Structural Adhesive Joints: State of the Art, Challenges, and Future Perspectives

The design of adhesive joints is crucial in industries like aerospace, automotive, and railways, where they offer a lightweight alternative to traditional methods such as welding and bolting. Adhesive joints distribute stress uniformly and enable the assembly of complex geometries. This review focuses on cutting-edge technologies, highlighting the role of nanomaterials in enhancing fatigue strength and chemical-thermal stability. It also explores the potential of additive manufacturing to create customized joint geometries and enable real-time monitoring through embedded sensors. The paper examines widely used adhesives, including epoxies and polyurethanes, as well as innovative joint designs, such as sinusoidal profiles and multi-material configurations, which improve stress distribution and structural integrity. Surface preparation techniques and advanced numerical tools, like cohesive zone modeling and artificial intelligence, are also discussed for their role in optimizing joint performance. The study identifies key challenges, including standardization of processes and integration of novel materials, and outlines strategies to enhance the performance of bonded joints in advanced industrial applications