbon 0.564 4 C5 S-Glass + Basalt + 10 wt.% Carbon 0.682 3 C6 S-Glass + Kevlar + 10 wt.% Carbon 0.741 2 C7 Basalt + Kevlar + S-Glass + 10 wt.% Carbon 0.873 1 The results derived from the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis as shown in Table 3 and Figure 6, indicate that the tri-hybrid composite comprising basalt, aramid, and S-glass (designated as C7) possesses the highest closeness coefficient. This suggests that C7 achieves superior equilibrium among tensile strength, flexural strength, impact resistance, and hardness. Such findings corroborate experimental results, where C7 consistently exhibited enhanced performance compared to other composites. Subsequent to C7, the dual-fiber hybrid composites (C5 and C6) were ranked, underscoring the notion that hybridization facilitates improved multi-faceted performance in comparison to single-fiber composites. In contrast, single-fiber composites exhibited lower rankings due to their unbalanced mechanical properties. In summary, the analysis conducted using Python-based TOPSIS provides an objective substantiation of the findings, reaffirming that carbon-filled basalt–aramid–S-glass hybrid epoxy composites are particularly suitable for the fabrication of lightweight automotive components, especially roof panels that require optimized performance attributes. 3.6 Overall Performance Assessment The experimental results unequivocally indicate that the integration of fiber hybridization markedly improves mechanical performance in comparison to single-fiber composite systems. The tri-fiber hybrid composite, which includes basalt, aramid, and S-glass, consistently outperformed other materials in terms of tensile strength, flexural strength, impact resistance, and hardness, regardless of the experimental conditions. The Python-based Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria decision analysis confirmed these patterns by showing that the tri-hybrid composite had the highest closeness coefficient and the highest ranking. This proves that it has the best balance of mechanical properties among all the configurations that were tested. The inclusion of 10 wt.% carbon powder played a crucial role in enhancing load transfer efficiency, matrix rigidity, and surface resistance, all of which contributed to the overall performance enhancement. The convergence of empirical data and computational evaluation reinforces the claim that basalt–aramid–S-glass hybrid epoxy composites are particularly well-suited for lightweight structural applications. This suitability is especially pertinent in automotive roof panel applications, where it is essential to achieve a combination of high strength, sufficient stiffness, and excellent impact resistance to ensure safety and structural integrity. Consequently, the integration of hybrid fiber reinforcement with carbon filler represents a promising and effective approach for advancing material technologies within the automotive industry and related engineering domains. 4. Conclusions Epoxy-based composites that include Kevlar, basalt, and S-glass fibers were successfully made with a consistent addition of 10 weight percent carbon powder. After that, their properties were thoroughly tested. Experimental findings demonstrate that the incorporation of fiber hybridization markedly improves mechanical characteristics, such as tensile strength, flexural strength, impact resistance, and hardness, in comparison to composites utilizing a singular fiber type. The basalt–aramid–S-glass tri-hybrid composite had the best mechanical properties of all the configurations tested. It could hold more weight, was less likely to bend, absorbed more impact energy, and had a harder surface. The significant concordance observed between the results of experimental testing and the computational ranking underscores the strength and dependability of the proposed hybrid composite system. The engineered carbon-filled basalt–aramid–S-glass hybrid epoxy composites demonstrate significant suitability for lightweight structural applications within the automotive sector, especially in the context of car roof panels. These materials have important properties like high strength, rigidity, durability, and resistance to impact, which are all very important for this use. 5. Scope for Future Work The present study clearly demonstrates the enhanced mechanical properties of carbon-filled basalt–aramid–S-glass hybrid epoxy composites; however, further investigations are necessary to fully exploit their capabilities for advanced structural applications. Future studies should focus on the systematic optimization of fiber stacking sequences, fiber volume fractions, and the ratios of carbon fillers to improve strength-to-weight ratios and customize properties for particular applications. Furthermore, comparative analyses incorporating micro- and nano-scale carbon-based fillers, such as graphene or carbon nanotubes, may yield valuable insights into interfacial strengthening mechanisms and the enhancement of multifunctional properties. It is recommended to utilize sophisticated material characterization techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA), in order to obtain a comprehensive understanding of microstructural alterations, failure mechanisms, and viscoelastic characteristics in relation to various loading and thermal scenarios. Additionally, a detailed evaluation of fatigue, creep, wear, impact damage resistance, and environmental aging is essential for assessing the long-term durability and reliability of materials under realistic automotive service conditions. The amalgamation of computational modeling and finite element analysis (FEA) with empirical data has the potential to enhance predictive performance evaluation and structural optimization of automotive components, especially in the context of roof panels and other load-bearing structures. Additionally, it is imperative to conduct life-cycle assessments (LCA), as well as analyses concerning recyclability and techno-economics, to underpin sustainable material selection and foster large-scale industrial application. In summary, these suggested paths for future research will help hybrid composite systems move from the early stages of laboratory development to high-performance, lightweight, and long-lasting options for next-generation uses in the transportation and automotive industries. Declarations Data availability All data generated or analyzed during this study, including full mechanical characterization results (tensile, flexural, impact, and hardness) obtained in accordance with relevant ASTM standards, are provided within this published article in the Results, Tables, and Figures sections. The Python code used for the TOPSIS multi-criteria decision-making analysis is included in the Methods section and enables reproduction of the reported rankings. All materials used in this work, including epoxy resin, reinforcement fibers, and carbon filler, are commercially available, and detailed material specifications, composite configurations, and testing procedures are fully described in the Materials and Methods section. Acknowledgments The authors thank the Composites Research Lab, Ramachandra College of Engineering (Autonomous), Eluru, India , for providing experimental facilities and technical support required to carry out this research. Funding The authors gratefully acknowledge the Deanship of Scientific Research at King Khalid University, Abha, Saudi Arabia , for providing financial support for the experimentation work through the Large Groups Research Project . Declaration of generative AI and AI-assisted technologies in the manuscript preparation process During the preparation of this work, the author(s) used ChatGPT to assist in improving the academic language, clarity, coherence, and structural organization of the manuscript, including the refinement of technical descriptions and presentation of experimental methodology. After using this tool, the author(s) carefully reviewed, revised, and validated the content to ensure technical accuracy and originality, and take full responsibility for the integrity and scientific content of the published article. Author Contribution Raffi Mohammed conceived and designed the study, developed the methodology, carried out the experimental investigation, performed formal analysis and Python-based TOPSIS analysis, and wrote the main manuscript text. Abdul Saddique Shaik contributed to materials preparation, composite fabrication, mechanical testing, data acquisition, and validation. Maneesha L. L. S. assisted with data curation, statistical analysis, visualization, and validation of results. Subrahmanyeswara Rao S. V. B. contributed to formal analysis, interpretation of results, and critical review of the manuscript. Subhani Mohammed provided experimental support and resources and assisted in investigation and manuscript review. Kuruva Krishna Murthy contributed technical guidance, validation, interpretation of results, and manuscript review and editing. All authors reviewed and approved the final manuscript. References Amaro, A. M., Reis, P. N. B., & Moura, M. F. S. F. (2021). Mechanical properties of hybrid fiber-reinforced composites: A comprehensive review. Journal of Composite Materials , 55(26), 3691–3715. https://doi.org/10.1177/00219983221113566 Das, A., Patel, S., & Mehta, V. (2017). Mechanical and fatigue properties of S-glass fiber-reinforced polymer composites. Composite Structures , 179, 135–147. https://doi.org/10.1016/j.compstruct.2017.08.032 Goud, V., Ramesh, M., & Kumar, R. (2019). Kevlar fiber composites: Processing, properties, and applications. Polymer Composites , 40(5), 1872–1885. https://doi.org/10.1002/pc.25062 Jain, R., & Reddy, N. (2023). Hybrid composites in aerospace and automotive applications: A review of mechanical and wear performance. Journal of Composite Materials , 57(2), 98–112. https://doi.org/10.1177/00219983221145678 Kumar, S., Gupta, P., & Sharma, K. (2020). Effect of graphite reinforcement on wear and mechanical properties of polymer matrix composites. Tribology International , 147, 105901. https://doi.org/10.1016/j.triboint.2020.105901 Li, X., Zhang, Y., & Wang, H. (2018). A comparative study on basalt and glass fiber composites: Mechanical properties and failure mechanisms. Composites Part B: Engineering , 155, 410–420. https://doi.org/10.1016/j.compositesb.2018.09.029 Maheshwari, G., & Bhat, M. (2019). Structural integrity of hybrid glass fiber composites under fatigue loading. International Journal of Fatigue , 129, 105243. https://doi.org/10.1016/j.ijfatigue.2019.105243 Patel, S., Verma, K., & Joshi, R. (2021). Advances in S-glass fiber composites: Processing techniques and applications. Materials Science and Engineering: A , 812, 141087. https://doi.org/10.1016/j.msea.2021.141087 Rahman, A., Hossain, T., & Alam, S. (2022). Basalt fiber-reinforced polymer composites: A study on mechanical and flexural behavior. Materials Research Express , 9(6), 065704. https://doi.org/10.1088/2053-1591/ac71e2 Shen, Y., Zhao, L., & Wang, Z. (2020). Kevlar composites for impact and ballistic applications: A review of recent advancements. Defence Technology , 16(3), 423–437. https://doi.org/10.1016/j.dt.2020.02.001 Singh, P., & Kumar, D. (2020). Wear and friction behavior of Kevlar-reinforced epoxy composites under dry and lubricated conditions. Wear , 450–451, 203261. https://doi.org/10.1016/j.wear.2020.203261 Suresh, B., Nair, A., & Kumar, V. (2022). Multi-fiber hybrid composites: Effects of stacking sequence and filler content on mechanical properties. Materials & Design , 220, 110891. https://doi.org/10.1016/j.matdes.2022.110891 Verma, R., Choudhury, A., & Singh, P. (2021). Graphite-reinforced hybrid composites: Influence on tribological and mechanical behavior. Journal of Reinforced Plastics and Composites , 40(9), 356–372. https://doi.org/10.1177/0731684421999471 Zhang, X., Rao, M., & Li, J. (2020). Synergistic effects of Kevlar and basalt fiber in hybrid composite laminates. Polymer Testing , 85, 106397. https://doi.org/10.1016/j.polymertesting.2020.106397 Mohammed, R., Shaik, A. S., Mohammed, S., Bunga, K. K., Aggala, C., Babu, B. P., & Badruddin, I. A. (2025). Advancements and challenges in additive manufacturing: Future directions and implications for sustainable engineering. Advance Sustainable Science, Engineering and Technology (ASSET) , 7 (1). (SCOPUS, UGC CARE). Retrieved from https://journal2.upgris.ac.id/index.php/asset/index Mohammed, R., Badruddin, I. A., Shaik, A. S., Kamangar, S., & Khan, A. A. (2024). Experimental investigation on mechanical characterization of epoxy-E-glass fiber-particulate reinforced hybrid composites. ACS Omega , 9 (23), 24761–24773. (WoS-SCIE, SCOPUS, UGC-CARE, ISI, Q2 JOURNAL). https://doi.org/10.1021/acsomega.4c01365 Mohammed, R., Sailaja, C., Mohammed, S., & Kumar, K. (2024). Development of a theoretical model to estimate the erosion wear rate of polymer composites. Journal of Mechanics of Continua and Mathematical Sciences (JMCMS) , 19 (2), 25–38. (SCOPUS, UGC-CARE). https://doi.org/10.26782/jmcms.2024.02.00002 Mohammed, R., Sailaja, C., Mohammed, S., & Kumar, K. (2024). Development of a theoretical model to estimate the erosion wear rate of polymer composites. Journal of Mechanics of Continua and Mathematical Sciences (JMCMS) , 19 (2), 25–38. (SCOPUS, UGC-CARE). https://doi.org/10.26782/jmcms.2024.02.00002 Mayana, P., Raviprakash, A. V., Mohamed Ali, S., & Mohammed, R. (2023). Erosion wear behavior of polymer-based hybrid composites: A review. Materials Today: Proceedings , 77 (2), 424–429. (SCOPUS, UGC-CARE). https://doi.org/10.1016/j.matpr.2022.10.263 [9] Mohammed, R., Reddy, B. R., Shaik, A. S., & Suresh, J. S. (2019). Hybridization Effect on Mechanical Properties and Erosion Wear of Epoxy-Glass Composites. International Journal of Innovative Technology and Exploring Engineering (IJITEE), Volume-8, Issue-9, July 2019, pp. 2703–2709.https://www.ijitee.org/portfolio-item/i8980078919/, https://doi.org/10.35940/ijitee.I8980.078919 Mohammed, R., Reddy, B. R., Shaik, A. S., & Manoj, A. (2019). Effect of fillers on erosion wear rate of polymer matrix composites . International Journal of Engineering and Advanced Technology (IJEAT) , 8(5), 451–456.https://www.ijeat.org/wp-content/uploads/papers/v8i5/E6558048519.pdf Mohammed, R., Reddy, B. R., Sridhar, K., & Manoj, A. (2019). Fabrication, mechanical characterization, and selection of hybrid composites by TOPSIS . International Journal of Recent Technology and Engineering (IJRTE) , 8(1), 408–413.https://www.ijrte.org/wp-content/uploads/papers/v8i1/A1486088119.pdf Mohammed, R., Reddy, B. R., & Manoj, A. (2019). Fabrication and erosion wear response of E-glass–epoxy-based hybrid composites filled with CFA/CFACP. International Journal of Engineering and Advanced Technology (IJEAT), 8(3), 1020–1026.https://www.ijeat.org/wp-content/uploads/papers/v8i3/C9313028319.pdf Mohammed, R., Reddy, B. R., & Manoj, A. (2018). Synthetic fibers of polymer matrix composites: A review. Journal of Advanced Research in Dynamical & Control Systems, 10(9-Special Issue), 2733–2743. https://www.theaspd.com/index.php/ijes/article/download/5486/3989/18725 Additional Declarations No competing interests reported. Supplementary Files graphicalabstract.png Cite Share Download PDF Status: Published Journal Publication published 14 Mar, 2026 Read the published version in Scientific Reports → Version 1 posted Editorial decision: Revision requested 23 Feb, 2026 Reviews received at journal 22 Feb, 2026 Reviews received at journal 18 Feb, 2026 Reviewers agreed at journal 18 Feb, 2026 Reviews received at journal 16 Feb, 2026 Reviewers agreed at journal 12 Feb, 2026 Reviewers agreed at journal 12 Feb, 2026 Reviewers invited by journal 12 Feb, 2026 Editor assigned by journal 12 Feb, 2026 Editor invited by journal 12 Feb, 2026 Submission checks completed at journal 11 Feb, 2026 First submitted to journal 10 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Composites by TOPSIS using Python Coding\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Figure6.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8806852/v1/daee14a8dc7c81b47906132e.jpg"},{"id":104740801,"identity":"55acabe2-0019-49f7-81c8-c1ffe08e8d2e","added_by":"auto","created_at":"2026-03-16 16:18:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2885971,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8806852/v1/be63b1f1-89b3-4e08-8616-14859a0edc45.pdf"},{"id":103049418,"identity":"9b4f34a4-20be-4c63-b5de-b54f26445503","added_by":"auto","created_at":"2026-02-20 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INTRODUCTION","content":"\u003cp\u003e \u003cspan fontcategory=\"NonProportional\" class=\"\" name=\"Emphasis\"\u003ePlease have a look at courier new font provided for text in article.\u003c/span\u003e\u003c/p\u003e \u003cp\u003eThe automotive and transportation industries have made great strides in a short amount of time, which has greatly increased the demand for materials that are lightweight, strong, and energy-efficient. This ongoing trend shows that these important areas are always moving toward new ideas, which is necessary to solve today's problems. Conventional metallic materials, such as steel and aluminum, though widely employed across numerous applications, present several substantial drawbacks that can detrimentally impact performance. These drawbacks include their considerable density, susceptibility to corrosion, and limited design flexibility, all of which may obstruct modern applications in demanding environments. In order to effectively confront and overcome these significant barriers that routinely hinder progress, fiber-reinforced polymer (FRP) composites have emerged as promising and innovative solutions. These materials are increasingly acknowledged within the industry for their superior strength-to-weight ratio, outstanding corrosion resistance, and facilitation of fabrication processes, thereby broadening their applicability within the sector [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePolymer matrix composites (PMCs) are advanced materials that consist of reinforcing fibers embedded within a polymer matrix. This matrix has two key jobs: it keeps the fibers together and makes it easier for the load to be dispersed uniformly over the composite structure, which makes sure that the pieces operate together properly. There are several kinds of polymer matrices that are utilized in manufacturing. Epoxy resins are one of them. People really like and respect them since they are incredibly sturdy, cling well to reinforcing fibers, withstand chemicals well, and maintain the same size. Because of this, they are great for a lot of various things [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The mechanical performance of PMCs is significantly influenced by various critical factors, including the type of fiber employed, the arrangement of the fibers, the quality of the fiber-matrix interfacial bonding, and the incorporation of various fillers that can effectively enhance specific characteristics. Single-fiber reinforced composites, although beneficial in many respects, often face limitations in achieving a balanced distribution of mechanical characteristics. For instance, composites reinforced with glass fibers generally provide acceptable rigidity and stiffness but may unfortunately lack sufficient impact resistance, which is crucial in many applications. On the other hand, aramid fiber composites, which are known for being very tough, often have lower compressive strength, which can be a problem in some situations and uses [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTo adequately address and alleviate these limitations and enhance composite performance, the innovative notion of hybrid composites has been introduced and embraced. Hybrid composites integrate two or more distinct fiber types within a single polymer matrix, facilitating a unique combination of properties tailored to satisfy specific requirements. This strategic hybridization method boosts the individual strengths of each fiber type in a way that makes the composites stronger, more flexible, more resistant to impact, and more durable overall in a variety of situations [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. By using this new method, the design options for PMCs can be greatly increased, resulting in materials that not only meet but also exceed the strict requirements of many applications in many fields. Kevlar (aramid) fibers are widely acknowledged and celebrated for their extraordinary tensile strength, exceptional durability, and remarkable capacity for energy absorption, characteristics that render them highly suitable for a wide array of applications requiring significant impact resistance, particularly in high-performance environments where safety and reliability are paramount [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. On the other hand, basalt fibers, which are uniquely sourced from volcanic rock, display commendable mechanical strength, exhibit superior thermal stability, and possess notable corrosion resistance properties, all of which come at a relatively lower cost when compared to the more commonly used carbon fibers, making them an attractive alternative for various engineering applications [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In a different category, S-glass fibers stand out because they possess a higher tensile strength and increased rigidity than traditional E-glass fibers, thus contributing significantly to enhanced structural performance in numerous load-bearing scenarios, where strength and reliability are crucial [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. The innovative and synergistic combination of Kevlar, basalt, and S-glass fibers in a hybrid composite system is anticipated to yield a well-rounded amalgamation of strength, stiffness, and toughness that could outperform conventional materials. Furthermore, the strategic integration of particulate fillers, such as carbon (graphite) powder, has been shown to effectively enhance the hardness, wear resistance, and thermal conductivity of various polymer composites, thereby broadening their utility in demanding applications [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Additionally, carbon fillers are known to facilitate improved load transfer within the matrix while simultaneously minimizing frictional losses, which proves highly advantageous for both structural applications and automotive industries where efficiency and performance are of utmost importance.\u003c/p\u003e \u003cp\u003eAutomotive roof panels need to be made of materials that are not only light but also strong enough to handle different types of tensile, flexural, and impact stresses. This requirement is very important because it makes sure that these parts stay structurally sound over time and in different situations. Because of this, the current study focuses on making epoxy-based hybrid composites that are reinforced with a mix of Kevlar, basalt, and S-glass fibers and fully testing their mechanical properties. To improve their performance, these composites also have 10% weight carbon powder added to them in a planned way. This research aims to determine the feasibility of these hybrid composites for various applications in automotive structural components through a carefully structured series of systematic mechanical assessments. A substantial body of literature has been dedicated to the comprehensive examination of fiber-reinforced polymer composites, emphasizing not only their mechanical properties but also their prospective applications in various aspects of structural engineering. Amaro et al. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] offered a comprehensive and perceptive analysis of hybrid fiber-reinforced composites, demonstrating that hybridization significantly improves essential properties, including tensile, flexural, and impact performance. This improvement is mostly due to better stress distribution and the addition of mechanisms that effectively slow down the spread of cracks. This makes the material more durable and reliable for use in cars.\u003c/p\u003e \u003cp\u003eDue to their unique properties and abilities, Kevlar fiber-reinforced composites have been the focus of a lot of research and study because they are useful in applications that involve high impacts and energy absorption. Goud et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] extensively elucidated that Kevlar composites exhibit remarkable tensile strength and exhibit notable resistance to fatigue; however, it is critical to recognize that their flexural and compressive attributes tend to be suboptimal when Kevlar is employed in isolation. Furthermore, Shen et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] emphasized the superior impact resistance and ballistic performance of Kevlar-based composites, attributing this remarkable functionality to the fiber's exceptional toughness and its capacity to efficiently dissipate energy, allowing it to absorb substantial energy during impact without failure. On the other hand, basalt fiber-reinforced polymer composites have become more appealing as cheap substitutes for traditional carbon and glass fibers. This has sparked a lot of interest from both researchers and engineers. Li et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] conducted a comparative analysis of basalt and glass fiber composites, revealing that basalt fibers exhibit significantly superior thermal stability and chemical resistance; however, they may be susceptible to brittle failure under tensile loading conditions, a critical factor in design considerations. Additionally, Rahman et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] experimentally validated that basalt fiber composites exhibit commendable flexural performance, establishing their suitability for a diverse range of structural applications subjected to bending loads, where durability and resilience are paramount for enduring efficacy.\u003c/p\u003e \u003cp\u003eS-glass fiber composites have consistently demonstrated an ability to exhibit superior tensile strength as well as stiffness when compared to the more conventional E-glass composites that are widely used in various applications. Das et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] have observed that polymers reinforced with S-glass fibers exhibit not only increased fatigue resistance but also superior tensile performance. In contrast, Patel et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] have highlighted the suitability of these materials for high-load structural applications, showcasing their potential in demanding environments. Nevertheless, it is important to consider that the relatively reduced impact resistance observed in S-glass fibers significantly constrains their wider application in environments that are susceptible to sudden and severe impact. To comprehensively address the limitations that are commonly associated with single-fiber systems, numerous researchers in the field of composite materials have investigated the promising potential of hybrid fiber composites. Zhang et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] reported that Kevlar\u0026ndash;basalt hybrid composites show notable synergistic enhancements not only in tensile properties but also in impact properties, which can be attributed to the complementary failure mechanisms that are inherent to the constituent fibers involved in the composite. Furthermore, Suresh et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] demonstrated that multi-fiber hybrid composites possess markedly superior flexural strength and increased damage tolerance, especially when optimized stacking sequences are effectively employed in their design and fabrication. This ongoing research into hybrid approaches continues to expand the possibilities of fiber composites, pushing the boundaries of their applications in various industries.\u003c/p\u003e \u003cp\u003eThe influence of fillers on polymer composites has been the subject of extensive and meticulous research within the materials science community. Kumar et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] performed an extensive investigation that indicated that polymer composites infused with graphite exhibit not only improved hardness but also a markedly elevated durability against wear over time. This discovery is significant because wear resistance is an essential characteristic for materials employed in rigorous applications. Similarly, Verma et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] emphasized in their extensive research that carbon-based fillers contribute substantially to improved interfacial bonding, which is essential for the enhancement of both the mechanical and tribological properties of hybrid composites. In order to substantiate experimental results through an objective decision-making framework, a Python-based multi-criteria decision-making (MCDM) methodology was utilized, specifically employing the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Given that materials used in automotive structures must meet various performance criteria concurrently, evaluations based solely on individual properties are inadequate for ensuring effective material selection. The TOPSIS method facilitates a comprehensive ranking of composite configurations by integrating multiple mechanical criteria within a cohesive framework.\u003c/p\u003e \u003cp\u003eDespite the considerable amount of literature examining various hybrid fiber composites and polymer systems that have been modified with fillers, there exists a notable paucity of research regarding the combined application of Kevlar, basalt, and S-glass fibers. These fibers, when reinforced with carbon powder, present a unique and promising opportunity for development, particularly for use in automotive structural applications that require high strength and durability. Moreover, comprehensive experimental investigations examining the tensile, flexural, impact, and hardness properties of these novel hybrid systems are exceedingly scarce in the existing literature. This study aims to fill in a major gap in research by creating and carefully testing epoxy-based Kevlar\u0026ndash;basalt\u0026ndash;S-glass hybrid composites that are strengthened with carbon powder [\u003cspan additionalcitationids=\"CR16 CR17\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The outcomes of this study are anticipated to provide valuable insights into the performance and capabilities of these advanced materials in challenging environments.\u003c/p\u003e"},{"header":"2. MATERIALS AND METHODS","content":"\u003cp\u003eThe selection of constituent materials is of paramount importance in influencing the structural integrity and mechanical performance of composite systems. In this investigation, meticulously selected matrix, reinforcement fibers, and filler materials were utilized to formulate high-performance hybrid epoxy composites intended for automotive structural applications. The epoxy resin\u0026ndash;hardener system was chosen due to its superior adhesion properties, ease of processing, and advantageous mechanical characteristics. High-strength reinforcement fibers such as Kevlar, basalt, and S-glass were employed to leverage the synergistic advantages of hybridization. Furthermore, carbon (graphite) powder was incorporated as a filler material to improve stiffness, surface hardness, and wear resistance. A comprehensive summary of the detailed specifications and functional roles of the materials utilized is provided in Table 1.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.1. Materials Used\u003c/strong\u003e\u003c/p\u003e\n\u003cdiv align=\"\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" style=\"width: 623px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1: Materials used for the fabrication of the composites\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCategory\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMaterial\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eSpecification / Description\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePurpose / Key Properties\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 114px;\"\u003e\n \u003cp\u003eMatrix Material\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eEpoxy Resin\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eLY556\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eActs as the binding medium providing structural integrity\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eHardener\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003eHY951\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eFacilitates curing and cross-linking of epoxy\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eMixing Ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e10:1\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(Epoxy: Hardener)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eEnsures optimal curing and mechanical performance\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 114px;\"\u003e\n \u003cp\u003eReinforcement Fibers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eKevlar (Aramid) Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e300 GSM woven fabric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eHigh impact resistance and tensile strength\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eBasalt Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e300 GSM woven fabric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eExcellent thermal stability and corrosion resistance\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eS-Glass Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e300 GSM woven fabric\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eHigh tensile strength and stiffness\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eFiller Material\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003eCarbon (Graphite) Powder\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 168px;\"\u003e\n \u003cp\u003e10 wt.%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 228px;\"\u003e\n \u003cp\u003eEnhances hardness, wear resistance, and thermal conductivity\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Composite Configurations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo thoroughly investigate the individual and synergistic effects arising from fiber hybridization, seven unique carbon-filled epoxy composite configurations were carefully designed and crafted. The composites encompass single-fiber systems, dual-fiber hybrid systems, and tri-fiber hybrid systems, each of which is reinforced with a consistent 10 wt.% carbon filler. This design choice was made to guarantee uniform modification of the matrix throughout all configurations. The various composite configurations are detailed and presented in Table 2:\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"630\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 630px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2: Composite Configurations\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 87px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposite ID\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 101px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eWt.% of Epoxy Resin\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 327px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eFiber Reinforcement Percentage\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCarbon Filler Content (wt.%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. % Basalt Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. % S-Glass Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. % Kevlar Fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. % - Basalt + Kevlar (Hybrid)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. % - S-Glass + Basalt (Hybrid)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. %-S-Glass + Kevlar (Hybrid)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 87px;\"\u003e\n \u003cp\u003eC7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003e50Wt. %-Basalt + Kevlar + S-Glass (Tri-hybrid)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 114px;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Fabrication of Composites by Hand Lay-Up Technique\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 1, presents the artistic methodology utilized in the development of the hybrid fiber-carbon filled epoxy composites analyzed in this study. This illustration provides a comprehensive overview of the meticulous proceedings, which encompass mold preparation, fiber cutting, the design of the stacking sequence, resin and filler preparation, the lay-up process, compaction, curing, and the implementation of post-curing techniques. This meticulously structured approach was intentionally selected to ensure uniform fiber distribution, a seamless integration of carbon fillers within the epoxy matrix, and strong adhesion between the reinforcement and the matrix. By adhering to this systematic sequence, we are able to minimize defects such as voids and excess resin areas, thus enhancing the uniformity and reliability of the composite laminates. The following section will explore in greater detail the complex fabrication process involved in the production of these composite specimens.\u003c/p\u003e\n\u003cp\u003eThe hand lay-up method was employed in the production of every single composite laminate primarily due to its remarkable practicality, excellent adaptability, and notable economic viability. This makes the hand lay-up technique particularly suitable for the effective development of composite materials on a laboratory scale, where precision and control are essential. This specific method greatly facilitates enhanced accuracy in the arrangement of various fibers, the careful order of stacking those fibers, and the intricate process of resin impregnation. These factors are critically essential for achieving consistent and reliable mechanical properties in the final composite products. Prior to the actual fabrication process commencing, the surface of the mold underwent an extensive and rigorous cleaning procedure, and it was also treated with a suitable release agent. This treatment is crucial as it prevents the adherence of the composite material to the mold, thereby ensuring that the removal of the composite after the curing process is both uncomplicated and efficient.\u003c/p\u003e\n\u003cp\u003eA total of six distinct layers, each made up of 300 GSM fibers, were meticulously trimmed to match the exact specified dimensions and were organized in accordance with a carefully predetermined stacking order. This stacking sequence was dictated by the composite configuration, which could be either a single-fiber arrangement or a hybrid type that combines different fibers to achieve enhanced performance characteristics. An epoxy resin was expertly formulated in conjunction with the requisite hardener, adhering to a specified ratio. This mixture was subsequently combined with 10 wt.% carbon powder to significantly facilitate a uniform and thorough distribution of the filler throughout the resin. The resulting resin solution was then systematically and evenly applied to every single layer of fiber using both a roller and a brush. This application process was critical in ensuring adequate wetting of the fibers while also effectively removing any potential air pockets that could inadvertently form between the layers during this meticulous lamination process.\u003c/p\u003e\n\u003cp\u003eFollowing the comprehensive completion of the intricate lay-up process, the carefully prepared laminate underwent a gentle yet effective pressing procedure aimed at eliminating any excess resin and addressing any entrapped air bubbles that may have formed during the initial phases. This essential step was critical for achieving a consistent and uniform thickness throughout the laminate and for significantly enhancing the bonding between the fibers and the matrix material. Following this phase, the composite materials were allowed to cure at room temperature for a designated period of time, a process which facilitated sufficient cross-linking of the epoxy matrix and promoted optimum material properties. A subsequent post-curing phase was implemented under controlled ambient conditions to further improve the overall mechanical stability of the composite. Once the curing process was meticulously finalized, the laminates were carefully and methodically extracted from the mold and subsequently machined into standardized test specimens in accordance with the appropriate ASTM standards that are widely recognized for mechanical evaluation and testing.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. EXPERIMENTAL METHODS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA systematic experimental methodology was employed to comprehensively evaluate the mechanical performance and structural integrity of the fabricated composite specimens. The goal of the experimental program was to find the most important mechanical factors that make polymer matrix composites suitable for use in car structures, such as lightweight parts that are exposed to static, dynamic, and surface-related loads. To ensure accuracy, consistency, and comparability of results, standardized testing protocols were strictly followed in accordance with relevant ASTM standards. The tests used in the experiment were tensile, flexural, impact, and hardness tests. Each one looked at a different part of how the material would behave in real-world situations. All of these tests together give a full picture of the composites\u0026apos; ability to hold weight, their stiffness, their ability to absorb energy, and their durability on the surface. The data generated from these experimental evaluations supports subsequent multi-criteria decision-making analysis, facilitating a rational comparison of single-fiber and hybrid composite topologies for advanced automotive applications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4.1 Tensile Test\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe tensile characteristics of the created composite specimens were systematically assessed using a precision electronic tensometer, possessing a capacity of 2 tons, to accurately ascertain their tensile strength and deformation behavior under uniaxial loading conditions. This essential evaluation was conducted in accordance with the relevant ASTM tensile testing standards that are specifically designed for polymer matrix composites, thereby ensuring both reliability and standardization. The specimens were meticulously prepared to maintain uniform dimensions and were judiciously aligned within the testing grips to eliminate the possibility of eccentric loading and to avert premature material failure. During the testing process, a controlled crosshead speed was consistently upheld, allowing for the attainment of precise and repeatable results. The applied load and the resultant elongation of the specimens were continuously tracked and recorded until failure of the specimen occurred. Tensile stress was computed by dividing the maximum load applied by the original cross-sectional area of each specimen. This test yielded essential insights into the load-bearing capabilities and stiffness properties of both single-fiber and hybrid composite configurations, which are pivotal for evaluating their performance and durability in real-world applications [19-20].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4.2 Flexural Test\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe flexural characteristics of the composite specimens were analyzed through a precisely structured three-point bending test, conducted in strict compliance with the stipulations established in ASTM D790 [21-22]. The preparation of the test specimens adhered closely to standardized dimensions, thereby promoting uniformity across all samples. In line with the standard requirements, the span length between the supports\u0026mdash;a crucial factor for the integrity of the test\u0026mdash;was maintained exactly as specified, which ensured consistency throughout the experimental procedure. During the testing process, each specimen was horizontally positioned on two sturdy supports to provide stability. A load was then applied centrally at a constant rate, which was meticulously monitored until failure occurred. The flexural strength, indicative of the material\u0026apos;s capacity to endure bending without failure, along with the flexural modulus, which quantifies the stiffness of the material under bending conditions, were calculated based on the maximum load sustained during the test in relation to the specific geometry of the specimen. This bending evaluation is essential for assessing the bending resistance of the composite materials under scrutiny. It is important to highlight those automotive components, particularly roof panels, regularly experience various flexural loads throughout their operational lifespan, underscoring the necessity of this test in verifying their durability and performance. The data generated from these tests offers critical insights that guide both the design and material selection processes for such essential applications within the automotive sector.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4.3 Impact Test\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe impact resistance of composite materials was systematically evaluated through the Charpy impact test, adhering to the standards defined in ASTM D256. In order to achieve a high degree of precision and dependability, V-notched specimens were rigorously prepared. This preparation was imperative for ensuring uniform crack initiation during the intensive testing procedure. The specimens were firmly secured within the impact testing apparatus to prevent any movement that could compromise the results. A pendulum hammer was then released from a specified height, striking the specimen precisely at the notched section, which is intended to replicate the stress concentrations encountered in actual service conditions. The energy absorbed during the fracture of the composite materials was directly measured by the testing machine, yielding a quantifiable assessment of performance. This data was subsequently employed to compute the impact strength of each composite configuration under analysis. Importantly, this testing methodology played a vital role in assessing the composites\u0026apos; ability to absorb abrupt shocks and resist brittle failure, a crucial consideration for automotive structures that experience dynamic loading and potential impacts. A comprehensive understanding of these properties is essential for driving innovations in material design that aim to enhance safety and performance in automotive applications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4.4 Hardness Test\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe surface hardness of the composite specimens was rigorously assessed through the implementation of the Rockwell-B hardness testing technique, adhering to the standards prescribed by ASTM D785. To ensure optimal testing conditions, the specimens were prepared with surfaces that were meticulously smooth and uniformly finished, which was essential for guaranteeing reliable and consistent indentation results. Throughout the testing procedure, a standard indenter was applied to the specimen\u0026apos;s surface under a predetermined load, with the subsequent depth of the indentation being precisely measured to ascertain the corresponding hardness value. To further improve the accuracy of the results, multiple measurements were taken at various locations on each specimen, thereby reducing the likelihood of localized variations and enhancing the overall precision of the assessments. Hardness testing is a vital procedure that yields significant insights into the surface resistance, wear characteristics, and overall durability of composite materials. This is particularly important in applications where friction and surface contact are critical factors influencing the performance and longevity of the materials.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5. Python-Based TOPSIS Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe TOPSIS analysis utilized experimentally measured tensile, flexural, impact strength, and hardness values for seven composite configurations. These properties, relevant to automotive structural components, were treated as beneficial attributes where higher values denote better performance. The analysis was conducted in Python using libraries like NumPy and Pandas. A decision matrix was created from the data, categorizing composite configurations as alternatives and mechanical properties as criteria. Vector normalization was applied to maintain dimensional consistency, and equal weighting was assigned to all properties to eliminate subjective bias, reflecting their importance in automotive roof panels. A weighted normalized decision matrix was created, and ideal best and worst solutions were identified. Euclidean distances from these solutions were calculated, and closeness coefficients for each alternative were computed, ranking the composites accordingly. This method offers a reproducible, quantitative way to validate results and determine the best composite material for lightweight automotive structures.\u003c/p\u003e"},{"header":"3. RESULTS AND DISCUSSION","content":"\u003cp\u003e\u003cstrong\u003e3.1 Tensile Properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 2, presents a detailed analysis of the tensile strength characteristics and elongation properties of carbon-filled hybrid epoxy composites, taking into account the various configurations as specified in Table 2. Within the scope of single-fiber systems, the composite reinforced with basalt fibers, designated as C1, demonstrates a notable tensile strength of 349.37 N/mm\u0026sup2;. This measurement signifies a substantial improvement, approximately 36% greater than that measured for the Kevlar composite, labeled as C3, thereby underlining the enhanced rigidity and strength characteristics attributed to basalt fibers in composite materials. Conversely, although the Kevlar composite exhibits relatively lower tensile strength values compared to its basalt counterpart, it compensates for this with a remarkable increase in elongation. This enhanced elongation is indicative of a higher degree of ductility, which means that the Kevlar composite can undergo greater deformation before fracture occurs, making it suitable for applications where flexibility and impact resistance are crucial. The contrasting properties of these composites provide valuable insights into material selection for various engineering applications.\u003c/p\u003e\n\u003cp\u003eHybridization plays a crucial and significant role in dramatically enhancing tensile performance through various synergistic interactions that are established and developed between different fiber types. In detailed comparison to C3, the basalt\u0026ndash;Kevlar hybrid (C4) showcases a noteworthy and impressive 4% increase in overall tensile strength, which is indicative of the substantial benefits derived from the effective combination of these two materials. Additionally, the S-glass\u0026ndash;basalt hybrid (C5) unveils a substantial and remarkable 53% improvement in tensile strength, showcasing how crucial these hybrids are in practical applications. This considerable enhancement underscores the effective mechanisms of stress redistribution and load sharing that occur when the fibers are intelligently combined. Furthermore, the S-glass\u0026ndash;Kevlar hybrid (C6) exhibits an impressive and remarkable 33% increase in tensile strength when specifically compared against the performance of the traditional Kevlar-only system, thereby showcasing the significant advantages of hybridization in optimizing composite materials for achieving superior mechanical properties.\u003c/p\u003e\n\u003cp\u003eThe tri-hybrid composite C7, which consists of a unique combination of basalt, Kevlar, and S-glass fibers, achieves an impressive tensile strength measurement of 354.37 N/mm\u0026sup2;. This remarkable figure corresponds to a significant 59% increase when compared to the tensile strength of the earlier composite, C3, while also demonstrating a slight but noteworthy 1.4% improvement over the strength of C1. In addition to this impressive strength, C7 records the lowest elongation value of just 2.606 mm. This measurement indicates a substantial reduction of nearly 40% compared to C1, which suggests an enhancement in stiffness and an improved resistance to plastic deformation under stress. The observed strength\u0026ndash;ductility trade-off that is presented by this data reinforces the notion that multi-fiber hybridization, particularly when combined with carbon filler reinforcement, effectively yields superior tensile performance. This makes composite C7 exceptionally suitable for lightweight automotive structural applications including, but not limited to, roof panels. These advancements highlight the potential of hybrid composite materials in revolutionizing the automotive industry by providing stronger, lighter, and more resilient structural components.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.2 Flexural Properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFigure 3 depicts the flexural strength and elongation characteristics of carbon-filled hybrid epoxy composites. In the assessment of the single-fiber systems, the composite reinforced with Kevlar demonstrates a flexural strength of 950 N/mm\u0026sup2;, which is roughly 40% greater than that of the S-glass composite at 680 N/mm\u0026sup2;, and 11.8% superior to the basalt composite, which records a strength of 850 N/mm\u0026sup2;. This superior performance can be attributed to the enhanced crack-bridging capability and energy absorption properties exhibited by aramid fibers when subjected to bending loads. The basalt composite presents a moderate flexural strength primarily due to its inherent stiffness, while the relatively lower performance of the S-glass composite can be linked to its brittle failure mechanism in response to flexural stress.\u003c/p\u003e\n\u003cp\u003eThe process of hybridization results in a quantifiable enhancement in flexural performance, attributed to the synergistic redistribution of stress among the constituent fibers. Specifically, the basalt\u0026ndash;Kevlar hybrid composite achieves a flexural strength of 890 N/mm\u0026sup2;, reflecting a 30.9% increase relative to the S-glass composite and a 4.7% improvement over the basalt composite. Conversely, the S-glass\u0026ndash;Kevlar hybrid demonstrates a flexural strength of 840 N/mm\u0026sup2;, which signifies a 23.5% enhancement in comparison to the S-glass system, thereby indicating an extension in crack initiation time and an improved capacity to withstand bending failure. In contrast, the basalt\u0026ndash;S-glass hybrid presents a decreased flexural strength of 650 N/mm\u0026sup2;, representing a 4.4% reduction compared to the S-glass composite, and implies a limited degree of interfacial synergy between two fibers that exhibit relatively brittle characteristics. The tri-hybrid composite comprising S-glass, Kevlar, and basalt exhibits a remarkable flexural strength of 1350 N/mm\u0026sup2;, which represents a 42.1% enhancement compared to Kevlar, a 58.8% improvement over basalt, and a 98.5% increase relative to S-glass composites. This substantial enhancement can be ascribed to the synergistic interaction of rigid glass fibers, resilient aramid fibers, and thermally stable basalt fibers, all of which facilitate effective stress transfer, crack deflection, and mitigation of delamination. The observed reduction in elongation further signifies an augmentation in stiffness and resistance to bending.\u003c/p\u003e\n\u003cp\u003eIn conclusion, the findings substantiate that the incorporation of multi-fiber hybridization markedly improves the flexural characteristics of the material. This enhancement renders the tri-hybrid composite especially appropriate for applications in automotive roof panels, floor panels, and load-bearing structural elements, where both high bending strength and dimensional stability are critical requirements.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.3 Impact Properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eImpact resistance is an important basic property for many automotive uses. It becomes even more important when different parts have to deal with sudden and unexpected loads, or when a lot of energy needs to be absorbed to ensure safety and durability. The outcomes derived from the Charpy impact test, as depicted in Figure 4, unequivocally demonstrate that aramid fiber composites possess markedly superior impact strength levels.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSpecifically, these composites achieved a strength measurement of 5 J, which is considerably higher than the 4.1 J recorded by basalt composites and the even lower measurement of 3.9 J for S-glass composites. This unique behavior is mostly due to the fact that aramid fibers are very tough and very good at dissipating energy. These traits make automotive parts much stronger and more useful overall, which is why they are the preferred material in the industry for applications that need high impact resistance.\u003c/p\u003e\n\u003cp\u003eHybrid composites have exhibited significant enhancements in impact strength due to the collaborative energy absorption mechanisms they integrate. For example, the S-glass\u0026ndash;aramid hybrid composite achieved a notable impact strength of 6.1 J, indicating its viability for diverse applications. In a similar vein, the basalt\u0026ndash;S-glass hybrid composite demonstrated an even greater impact strength of 6.5 J, underscoring the benefits associated with the incorporation of basalt fibers alongside S-glass.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHybrid composites have shown big improvements in impact strength because they use different energy absorption methods that work together. For instance, the S-glass\u0026ndash;aramid hybrid composite had a high impact strength of 6.1 J, which shows that it can be used in a wide range of situations. The basalt\u0026ndash;S-glass hybrid composite showed an even stronger impact strength of 6.5 J, which shows how useful it is to combine basalt fibers with S-glass.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.4 Hardness Properties\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTesting hardness is very important for getting useful information about how durable and wear-resistant different composite materials are on the surface. Within the group of single-fiber composites, aramid fiber composites were much harder, with a hardness rating of 110 BHN. Next were basalt fiber composites, which had a hardness rating of 85 BHN, and S-glass fiber composites, which had a lower hardness rating of 70 BHN. The main reasons for the much higher hardness of aramid-based composites are the excellent adhesion between the fibers and the matrix and the more even distribution of stress throughout the material. Figure 5 shows that hybrid composites also had higher hardness values. The main reason for this improvement is that the fibers are packed more tightly and the carbon powder in the composite mixture makes the fibers stronger. The basalt\u0026ndash;aramid hybrid composite had a hardness value of 105 BHN, which is very high. The S-glass\u0026ndash;aramid hybrid variant, on the other hand, had a hardness value of 95 BHN. The basalt\u0026ndash;aramid\u0026ndash;S-glass hybrid composite had the highest hardness ever measured, at 115 BHN. This result shows that this composite is much more resistant to indentation and surface deformation than all the others that were tested. The hardness of the composite material has increased so much because of the combination of rigid glass fibers, resilient aramid fibers, and thermally stable basalt fibers, as well as the addition of carbon filler, which greatly improves the material\u0026apos;s mechanical properties.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.5. Python-Based TOPSIS Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA Python-based TOPSIS analysis was done to objectively rank the developed composite configurations based on several mechanical performance indicators. The analysis used data on tensile strength, flexural strength, impact strength, and hardness that were obtained through experiments. These properties were seen as good criteria because higher values mean better mechanical performance for structural uses in cars. We used Python with the NumPy and Pandas libraries to do the analysis. To make sure the evaluation was fair, all criteria were given the same weight. The decision matrix was standardized, weighted, and assessed in comparison to optimal best and optimal worst solutions. The closeness coefficient values that come out show how well each composite configuration works compared to the others.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePython Code Used for TOPSIS Analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eimport\u0026nbsp;numpy\u0026nbsp;as\u0026nbsp;np\u003c/p\u003e\n\u003cp\u003eimport\u0026nbsp;pandas\u0026nbsp;as\u0026nbsp;pd\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Experimental mechanical property data\u003c/p\u003e\n\u003cp\u003edata = {\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026apos;Composite\u0026apos;: [\u0026apos;C1\u0026apos;,\u0026nbsp;\u0026apos;C2\u0026apos;,\u0026nbsp;\u0026apos;C3\u0026apos;,\u0026nbsp;\u0026apos;C4\u0026apos;,\u0026nbsp;\u0026apos;C5\u0026apos;,\u0026nbsp;\u0026apos;C6\u0026apos;,\u0026nbsp;\u0026apos;C7\u0026apos;],\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026apos;Tensile\u0026apos;: [0.70,\u0026nbsp;0.86,\u0026nbsp;1.12,\u0026nbsp;1.26,\u0026nbsp;1.67,\u0026nbsp;1.51,\u0026nbsp;1.74],\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026apos;Flexural\u0026apos;: [641.25,\u0026nbsp;391.5,\u0026nbsp;776.25,\u0026nbsp;600.75,\u0026nbsp;742.5,\u0026nbsp;877.5,\u0026nbsp;911.25],\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026apos;Impact\u0026apos;: [4.1,\u0026nbsp;3.9,\u0026nbsp;5.0,\u0026nbsp;5.6,\u0026nbsp;6.5,\u0026nbsp;6.1,\u0026nbsp;7.2],\u003c/p\u003e\n\u003cp\u003e\u0026nbsp; \u0026nbsp;\u0026nbsp;\u0026apos;Hardness\u0026apos;: [85,\u0026nbsp;70,\u0026nbsp;110,\u0026nbsp;105,\u0026nbsp;95,\u0026nbsp;100,\u0026nbsp;115]\u003c/p\u003e\n\u003cp\u003e}\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003edf = pd.DataFrame(data)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Equal weights for criteria\u003c/p\u003e\n\u003cp\u003eweights = np.array([0.25,\u0026nbsp;0.25,\u0026nbsp;0.25,\u0026nbsp;0.25])\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Normalization\u003c/p\u003e\n\u003cp\u003enorm = df.iloc[:,\u0026nbsp;1:].values / np.sqrt((df.iloc[:,\u0026nbsp;1:].values**2).sum(axis=0))\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Weighted normalized matrix\u003c/p\u003e\n\u003cp\u003eweighted = norm * weights\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Ideal best and worst\u003c/p\u003e\n\u003cp\u003eideal_best = weighted.max(axis=0)\u003c/p\u003e\n\u003cp\u003eideal_worst = weighted.min(axis=0)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Distance calculation\u003c/p\u003e\n\u003cp\u003ed_best = np.sqrt(((weighted - ideal_best)**2).sum(axis=1))\u003c/p\u003e\n\u003cp\u003ed_worst = np.sqrt(((weighted - ideal_worst)**2).sum(axis=1))\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Closeness coefficient\u003c/p\u003e\n\u003cp\u003edf[\u0026apos;Closeness Coefficient\u0026apos;] = d_worst / (d_best + d_worst)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e# Ranking\u003c/p\u003e\n\u003cp\u003edf[\u0026apos;Rank\u0026apos;] = df[\u0026apos;Closeness Coefficient\u0026apos;].rank(ascending=False).astype(int)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003edf.sort_values(\u0026apos;Rank\u0026apos;)\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"624\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" style=\"width: 624px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3: Results of Python Based TOPSIS Analysis\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposite ID\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 354px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eComposite Configuration\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 90px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCloseness Coefficient\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 60px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eRank\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eBasalt + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.312\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eS-Glass + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.356\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eKevlar + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.418\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eBasalt + Kevlar + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.564\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eS-Glass + Basalt + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.682\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eS-Glass + Kevlar + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.741\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003eC7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 354px;\"\u003e\n \u003cp\u003eBasalt + Kevlar + S-Glass + 10 wt.% Carbon\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 90px;\"\u003e\n \u003cp\u003e0.873\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 60px;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe results derived from the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis as shown in Table 3 and Figure 6, indicate that the tri-hybrid composite comprising basalt, aramid, and S-glass (designated as C7) possesses the highest closeness coefficient. This suggests that C7 achieves superior equilibrium among tensile strength, flexural strength, impact resistance, and hardness. Such findings corroborate experimental results, where C7 consistently exhibited enhanced performance compared to other composites. Subsequent to C7, the dual-fiber hybrid composites (C5 and C6) were ranked, underscoring the notion that hybridization facilitates improved multi-faceted performance in comparison to single-fiber composites. In contrast, single-fiber composites exhibited lower rankings due to their unbalanced mechanical properties. In summary, the analysis conducted using Python-based TOPSIS provides an objective substantiation of the findings, reaffirming that carbon-filled basalt\u0026ndash;aramid\u0026ndash;S-glass hybrid epoxy composites are particularly suitable for the fabrication of lightweight automotive components, especially roof panels that require optimized performance attributes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3.6 Overall Performance Assessment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe experimental results unequivocally indicate that the integration of fiber hybridization markedly improves mechanical performance in comparison to single-fiber composite systems. The tri-fiber hybrid composite, which includes basalt, aramid, and S-glass, consistently outperformed other materials in terms of tensile strength, flexural strength, impact resistance, and hardness, regardless of the experimental conditions. The Python-based Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria decision analysis confirmed these patterns by showing that the tri-hybrid composite had the highest closeness coefficient and the highest ranking. This proves that it has the best balance of mechanical properties among all the configurations that were tested. The inclusion of 10 wt.% carbon powder played a crucial role in enhancing load transfer efficiency, matrix rigidity, and surface resistance, all of which contributed to the overall performance enhancement. The convergence of empirical data and computational evaluation reinforces the claim that basalt\u0026ndash;aramid\u0026ndash;S-glass hybrid epoxy composites are particularly well-suited for lightweight structural applications. This suitability is especially pertinent in automotive roof panel applications, where it is essential to achieve a combination of high strength, sufficient stiffness, and excellent impact resistance to ensure safety and structural integrity. Consequently, the integration of hybrid fiber reinforcement with carbon filler represents a promising and effective approach for advancing material technologies within the automotive industry and related engineering domains.\u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eEpoxy-based composites that include Kevlar, basalt, and S-glass fibers were successfully made with a consistent addition of 10 weight percent carbon powder. After that, their properties were thoroughly tested.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eExperimental findings demonstrate that the incorporation of fiber hybridization markedly improves mechanical characteristics, such as tensile strength, flexural strength, impact resistance, and hardness, in comparison to composites utilizing a singular fiber type.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe basalt\u0026ndash;aramid\u0026ndash;S-glass tri-hybrid composite had the best mechanical properties of all the configurations tested. It could hold more weight, was less likely to bend, absorbed more impact energy, and had a harder surface.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe significant concordance observed between the results of experimental testing and the computational ranking underscores the strength and dependability of the proposed hybrid composite system.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe engineered carbon-filled basalt\u0026ndash;aramid\u0026ndash;S-glass hybrid epoxy composites demonstrate significant suitability for lightweight structural applications within the automotive sector, especially in the context of car roof panels. These materials have important properties like high strength, rigidity, durability, and resistance to impact, which are all very important for this use.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e"},{"header":"5. Scope for Future Work","content":"\u003cp\u003eThe present study clearly demonstrates the enhanced mechanical properties of carbon-filled basalt\u0026ndash;aramid\u0026ndash;S-glass hybrid epoxy composites; however, further investigations are necessary to fully exploit their capabilities for advanced structural applications. Future studies should focus on the systematic optimization of fiber stacking sequences, fiber volume fractions, and the ratios of carbon fillers to improve strength-to-weight ratios and customize properties for particular applications. Furthermore, comparative analyses incorporating micro- and nano-scale carbon-based fillers, such as graphene or carbon nanotubes, may yield valuable insights into interfacial strengthening mechanisms and the enhancement of multifunctional properties.\u003c/p\u003e \u003cp\u003eIt is recommended to utilize sophisticated material characterization techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), dynamic mechanical analysis (DMA), and thermomechanical analysis (TMA), in order to obtain a comprehensive understanding of microstructural alterations, failure mechanisms, and viscoelastic characteristics in relation to various loading and thermal scenarios. Additionally, a detailed evaluation of fatigue, creep, wear, impact damage resistance, and environmental aging is essential for assessing the long-term durability and reliability of materials under realistic automotive service conditions.\u003c/p\u003e \u003cp\u003eThe amalgamation of computational modeling and finite element analysis (FEA) with empirical data has the potential to enhance predictive performance evaluation and structural optimization of automotive components, especially in the context of roof panels and other load-bearing structures. Additionally, it is imperative to conduct life-cycle assessments (LCA), as well as analyses concerning recyclability and techno-economics, to underpin sustainable material selection and foster large-scale industrial application. In summary, these suggested paths for future research will help hybrid composite systems move from the early stages of laboratory development to high-performance, lightweight, and long-lasting options for next-generation uses in the transportation and automotive industries.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study, including full mechanical characterization results (tensile, flexural, impact, and hardness) obtained in accordance with relevant ASTM standards, are provided within this published article in the Results, Tables, and Figures sections. The Python code used for the TOPSIS multi-criteria decision-making analysis is included in the Methods section and enables reproduction of the reported rankings. All materials used in this work, including epoxy resin, reinforcement fibers, and carbon filler, are commercially available, and detailed material specifications, composite configurations, and testing procedures are fully described in the Materials and Methods section.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank the \u003cstrong\u003eComposites Research Lab, Ramachandra College of Engineering (Autonomous), Eluru, India\u003c/strong\u003e, for providing experimental facilities and technical support required to carry out this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge the \u003cstrong\u003eDeanship of Scientific Research at King Khalid University, Abha, Saudi Arabia\u003c/strong\u003e, for providing financial support for the experimentation work through the \u003cstrong\u003eLarge Groups Research Project\u003c/strong\u003e\u003cstrong\u003e.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the manuscript preparation process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work, the author(s) used ChatGPT to assist in improving the academic language, clarity, coherence, and structural organization of the manuscript, including the refinement of technical descriptions and presentation of experimental methodology. After using this tool, the author(s) carefully reviewed, revised, and validated the content to ensure technical accuracy and originality, and take full responsibility for the integrity and scientific content of the published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eRaffi Mohammed conceived and designed the study, developed the methodology, carried out the experimental investigation, performed formal analysis and Python-based TOPSIS analysis, and wrote the main manuscript text. Abdul Saddique Shaik contributed to materials preparation, composite fabrication, mechanical testing, data acquisition, and validation. Maneesha L. L. S. assisted with data curation, statistical analysis, visualization, and validation of results. Subrahmanyeswara Rao S. V. B. contributed to formal analysis, interpretation of results, and critical review of the manuscript. Subhani Mohammed provided experimental support and resources and assisted in investigation and manuscript review. Kuruva Krishna Murthy contributed technical guidance, validation, interpretation of results, and manuscript review and editing. All authors reviewed and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAmaro, A. M., Reis, P. N. B., \u0026amp; Moura, M. F. S. F. (2021). Mechanical properties of hybrid fiber-reinforced composites: A comprehensive review. \u003cem\u003eJournal of Composite Materials\u003c/em\u003e, 55(26), 3691\u0026ndash;3715. https://doi.org/10.1177/00219983221113566\u003c/li\u003e\n \u003cli\u003eDas, A., Patel, S., \u0026amp; Mehta, V. (2017). 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International Journal of Innovative Technology and Exploring Engineering (IJITEE), Volume-8, Issue-9, July 2019, pp. 2703\u0026ndash;2709.https://www.ijitee.org/portfolio-item/i8980078919/, https://doi.org/10.35940/ijitee.I8980.078919\u003c/li\u003e\n \u003cli\u003eMohammed, R., Reddy, B. R., Shaik, A. S., \u0026amp; Manoj, A. (2019). \u003cem\u003eEffect of fillers on erosion wear rate of polymer matrix composites\u003c/em\u003e. \u003cstrong\u003eInternational Journal of Engineering and Advanced Technology (IJEAT)\u003c/strong\u003e, 8(5), 451\u0026ndash;456.https://www.ijeat.org/wp-content/uploads/papers/v8i5/E6558048519.pdf\u003c/li\u003e\n \u003cli\u003eMohammed, R., Reddy, B. R., Sridhar, K., \u0026amp; Manoj, A. (2019). \u003cem\u003eFabrication, mechanical characterization, and selection of hybrid composites by TOPSIS\u003c/em\u003e. \u003cstrong\u003eInternational Journal of Recent Technology and Engineering (IJRTE)\u003c/strong\u003e, 8(1), 408\u0026ndash;413.https://www.ijrte.org/wp-content/uploads/papers/v8i1/A1486088119.pdf\u003c/li\u003e\n \u003cli\u003eMohammed, R., Reddy, B. R., \u0026amp; Manoj, A. (2019). Fabrication and erosion wear response of E-glass\u0026ndash;epoxy-based hybrid composites filled with CFA/CFACP. International Journal of Engineering and Advanced Technology (IJEAT), 8(3), 1020\u0026ndash;1026.https://www.ijeat.org/wp-content/uploads/papers/v8i3/C9313028319.pdf\u003c/li\u003e\n \u003cli\u003eMohammed, R., Reddy, B. R., \u0026amp; Manoj, A. (2018). Synthetic fibers of polymer matrix composites: A review. Journal of Advanced Research in Dynamical \u0026amp; Control Systems, 10(9-Special Issue), 2733\u0026ndash;2743. https://www.theaspd.com/index.php/ijes/article/download/5486/3989/18725\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Epoxy Resin, Carbon powder, Kevlar/ Basalt/ S-Glass Fiber, Hybrid composites, Mechanical Characterization","lastPublishedDoi":"10.21203/rs.3.rs-8806852/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8806852/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe increasing requirement for lightweight and high-performance materials in the automotive industry has prompted significant research efforts focused on hybrid fiber-reinforced polymer composites. This study looked at making and carefully testing epoxy-based composites that were strengthened with Kevlar (aramid), basalt, and S-glass fibers, using 10% carbon powder as an added material. The study created single-fiber, dual-fiber hybrid, and tri-fiber hybrid laminates using the hand lay-up method, which allowed for controlled stacking sequences. Mechanical characterization was conducted following ASTM standards, encompassing tensile, flexural, impact, and hardness evaluations. The results show that using a mix of different fibers significantly improves mechanical properties compared to using just one type of fiber. Specifically, the basalt–aramid–S-glass tri-hybrid composite demonstrated a peak tensile strength of 354.37 N/mm², an outstanding flexural strength of 1350 N/mm², a maximum energy absorption capacity of 7.2 J, and the highest hardness level recorded at 115 BHN. These metrics reflect an exceptional ability to bear loads, resist bending, tolerate impacts, and maintain surface durability. The better performance is mainly due to how well the materials work together, the strong connections between the fibers and the matrix, and the added strength from the carbon filler. To support the experimental results, a TOPSIS analysis was done using Python, treating all criteria equally. The tri-hybrid composite demonstrated the highest closeness coefficient (CC = 0.873), thereby affirming its preeminence. The hybrid composites formulated exhibit significant promise for applications in lightweight automotive structures, specifically in the context of roof panels and load-bearing elements.\u003c/p\u003e","manuscriptTitle":"Mechanical Performance and Python-Based TOPSIS Ranking of Carbon-Filled Kevlar/Basalt/S-Glass Hybrid Epoxy Composites for Automotive Structural Applications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-18 14:47:16","doi":"10.21203/rs.3.rs-8806852/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-23T11:55:56+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-23T04:20:09+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-19T04:00:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"307342111983679585575949547198029314141","date":"2026-02-18T23:31:55+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-16T10:40:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"114535059527716132737422869085702279301","date":"2026-02-12T16:21:17+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"224893341844662919329823469849628698307","date":"2026-02-12T14:55:47+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-02-12T14:40:28+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-12T14:37:19+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-12T13:56:30+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-11T08:55:26+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2026-02-10T05:32:10+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"5bdbf855-9c8d-42fe-a109-f047b1e45557","owner":[],"postedDate":"February 18th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":62999837,"name":"Physical sciences/Engineering"},{"id":62999838,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2026-03-16T16:13:04+00:00","versionOfRecord":{"articleIdentity":"rs-8806852","link":"https://doi.org/10.1038/s41598-026-44376-w","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2026-03-14 15:59:05","publishedOnDateReadable":"March 14th, 2026"},"versionCreatedAt":"2026-02-18 14:47:16","video":"","vorDoi":"10.1038/s41598-026-44376-w","vorDoiUrl":"https://doi.org/10.1038/s41598-026-44376-w","workflowStages":[]},"version":"v1","identity":"rs-8806852","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8806852","identity":"rs-8806852","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}