Evolving sandwich composites through structural modifications with polyurethane foam and glass fiber

Abstract

This study aimed to enhance the mechanical properties of sandwich composites through structural modifications using E-glass fiber and polyurethane foam. Six types of sandwich composites were fabricated via the hand layup method, categorized based on core modifications focused on reinforcing the core to improve structural capabilities. Mechanical testing—including tensile, compression, flexural, impact, and hardness tests—revealed significant enhancements in strength and stiffness, particularly in composites with reinforced cores. Tensile tests showed that PCR20 exhibited the highest strength (1.59 MPa) and modulus (60.45 MPa), while compression tests indicated PCR20 had the highest strength (3.7819 MPa). Flexural tests revealed similar trends, with PCR20 showing the highest strength (10.17 MPa). Impact tests demonstrated that PCR10 was the strongest (243 J), and hardness tests showed PCR10 had the highest Shore D hardness (61). Scanning Electron Microscopy provided insights into the microstructural behavior and failure mechanisms, highlighting the ductile nature of reinforced composite columns. These findings underscore the effectiveness of core modifications in enhancing the mechanical performance of sandwich composites, emphasizing their potential across diverse industrial applications.This research can be applied in aerospace for lightweight yet strong structural components, in the automotive industry for reducing vehicle weight while maintaining durability, and in marine applications to enhance strength and corrosion resistance in shipbuilding.

Keywords:
Fine particles; Epoxy; Polymer composite; Mechanical properties; Scanning electron microscope

1. INTRODUCTION

Composite materials have emerged as essential components across various industries, offering a unique combination of properties that traditional materials often lack. These materials, comprised of two or more distinct constituents, have a long and diverse history, with examples found in both natural and human-made structures [¹]. The concept of composites can be traced back to ancient civilizations, where early humans utilized naturally occurring materials like mud, straw, and animal hides to create rudimentary composite structures. One of the earliest documented uses of composites dates back to Babylonia around 4000–2000 B.C., where bitumen or pitch was reinforced with fibrous materials to enhance its strength and durability. The early use of composites in ancient Babylonia, where bitumen was reinforced with fibrous materials, was significant as it demonstrated the principle of enhancing material properties through reinforcement. This foundational concept influenced modern composite technology by establishing the basic idea of combining materials to improve strength and durability, which is central to today’s advanced composite materials used in industries like aerospace and automotive.These early composites paved the way for the development of more sophisticated materials and manufacturing techniques over time [²].

Throughout history, composite materials have played a significant role in shaping human civilization. In ancient Egypt, for example, composite materials were used in the construction of boats and other watercraft, where wood and plant fibers were combined to create lightweight yet durable vessels capable of navigating the Nile River. Similarly, in ancient Greece and Rome, composite materials were used in the construction of buildings, bridges, and other infrastructure projects, where materials like concrete and stone were reinforced with metal rods or fibers to increase their strength and resilience [³]. The use of composite materials continued to evolve over the centuries, with advancements in manufacturing techniques and the discovery of new materials leading to the development of stronger, lighter, and more versatile composites. Advancements in synthetic polymers during the Industrial Revolution revolutionized composite materials by providing stronger, lighter, and more versatile matrix materials. These polymers, such as Bakelite, enabled the creation of high-performance composites, expanding applications in industries like aerospace, automotive, and construction, where enhanced durability, corrosion resistance, and weight reduction were critical [⁴]. Composite materials like fiberglass, carbon fiber, and Kevlar^® have revolutionized the aerospace and defense industries due to their exceptional strength-to-weight ratios, durability, and resistance to corrosion, fatigue, and high temperatures. These properties make them ideal for reducing aircraft weight, improving fuel efficiency, and enhancing overall performance. Fiberglass offers flexibility and insulation, while carbon fiber provides high stiffness and lightweight properties crucial for structural components like fuselages and wings. Kevlar^®, known for its exceptional toughness and impact resistance, is used in protective gear and armor. Together, these materials enable enhanced safety, efficiency, and innovation in aerospace and defense applications. These advancements in composite technology not only revolutionized the aerospace industry but also had a significant impact on other sectors, including automotive, marine, and sporting goods [⁵]. Today, composite materials are ubiquitous in modern society, found in everything from consumer electronics and sporting equipment to infrastructure and renewable energy systems. Fiber-reinforced polymers (FRPs) offer high strength-to-weight ratios, corrosion resistance, and durability, making them ideal for aerospace, automotive, and construction industries. Despite high costs, they reduce maintenance, improve performance, and enable complex designs. Challenges include high production costs, recycling issues, and limited scalability, but their advantages justify their use in high-performance applications [⁶]. These materials offer a unique combination of properties, including high strength, low weight, corrosion resistance, and design flexibility, making them ideal for a wide range of applications. Despite their many advantages, composite materials also present unique challenges and obstacles to widespread adoption. One of the primary challenges facing the composites industry is the lack of standardization and certification processes, which can make it difficult for manufacturers to ensure the quality and reliability of their products. The lack of standardization in the composite materials industry leads to inconsistent quality, regulatory challenges, and increased costs for manufacturers. It complicates collaboration and delays product development, affecting industries like aerospace, where stringent certification is crucial for safety and reliability [⁷]. Additionally, the high cost of raw materials and manufacturing processes can pose barriers to entry for smaller companies and startups looking to enter the market [⁸].

The main challenges in improving the recyclability and sustainability of composite materials include the difficulty of separating fibers from resin, limited recycling technologies, and energy-intensive processes. These issues make it hard to reuse or repurpose composites, leading to waste and environmental concerns. Potential solutions involve developing bio-based or recyclable resins, advancing mechanical and chemical recycling techniques, and designing composites with end-of-life considerations.The circular economy plays a crucial role by promoting the reuse, recycling, and repurposing of materials to minimize waste. It encourages manufacturers to design for recyclability, reducing environmental impact and enhancing resource efficiency in the lifecycle of composite materials [⁹]. Developing more efficient recycling technologies and implementing circular economy principles will be essential for minimizing the environmental impact of composite materials. In addition to these technical challenges, the composites industry also faces cultural and organizational barriers to adoption [¹⁰]. Many industries have a long history of using traditional materials like steel, concrete, and wood, and may be reluctant to invest in new materials and technologies. Overcoming these barriers will require collaboration and cooperation between industry stakeholders, government agencies, and research institutions to promote the benefits of composite materials and support their widespread adoption [¹¹]. Despite these challenges, the future of composite materials looks promising, with ongoing research and development efforts focused on improving performance, reducing costs, and enhancing sustainability. Advances in materials science, manufacturing techniques, and digital technologies are driving innovation in the composites industry, leading to the development of new materials with even greater strength, durability, and functionality [¹¹]. In conclusion, composite materials have a rich history and a bright future, with the potential to revolutionize countless industries and transform the way we design, build, and use products and infrastructure. By overcoming technical, economic, and cultural barriers to adoption, composite materials can help create a more sustainable and resilient world for future generations [¹²].

2. MATERIALS USED

2.1. E glass fiber (skin material)

E Glass Fiber is an ideal reinforcement material for composites due to its high tensile strength and stiffness, which enhance the load-bearing capacity and rigidity of the composite. Its chemical resistance ensures durability in harsh environments, while its electrical insulation properties make it suitable for applications requiring non-conductive materials. This makes E Glass Fiber ideal for use in electrical and electronic applications, including insulation materials and protective coatings. These characteristics collectively make E Glass Fiber highly effective in improving the mechanical performance and versatility of composite materials. where electrical conductivity is a concern. In composite material, E Glass Fiber is commonly used as a reinforcement material due to its high tensile strength and stiffness [¹³]. The “220 Gsm” specification likely refers to the weight of the glass fiber fabric, measured in grams per square meter. This indicates the density of the fabric and can affect its mechanical properties and handling characteristics during fabrication. Figure 1 shows the E glass skin.

Figure 1
E glass skin.

2.2. Fabricated polyurethane foam sheet (core material)

Polyurethane foam is a versatile and lightweight material commonly used in composite sandwich structures as a core material [¹⁴]. It is created through a chemical reaction between polyols and isocyanates. Polyols and isocyanates react to form a polymer network. A blowing agent is added to produce gas bubbles, causing the mixture to expand into foam. The foam then cures and solidifies, resulting in a lightweight, versatile material. Polyol is a type of alcohol containing multiple hydroxyl groups, which reacts with isocyanate to form the polyurethane polymer. Isocyanate is a highly reactive compound containing isocyanate functional groups, which reacts with polyol to initiate polymerization. Polyurethane foam is made by reacting polyols and isocyanates, creating a lightweight, cellular material. In composite sandwich structures, it provides a strong, rigid core with excellent thermal insulation, impact resistance, and low weight, enhancing overall performance and efficiency in industries like aerospace and construction [¹⁵]. Figure 2 shows the PU foam preparation.

Figure 2
PU foam preparation.

2.3. Epoxite resin systems (resin + hardener)

Epoxite resin systems consist of two main components: epoxy resin and hardener. When epoxy resin is mixed with a hardener, a chemical reaction called cross-linking or curing occurs. The hardener, typically an amine or an anhydride, reacts with the epoxy groups in the resin, forming a network of interconnected polymer chains. This cross-linking process creates a rigid, three-dimensional polymer structure [¹⁶]. The reaction enhances the mechanical properties of the composite by increasing its strength, rigidity, and durability. The cross-linked network improves the material’s resistance to impact, heat, and chemical exposure, resulting in a composite with superior mechanical performance and stability [¹⁷]. Epoxite resin systems are commonly used in composite manufacturing due to their excellent mechanical properties, versatility, and ease of processing. Overall, these materials - E Glass Fiber, Polyurethane Foam Sheet, and Epoxite Resin Systems - play crucial roles in the fabrication of composite structures, offering a combination of mechanical strength, lightweight properties, and durability essential for various industrial applications [¹⁸].

3. PROCESS AND METHODS

In this study, we made six different types of sandwich composites divided into two main groups: those with single cores and those with divided cores. Each composite is identified by a code consisting of a letter and a number:

• “R” stands for reference sandwich composites. For example, R20 represents a reference sandwich composite with a plain core (no modifications) and a thickness of 20 mm.

• “PER” stands for perforated with epoxy resin column sandwich composites. For instance, PER20 indicates a sandwich composite with holes in the core and a core thickness of 20 mm. These holes are filled with columns made of epoxy resin systems.

• “PCR” stands for perforated with composite column sandwich composites. For example, PCR20 represents a sandwich composite with holes in the core and a core thickness of 20 mm. These holes are filled with columns made of Epoxy resin-wetted E-glass fiber. The top and bottom sides of the glass fiber column have slits, which are spread over adjacent layers and stitched.

The structure of the reference sandwich composites consists of two face sheets separated by and attached to a core. For single-core composites, the layer stacking sequence is: +45/-45/(0/90)2/core/(90/0)2/+45/-45. For divided-core composites, the layer stacking sequence is: +45/-45/0/90/core/90/0/core/90/0/+45/-45. These codes and structures help us identify and understand the different types of sandwich composites used in the study. In sandwich composites, single-core stacking uses a continuous core, providing higher stiffness and uniform strength, ideal for resisting bending. Divided-core stacking uses multiple smaller cores, enhancing flexibility, damage tolerance, and energy absorption but often reducing overall stiffness. The choice depends on the need for stiffness versus impact resistance. Figure 3 and 4 shows the R20 - Single core composite ply stacking sequenc and R10 - Divided core composite ply stacking sequence.

Figure 3
R20 - Single core composite ply stacking sequence.

Figure 4
R10 - Divided core composite ply stacking sequence.

5. COMPOSITE ENHANCEMENTS

In this process, we aim to enhance the structural capability of sandwich composites by reinforcing only the core. To achieve this, we’ll drill holes in the foam core and insert resin columns and composite rods during manufacturing. These reinforcements will be placed into grooves drilled into the foam core, known as shear key elements [¹⁹]. This modification strengthens the composite structure without adding significant weight, improving its overall performance. Reinforcing the core of sandwich composites with resin columns and composite rods offers several benefits that significantly enhance structural capabilities. This method increases the core’s strength and stiffness, allowing the composite to support greater loads and stresses while distributing them more evenly across the structure. It also improves resistance to shear forces, contributing to overall structural stability [²⁰]. Notably, this approach achieves these enhancements without adding substantial weight, which is crucial for applications where maintaining a lightweight is essential. Additionally, the reinforcements boost impact resistance, making the composite more durable and long-lasting. Thus, reinforcing the core effectively strengthens the composite structure, enhancing performance and durability without compromising on weight [²¹]. Figure 5 and 6 shows the sandwich and composite ply stacking sequence.

Figure 5
Sandwich.

Figure 6
Composite ply stacking sequence.

6. MANUFACTURING METHODS

Hand layup is a manual process utilized in composite manufacturing, involving the meticulous layering of reinforcing fibers and resin onto a mold. This method, commonly used in aerospace, automotive, and marine industries, allows for the creation of composite parts with varying sizes and shapes [²²]. Hand layup is a cost-effective, flexible method suitable for small runs and complex shapes, but it suffers from inconsistent quality, labor intensity, and risk of air bubbles. In contrast, techniques like vacuum bagging improve consistency and reduce defects, though they involve higher setup costs. Filament winding and Resin Transfer Molding offer high strength and precise control but are more expensive and suited to specific applications. The process begins with mold preparation and the application of a release agent. Materials, including polyurethane foam and E-glass fibers, are then prepared and arranged according to specifications. Resin is mixed according to manufacturer instructions and applied to each layer of reinforcement material. The layers are carefully stacked, ensuring proper alignment and the removal of air bubbles [²³]. Pressure is applied to consolidate the layers, and the process is repeated until the desired thickness is achieved. After curing for 24 hours at ambient temperature, the fabricated composite materials are demolded, trimmed, and finished to final dimensions. This simple and cost-effective method offers flexibility in design changes and produces consistent quality with skilled operators [²⁴]. Figure 7 and 8 shows the preparation and sandwich.

Figure 7
Preparation.

Figure 8
Final sandwich.

7. RESULTS AND DISCUSSION

The experimental phase of this study encompassed out-of-plane compression and tensile tests, each repeated five times to ascertain consistency. Mean values and standard deviations were calculated for all parameters. The aim was to evaluate the distinct behavior observed in various sandwich compositions [²⁵]. Additionally, supplementary mechanical tests were performed to validate the outcomes of the compression and tension tests. These included Shore D hardness, Charpy Impact, Flexural, and Scanning Electron Microscope analyses. These comprehensive tests provided a holistic understanding of the mechanical properties and behavior of the sandwich compositions under different loading conditions.

7.1. Tensile test

The provided table presents the strength and modulus values of different samples: R20, PER20, PCR20, R10, PER10, and PCR10. Among these, PCR20 stands out with the highest strength of 1.59 MPa and a modulus of 60.45 MPa, indicating superior mechanical properties compared to the rest. Despite its lower strength of 1.30 MPa, PER20 exhibits a higher modulus of 48.68 MPa, suggesting enhanced stiffness. In contrast, R20 demonstrates a moderate strength of 1.42 MPa and a modulus of 35.06 MPa. Moving to thinner specimens, R10 surprisingly displays the highest strength of 1.95 MPa among the group, while maintaining a modulus comparable to R20 at 39.07 MPa. Similarly, PER10 shows a strength of 1.33 MPa and a modulus of 50.76 MPa, indicating a balance between strength and stiffness. Finally, PCR10 exhibits a strength of 1.71 MPa and a modulus of 57.96 MPa, indicating notable mechanical properties attributed to the inclusion of glass fiber reinforcement in the resin matrix. Overall, the variations in strength and modulus values reflect the influence of core modifications and reinforcement methods on the mechanical performance of the composite samples. Figure 9 shows the results of tensile strength. Core modifications and reinforcement methods, particularly the inclusion of glass fiber, have a significant impact on the tensile properties of composite samples. PCR20 and PCR10, which include glass fiber reinforcement, show the highest strength and modulus, highlighting the role of fibers in enhancing both strength and stiffness. Thinner samples like R10 also demonstrate improved strength, suggesting that reducing core thickness can increase tensile strength. Overall, variations in core composition and reinforcement directly affect the balance between strength and stiffness in these composites.

Figure 9
Tensile strength.

7.2. Compression test

These samples represent different configurations of sandwich composites. R20, serving as the reference, shows a modest strength of 0.7330 MPa. However, PER20 exhibits a significant improvement with a strength of 2.9488 MPa, attributed to the inclusion of epoxy resin columns in the core structure. PCR20 surpasses both, boasting a strength of 3.7819 MPa, likely due to the added reinforcement of glass fiber blended with resin. Moving to thinner samples, R10 displays a strength of 0.8579 MPa, while PER10 shows a remarkable enhancement with a strength of 3.0571 MPa, reflecting the efficacy of epoxy resin columns. Similarly, PCR10 demonstrates notable strength at 3.6318 MPa, reaffirming the effectiveness of glass fiber reinforcement. These results underscore the impact of core modifications and reinforcement methods on the overall strength of sandwich composites. Figure 10 show the test results of compression strength. Core modifications and reinforcement methods significantly enhance the overall strength of the sandwich composites. The addition of epoxy resin columns, as seen in PER samples, leads to a substantial increase in strength compared to the reference samples (R20 and R10). Glass fiber reinforcement, as in PCR samples, provides even greater strength, surpassing both the reference and resin-reinforced composites. This highlights the critical role of both resin column inclusion and fiber reinforcement in improving the mechanical strength of sandwich composites.

Figure 10
Compression strength.

7.3. Flexural strength

These samples represent different configurations subjected to flexural testing, evaluating their resistance to bending forces. R20 serves as the baseline, displaying a flexural strength of 8.85 MPa. PER20 exhibits a slight improvement with a strength of 9.54 MPa, likely due to the inclusion of epoxy resin columns in the core structure. PCR20 surpasses both with a strength of 10.17 MPa, attributed to the reinforcement of glass fibers blended with resin. Despite its thinner profile, R10 demonstrates comparable strength at 9.13 MPa. PER10 shows enhancement at 9.87 MPa, showcasing the effectiveness of epoxy resin columns. PCR10 demonstrates the highest strength at 10.68 MPa, highlighting the significant impact of glass fiber reinforcement in improving the structural integrity of the composites. These results underscore the importance of core modifications in enhancing the flexural properties of sandwich composites. Core structure modifications and reinforcement significantly influence the composites’ resistance to bending forces. The inclusion of epoxy resin columns, as seen in PER samples, improves flexural strength, while glass fiber reinforcement, as in PCR samples, provides the highest resistance to bending forces. Even thinner samples like R10 show strength comparable to thicker counterparts, emphasizing the effectiveness of these modifications in enhancing structural integrity. Overall, core modifications and reinforcement, especially with glass fiber, lead to improved flexural properties in sandwich composites. Figure 11 shows the test results of flexural strength.

Figure 11
Flexural strength.

7.4. Impact strength

The provided data outlines the Charpy impact strength, measured in joules (J), for different sandwich composite samples labeled as R20, PER20, PCR20, R10, PER10, and PCR10. These samples underwent Charpy impact testing to evaluate their ability to withstand sudden loading or impact forces. R20 serves as the baseline with impact strength of 232 J. PER20 exhibits a slightly higher strength at 236 J, possibly due to the inclusion of epoxy resin columns in its core structure. PCR20 demonstrates a further increase to 240 J, likely attributed to the incorporation of glass fiber reinforcement in the resin matrix. Despite being thinner, R10 displays a comparable impact strength of 235 J. PER10 shows improvement at 238 J, indicating the efficacy of epoxy resin columns. Finally, PCR10 exhibits the highest impact strength at 243 J, emphasizing the significant role of glass fiber reinforcement. These results underscore the importance of core modifications in enhancing the impact resistance of sandwich compositesThe data suggests that core modifications and reinforcement methods play a significant role in enhancing the impact resistance of sandwich composites. The inclusion of epoxy resin columns, as seen in PER samples, provides a modest improvement in impact strength compared to the baseline (R20 and R10). Glass fiber reinforcement, present in PCR samples, results in the highest impact resistance, with PCR20 and PCR10 outperforming their counterparts. Even thinner samples like R10 exhibit comparable strength, highlighting the overall effectiveness of these modifications in improving the composites’ ability to withstand sudden loading or impact forces. Figure 12 shows the test results of impact strength.

Figure 12
Impact value in J.

7.5. Hardness test

The provided data illustrates the Shore D hardness values for various sandwich composite samples labeled as R20, PER20, PCR20, R10, PER10, and PCR10. Shore D hardness is indicative of a material’s resistance to indentation or penetration by a harder object. R20 serves as the baseline with a hardness of 55. PER20 exhibits a slightly higher hardness at 58, suggesting a minor improvement possibly due to epoxy resin column reinforcement. PCR20 displays a further increase to 59, likely owing to the addition of glass fiber reinforcement in the resin matrix. Despite being thinner, R10 shows comparable hardness at 57. PER10 demonstrates a similar hardness to PCR20 at 59, indicating the effectiveness of epoxy resin columns. PCR10 exhibits the highest hardness at 61, emphasizing the significant impact of glass fiber reinforcement. These results underscore the importance of core modifications in enhancing the hardness properties of sandwich composites, potentially improving their durability and resistance to external forces. Shore D hardness values assess a composite’s resistance to indentation, indicating its durability and ability to withstand external forces. The data shows that core modifications, like epoxy resin columns, increase hardness, while glass fiber reinforcement, as in PCR samples, provides the highest hardness. Despite being thinner, R10 maintains comparable hardness to thicker samples. These modifications enhance the composites’ resistance to damage, improving their durability and performance. Figure 13 shows the test results of hardness.

Figure 13
Hardness in SD.

8. SCANNING ELECTRON MICROSCOPY ANALYSIS

In this study, Scanning Electron Microscopy (SEM) analysis emerged as a pivotal tool for deciphering the microstructure and failure mechanisms of tensile-tested composite specimens [²⁶]. SEM, renowned for its wide depth of focus, proved adept at topographic imaging, illuminating the intricacies of the reinforced composite columns in both single and divided core specimens. By bombarding the specimen with a convergent electron beam, SEM generated an array of signals from the impinged areas, facilitating surface morphology monitoring. As observed in the analysis, the reinforced fibers within the specimen columns exhibited gradual stretching and subsequent fracture under tensile load. Notably, the diameter of these fibers progressively diminished prior to fracture, inducing oscillations in the stress-strain curve. This behavior underscores the ductile nature of reinforced columns, where deformation precedes ultimate failure. Contrastingly, examination of reinforced neat resin columns revealed immediate failure post the generation of microcracks. SEM analysis provides critical insights into the microstructure and failure mechanisms of tensile-tested composite specimens. It reveals that reinforced columns, under tensile load, show gradual fiber stretching and eventual fracture, with fibers thinning before breaking. This behavior indicates ductility in reinforced composites, where deformation occurs before failure. In contrast, neat resin columns exhibit immediate failure after the formation of microcracks, highlighting their brittleness. SEM analysis thus illustrates that reinforcement enhances ductility and impacts the mechanical properties and failure modes of composite materials, contrasting with the more brittle nature of unreinforced resin columns. Figure 14 shows the SEM images of broken resin column and broken fibres.

Figure 14
SEM with broken resin column and fiber.

9. CONCLUSION

The experimental tests conducted on six distinct sandwich composites, incorporating E glass, epoxy resin, and low-density cores, led to several important conclusions:

• Resin Columns Integration: The inclusion of resin columns within the low-density core substantially enhanced the compressive, flexural, and impact strength of the sandwich composites compared to those with a standard core. This improvement underscores the effectiveness of resin columns in reinforcing the core structure. However, the addition of composite columns did not produce significant gains in tensile strength, suggesting that while resin columns effectively boost certain mechanical properties, they may not uniformly enhance all aspects of the composite’s performance.

• Reinforced Composite Columns: When comparing different reinforcement methods, composites with reinforced composite columns demonstrated superior compressive, flexural, and impact strength over those with neat resin columns. This indicates that the combination of glass fibers and resin in the composite columns provides a more robust reinforcement, leading to enhanced mechanical performance in various load-bearing scenarios.

• Divided vs. Single-Core Configurations: Sandwich composites with divided cores outperformed those with single-core configurations in terms of compressive, flexural, impact, and tensile strength. The divided-core design appears to distribute loads and stresses more effectively, leading to improved overall performance. However, Shore D hardness did not show significant improvements with core modifications, and there was a slight increase in the weight of the specimens with these modifications.

• SEM Analysis Insights: Scanning Electron Microscopy (SEM) analysis revealed that reinforced composite columns exhibit a ductile nature, characterized by gradual stretching and deformation before failure. In contrast, neat resin columns showed brittle behavior, failing immediately after the formation of microcracks. This observation highlights the enhanced durability and resistance to deformation provided by reinforced composite columns, compared to the more brittle neat resin counterparts.

10. FUTURE PROSPECTS AND POTENTIAL ADVANCEMENTS

The future of composite material technology holds promising advancements, particularly through enhanced reinforcement methods, sustainability efforts, and manufacturing innovations. Research is expected to focus on developing advanced reinforcement materials, such as high-performance fibers and nanomaterials, to further boost the strength and stiffness of composites. Sustainability is a key priority, with ongoing efforts aimed at creating eco-friendly materials, like bio-based resins and recyclable fibers, to reduce environmental impact. Innovations in manufacturing techniques, including automated processes and 3D printing, will enhance production efficiency and enable more complex designs. Additionally, the integration of smart materials and embedded sensors into composites could lead to self-monitoring structures that improve durability and safety. These advancements will collectively enhance the performance, sustainability, and applicability of composite materials across various industries.

11. ACKNOWLEDGMENTS

This research is funded under seed money research grant by the Karpagam Academy of Higher Education, Tamil Nadu, India, with grant number KAHE/R-Acad/A1/Seed Money/017, dated 11^th May 2022. The authors (First authors) sincerely thank Karpagam Academy of Higher Education, Tamil Nadu, India, for providing research facilities to carry out the research work.

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Publication Dates

• Publication in this collection
  28 Oct 2024
• Date of issue
  2024

History

• Received
  01 Aug 2024
• Accepted
  12 Sept 2024