Advances in Composite Structures: A Systematic Review of Design, Performance, and <br> Sustainability Trends

Composite materials have become integral to modern engineering due to their high strength-to-weight ratios, durability, and versatility. This systematic review provides a comprehensive analysis of recent advances in the design, performance optimization, and sustainability of composite structures, focusing on innovations over the past decade. The study addresses the latest developments in material configurations, including hybrid and bio-based composites, novel geometric designs, and advanced manufacturing techniques such as additive manufacturing and automated fiber placement. These innovations have enabled greater customization, enhanced load distribution, and material efficiency across various applications. A significant portion of this review is devoted to performance optimization strategies, encompassing mechanical properties, damage tolerance, and fire resistance. Recent breakthroughs in Structural Health Monitoring (SHM) technologies, particularly those incorporating embedded sensors and artificial intelligence, are evaluated for their role in enhancing damage prediction and durability. Thermal resilience is also explored, especially concerning fire-retardant composites for aerospace, automotive, and infrastructure applications. In addressing sustainability, this review discusses environmental impact assessment through lifecycle analysis (LCA) and explores emerging trends in composite recycling and end-of-life (EoL) strategies. The challenges associated with thermoset and thermoplastic composite recycling is examined, alongside advances in renewable, low-carbon composite materials that cater to the growing demand for eco-friendly solutions. The review also highlights applications in industries such as aerospace, automotive, construction, and renewable energy, emphasizing the critical role of composite structures in reducing emissions and improving energy efficiency. This review identifies existing technological and economic challenges, proposes future research directions, and provides actionable recommendations for industry and policymakers to foster sustainable advancements in composite technologies. The findings aim to guide researchers and industry professionals toward a future where composite structures can meet the demands for high-performance, lightweight, and environmentally responsible materials across diverse sectors.